CN101577823B - Video encoding method and encoding system, and camera device with video encoding function - Google Patents

Abstract

The invention relates to a video coding method, a video coding system and a camera with video coding function. The video coding method comprises the following steps: a reference pixel data and a reference histogram data are generated. Then, a current pixel data and a current histogram data are generated. Then, a normalized pixel difference value is calculated, whether the pixel difference value is larger than or equal to a first threshold value is judged, and if yes, the in-frame coding is carried out. Then, a normalized histogram difference value is calculated, whether the histogram difference value is larger than or equal to a second threshold value is judged, and if yes, the intra-frame coding is carried out. Then, whether the number of macro blocks is greater than a third threshold is calculated. Then, when the number of macro blocks is larger than the third threshold, the intra-frame coding is performed, and conversely, the inter-frame coding is performed. The invention determines each current original image to be compressed into I or P frame in advance, which can effectively reduce the system operation load, especially when the scene conversion between the reference original image and the current original image is included.

Description

Video coding method and coding system and camera device with video coding function

technical field

The present invention relates to a video coding method and its coding system and a photographing device with video coding function, in particular to a video coding method and coding system which can effectively reduce system computing load and is suitable for a large number of split-mirror conversions and has video coding functional photographic device. the

Background technique

Video coding in an embedded system (Embedded System, also known as an embedded system), compared with a general computer system, the energy required for image compression is amazing, especially in a motion estimation (Motion Estimation) Calculation module. The so-called motion estimation is to process the continuous original image (Raw Image) to remove temporal redundancy (Temporal Redundancy) for the purpose of image compression. The calculation module that performs motion estimation can analyze each original image and decide whether the original image should be compressed into an I frame (IFrame) using intra frame encoding (Intra Frame Encoding) or compressed into a P frame using inter frame encoding (Inter Frame Encoding) Frame (PFrame), where the I frame is compressed from the original image alone, and the P frame is to discard the corresponding original image and re-encode it in a predictive way. In this way, the continuous I frame and P frame Creating a video that is very similar to the continuous original image can greatly remove the temporal redundancy of the continuous original image and achieve the effect of image compression. the

Using the above-mentioned existing calculation module for motion estimation, although continuous images can be effectively compressed, when a shot change occurs between one original image and the next original image, the calculation module for motion estimation is executed, It is still necessary to fully analyze the content of the original image to determine whether the original image should be compressed into an I frame or a P frame, and it is impossible to efficiently identify the next original image based on the difference between the next original image and the previous original image. Images should be compressed into I-frames. the

As mentioned above, in order to prevent the embedded system from performing a large amount of motion estimation and improve the overall operating performance of the embedded system, it is necessary to find a solution. the

In view of the problems existing in the above-mentioned prior art, the present inventor, based on years of rich practical experience and professional knowledge engaged in the design and manufacture of such products, combined with the application of academic theory, actively researched and innovated, in order to create a new video encoding method and The encoding system and the camera device with video encoding function make it more practical. Through continuous research, design, and after repeated trials and improvements, the present invention with practical value is finally created. the

Contents of the invention

The main purpose of the present invention is to provide a video coding method. the

Another object of the present invention is to provide a video encoding system. the

Another object of the present invention is to provide a photographing device with a video encoding function. the

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. According to a video encoding method proposed by the present invention, it includes the following steps: (a). Extracting a plurality of pixels of a plurality of scanning lines of a reference original image to generate a reference pixel data and a reference histogram data; (b) .Extract a plurality of pixels of a plurality of scanning lines of a current original image to generate a current pixel data and a current histogram data; (c). Calculate a normalized pixel difference based on the current pixel data and the reference pixel data Value, and then judge whether the pixel difference is greater than or equal to a first threshold value, if so, set the frame encoding of the current original image; (d). If the pixel difference is less than the first threshold value, Calculate a normalized histogram difference based on the current histogram data and the reference histogram data, and then determine whether the histogram difference is greater than or equal to a second threshold value, and if so, set the current original The image is encoded in the frame; (e). If the histogram difference is less than the second threshold value, then calculate the number of macroblocks scheduled to be encoded in the frame of the current original image as the number of macroblocks, And while calculating the number of the macroblocks, judge whether the number of the macroblocks is greater than a third threshold value in real time; and (f). When the number of the macroblocks is greater than the third threshold value, set Intra-frame encoding is performed on the current original image, and on the contrary, inter-frame encoding is performed on the current original image. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned video coding method, in the (a) step and (b) step, the number of scanned lines extracted in the reference original image is 3 to 8, and the extracted scan lines in the current original image The number of is set to 3 to 8 correspondingly according to the number of scanned lines extracted in the reference original image. the

In the aforementioned video coding method, in the step (c), the first threshold is set to 0.4 to 0.6. the

In the aforementioned video coding method, in the step (d), the second threshold is set to 0.7 to 0.9. the

The aforementioned video coding method, wherein in the (e) step, the third threshold value=the total number of the macro blocks-(the number of a basic macro block+the number of the basic macro blocks×the regular histogram difference). the

The purpose of the present invention and the solution to its technical problem also adopt the following technical solutions to achieve. A video coding system proposed according to the present invention is used to compress a plurality of continuous original images, and includes an input unit, which sequentially receives one of the original images as a reference original image, and the next continuous original image For a current original image, the video encoding system also includes: a judging unit, used to determine whether the current original image should be compressed by intra-frame coding or inter-frame coding, and the judging unit includes: an extraction module, used to extract the Referring to multiple pixels of multiple scan lines of the original image to generate a reference pixel data and a reference histogram data, in addition, extracting multiple pixels of multiple scan lines of the current original image is to generate a current pixel data and a Current histogram data; a pixel difference judgment module, used to subtract the reference pixel data from the current pixel data to generate a pixel difference and normalize it, and then judge whether the pixel difference is greater than or equal to a first threshold value , if so, set the current original image to be encoded in the frame; the histogram difference discrimination module is used to subtract the reference histogram data from the current histogram data to generate a histogram difference value and normalize it, Then judge whether the histogram difference value is greater than or equal to a second threshold value, if so, then set the frame encoding of the current original image; and a motion estimation discrimination module to calculate a plurality of macros of the current original image The number of blocks scheduled to be encoded in the frame is the number of a macroblock, and while calculating the number of macroblocks, it is judged in real time whether the number of macroblocks is greater than a third threshold value, when the number of macroblocks is greater than When the third threshold value is reached, it is set to perform intra-frame encoding on the current original image, and on the contrary, it is set to perform inter-frame encoding on the current original image; an intra-frame encoding unit is used to compress the set as The current original image for intra-frame encoding is an I frame; an inter-frame encoding unit is used to calculate the current original image set for inter-frame encoding as a P frame; and an output unit is used for compressing The raw images of the I frame and the P frame are sequentially output as a video bit stream. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned video coding system, the extraction module of the judging unit sets the number of extracted scan lines in the reference original image to 3 to 8, and the number of extracted scan lines in the current original image is based on The number of scanned lines extracted from the reference original image is correspondingly set to 3 to 8. the

In the aforementioned video coding system, the pixel difference judging module of the judging unit sets the first threshold to 0.4 to 0.6. the

In the aforementioned video coding system, the histogram difference judging module of the judging unit sets the second threshold to 0.7 to 0.9. the

The aforementioned video coding system, wherein the motion estimation judgment module of the judging unit sets the third threshold value=the total number of the macroblocks-(the number of a basic macroblock+the number of the basic macroblock amount × the normalized histogram difference). the

The purpose of the present invention and the solution to its technical problems are also achieved by the following technical solutions. According to the present invention, a camera device with video encoding function includes a camera unit and an input unit, the camera unit is used to record a plurality of continuous original images, and the input unit receives one of the original images sequentially as a Referring to the original image, and the next continuous original image is a current original image, the photography device with video coding function also includes: a judging unit for determining whether the current original image should be compressed by intra-frame coding or inter-frame coding, The judging unit includes: an extraction module for extracting a plurality of pixels of a plurality of scan lines of the reference original image, generating a reference pixel data and a reference histogram data, and extracting a plurality of scan lines of the current original image A plurality of pixels of the line to generate a current pixel data and a current histogram data; a pixel difference judgment module, used to subtract the reference pixel data from the current pixel data to generate a pixel difference and normalize it, and then judge Whether the pixel difference value is greater than or equal to a first threshold value, if so, set the current original image to be encoded in the frame; a histogram difference value judgment module is used to subtract the reference from the current histogram data The histogram data generates a histogram difference and normalizes it, and then judges whether the histogram difference is greater than or equal to a second threshold value, and if so, sets the current original image to be encoded in a frame; and a motion estimation judgment A module that calculates the number of macroblocks scheduled to be encoded in the frame of the current original image as the number of macroblocks, and while calculating the number of macroblocks, immediately judges whether the number of macroblocks is greater than one A third threshold value, when the number of macroblocks is greater than the third threshold value, it is set to perform intra-frame coding on the current original image, and on the contrary, it is set to perform inter-frame coding on the current original image; An intra-frame coding unit is used to compress the current original image set for intra-frame coding into an I frame; an inter-frame coding unit is used to calculate the current original image set for inter-frame coding as an I frame P frame; an output unit for sequentially outputting the original image compressed into I frame and P frame as a video bit stream; and a storage unit for storing the video bit stream. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned camera device with video coding function, the extraction module of the judging unit sets the number of extracted scan lines in the reference original image to 3 to 8, and the extracted scan lines in the current original image The number of lines is correspondingly set to 3 to 8 according to the number of scanned lines extracted from the reference original image. the

In the aforementioned camera device with video coding function, the pixel difference judgment module of the judging unit sets the first threshold to 0.4 to 0.6. the

In the aforementioned camera device with video encoding function, wherein the histogram difference judgment module of the judging unit sets the second threshold to 0.7 to 0.9. the

The aforementioned camera device with video coding function, wherein the motion estimation judgment module of the judging unit sets the third threshold value=the total number of the macroblocks-(the number of a basic macroblock+the basic The number of macro blocks × the normalized histogram difference). the

Compared with the prior art, the present invention has obvious advantages and beneficial effects. As can be seen from above technical scheme, main technical contents of the present invention are as follows:

A video encoding method of the present invention includes the following steps: extracting a plurality of pixels of a plurality of scanning lines of a reference original image, and generating a reference pixel data and a reference histogram data. Then, a plurality of pixels of a plurality of scanning lines of a current original image are extracted to generate a current pixel data and a current histogram data. Next, calculate a normalized pixel difference value based on the current pixel data and the reference pixel data, and then determine whether the pixel difference value is greater than or equal to a first threshold value, and if so, set the current original image to perform in-frame coding . If the pixel difference is less than the first threshold value, calculate a normalized histogram difference based on the current histogram data and the reference histogram data, and then determine whether the histogram difference is greater than or equal to a second threshold If it is the limit value, it is set to perform in-frame encoding on the current original image. If the histogram difference is less than the second threshold value, calculate the number of macroblocks scheduled to be frame-coded in the current original image as the number of macroblocks, and while calculating the number of macroblocks, immediately It is judged whether the number of macroblocks is greater than a third threshold. Then, when the number of macroblocks is greater than the third threshold, it is set to perform intra-frame encoding on the current original image, and on the contrary, it is set to perform inter-frame encoding on the current original image. the

A video encoding system of the present invention is used to compress a plurality of continuous original images, which includes: an input unit, a judging unit, an intra-frame encoding unit, an inter-frame encoding unit, and an output unit. The input unit sequentially receives one of the original images as a reference original image, and the next consecutive original image as a current original image. The judgment unit is used to determine whether the current original image should be compressed by intra-frame coding or inter-frame coding, and includes: an extraction module, a pixel difference judgment module, a histogram difference judgment module and a motion estimation judgment module . The extracting module is used to extract a plurality of pixels of a plurality of scanning lines of the reference original image to generate a reference pixel data and a reference histogram data; in addition, extract a plurality of pixels of a plurality of scanning lines of the current original image to generate a current Pixel data and a current histogram data. The pixel difference judgment module is used to subtract the current pixel data from the reference pixel data to generate a pixel difference and normalize it, and then judge whether the pixel difference is greater than or equal to a first threshold value, and if so, set the current original image In-frame encoding. The histogram difference discrimination module is used to subtract the reference histogram data from the current histogram data to generate a histogram difference value and normalize it, and then judge whether the histogram difference value is greater than or equal to a second threshold value, and if so, set It is specified to perform in-frame encoding on the current original image. The motion estimation and discrimination module calculates the number of macroblocks scheduled to be encoded in the frame of the current original image as a macroblock number, and while calculating the macroblock number, it immediately judges whether the macroblock number is greater than a first Three thresholds, when the number of macroblocks is greater than the third threshold, it is set to perform intra-frame coding on the current original image, otherwise, it is set to perform inter-frame coding on the current original image. The intra-frame coding unit is used for compressing the current original image set for intra-frame coding into an I frame. The inter-frame coding unit is used to calculate the current original image set for inter-frame coding as a P frame. The output unit is used for sequentially outputting the original images compressed into I frame and P frame into a video bit stream. the

A camera device with video encoding function of the present invention includes: a camera unit, an input unit, a judgment unit, an intra-frame encoding unit, an inter-frame encoding unit, an output unit and a storage unit. The camera unit is used for recording a plurality of continuous original images. The input unit sequentially receives one of the original images as a reference original image, and the next consecutive original image as a current original image. The judging unit is used to determine whether the current original image should be compressed by intra-frame coding or inter-frame coding. The judging unit includes: an extraction module, a pixel difference judgment module, a histogram difference judgment module and a motion estimation judgment module mod. The extracting module is used to extract a plurality of pixels of a plurality of scanning lines of the reference original image to generate a reference pixel data and a reference histogram data; in addition, extract a plurality of pixels of a plurality of scanning lines of the current original image to generate a current Pixel data and a current histogram data. The pixel difference discrimination module is used to subtract the current pixel data from the reference pixel data to generate a pixel difference and normalize it, and then judge whether the pixel difference is greater than or equal to a first threshold value, and if so, set the current original The image is frame coded. The histogram difference discrimination module is used to subtract the reference histogram data from the current histogram data to generate a histogram difference value and normalize it, and then judge whether the histogram difference value is greater than or equal to a second threshold value, and if so, set It is specified to perform in-frame encoding on the current original image. The motion estimation and discrimination module calculates the number of macroblocks scheduled to be encoded in the frame of the current original image as a macroblock number, and while calculating the macroblock number, it immediately judges whether the macroblock number is greater than a first Three thresholds, when the number of macroblocks is greater than the third threshold, it is set to perform intra-frame coding on the current original image, otherwise, it is set to perform inter-frame coding on the current original image. The intra-frame coding unit is used for compressing the current original image set for intra-frame coding into an I frame. The inter-frame coding unit is used to calculate the current original image set for inter-frame coding as a P frame. The output unit is used for sequentially outputting the original images compressed into I frame and P frame into a video bit stream. The storage unit is used for storing the bit stream of the video. the

By means of the above-mentioned technical solution, the video coding method and coding system of the present invention and the camera device with video coding function have at least the following advantages and beneficial effects: the present invention determines in advance that each current original image should be compressed into an I frame or a P frame, It can effectively reduce the computing load of the system, especially when the scene transition is included between the reference original image and the current original image, the effect is more remarkable. the

To sum up, the present invention relates to a video encoding method, its encoding system, and a photographing device with video encoding function. The video coding method includes the steps of: generating a reference pixel data and a reference histogram data. Then, generate a current pixel data and a current histogram data. Next, a normalized pixel difference is calculated, and then it is judged whether the pixel difference is greater than or equal to a first threshold value, and if so, intra-frame encoding is performed. Then, calculate a normalized histogram difference, and then judge whether the histogram difference is greater than or equal to a second threshold value, and if so, perform intra-frame coding. Next, it is calculated whether the number of a macro block is greater than a third threshold. Then, when the number of macroblocks is greater than the third threshold, intra-frame coding is performed, and on the contrary, inter-frame coding is performed. The present invention can clearly provide a suitable and practical video coding method. Before performing motion estimation, the video coding method of the present invention can be used to judge in advance that each current original image should be compressed into an I frame or a P frame, which can effectively reduce the The computational load of the embedded system is especially significant when the reference original image and the current original image involve a large number of scene transitions. The present invention has the above-mentioned many advantages and practical value, it has great improvement no matter in method, product structure or function, has significant progress in technology, and has produced easy-to-use and practical effect, thus is more suitable for practical use, Honesty is a novel, progressive and practical new design. the

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings. the

Description of drawings

FIG. 1 is a system block diagram illustrating a preferred embodiment of a photographing device with a video encoding function of the present invention. the

FIG. 2 is a schematic diagram illustrating a plurality of scan lines in a preferred embodiment. the

Fig. 3 is a flowchart illustrating the operation flow of the preferred embodiment. the

FIG. 4 is a flowchart illustrating a preferred embodiment of the video encoding method of the present invention. the

Detailed ways

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, below in conjunction with the accompanying drawings and preferred embodiments, the video coding method and coding system proposed according to the present invention and the photographing device with video coding function are described below. Specific embodiments, methods, steps, structural features and effects thereof are described in detail below. the

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the drawings. Through the description of the specific implementation mode, when the technical means and functions adopted by the present invention to achieve the predetermined purpose can be obtained a deeper and more specific understanding, but the accompanying drawings are only for reference and description, and are not used to explain the present invention be restricted. the

Please refer to FIG. 1 , which is a system block diagram illustrating a preferred embodiment of the camera device with video encoding function of the present invention. The video coding system 1 of the preferred embodiment of the present invention is implemented with an integrated circuit (Integrated Circuit, IC) chip, and is suitable for installation on a camera device that needs to have a video coding function, but it is not limited to this, and can also be used On any electronic device that requires video encoding capabilities. Wherein, the photography device includes a camera unit 2 and a storage unit 3, and the camera unit 2 includes a lens module (not shown in the figure) in this preferred embodiment to obtain a plurality of continuous original images (Raw Image), and the storage unit 3 is used to store a video bit stream (Bit Stream) processed by the coding system 1. If the photographing device is a recording camera, the storage unit 3 can record the video bit stream for a long time. If the camera device is a transmission device, such as a video server device used in a video conference, the storage unit 3 can temporarily record the bit stream of the video, and then transmit the bit stream to at least one receiving video through an Internet. terminal device. the

The video coding system 1 of the preferred embodiment of the present invention includes an input unit 11, a judging unit 12, an intra-frame coding unit 13, an inter-frame coding unit 14, and an output unit 15, all of which are designed and manufactured with electronic circuits . the

The above-mentioned input unit 11 receives original images, and sets one of the original images as a reference original image, and another original image after the reference original image as a current original image. the

The above-mentioned judging unit 12 judges that each current original image should be compressed into an I frame by intra-frame coding, or be compressed into a P frame by inter-frame coding. The judgment unit 12 includes an extraction module 121, a pixel difference judgment module 122, a histogram difference judgment module 123, and a motion estimation judgment module 124. the

Please refer to FIG. 1 , FIG. 2 and FIG. 3 . FIG. 2 is a schematic diagram illustrating a plurality of scanning lines in a preferred embodiment of the present invention, and FIG. 3 is a flow chart illustrating the operation process of a preferred embodiment of the present invention. The extracting module 121 can extract (Fetch) a plurality of pixels (Pixel) of a plurality of scanning lines (ScanLine) 41 of the reference original image 4. In this preferred embodiment and as shown in FIG. 2, the reference original image 4 The resolution is 320 pixels×240 pixels, and the extracted scan lines are five horizontal scan lines 41 spaced apart from each other. The reason for not extracting all the scan lines 41 is that the calculation energy can be greatly saved and the efficiency of judgment can be accelerated. The extraction module 121 generates a reference pixel data and a reference histogram data after extracting pixels. It must be noted that the reference pixel data refers to the color values of the three primary colors of each pixel: red, green, blue (Red, Green, Blue, RGB) in the five scan lines 41 of the original image 4 . The reference histogram data refers to the statistical histogram of the graphic color or brightness feature distribution of the five scan lines 41 of the reference original image 4 . the

Similarly, the extraction module 121 extracts a plurality of pixels of a plurality of scan lines of the current original image, and the extracted scan lines in the current original image are identical to the five horizontal scan lines 41 of the reference original image 4 as shown in FIG. 2 . are mutually corresponding. It should be noted that the extraction methods of the reference pixel data and the reference histogram data of the reference original image 4 and the current pixel data and current histogram data of the current original image are existing image compression techniques, so details are not repeated here. the

Please refer to FIG. 1, the pixel difference discrimination module 122 calculates a normalized pixel difference (Pixel Difference) based on the current pixel data and reference pixel data, wherein the normalized value range of the pixel difference is 0 ~1. The calculation of the pixel difference value is a common judging method in existing researches related to the detection of image frame change, which is not the focus of the present invention, so it will not be repeated here. The pixel difference judging module 122 then judges whether the pixel difference is greater than or equal to a first threshold. In this preferred embodiment, the first threshold is set to 0.5. If yes, it means that there is a large difference between the current original image and the reference original image, so the judging unit 12 sets to perform intra-frame encoding on the current original image. If the pixel difference is less than 0.5, the pixel difference judging module 122 hands over the current original image to the histogram difference judging module 123 for further processing. the

The histogram difference discrimination module 123 processes the current original image whose pixel difference is less than 0.5. The histogram difference discrimination module 123 calculates a normalized histogram difference (Histogram Difference) according to the current histogram data and the reference histogram data, wherein the normalized value range of the histogram difference is 0-1. Same as the pixel difference value, the calculation of the histogram difference value is a common judgment method in the existing research on detecting image frame changes, and it is not the focus of the present invention, so it will not be repeated here. The histogram difference judging module 123 then judges whether the histogram difference is greater than or equal to a second threshold. In this preferred embodiment, the second threshold is set to 0.8. If yes, it means that there is a large difference between the current original image and the reference original image, so the judging unit 12 sets to perform intra-frame encoding on the current original image. If the histogram difference is less than 0.8, the histogram difference judging module 123 hands over the current original image to the motion estimation judging module 124 for further processing. the

The motion estimation discrimination module 124 receives the current original image whose histogram difference value is less than 0.8, and calculates the number of macro blocks (Macro Blocks) of the current original image that are scheduled to be coded in the frame as the number of macro blocks, And while calculating the number of macro blocks, it is judged in real time whether the number of macro blocks is greater than or equal to a third threshold value. For example, the number of macroblocks in the current original image is 300, and the third threshold is set to 200. When the motion estimation determination module 124 calculates the 200th macroblock in the current original image, it is scheduled to be in the frame If the coded macro block is used, the judging unit 12 sets to perform intra-frame encoding on the current original image, and on the contrary, the judging unit 12 sets to perform inter-frame encoding on the current original image. the

It should be noted that, in order to achieve the best computing performance, the third threshold is not limited to be preset as a constant, but can be flexibly adjusted according to the above-mentioned histogram difference. In this preferred embodiment, the third threshold value=the total number of macroblocks-(the number of basic macroblocks+the number of basic macroblocks×the normalized histogram difference). For example, the total number of macroblocks is 300, the number of basic macroblocks is 100, and the normalized histogram difference between the current original image and the reference original image is 0.6, then the third threshold=300-( 100+100×0.6)=140 pieces. The principle is that if the histogram difference between the current original image and the reference original image is higher, it means that the difference between the current original image and the reference original image is greater, and frame encoding should be performed. The above-mentioned calculation method of the third threshold can improve the efficiency of the motion estimation and determination module 124 in determining the current original image for intra-frame coding, and greatly increase the efficiency of calculation. the

The above-mentioned intra-frame coding unit 13 performs intra-frame coding on the current original image set as intra-frame coding after processing by the judging unit 12 . The current original image encoded in the frame is called an I frame, which is an independently compressed image frame. the

The above-mentioned inter-frame coding unit 14 performs inter-frame coding on the current original image set as inter-frame coding after processing by the judging unit 12 . The current original image coded between frames is called a P frame, which is an image frame simulated by using a reference original image. Compared with the current original image, the P frame occupies very few bits. the

The above-mentioned output unit 15 sequentially outputs the current original image that has undergone intra-frame coding and inter-frame coding, that is, a series of I frames and P frames, as a video bit stream for storage unit 3 to record. the

Please refer to Fig. 1, shown in Fig. 3, the video coding method of the preferred embodiment of the present invention is applicable to the photography device that above-mentioned coding system 1 is installed, and comprises the following steps:

As shown in step 51 , the camera unit 2 records the original video including continuous original images through the lens module. the

Then, as shown in step 52 , the input unit 11 sequentially receives one of the original images as the reference original image, and the next continuous original image as the current original image. the

Next, as shown in step 53, the judging unit 12 judges that the current original image should be compressed into an I frame with intra-frame coding, or compressed into a P frame with inter-frame coding, which includes the following sub-steps:

Please refer to FIG. 1 and FIG. 4 . FIG. 4 is a flowchart illustrating a preferred embodiment of the video encoding method of the present invention. As shown in sub-step 531 , the extraction module 121 extracts the pixels of the scan line of the reference original image to generate reference pixel data and reference histogram data. the

Then, as shown in sub-step 532 , the extraction module 121 extracts the pixels of the scan line of the current original image to generate current pixel data and current histogram data. the

Next, as shown in sub-step 533, the normalized pixel difference value is calculated according to the current pixel data and the reference pixel data, and then it is judged whether the pixel difference value is greater than or equal to the first threshold value (set to 0.5 in this preferred embodiment) . If yes, as shown in sub-step 534 , the judging unit 12 sets to perform intra-frame encoding on the current original image. the

If the pixel difference is less than the first threshold value, as shown in sub-step 535, the histogram difference discrimination module 123 calculates the normalized histogram difference based on the current histogram data and the reference histogram data, and then judges the histogram Whether the map difference is greater than or equal to the second threshold (set to 0.8 in this preferred embodiment). If yes, as shown in sub-step 534 , the judging unit 12 sets to perform intra-frame encoding on the current original image. the

If the histogram difference is less than the second threshold value, then as shown in sub-step 536, the motion estimation discrimination module 124 calculates the number of scheduled intra-frame coding in all macroblocks of the current original image as the number of macroblocks, and While calculating the number of macro blocks, it is judged immediately whether the number of macro blocks is greater than the third threshold. If the number of macroblocks is greater than the third threshold, then as shown in sub-step 534 , the coding unit sets to perform intra-frame coding on the current original image. Conversely, if all the macroblocks of the current original image have been calculated, and the number of macroblocks is less than or equal to the third threshold value, then as shown in sub-step 537, the judging unit 12 is set to perform frame-to-frame interpolation on the current original image. coding. As mentioned above, the third threshold is not limited to be set as a constant, and can also be flexibly adjusted according to the normalized histogram difference. the

Please refer to Fig. 1, shown in Fig. 3, if judging unit 12 sets and carries out intra-frame encoding to current original image, then as shown in step 54, intra-frame encoding unit 13 carries out intra-frame encoding to current original image, to compress as I frame. If the judging unit 12 sets to perform inter-frame coding on the current original image, then as shown in step 55 , the inter-frame coding unit 14 performs inter-frame coding on the current original image to compress it into a P frame. the

Next, as shown in step 56 , the output unit 15 sequentially outputs the I frame and the P frame as a video bit stream to replace the original continuous original image. the

Then, as shown in step 57, the storage unit 3 stores the video bit stream. If the photographing device is a video camera, the storage unit 3 can record the video bit stream for a long time. If the photographing device is a video server device used in video conferencing, the storage unit 3 can temporarily record the video bit stream, and then transmit the bit stream to the receiving video terminal device through the Internet. the

Utilize the present invention and prior art to carry out film coding experiment to following four sections of test films, wherein first three sections of test films are the films that comprise less scene conversion (Shot Change), and in the test film of file name High_Motion_and_Shot_Change.yuv Yes includes a lot of scene transitions. After experimentation, the results shown in Table 1 below can be obtained in terms of encoding time. the

Table 1

The file name of the test video Encoding Time (Prior State of the Art) Encoding time (this invention) Video_Conference1.yuv 31313ms 31251ms Webcam_moving. Yuv 27110ms 26985ms Video_Conference2.yuv 39469ms 39251ms High_Motion_and_Shot_Change.yuv 45016ms 39454ms

By the comparison of the coding time of the present invention and the previous prior art, it can be found that the present invention has the same efficacy compared with the prior art in general test films, and in the films comprising a large number of scene transitions, the present invention is more efficient than the prior art. It can greatly reduce the coding time and is very suitable for practical use. the

In view of the above, the features of the present invention can indeed provide a practical video encoding method. Before performing motion estimation, using the video coding method of the present invention to determine in advance that each current original image should be compressed into an I frame or a P frame can indeed effectively reduce the computing load of the embedded system. In particular, the effect is more pronounced when a large number of scene transitions are involved between the reference original image and the current original image. the

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify them into equivalent embodiments with equivalent changes, but as long as they do not depart from the technical solution of the present invention, the Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention. the

Claims (15)

1. A video encoding method, characterized in that it comprises the following steps: (a). Extracting a plurality of pixels of a plurality of scanning lines of a reference original image to generate a reference pixel data and a reference histogram data; (b). Extracting a plurality of pixels of a plurality of scanning lines of a current original image to generate a current pixel data and a current histogram data; (c). Calculate a normalized pixel difference value based on the current pixel data and the reference pixel data, and then determine whether the pixel difference value is greater than or equal to a first threshold value, and if so, set the current original image In-frame coding; (d). If the pixel difference is less than the first threshold value, calculate a normalized histogram difference based on the current histogram data and the reference histogram data, and then determine whether the histogram difference is greater than Equal to a second threshold value, if so, then set the current original image to be encoded in the frame; (e). If the histogram difference is less than the second threshold value, then calculate the number of macroblocks scheduled to be frame-coded in all macroblocks of the current original image as a macroblock quantity, and While calculating the number of macro blocks, it is judged in real time whether the number of macro blocks is greater than a third threshold; and (f). When the number of macroblocks is greater than the third threshold value, it is set to perform intra-frame encoding on the current original image; on the contrary, it is set to perform inter-frame encoding on the current original image to compress is a P frame. 2. The video encoding method according to claim 1, wherein in the (a) step and (b) step, the number of scanned lines extracted in the reference original image is 3 to 8, and The number of extracted scan lines in the current original image is correspondingly set to 3 to 8 according to the number of extracted scan lines in the reference original image. 3. The video encoding method according to claim 1, wherein in the step (c), the first threshold is set to 0.4 to 0.6. 4. The video coding method according to claim 1, wherein in the step (d), the second threshold is set to 0.7 to 0.9. 5. The video coding method as claimed in claim 1, wherein in the (e) step, the third threshold value=the total number of the macroblocks-(the number of basic macroblocks+ The number of basic macroblocks x the normalized histogram difference). 6. A video encoding system for compressing a plurality of continuous original images, and comprising an input unit which sequentially receives one of the original images as a reference original image, and the next consecutive original image as a current The original image is characterized in that the video coding system also includes: A judging unit, used to determine that the current original image should be compressed by intra-frame coding or inter-frame coding, the judging unit includes: An extraction module, used to extract a plurality of pixels of a plurality of scanning lines of the reference original image, generate a reference pixel data and a reference histogram data, in addition, extract a plurality of pixels of a plurality of scanning lines of the current original image , generating a current pixel data and a current histogram data; A pixel difference judgment module, used to subtract the reference pixel data from the current pixel data to generate a pixel difference and normalize it, and then judge whether the pixel difference is greater than or equal to a first threshold value, if so, set It is determined to perform in-frame encoding on the current original image; A histogram difference discrimination module, used to subtract the reference histogram data from the current histogram data to generate a histogram difference value and normalize it, and then determine whether the histogram difference value is greater than or equal to a second threshold value , if so, set the current original image to be frame-encoded; and A motion estimation and discrimination module, which calculates the number of macroblocks scheduled to be encoded in the frame in all macroblocks of the current original image as a macroblock quantity, and judges in real time while calculating the macroblock quantity Whether the number of macroblocks is greater than a third threshold value, when the number of macroblocks is greater than the third threshold value, then set the frame encoding of the current original image, otherwise, set the The current original image is encoded between frames; An intra-frame coding unit, used to compress the current original image set for intra-frame coding into an I frame; an inter-frame coding unit, used to compress the current original image set for inter-frame coding into a P frame; and An output unit is used for sequentially outputting the original images compressed into I frame and P frame into a video bit stream. 7. The video coding system as claimed in claim 6, wherein the extraction module of the judging unit sets the number of scanned lines extracted in the reference original image to be 3 to 8, and the current original image The number of extracted scan lines in the image is correspondingly set to 3 to 8 according to the number of extracted scan lines in the reference original image. 8. The video coding system as claimed in claim 6, wherein the pixel difference judging module of the judging unit sets the first threshold to 0.4 to 0.6. 9. The video coding system as claimed in claim 6, wherein the histogram difference judging module of the judging unit sets the second threshold to 0.7 to 0.9. 10. The video coding system as claimed in claim 6, wherein the motion estimation judgment module of the judging unit sets the third threshold value=the total number of the macro blocks-(a basic macro The number of blocks + the number of basic macro blocks × the normalized histogram difference). 11. A camera device with video encoding function, comprising a camera unit and an input unit, the camera unit is used to record a plurality of continuous original images, and the input unit sequentially receives one of the original images as a reference original image , and the next continuous original image is a current original image, characterized in that the camera device with video coding function also includes: A judging unit, used to determine that the current original image should be compressed by intra-frame coding or inter-frame coding, the judging unit includes: An extraction module, used to extract a plurality of pixels of a plurality of scanning lines of the reference original image, generate a reference pixel data and a reference histogram data, in addition, extract a plurality of pixels of a plurality of scanning lines of the current original image , generating a current pixel data and a current histogram data; A pixel difference judgment module, used to subtract the reference pixel data from the current pixel data to generate a pixel difference and normalize it, and then judge whether the pixel difference is greater than or equal to a first threshold value, if so, set It is determined to perform in-frame encoding on the current original image; A histogram difference discrimination module, used to subtract the reference histogram data from the current histogram data to generate a histogram difference value and normalize it, and then determine whether the histogram difference value is greater than or equal to a second threshold value , if so, set the current original image to be frame-encoded; and A motion estimation and discrimination module, which calculates the number of macroblocks scheduled to be encoded in the frame in all macroblocks of the current original image as a macroblock quantity, and judges in real time while calculating the macroblock quantity Whether the number of macroblocks is greater than a third threshold value, when the number of macroblocks is greater than the third threshold value, then set the frame encoding of the current original image, otherwise, set the The current original image is encoded between frames; An intra-frame coding unit, used to compress the current original image set for intra-frame coding into an I frame; An inter-frame coding unit, used to compress the current original image set for inter-frame coding into a P frame; an output unit for sequentially outputting the original images compressed into I frame and P frame into a video bit stream; and A storage unit is used for storing the bit stream of the video. 12. The camera device with video coding function as claimed in claim 11, wherein the extraction module of the judgment unit sets the number of scanned lines extracted in the reference original image to be 3 to 8, And the number of extracted scan lines in the current original image is correspondingly set to 3 to 8 according to the number of extracted scan lines in the reference original image. 13. The camera device with video coding function as claimed in claim 11, wherein the pixel difference judgment module of the judging unit sets the first threshold value to 0.4 to 0.6. 14. The camera device with video coding function as claimed in claim 11, wherein the histogram difference judgment module of the judging unit sets the second threshold value to 0.7 to 0.9. 15. The camera device with video coding function as claimed in claim 11, wherein the motion estimation and judgment module of the judging unit sets the third threshold value=the total number of macroblocks-( - the number of basic macro blocks + the number of basic macro blocks × the normalized histogram difference).

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