CN104104948A - Video transcoding method and video transcoder - Google Patents

Abstract

The invention discloses a video transcoding method and a video transcoding device. The video transcoding method includes: decoding a video stream containing multiple frames of images that conforms to the first video codec standard to generate decoded data; acquiring the coded block size and Prediction mode; according to the encoding block size and prediction mode of the video codec under the first video codec standard, determine its encoding block size and prediction mode in the encoding process conforming to the second video codec standard; according to the determined The coded block size and prediction mode conforming to the second video decoding standard encode the decoded data into a video stream conforming to the second video encoding and decoding standard.

Description

Video transcoding method and video transcoder

technical field

The invention relates to a video transcoding method and a video transcoder, in particular to video transcoding from one video codec signal to another video codec signal.

Background technique

Digital video technology is widely used in communications, computers, radio and television, etc., bringing a series of applications such as conference TV, videophone, digital TV, and media storage, and has prompted the emergence of many video codec standards, such as H.261, H.262, H.263, H.264, HEVC, etc.

Whenever a new video codec standard is released, the industry will produce new products based on the video codec standard to better meet user needs. In the more than 20 years since H.261 was released in 1990, H.262, H.263, H.264, and HEVC have been released successively. Although video codec devices adapted to the above-mentioned standards are updated quite rapidly, there are usually devices using different video codec standards on the market within a certain period of time.

And with the continuous advancement of technology, various video codec standards are also continuously improving parameters such as the compression rate and definition of video image data, but at the same time, it also brings a significant increase in the amount of calculation in the process of encoding and decoding. Therefore, there is a need for a video transcoding method and a transcoding device between different video codec standards, so that the existing video codec equipment has a longer service time, and can reduce the number of video codecs directly using new video codec standards. The amount of computation required to encode the data.

Contents of the invention

Embodiments of the present invention provide an efficient video transcoding method and device for converting video data in one video encoding format (hereinafter referred to as the first video encoding format) into another video encoding format (hereinafter referred to as the first video encoding format) is the second video encoding format), where the existing codec information in the first video encoding format can be used, thereby reducing the amount of calculation for encoding and decoding the second video encoding format.

A brief overview of the invention is given below in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical parts of the invention nor to delineate the scope of the invention. Its purpose is merely to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

According to one aspect of the present invention, a video transcoding method is disclosed, including: decoding a video code stream that conforms to the first video codec standard containing multiple frames of images to generate decoded data; The coding block size and prediction mode of a video codec standard; according to the coding block size and prediction mode of the video codec under the first video codec standard, it is determined that it conforms to the coding process of the second video codec standard encoding block size and prediction mode; encoding the decoded data into a video code stream conforming to the second video encoding and decoding standard according to the determined encoding block size and predicting mode conforming to the second video encoding and decoding standard.

According to another aspect of the present invention, a video transcoder is disclosed, including a first video codec standard decoding unit, configured to decode a video stream containing multiple frames of images that conforms to the first video codec standard, Generate decoded data; buffer, used to determine the encoding block size and prediction mode in each frame of image conforming to the first video codec standard, and store in it; parameter information conversion unit, used for according to the video codec in the The encoding block size and prediction mode under the first video codec standard are used to determine the encoding block size and prediction mode in the encoding process conforming to the second video codec standard; the second video codec standard coding unit is used to determine according to the determined The coded block size and prediction mode conforming to the second video codec standard encode the decoded data into a video code stream conforming to the second video codec standard.

Description of drawings

The above and other objects, features and advantages of the present invention will be more easily understood with reference to the following description of the embodiments of the present invention in conjunction with the accompanying drawings.

Fig. 1 shows the schematic flowchart of the video transcoding method according to the present invention;

FIG. 2 shows a schematic structural diagram of a video transcoder 200 according to the present invention;

Figure 3 shows different coded block sizes of macroblocks in the H.264 video codec standard;

Fig. 4 shows the prediction mode of a coded block whose size is 16x16 in the H.264 video codec standard;

Fig. 5 shows the prediction modes of coding blocks whose sizes are 8x8 and 4x4 in the H.264 video codec standard;

Figure 6 shows the relationship between the Coding Tree Unit (CTU) and the Coding Unit (CU) in the HEVC video codec standard;

FIG. 7 shows prediction directions of coding units with sizes 8x8, 16x16 and 32x32 in the HEVC video codec standard;

Fig. 8 shows a schematic structural diagram of a video transcoder according to an embodiment of the present invention;

FIG. 9 shows a schematic flowchart of a video transcoding method according to an embodiment of the present invention;

Figure 10a shows a positional relationship diagram of adjacent coding blocks whose current coding block size is 16x16;

Figure 10b shows a positional relationship diagram of adjacent coding blocks with a current coding unit size of 32x32;

FIG. 11 shows a schematic structural diagram of a video transcoder applied in the field of video surveillance;

FIG. 12 shows a schematic structural diagram of a computer that can be used to implement an embodiment of the present disclosure.

Detailed ways

Existing video codec standards, such as H.261, H.262, H.263, H.264, and HEVC, all use coding blocks as operation units to encode video images, and use parameters such as prediction modes to achieve video Image codec. Embodiments of the present invention provide a video transcoding method and device for converting video data of one video codec standard into another video codec standard.

Fig. 1 shows a schematic flowchart of a video transcoding method according to the present invention.

First, in step S101, decode the video code stream that complies with the first video codec standard including multiple frames of images to generate decoded data; Coding block size and prediction mode; in step S103, according to the coding block size and prediction mode of the video codec under the first video codec standard, it is determined that it is encoded in the coding process conforming to the second video codec standard block size and prediction mode; finally, in step S104, according to the coding block size and prediction mode determined in step S103 in compliance with the second video decoding standard, the decoded data is encoded as a video code conforming to the second video codec standard flow.

The prediction modes of the above-mentioned first and second video codec standards may be represented by prediction directions, and the above-mentioned step S103 may further include, for blocks in each image frame that conform to the non-maximum coded block size in the first video codec standard , directly use the coding block size as the coding block size conforming to the second video codec standard, and select the prediction direction that is the same as or adjacent to the prediction direction conforming to the first video codec standard as a candidate for conforming to the second video codec standard Choose the forecast direction. For a block with the largest coding block size in the first video codec standard in each frame, determine whether its neighboring blocks with the same coding block size have the same prediction direction, and if so, merge the block with its neighboring blocks , extract the combined coded block size as the coded block size conforming to the second video codec standard, and extract all the prediction directions corresponding to the largest coded block size in the first video codec standard as the codec conforming to the second video codec standard If not, extract the coding block size and prediction direction directly as the coding block size and prediction direction conforming to the second video codec standard.

And, if the coded block size after the above-mentioned merging is smaller than the maximum coded block size allowed by the second video codec standard, it is judged whether the adjacent blocks having the same coded block size have the same prediction direction, and if so, the block Merge with its adjacent blocks again, use the coded block size after re-combination as the coded block size of the second video codec standard, and use all prediction directions corresponding to the coded block size after re-combined in the second video codec standard as The prediction direction of the combined block again; if not, its coding block size and prediction mode are directly used as the coding block size and prediction direction of the second video codec standard.

In the process of transcoding from the first video codec standard to the second video codec standard, since the change of the background area in each frame of the video image relative to the foreground area is small, for the coded blocks in the background area, you can take Easier conversion steps. The coded block sizes and prediction modes of blocks at the same position in two adjacent frames can be compared, and if they are the same, it can be determined that the block is in the background area.

After identifying the background area in each frame, for a block in the background area that has a non-maximum coding block size in the first video codec standard, its coding block size is directly used as the coding block size of the second video codec standard , select the same prediction direction as its prediction direction in the second video codec standard. For a block in the background area that conforms to the largest coding block size in the first video codec standard, judge whether its adjacent blocks with the same coding block size have the same prediction direction, and if so, then the block and its neighboring blocks Merging, extracting the combined coding block size as the coding block size conforming to the second video codec standard, and extracting the same prediction direction as the prediction direction in the second video codec standard; if not, extracting its coding block The size and prediction direction are directly used as the coding block size and prediction direction of the second video codec standard.

If the coded block size after the above merging is smaller than the maximum coded block size allowed by the second video codec standard, it is judged whether the adjacent block having the same coded block size has the same prediction mode, and if so, the block is compared with it Adjacent blocks are merged, and the coded block size after re-merging is used as the coded block size conforming to the second video codec standard, and the same prediction mode is used as the prediction mode conforming to the second video codec standard; if not, then the The coding block size and prediction mode are directly used as the coding block size and prediction mode conforming to the second video codec standard.

And because the background area changes little in each frame, for the blocks in the background area, the determined coding block size and prediction direction conforming to the second video codec standard can be reused in different frames.

FIG. 2 shows a schematic structural diagram of a video transcoder 200 according to the present invention.

The decoder 200 includes a first video codec standard decoding unit 201, which is used to decode a video code stream that conforms to the first video codec standard containing multiple frames of images, and generates decoded data; a buffer 202, used to obtain each frame of image The encoding block size and prediction mode conforming to the first video codec standard in the first video codec standard and stored therein; the parameter information conversion unit 203 is used for encoding block size and the first video codec standard according to the video codec The prediction mode is used to determine the encoding block size and the prediction mode in the encoding process conforming to the second video codec standard; The block size and prediction mode encode the decoded data into the video code stream conforming to the second video codec standard.

Wherein, the parameter information converting unit 203 is further configured to, for a block conforming to a non-maximum encoding block size in the first video encoding and decoding standard in each frame, directly use the encoding block size as an encoding block conforming to the second video encoding and decoding standard Size, and select the prediction direction that is the same as or adjacent to the prediction direction that conforms to the first video codec standard as the candidate prediction direction that conforms to the second video codec standard; For the block with the largest coded block size, it is judged whether its adjacent blocks with the same coded block size have the same prediction direction, if so, the block is merged with its adjacent blocks, and the coded block size after the merger is extracted as a code that meets the second video codec size. Decode the coding block size of the standard, and extract all the prediction directions corresponding to the largest coding block size in the first video codec standard as the alternative prediction direction during coding that conforms to the second video codec standard; if not, extract its coding The block size and prediction direction are directly used as the coding block size and prediction direction conforming to the second video codec standard.

And, in the case that the combined coding block size is smaller than the maximum coding block size allowed by the second video codec standard, it is judged whether the adjacent blocks having the same coding block size have the same prediction direction, if so, then The block and its adjacent blocks are merged again, and the size of the coded block after the merger is used as the coded block size of the second video codec standard, and the size of the coded block corresponding to the coded block after the merger is used in the second video codec standard All the prediction directions of the blocks are used as the prediction directions of the re-merged block; if not, the coding block size and prediction mode are directly used as the coding block size and prediction direction of the second video codec standard.

The transcoder 200 further includes a background area determining unit (not shown) for identifying a background area in each frame. For the background area in each frame, the parameter information conversion unit 203 is configured to, for a block in the background area with a non-maximum encoding block size in the first video encoding and decoding standard, directly use its encoding block size as the second video encoding and decoding standard. The coded block size of the decoding standard, choose the same prediction direction as its prediction direction in the second video codec standard; for the block in the background area with the largest coded block size in the first video codec standard , to determine whether the adjacent blocks with the same coding block size have the same prediction direction, if so, merge the block with its adjacent blocks, and extract the combined coding block size as the coding block size conforming to the second video codec standard , and extract the same prediction direction as the prediction direction in the second video codec standard; if not, extract its coding block size and prediction direction directly as the coding block size and prediction direction of the second video codec standard.

And, in the case that the combined coding block size is smaller than the maximum coding block size allowed by the second video codec standard, it is judged whether the adjacent blocks having the same coding block size have the same prediction mode, and if so, the The block and its adjacent blocks are merged again, and the re-merged coded block size is used as the coded block size conforming to the second video codec standard, and the same prediction mode is used as the prediction mode conforming to the second video codec standard; If not, the coding block size and prediction mode are directly used as the coding block size and prediction mode conforming to the second video codec standard.

The transcoder 200 may also include a background area parameter buffer (not shown), in which the converted coding block size and prediction direction conforming to the second video codec standard may be stored, so as to be reused in different frames, This frees the blocks in the background area from having to be transformed every frame.

In the following, in order to describe the method and device of the present invention more clearly, the transcoding between two video codec standards, H.264 and HEVC, will be taken as an example for illustration. It should be understood that the embodiments of the present invention are not limited to video transcoding between these two video coding standards, but can also be applied to transcoding between other coding block-based video coding standards.

In H.264, the basic processing unit is a macroblock with a maximum size of 16x16. Wherein, two parameters of coding block size and prediction mode (ie, prediction direction) are used to characterize the coding mode of a macroblock. A macroblock of H.264 has three optional coding block sizes, namely 16x16, 8x8 (one macroblock is divided into four coding blocks) and 4x4 (one macroblock is divided into 16 coding blocks). Fig. 3 shows coding blocks of various sizes of macroblocks in H.264. There are different prediction modes for different coding block sizes. Among them, a coding block with a size of 16x16 has 4 prediction modes, as shown in Figure 4, and a coding block with a size of 8x8 and 4x4 has 8 prediction modes, as shown in Figure 5 Show.

The basic processing unit in HEVC is the coding tree unit, which can reach a maximum of 64x64. Coding tree units include coding units with different sizes, and the coding units in HEVC are equivalent to coding blocks in H.264. The size of the coding unit can be 64x64, 32x32, 16x16, 8x8, 4x4. The coding tree units shown in Fig. 6 are of size 32x32, coding units 0, 15 are of size 16x16, coding units 1-4, 9, 14 are of size 8x8, coding units 5-8, 10-13 are of size 4x4. Compared with H.264, HEVC coding unit prediction modes have also increased a lot, up to 34, as shown in Figure 7. Table 1 shows the number of prediction directions corresponding to coding units of different sizes.

Table 1

code unit size Forecast direction 4x4 17 8x8 34 16x16 34 32x32 34 64x64 3

It can be seen that, compared with H.264, HEVC allows a larger coding unit (coding block) size, more types of coding units of different sizes, and more corresponding prediction directions. Therefore, the HEVC encoding and decoding process also requires more calculation than the H.264 encoding and decoding process. However, if the existing coding block size information and prediction direction information in H.264 are converted into coding unit size information and prediction direction information in HEVC, that is, video transcoding from H.264 to HEVC, compared to directly using HEVC for The video signal is encoded and decoded, and the amount of calculation can be greatly reduced.

FIG. 8 shows a schematic structural diagram of a video transcoder 800 according to an embodiment of the present invention. The video transcoder 800 includes an H.264 decoding unit 801, a buffer 802, a feature information conversion unit 803, and an HEVC encoding unit 804, wherein the feature information conversion unit 803 also includes a coding unit size mapping module 8031 and a prediction mode selection module 8032.

When the video encoder 800 is working, the H.264 video stream is input to the H.264 decoding unit 801 for decoding to obtain decoded data, and the buffer 802 acquires and caches the H.264 encoding block size information and prediction mode in the decoded data information. The coding unit size mapping module 8031 and the prediction mode selection module 8032 in the feature information converting unit 803 respectively convert the coding block size information and prediction mode information of H.264 into coding unit size information and prediction mode information in HEVC. The HEVC coding unit encodes the decoded data by using the converted HEVC coding unit size information and prediction mode information, so as to obtain a video stream of the HEVC video codec standard.

Fig. 9 shows a flowchart of a video transcoding method according to an embodiment of the present invention. In step S901, firstly, the input video code stream of H.264 is decoded; in step S902, the encoding block size and prediction mode in H.264 of each macroblock in each frame are acquired; in step S903, the The coding block size and prediction mode of each macroblock in each frame in H.264 are converted to the coding unit size and prediction mode in HEVC, and the conversion process is realized through the following process:

(1) If the coding block size of the current macroblock in H.264 is 4x4 or 8x8, then the size of the coding unit at the corresponding position in HEVC is consistent with the coding block size in H.264, and the candidate prediction modes are listed in Table 2 to map;

Table 2

(2) If the coding block size of the current macroblock in H.264 is 16x16, check the adjacent blocks with the coding size of 16x16 according to the position of the block with the coding block size of 16x16. As shown in Figure 10a, if the current macroblock is at position B0, then check B1-B3, if the current macroblock is at position B1, then check B0, B2, B3, if the current macroblock is at position B2, then check B0, B1, B3, if the current macroblock is at position B3, check B0-B2. If B0-B3 are all 16x16 blocks and their prediction modes are the same, the four 16x16 blocks are merged into one 32x32 coding unit in HEVC for encoding, otherwise the four coding blocks are still converted to HEVC according to the size of 16x16 The encoding unit in is encoded;

If the size of the converted coding unit is 16x16, the prediction direction of the coding unit is the prediction direction of each coding block in H.264; if the size of the converted coding unit is 32x32, the candidate prediction mode of the coding unit is DC , planar, vertical and horizontal.

(3) If the size of the converted CU is 32x32, and the largest CU size in HEVC is 64x64, check the CUs at adjacent positions, as shown in Figure 10b. If the position of the transformed coding unit is at B0, check B1-B3, if the position of the transformed coding unit is at B1, check B0, B2, B3, if the position of the transformed coding unit is at B2, Then check B0, B1, B3, if the position of the converted coding unit is at B3, then check B0-B2. If B0, B1, B2, and B3 are all 32x32 coding units and have the same prediction direction, then merge the four converted 32x32 coding units into a 64x64 coding unit, otherwise the 32x32 encoding is still used The unit is coded;

If the converted CU can be merged into a 64x64 CU again, the candidate prediction modes of the re-merged CU are DC, planar, vertical and horizontal.

In step S904, encode the decoded data by using the CU size and prediction direction converted into HEVC, so as to output a video stream of the HEVC video codec standard.

H.264 and HEVC video codec standards are widely used in the field of video surveillance. In the field of video surveillance, there is a significant difference between the foreground area and the background area of a video image. Background regions usually contain less useful information for the user and usually remain unchanged across frames. So once the background area in the current frame is recognized, the background area in the subsequent frame can follow the background area in the current frame. The image of the foreground area contains more useful information for the user, therefore, the user needs to obtain a high-quality image of the foreground area.

It can be seen that performing video transcoding on the foreground and background regions of video images in the field of video surveillance is conducive to more efficient implementation of the transcoding method, and can further reduce the amount of calculation for video transcoding. An embodiment in which the video transcoding method and the video transcoder according to the present invention are applied in the field of video surveillance will be described below with reference to FIG. 11 .

Fig. 11 is a schematic structural diagram of a video transcoder applied in the field of video surveillance.

Wherein, the transcoder 1100 includes buffers 1102 and 1103, a comparison unit 1104, a subtractor 1105, a foreground area prediction mode selection/coding unit size mapping unit 1106, a background area prediction mode selection/coding unit size mapping unit 1107, Background parameter buffer 1108 , HEVC encoder 1109 .

When the transcoder 1100 works normally, the H.264 decoder 1101 decodes the H.264 video code stream, and transmits the decoded data to the buffer 1102 . Buffer 1102 stores the information in the first frame it receives, that is, the coding block size information and prediction direction information in the first frame, and directly processes the first frame as the foreground area, and the coding block size in the frame The information and prediction mode information are sent to the foreground region prediction mode selection/CU mapping unit 1106 . After the second frame is decoded, the data in the buffer 1102 is transferred to the buffer 1103 , and at the same time, the coded block size information and prediction mode information in the second frame are stored in the buffer 1102 which has been emptied. When data is stored in buffers 1102 and 1103, comparison unit 1104 compares the data in the two buffers, if the coded block sizes and prediction modes of the two macroblocks at the same position in the two video image frames are the same , it is determined that the area where the macroblock is located belongs to the background area. After the background area of the video image frame is determined, the foreground area of the video image frame is determined by the subtractor 1105 . After the decoding of the third frame is completed, all the data in the buffer 1102 is transferred to the buffer 1103, and at the same time, the coding block size information and prediction mode information in the third frame are written into the buffer 1102, and the subsequent process is similar.

After determining that the macroblock in the video image frame belongs to the foreground area or the background area, the foreground area and the background area are respectively selected by the foreground area prediction mode selection/coding unit mapping unit 1106 and the background area prediction mode selection/coding unit mapping unit 1107 The coded block size and prediction mode of the macroblock are converted.

In the foreground area prediction mode selection/coding unit mapping unit 1106, the macroblocks in the foreground area are converted through the following steps:

(1) If the coding size of the current macroblock in H.264 is 4x4 or 8x8, then the size of the coding unit at the corresponding position in HEVC is consistent with the coding block size in H.264, and the candidate prediction mode is passed through the above table 2 to map;

(2) If the encoding size of the current macroblock in H.264 is 16x16, check the adjacent blocks whose encoding size is also 16x16 according to the position of the block whose encoding block size is 16x16. As shown in Figure 10a, if the current macroblock is at position B0, then check B1-B3, if the current macroblock is at position B1, then check B0, B2, B3, if the current macroblock is at position B2, then check B0, B1, B3, if the current macroblock is at position B3, check B0-B2. If B0-B3 are all 16x16 blocks, and their prediction modes are the same, these 4 16x16 blocks are combined into a 32x32 coding unit in HEVC for encoding, otherwise the 4 coding blocks are still converted into HEVC according to the 16x16 size The encoding unit is encoded;

If the size of the converted coding unit is 16x16, the prediction direction of the coding unit is the prediction direction of each coding block in H.264; if the size of the converted coding unit is 32x32, the candidate prediction mode of the coding unit is DC, planar, vertical and horizontal.

(3) If the size of the converted CU is 32x32, and the largest CU size in HEVC is 64x64, check the CUs at adjacent positions, as shown in Figure 10b. If the position of the transformed coding unit is at B0, check B1-B3, if the position of the transformed coding unit is at B1, check B0, B2, B3, if the position of the transformed coding unit is at B2, Then check B0, B1, B3, if the position of the converted coding unit is at B3, then check B0-B2. If B0, B1, B2, and B3 are all 32x32 coding units and have the same prediction direction, then merge the four converted 32x32 coding units into a 64x64 coding unit, otherwise the 32x32 encoding is still used The unit is coded;

If the converted CU can be merged into a 64x64 CU again, the candidate prediction modes of the re-merged CU are DC, planar, vertical and horizontal.

In the background area prediction mode selection/coding unit mapping unit 1107, the macroblocks in the background area are converted through the following steps:

(1) If the coding block size of the current macroblock in H.264 is 4x4 or 8x8, the size of the coding unit at the corresponding position in HEVC is consistent with the coding block size in H.264, and the prediction direction is the same as that of H. 264, the prediction direction of the coding block at the corresponding position is the same.

(2) If the coding size of the current macroblock in H.264 is 16x16, then according to the position of the block with the coding size of 16x16, the adjacent coding size is also 16x16 blocks. As shown in Figure 10a, if the current macroblock is at position B0, then check B1-B3, if the current macroblock is at position B1, then check B0, B2, B3, if the current macroblock is at position B2, then check B0, B1, B3, if the current macroblock is at position B3, check B0-B2. If B0-B3 are all 16x16 blocks and their prediction modes are the same, the four 16x16 blocks are merged into one 32x32 coding unit in HEVC for encoding, otherwise the four coding units are converted to HEVC according to the 16x16 size The coding unit in is encoded.

If the size of the converted coding unit is 16x16, the prediction direction of the coding unit is the prediction direction of each coding block in H.264; if the size of the converted coding unit is 32x32, the above four 16x16 coding blocks The common prediction direction in H.264 is used as the prediction direction of the 32x32 coding unit in the converted HEVC;

(3) If the size of the converted CU is 32x32, and the largest CU size in HEVC is 64x64, check the CUs at adjacent positions, as shown in Figure 10b. If the position of the transformed coding unit is at B0, check B1-B3, if the position of the transformed coding unit is at B1, check B0, B2, B3, if the position of the transformed coding unit is at B2, Then check B0, B1, B3, if the position of the converted coding unit is at B3, then check B0-B2. If B0, B1, B2, and B3 are all 32x32 coding units and have the same prediction direction, then merge the four converted 32x32 coding units into a 64x64 coding unit, otherwise the 32x32 encoding is still used The unit is coded;

If the converted CU can be re-merged into a 64x64 CU, the common prediction direction of the above four 32x32 CUs is used as the prediction direction of the re-merged 32x32 CU.

The HEVC encoder 1109 uses the coding unit size information and prediction direction information of the foreground and background regions converted by the foreground region prediction mode selection/coding unit mapping unit 1106 and the background region prediction mode selection/coding unit mapping unit 1107 under the HEVC standard to decode The data is encoded to form an HEVC video stream.

In addition, the background region prediction mode selection/coding unit mapping unit 1107 converts the coding unit size information and prediction direction information of the background region of the HEVC standard can also be stored in the background region parameter buffer 1108, so that in the conversion of each video image frame The coding unit size information and prediction direction information of the background area buffered in the background area parameter buffer 1108 are reused in the background area parameter buffer 1108, without converting the coding unit size information and prediction direction information of the background area in each video image frame.

It should be understood that the above-described embodiments and examples are illustrative rather than exhaustive, and the present disclosure should not be viewed as limited to any specific embodiment or example.

As an example, each step of the above method and each component module and/or device of the above device may be implemented as software, firmware, hardware or a combination thereof. For example, it can be used as a part of various devices with image processing functions (such as computers, personal digital assistants, cameras, video cameras, and other image processing devices, etc., not listed here). The specific means or methods that can be used when each component module of the above-mentioned device is configured by means of software, firmware, hardware or a combination thereof are well known to those skilled in the art, and will not be repeated here.

As mentioned above, the steps and modules of image processing in the above method and device can be realized by software. The programs constituting the software are installed from a storage medium or a network to a computer having a dedicated hardware configuration (for example, the general-purpose computer 1200 shown in FIG. 12 ), and the computer can execute various functions and the like when various programs are installed.

In FIG. 12 , a central processing unit (CPU) 1201 executes various processes according to programs stored in a read only memory (ROM) 1202 or loaded from a storage section 1208 to a random access memory (RAM) 1203 . In the RAM 1203, data required when the CPU 1201 executes various processes and the like is also stored as necessary. The CPU 1201 , ROM 1202 , and RAM 1203 are connected to each other via a bus 1204 . The input/output interface 1205 is also connected to the bus 1204 .

The following components are connected to the input/output interface 1205: an input section 1206 (including a keyboard, a mouse, etc.), an output section 1207 (including a display such as a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.), Storage part 1208 (including hard disk, etc.), communication part 1209 (including network interface cards such as LAN cards, modems, etc.). The communication section 1209 performs communication processing via a network such as the Internet. A driver 1210 may also be connected to the input/output interface 1205 as needed. A removable medium 1211 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 1210 as necessary, so that a computer program read therefrom is installed into the storage section 1208 as necessary.

In the case of realizing the above-described series of processing by software, the programs constituting the software are installed from a network such as the Internet or a storage medium such as the removable medium 1211 .

Those skilled in the art should understand that such a storage medium is not limited to the removable medium 1211 shown in FIG. 12 in which the program is stored and distributed separately from the device to provide the program to the user. Examples of the removable media 1211 include magnetic disks (including floppy disks (registered trademark)), optical disks (including compact disk read only memory (CD-ROM) and digital versatile disks (DVD)), magneto-optical disks (including MiniDisc (MD) (registered trademark )) and semiconductor memory. Alternatively, the storage medium may be the ROM 1202, a hard disk contained in the storage section 1208, or the like, in which the programs are stored and distributed to users together with devices containing them.

The present disclosure also proposes a program product storing machine-readable instruction codes. When the instruction code is read and executed by a machine, the above-mentioned method according to the embodiments of the present disclosure can be executed.

Correspondingly, a storage medium for carrying the program product storing the above-mentioned machine-readable instruction codes is also included in the disclosure of the present disclosure. The storage medium includes, but is not limited to, a floppy disk, an optical disk, a magneto-optical disk, a memory card, a memory stick, and the like.

In the above description of specific embodiments of the present disclosure, features described and/or illustrated for one embodiment can be used in one or more other embodiments in the same or similar manner, and features in other embodiments Combination or replacement of features in other embodiments.

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, element, step or component, but does not exclude the presence or addition of one or more other features, elements, steps or components.

In addition, the methods of the present disclosure are not limited to being performed in the chronological order described in the specification, and may also be performed in other chronological order, in parallel or independently. Therefore, the execution order of the methods described in this specification does not limit the technical scope of the present disclosure.

It can be seen from the above description that according to the embodiments of the present disclosure, the following solutions are provided:

Note 1. A video transcoding method, comprising:

Decoding a video code stream that complies with the first video codec standard and includes multiple frames of images to generate decoded data;

Obtain the coding block size and prediction mode in each frame of image conforming to the first video codec standard;

Determine the coding block size and prediction mode in the encoding process conforming to the second video codec standard according to the coding block size and prediction mode of the video codec under the first video codec standard;

Encode the decoded data into a video stream conforming to the second video encoding and decoding standard according to the determined encoding block size and prediction mode conforming to the second video encoding and decoding standard.

Note 2. The method as described in Supplement 1, wherein the prediction mode is the prediction direction, and wherein, according to the coding block size and prediction mode of the video codec conforming to the first video codec standard, it is determined that the second The coding block size and coding prediction mode of the video codec standard include:

For a block in each frame that conforms to the non-maximum encoding block size in the first video codec standard, use the encoding block size directly as the encoding block size conforming to the second video codec standard, and select the block that conforms to the first video codec The standard prediction direction is the same or adjacent to the prediction direction as an alternative prediction direction conforming to the second video codec standard;

For a block with the largest coding block size in the first video codec standard in each frame, determine whether its neighboring blocks with the same coding block size have the same prediction direction, and if so, merge the block with its neighboring blocks , extract the combined coded block size as the coded block size conforming to the second video codec standard, and extract all the prediction directions corresponding to the largest coded block size in the first video codec standard as the codec conforming to the second video codec standard If not, extract the coding block size and prediction direction directly as the coding block size and prediction direction conforming to the second video codec standard.

Note 3. The method described in Appendix 2, further comprising:

If the size of the combined coding block is smaller than the maximum coding block size allowed by the second video codec standard, it is judged whether the adjacent block having the same coding block size has the same prediction direction, and if so, the block is compared with the Adjacent blocks are merged again, and the coded block size after recombination is used as the coded block size of the second video codec standard, and all prediction directions corresponding to the coded block size after recombined in the second video codec standard are used as the coded block size again The prediction direction of the merged block; if not, its coding block size and prediction mode are directly used as the coding block size and prediction direction of the second video codec standard.

Note 4. The method described in Supplementary Note 2 or 3, further comprising: identifying background regions in each frame.

Note 5. The method described in Appendix 4, further comprising:

For a block in the background area that has a non-maximum coding block size in the first video codec standard, its coding block size is directly used as the coding block size of the second video codec standard, and the same prediction direction as its prediction direction is selected as its a prediction direction in the second video codec standard;

For a block in the background area that conforms to the largest coding block size in the first video codec standard, judge whether its adjacent blocks with the same coding block size have the same prediction direction, and if so, then the block and its neighboring blocks Merging, extracting the combined coding block size as the coding block size conforming to the second video codec standard, and extracting the same prediction direction as the prediction direction in the second video codec standard; if not, extracting its coding block The size and prediction direction are directly used as the coding block size and prediction direction of the second video codec standard.

Note 6. The method described in Appendix 5, further comprising:

If the combined coded block size is smaller than the maximum coded block size allowed by the second video codec standard, it is judged whether the adjacent block having the same coded block size has the same prediction mode, and if so, the block is compared with Adjacent blocks are merged, and the coded block size after re-merging is used as the coded block size conforming to the second video codec standard, and the same prediction mode is used as the prediction mode conforming to the second video codec standard; if not, then The coding block size and prediction mode are directly used as the coding block size and prediction mode conforming to the second video codec standard.

Note 7. The method described in appendix 5 or 6, wherein,

For the blocks in the background area, the determined coding block size and prediction direction conforming to the second video codec standard can be reused in different frames.

Note 8. As in the method described in Appendix 4, identifying the background area in each frame includes:

Compare the coded block size of the block at the same position in two adjacent frames with the prediction mode, and if they are the same, it is determined that the block is in the background area.

Note 9. The method described in appendix 1, wherein

Multiple coding block sizes and multiple prediction modes are allowed in the first and second video codec standards, and the coding block size of the second video codec standard includes and is larger than the coding block size of the first video codec standard.

Note 10. The method described in appendix 1, wherein

The prediction modes of the second video codec standard include more than the prediction modes of the first video codec standard.

Note 11. The method described in appendix 1, wherein

The first video codec standard is the H.264 standard.

Note 12. The method described in appendix 1, wherein

The second video codec standard is the HEVC standard.

Note 13. A video transcoder comprising:

The first video codec standard decoding unit is used to decode a video code stream that complies with the first video codec standard including multiple frames of images to generate decoded data;

The buffer is used to obtain the coding block size and prediction mode conforming to the first video codec standard in each frame image, and store them therein;

A parameter information conversion unit, configured to determine the encoding block size and prediction mode in the encoding process conforming to the second video encoding and decoding standard according to the encoding block size and prediction mode of the video codec under the first video encoding and decoding standard ;

The second video codec standard encoding unit is configured to encode the decoded data into a video code stream conforming to the second video codec standard according to the determined coding block size and prediction mode conforming to the second video codec standard.

Supplement 14. The video transcoder according to Supplement 13, wherein the prediction mode is the prediction direction, and

Wherein, the parameter information converting unit is configured to: for a block conforming to the non-maximum encoding block size in the first video encoding and decoding standard in each frame, directly use the encoding block size as an encoding conforming to the second video encoding and decoding standard block size, and select the prediction direction that is the same as or adjacent to the prediction direction that conforms to the first video codec standard as an alternative prediction direction that conforms to the second video codec standard; A block with the largest coding block size, judge whether its adjacent blocks with the same coding block size have the same prediction direction, if so, merge the block with its neighboring blocks, and extract the combined coding block size as conforming to the second video codec standard coding block size, and extract all the prediction directions corresponding to the largest coding block size in the first video codec standard as the candidate prediction direction during encoding that conforms to the second video codec standard; if not, extract its The coding block size and prediction direction are directly used as the coding block size and prediction direction conforming to the second video codec standard.

Note 15. The video transcoder described in Supplementary Note 14, wherein the parameter information conversion unit is further configured as:

In the case that the combined coding block size is smaller than the maximum coding block size allowed by the second video codec standard, it is judged whether the adjacent blocks having the same coding block size have the same prediction direction, and if so, the The block and its adjacent blocks are merged again, and the coded block size after the merge is used as the coded block size of the second video codec standard, and all the coded block sizes in the second video codec standard corresponding to the coded block size after the merge are used The prediction direction is used as the prediction direction of the re-merged block; if not, the coding block size and prediction mode are directly used as the coding block size and prediction direction of the second video codec standard.

Note 16. The video transcoder according to Supplementary Note 14 or 15, further comprising a background area determining unit, configured to identify the background area in each frame.

Note 17. The video transcoder described in Supplementary Note 16, wherein the parameter information converting unit is further configured as:

For a block in the background area that has a non-maximum coding block size in the first video codec standard, its coding block size is directly used as the coding block size of the second video codec standard, and the same prediction direction as its prediction direction is selected as its a prediction direction in the second video codec standard;

For a block in the background area that conforms to the largest coding block size in the first video codec standard, judge whether its adjacent blocks with the same coding block size have the same prediction direction, and if so, then the block and its neighboring blocks Merging, extracting the combined coding block size as the coding block size conforming to the second video codec standard, and extracting the same prediction direction as the prediction direction in the second video codec standard; if not, extracting its coding block The size and prediction direction are directly used as the coding block size and prediction direction of the second video codec standard.

Note 18. The video transcoder described in Supplementary Note 17, wherein the parameter information conversion unit is further configured as:

In the case that the size of the combined coding block is smaller than the maximum coding block size allowed by the second video codec standard, it is judged whether the adjacent block having the same coding block size has the same prediction mode, and if so, the The block and its adjacent blocks are merged again, and the coded block size after remerging is used as the coded block size conforming to the second video codec standard, and the same prediction mode is used as the prediction mode conforming to the second video codec standard; If not, use the coding block size and prediction mode directly as the coding block size and prediction mode conforming to the second video codec standard.

Note 19. The video transcoder as described in Supplementary Note 17 or 18, further comprising a background area parameter buffer for storing the converted coding block size and prediction direction conforming to the second video codec standard.

Note 20. In the video transcoder described in Supplementary Note 16, the background area determination unit is configured to compare the coding block size of the block at the same position in two adjacent frames with the prediction mode, and if they are the same, determine that the block is in the in the background area.

Note 21. The video transcoder described in appendix 13, wherein

Multiple coding block sizes and multiple prediction modes are allowed in the first and second video codec standards, and the coding block size of the second video codec standard includes and is larger than the coding block size of the first video codec standard.

Note 22. The video transcoder described in appendix 13, wherein

The prediction modes of the second video codec standard include more than the prediction modes of the first video codec standard.

Note 23. The video transcoder described in appendix 13, wherein

The first video codec standard is the H.264 standard.

Note 24. The video transcoder described in appendix 13, wherein

The second video codec standard is the HEVC standard.

Although the present invention has been disclosed by the description of specific embodiments of the present invention above, it should be understood that all the above embodiments and examples are illustrative rather than restrictive. Those skilled in the art can devise various modifications, improvements or equivalents to the present invention within the spirit and scope of the appended claims. These modifications, improvements or equivalents should also be considered to be included in the protection scope of the present invention.

Claims (14)

1. a video transcoding method, comprising:

The video code flow that meets the first video encoding and decoding standard that comprises multiple image is decoded, generating solution code data;

Obtain the encoding block size and the predictive mode that meet the first video encoding and decoding standard in each two field picture;

Determine encoding block size and predictive mode in its cataloged procedure that is meeting the second video encoding and decoding standard according to the encoding block size under the first video encoding and decoding standard of described video code flow and predictive mode;

Described in decoded data being encoded to according to the determined encoding block size that meets the second video decode standard and predictive mode, meet the video code flow of the second video encoding and decoding standard.

2. the method for claim 1, wherein, described predictive mode is prediction direction, and wherein, determine that according to the encoding block size of the described video code flow that meets the first video encoding and decoding standard and predictive mode the encoding block size and the coded prediction pattern that meet the second video encoding and decoding standard comprise:

For the piece that meets the non-maximum encoding block size in the first video encoding and decoding standard in each frame, using direct this encoding block size as the encoding block size that meets the second video encoding and decoding standard, and select the prediction direction identical or adjacent with the prediction direction that meets the first video encoding and decoding standard as the alternative prediction direction that meets the second video encoding and decoding standard;

For the piece with the maximum encoding block size in the first video encoding and decoding standard in each frame, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges, extract encoding block size after merging as the encoding block size that meets the second video encoding and decoding standard, and extract in the first video encoding and decoding standard corresponding to whole prediction direction of maximum encoding block size as meet the second video encoding and decoding standard coding time alternative prediction direction; As no, extract its encoding block size and prediction direction directly as the encoding block size and the prediction direction that meet the second video encoding and decoding standard.

3. method as claimed in claim 2, further comprises:

If the encoding block size after described merging is less than the maximum encoding block size that the second video encoding and decoding standard allows, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges again, encoding block size after again merging is as the encoding block size of the second video encoding and decoding standard, and using in the second video encoding and decoding standard corresponding to whole prediction direction of the encoding block size after again merging the prediction direction of the piece after again merging; As no, using its encoding block size and predictive mode directly as encoding block size and the prediction direction of the second video encoding and decoding standard.

4. method as claimed in claim 2 or claim 3, further comprises: identify the background area in each frame.

5. method as claimed in claim 4, also comprises:

For the piece with the non-maximum encoding block size in the first video encoding and decoding standard in background area, using its encoding block size directly as the encoding block size of the second video encoding and decoding standard, select the prediction direction identical with its prediction direction as it prediction direction in the second video encoding and decoding standard;

Meet the piece of the maximum encoding block size in the first video encoding and decoding standard for having in background area, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges, extract encoding block size after merging as the encoding block size that meets the second video encoding and decoding standard, and extract described identical prediction direction as the prediction direction in the second video encoding and decoding standard; As no, extract its encoding block size and prediction direction directly as encoding block size and the prediction direction of the second video encoding and decoding standard.

6. method as claimed in claim 5, further comprises:

If the encoding block size after described merging is less than the maximum encoding block size that the second video encoding and decoding standard allows, whether judgement has identical predictive mode with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges, encoding block size after again merging is as the encoding block size that meets the second video encoding and decoding standard, and using described identical predictive mode as the predictive mode that meets the second video encoding and decoding standard; As no, using direct as the encoding block size and the predictive mode that meet the second video encoding and decoding standard to its encoding block size and predictive mode.

7. the method as described in claim 5 or 6, wherein,

For the piece in background area, determined encoding block size and the prediction direction that meets the second video encoding and decoding standard can be reused in different frames.

8. a video code translator, comprising:

The first video encoding and decoding standard decoding unit, for the video code flow that meets the first video encoding and decoding standard that comprises multiple image is decoded, generating solution code data;

Buffer, for obtaining the encoding block size and the predictive mode that meet the first video encoding and decoding standard of each two field picture, and is stored in wherein;

Parameter information converting unit, for determining that according to the encoding block size under the first video encoding and decoding standard of described video code flow and predictive mode it is meeting cataloged procedure encoding block size and the predictive mode of the second video encoding and decoding standard;

The second video encoding and decoding standard coding unit, for meeting the video code flow of the second video encoding and decoding standard described in decoded data being encoded to according to the determined encoding block size that meets the second video encoding and decoding standard and predictive mode.

9. video code translator as claimed in claim 8, wherein, described predictive mode is prediction direction, and

Wherein, described parameter information converting unit is configured to: for the piece that meets the non-maximum encoding block size in the first video encoding and decoding standard in each frame, using direct this encoding block size as the encoding block size that meets the second video encoding and decoding standard, and select the prediction direction identical or adjacent with the prediction direction that meets the first video encoding and decoding standard as the alternative prediction direction that meets the second video encoding and decoding standard; For the piece with the maximum encoding block size in the first video encoding and decoding standard in each frame, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges, extract encoding block size after merging as the encoding block size that meets the second video encoding and decoding standard, and extract in the first video encoding and decoding standard corresponding to whole prediction direction of maximum encoding block size as meet the second video encoding and decoding standard coding time alternative prediction direction; As no, extract its encoding block size and prediction direction directly as the encoding block size and the prediction direction that meet the second video encoding and decoding standard.

10. video code translator as claimed in claim 9, wherein, described parameter information converting unit is further configured to:

Encoding block size after described merging is less than the maximum encoding block size that the second video encoding and decoding standard allows, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges again, encoding block size after again merging is as the encoding block size of the second video encoding and decoding standard, and using in the second video encoding and decoding standard corresponding to whole prediction direction of described encoding block size after again merging the prediction direction of the piece after again merging; As no, using its encoding block size and predictive mode directly as encoding block size and the prediction direction of the second video encoding and decoding standard.

11. video code translators as claimed in claim 8 or 9, further comprise background area determining unit, for identifying the background area of each frame.

12. video code translators as claimed in claim 11, wherein, described parameter information converting unit is further configured to:

For the piece with the non-maximum encoding block size in the first video encoding and decoding standard in background area, using its encoding block size directly as the encoding block size of the second video encoding and decoding standard, select the prediction direction identical with its prediction direction as it prediction direction in the second video encoding and decoding standard;

Meet the piece of the maximum encoding block size in the first video encoding and decoding standard for having in background area, whether judgement has identical prediction direction with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges, extract encoding block size after merging as the encoding block size that meets the second video encoding and decoding standard, and extract described identical prediction direction as the prediction direction in the second video encoding and decoding standard; As no, extract its encoding block size and prediction direction directly as encoding block size and the prediction direction of the second video encoding and decoding standard.

13. video code translators as claimed in claim 12, wherein, described parameter information converting unit is further configured to:

Encoding block size after described merging is less than the maximum encoding block size that the second video encoding and decoding standard allows, whether judgement has identical predictive mode with its adjacent block with same-code piece size, in this way, this piece being adjacent to piece merges again, encoding block size after again merging is as the encoding block size that meets the second video encoding and decoding standard, and using described identical predictive mode as the predictive mode that meets the second video encoding and decoding standard; As no, using direct as the encoding block size and the predictive mode that meet the second video encoding and decoding standard to its encoding block size and predictive mode.

14. video code translators as described in claim 12 or 13, wherein further comprise background area parameter buffer, for storing the encoding block size and the prediction direction that meet the second video encoding and decoding standard after conversion.