JPH08129831A - Device and method for coding - Google Patents

Abstract

PURPOSE: To reduce local deterioration in information by encoding and decoding time sequential information corresponded to absolute time information and detecting the time information corresponding to a deteriorated part of the decoded data. CONSTITUTION: An original signal regenerated by a VTR 21 is supplied to an encoder 11 through a terminal b1 and a switch SW1 . After being encoded, the signal is returned to the step S12, and processing of the step S12 to the step S16 are repeated until the fact that no picture quality of a demodulated image signal displayed on a monitor 31 is not deteriorated (not extremely deteriorated) in comparison with the original signal displayed on the monitor 32 is decided in the step 14. Thus, in such a case, a part of which picture quality is deteriorated extremely is prevented from occurring in a demodulated image in which the finally obtained decoded data are demodulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding device suitable for use in the case of encoding information such as image signals and audio signals and transmitting it through a transmission line or recording it on a recording medium. And an encoding method.

[0002]

2. Description of the Related Art Conventionally, in an image coding apparatus for coding an image signal, for example, the image signal is converted by a DCT.
(Discrete cosine transform) processing and the resulting DCT
The coefficient is quantized and further variable-length coded.

Further, in such an image coding apparatus,
When encoding an image signal, for example, a quantization step of quantizing a DCT coefficient or an encoding mode (for example, a quantization mode) so as to balance the data amount of generated encoded data (generated code amount) and the image quality of a decoded image. , A mode in which the image signal itself to be encoded is encoded (intra-encoding), or the difference between the image signal to be encoded and the predicted image of the image signal is encoded (inter-encoding)), The characteristics of a filter for filtering an image signal to be encoded are set (hereinafter, parameters set in such encoding are referred to as encoding parameters as appropriate).

Further, since it is usually necessary to perform transmission of encoded data and recording on a recording medium at a predetermined constant rate, in the image encoding device, the encoded data is stored in a temporary buffer, The data is output at a predetermined constant rate.

[0005]

By the way, when the amount of generated codes locally increases due to continuous encoding of complex image signals, and the buffer is about to overflow, the image encoding is performed. In the device, due to deterioration of the image quality of the image, such as roughening the quantization step,
The encoding parameters are controlled by giving priority to the prevention of buffer overflow.

This is because when the buffer overflows, a fatal error (unrecoverable error) occurs in the encoded data, and the decoded image cannot be obtained.

Therefore, there is a problem in that the decoded image corresponding to the case where the above-mentioned control of the encoding parameter is performed has a locally significantly deteriorated image quality.

Therefore, the encoding is performed at least twice, and the portion where the image quality is locally deteriorated is detected based on the encoding result of the first pass, and the encoding is performed in the second and subsequent passes. In order to reduce the deterioration, for example, it is conceivable to allocate a part of the code amount allocated to the part having almost no deterioration in image quality to the part detected in the first pass.

However, in the conventional image coding apparatus, information indicating the absolute time of the image signal (for example,
If the frame of the image signal currently being encoded is from the first frame of the image signal or if a block forming the image signal of a certain frame is encoded, the block is the image signal Information that indicates which part of the image is to be processed). Therefore, even if the first pass encoding detects a part with significant deterioration in image quality, that part is not It was difficult to identify the frame number from the first frame of the signal and the block position of the frame.

Therefore, it is not known at which timing of the image signal the processing for reducing the deterioration of the image quality should be performed during the second and subsequent encodings, and the above-mentioned local deterioration of the image quality can be improved. It was difficult.

Therefore, a method of changing the coding algorithm of the image coding apparatus is conceivable, but it is not clear whether the changed algorithm acts to reduce the locally deteriorated image quality. It was

The present invention has been made in view of such a situation, and makes it possible to identify the portion of the image signal in which the local deterioration of the image quality has occurred, thereby reducing the deterioration. It is to enable the conversion.

[0013]

An encoding apparatus according to claim 1 is an encoding apparatus for encoding time-series information associated with absolute time information, and encoding the information. Encoding means (for example, the encoder 11 shown in FIGS. 1 and 3) and decoding means for decoding encoded data output from the encoding means (for example, decoding shown in FIGS. 1 and 3) Unit 12) and a detecting unit for recognizing a deteriorated part of the decoded data output from the decoding unit and detecting deteriorated partial time information which is time information corresponding to the part (for example, in FIG. 1). S / N comparator 3 shown, the image quality evaluator 30 shown in FIG. 3, etc.), and storage means for storing the deterioration partial time information detected by the detection means (for example, the memory 14 shown in FIGS. 1 and 3). And when the information is re-encoded by the encoding means, Control means for controlling the encoding means such that the deterioration of the part of the decoded data corresponding to the deteriorated partial time information stored in the storage means is reduced (for example, the control unit 15 shown in FIGS. 1 and 3). And is provided.

In the encoding device according to the second aspect, the detecting means measures the S / N of the decoded data with respect to the information, and recognizes the deteriorated portion of the decoded data based on the measurement result. It is characterized by

An encoding apparatus according to a third aspect records information or decoded data together with time information,
A first or second recording / reproducing means (for example, VTR 21 or 22 shown in FIG. 3) for reproducing the recorded information or the decoded data together with the time information, and information reproduced by the first recording / reproducing means. , And supply means for supplying to the encoding means (for example, the switch SW1 shown in FIG. 3), and the detecting means outputs information or decoded data reproduced by the first or second recording / reproducing means, respectively. Output means (for example, the monitor 31 or 32 shown in FIG. 3) and a designation means (for example, shown in FIG. 3) for designating the deteriorated portion of the decoded data by comparing the information output from the output means. Recognizing the portion of the decoded data designated by the designating means, and detecting the time information corresponding to that portion as the deteriorated partial time information. When the control unit supplies the information reproduced by the first recording / reproducing unit to the encoding unit by the supplying unit and encodes it again by the encoding unit, the deterioration partial time information stored in the storage unit and The encoding means is controlled so that the deterioration of the corresponding decoded data is reduced.

An encoding method according to a fourth aspect is an encoding method for encoding time-series information associated with absolute time information, encoding the information, and the resulting encoding. Decode the data, recognize the deteriorated part of the resulting decoded data, detect the deteriorated partial time information that is the time information corresponding to that part, store the deteriorated partial time information, and store the deteriorated partial time. The information is re-encoded so that the deterioration of the part of the decoded data corresponding to the information is reduced.

An encoding method according to a fifth aspect is characterized in that the S / N of the decoded data with respect to the information is measured, and the deteriorated portion of the decoded data is detected based on the measurement result. To do.

According to a sixth aspect of the present invention, an encoding method encodes information, records the information and time information on a first recording medium, and decodes the encoded data.
The resulting decoded data and time information are recorded on a second recording medium, and the recorded information or the decoded data is synchronized from the first or second recording medium based on the recorded time information. Then, the reproduced information or decoded data is output and compared with the information, the deteriorated part of the decoded data is specified, the specified part of the decoded data is recognized, and that part is recognized. The corresponding time information is detected as deteriorated partial time information, the information is reproduced from the first recording medium, and the reproduced information is reduced so that deterioration of the part of the decoded data corresponding to the deteriorated partial time information is reduced. Is encoded again.

[0019]

In the coding apparatus and the coding method according to claim 4, time series information associated with absolute time information is coded and decoded, and the result is obtained. The deteriorated part of the decoded data is recognized and the deteriorated partial time information corresponding to the part is detected. Then, the deteriorated partial time information is stored, and the information is encoded again so that the deterioration of the part of the decoded data corresponding to the stored deteriorated partial time information is reduced. Therefore, local deterioration of information due to encoding can be reduced.

In the encoding device according to the second aspect and the encoding method according to the fifth aspect, the S / N of the decoded data for the information is measured, and the decoded data is deteriorated based on the measurement result. Recognize that part. Therefore, local S / N deterioration of information can be reduced.

In the encoding device according to the third aspect and the encoding method according to the sixth aspect, the information is encoded, the information and the time information are recorded, and the encoded data is decoded. At the same time, the decoded data obtained as a result and the time information are recorded. Then, based on the recorded time information, the recorded information or the decoded data is reproduced in synchronization with each other, and the deteriorated portion of the decoded data is designated by comparing with the information. Further, the portion of the designated decoded data is recognized, and the time information corresponding to that portion is detected as the deteriorated partial time information. afterwards,
The recorded information is reproduced, and the reproduced information is encoded so that the deterioration of the part of the decoded data corresponding to the deteriorated partial time information is reduced. Therefore, local deterioration of information can be reduced.

[0022]

1 is a block diagram showing the configuration of a first embodiment of an image coding apparatus to which the present invention is applied. This device includes an encoding device 1, a delay circuit 2, and an S / N comparator 3.
The image signal, which is time-series information, has absolute time information (for example, time code (for example, SMPTE TI
ME CODE etc.))). An image signal (hereinafter, appropriately referred to as an original signal) input to the device is supplied to the encoder 11 and the delay circuit 2 of the encoding device 1, and the time information input to the device is , And is supplied to the delay circuit 13 and the control unit 15 which constitute the encoding device 1.

The coding apparatus 1 is composed of a coding unit 11, a decoding unit 12, a delay circuit 13, a memory 14, and a control unit 15. The encoder 11 performs, for example, DCT (discrete cosine transform) processing on the input image signal, quantizes the DCT coefficient obtained as a result, and further performs variable length coding to output the coded data. It is done like this. The encoding parameter in the encoder 11 is controlled based on, for example, the data amount of encoded data, and can also be controlled by the control unit 15.

The decoder 12 decodes the encoded data output from the encoder 11 (for example, variable length decoding and inverse quantization, and the resulting DCT coefficient is inverse DCT).
Processing), and the resulting decoded image signal (decoded data) is output to the S / N comparator 3.

The delay circuit 13 outputs the time information input to the apparatus together with the image signal for the time required for the encoder 11 and the decoder 12 to process (encode and decode) the image signal. It is delayed and output to the S / N comparator 3. Therefore, the phase relationship between the decoded image signal (encoded and decoded image signal) output from the encoding device 1 and the time information is the phase relationship between the image signal input to the encoding device 1 and the time information. It is designed to be the same as the relationship.

That is, for example, when the time information is a time code (SMPTE TIME CODE), for example, 00: 00: 00: 00: 00 from the first frame (starting frame) of the image signal input to the encoding device 1. ，
00: 00: 00: 01, 00: 00: 00: 02, ...
.., etc., the same encoding device 1 (delay circuit 13) is output at the timing when the first frame of the decoded image signal is output from the encoding device 1 (decoder 12). From 00:00 as time information
At the timing when the time code of 0:00:00 is output and then the frames following the first frame of the decoded image signal are sequentially output, 00: 00: 00: 01, 00:00
A time code, which is time information such as 0:00:02, ..., Is also sequentially output.

Here, as described above, when the time information is a time code (SMPTE TIME CODE), the time information indicates the position (temporal position) of the image signal.
Expressed in frame units. Therefore, in this case, according to the time information, the image signal can be specified in 1-frame units, but a smaller unit (for example, an arbitrary block or pixel in the 1-frame image signal) can be specified. You cannot do it. Hereinafter, the range of the image signal in which the time information can be specified in this way is referred to as a minimum area.

The memory 14 is adapted to store time / position information, which will be described later, output from the S / N comparator 3. When the encoder 11 encodes the once-encoded original signal again, the control unit 15 refers to the time information associated with the original signal and refers to the time / position stored in the memory 14. The encoding parameter of the encoder 11 is controlled at the timing when the portion of the original signal corresponding to the information is encoded by the encoder 11.

The delay circuit 2 delays the original signal by the same amount as the delay time in the delay circuit 13, that is, the time required for the encoder 11 and the decoder 12 to process the original signal, and S / The output is output to the N comparator 3.
Therefore, the original signal and the decoded image signal obtained by encoding and decoding the original signal are output to the S / N comparator 3 at the same timing (synchronously).

That is, at the timing when the Nth frame from the beginning of the original signal is output from the delay circuit 2, the Nth frame from the beginning of the decoded image signal is output from the encoding device 1 (decoder 12). It is designed to be output.

The S / N comparator 3 measures the S / N of the decoded image signal output from the encoding device 1 with respect to the original signal output from the delay circuit 2, and the measured value is below a predetermined threshold value. The part of the decoded image signal (or the part of the original signal from the delay circuit 2 corresponding to that part) which is the following is detected, and the S / N of the decoded image signal is extremely deteriorated at that part. It is designed to be recognized as a part. Further, the S / N comparator 3 detects the above-mentioned S / N in a portion of the decoded image signal where the S / N is equal to or less than a predetermined threshold (a portion in which the S / N is extremely deteriorated) (hereinafter, appropriately referred to as a deteriorated portion) The corresponding time information from the delay circuit 13 is detected, and this is output to the memory 14 as time / position information.

Here, as described above, when the time information is a time code, the minimum area is a frame, and therefore the deteriorated portion is in a very small range (for example, 1 in extreme cases).
Even if it is a pixel, a time code indicating a frame including the deteriorated part is output as time / position information. That is, in this case, even if the deteriorated portion is in a small range, the entire frame including the deteriorated portion is considered to be deteriorated.

In this way, the time information is directly converted to the time /
If the position information is used, the position of the deteriorated portion cannot be accurately represented as the deteriorated portion is in a smaller range.

Therefore, in the S / N comparator 3, one frame is divided into, for example, so-called macroblocks or small blocks of 8 pixels × 8 pixels, and macroblocks or small blocks containing a deteriorated portion Position (for example, block number (number assigned to each block when a frame is divided into macroblocks, etc.)) (hereinafter referred to as position information as appropriate)
Is detected and this position information can be output as time / position information in addition to the above-mentioned time information.

The minimum unit of the image signal indicated by the time / position information can be a pixel, but the encoder 1
It is preferable that 1 is a coding unit for coding the original signal. That is, for example, when the encoder 11 is adapted to perform coding in macroblock units, it is preferable that the minimum unit of the image signal indicated by the time / position information is a macroblock.

Next, referring to the flowchart of FIG.
The operation will be described. When an image signal (original signal) associated with the time information is input together with the time information, the original signal is supplied to the encoder 11 and the delay circuit 2, and the time information is supplied to the delay circuit 13 and the control unit. 1
5 is supplied.

Then, in step S1, the original signal is encoded by the encoder 11, the encoded data obtained as a result is output to the decoder 12, and the process proceeds to step S2. In step S2, the coded data from the encoder 11 is decoded, and thereby the decoded image signal is obtained.
It is output to the N comparator 3.

On the other hand, the original signal or the time information supplied to the delay circuit 2 or 13 is subjected to the processing of steps S1 and S2, that is, the encoding processing in the encoder 11 and the decoding processing in the decoder 12. Each is delayed by time and output to the S / N comparator 3.

Therefore, the delay circuits 2 and 13 or the decoder 12 output the original signal, the time information, and the decoded image signal to the S / N comparator 3 with their phases synchronized. It

Then, in step S3, the S / N comparator 3 measures the S / N of the decoded image signal from the decoder 12 with respect to the original signal from the delay circuit 2, and the process proceeds to step S4. It is determined whether / N is larger than a predetermined threshold value. When it is determined in step S4 that the S / N of the decoded image signal measured by the S / N comparator 3 is larger than a predetermined threshold value, the image quality of the original signal becomes extremely high due to the encoding by the encoder 11. It is assumed that there is no deteriorated portion, and the processing ends. In this case, the encoded data output from the encoder 11 is directly transmitted via the transmission path or recorded in the recording medium.

On the other hand, in step S4, when it is determined that the S / N of the decoded image signal measured by the S / N comparator 3 is not larger than the predetermined threshold value, that is, the decoded image signal has the S / N of S / N. If there is a small portion (extremely small portion), the process proceeds to step S5, where the S / N comparator 3 outputs the S / N
The time information from the delay circuit 13 corresponding to the extremely small portion of N, that is, the deteriorated portion is detected, and further, the position information of the deteriorated portion is detected as necessary. Then, these are output from the S / N comparator 3 to the memory 14 and stored as time / position information.

After that, when the original signal (the same as the image signal encoded in the previous step S1) is input again together with the time information (the original signal is the encoder 11 and the delay circuit). 2 and the time information is supplied to the delay circuit 13 and the control unit 15), step S
Returning to 1, the original signal is encoded again.

However, in this case, the control unit 15 reads the time / position information stored in the memory 14, and the timing at which the time / position information is matched with the time information associated with the original signal. The coding parameters of the encoder 11 are controlled so that the code amount assigned to the original signal coded by the encoder 11 at 1 increases compared to the previous coding.

Since the original signal coded at the timing of the time information that matches the time / position information stored in the memory 14 corresponds to the above-mentioned deteriorated portion, the code amount to be assigned to this portion is set to be smaller than that at the previous time. By increasing
It is possible to reduce the S / N deterioration due to the coding of that portion.

The control unit 15 reduces the code amount to be assigned to the portion before and after it and the portion having a high S / N by the increment of the code amount assigned to the original signal portion corresponding to the deteriorated portion. The amount of generated code of the entire original signal or the coding rate in the vicinity of that part is adjusted to be substantially the same as the previous time.

Further, when the minimum unit of the original signal indicated by the time / position information is smaller than that of the time information (the minimum area of the time information), the control unit 15 starts the encoder from the timing indicated by the time information. In consideration of the processing speed of 11, the timing indicated by the time / position information is calculated, and the encoding parameter of the encoder 11 is increased so as to increase the code amount assigned to the portion of the original signal encoded at that timing. Is designed to control.

After the coding is performed as described above, the process proceeds to step S2 and subsequent steps, and in step S4 described above, S / N of the decoded image signal measured by the S / N comparator 3 is measured.
The processes of steps S1 to S5 are repeated until it is determined that N is larger than the predetermined threshold value.

Therefore, in this case, the decoded image obtained by decoding the finally obtained coded data has an extremely deteriorated S / N portion, that is, the S / N variation occurs in the decoded image. Can be prevented.

By the way, there are times when it is necessary for the image coding apparatus shown in FIG. 1 to input the original signal associated with absolute time information a plurality of times. In some cases, it is difficult to encode the output of a video camera or the like performing the above-described processing so as to reduce the deteriorated portion of the decoded image as described above.

Therefore, FIG. 3 shows the configuration of the second embodiment of the image coding apparatus to which the present invention is applied. In addition, in the figure, the same reference numerals are given to the portions corresponding to the case in FIG.

In this case, an image signal (original signal) which is an output of, for example, a video camera (not shown) or absolute time information synchronized with it is sent to the encoding device 1 via the switch SW1 or SW2. Are input respectively. Further, the respective original signal or time information is adapted to be inputted to an image input terminal s _in or time information input terminal (time code input) t _in the VTR 21.

The VTR 21 has its input terminal s _in or t
_The original signal input via _in or the time information synchronized therewith is recorded, and the recorded original signal or time information is reproduced, and the image signal is output from the image output terminal s _out or the time information output terminal (time code output). Terminal) t _out
It is designed to be output via. The image signal (original signal) output from the VTR 21 is supplied to the terminal b1 of the switch SW1 and the monitor 32 of the image quality evaluator 30. The time information output from the VTR 21 is supplied to the terminal b2 of the switch SW2 and the synchronizer 23.

The switch SW1 selects one of the terminals a1 and b1 to supply the original signal output from either the video camera or the VTR 21 to the encoding device 1. . The switch SW2 selects one of the terminals a2 and b2, which causes the encoding device 1 to be connected to the video camera and the VT.
The time information output from any one of R21 is supplied.

The VTR 22 is supplied with a decoded image signal or time information from the encoding device 1 via the image input terminal s _in or the time information input terminal t _in, respectively. The VTR 22 records the decoded image signal or time information from the encoding device 1 and reproduces the recorded decoded image signal or time information, respectively, via the image output terminal s _out or the time information output terminal t _out thereof. The image is output to the monitor 31 or the display 33 of the image quality evaluator 30. Further, the time information reproduced by the VTR 22 is also supplied to the synchronizer 23.

The synchronizer 23 uses the time information from the VTR 22 or 23, respectively, so that the original signal or the decoded image signal is reproduced in synchronization with the VTR 22.
Alternatively, each of the 23 is controlled.

The image quality evaluator 30 is composed of monitors 31, 32 and a display 33. The monitor 31 or 32 is adapted to display the decoded image signal or the original signal reproduced by the VTR 22 or 21, respectively. When the decoded image signal displayed on the monitor 31 has a part where the image quality is deteriorated (extremely deteriorated part) compared to the original signal displayed on the monitor 32, the operation unit 24 The user operates so as to specify that part, and from there, a deterioration part specifying signal indicating a part where the image quality of the decoded image signal displayed on the monitor 31 is deteriorated is output to the display device 33. Has been done.

The display device 33 detects the time information from the VTR 22 corresponding to the deteriorated part of the decoded image signal indicated by the deteriorated part designation signal, and also detects the above-mentioned position information of the deteriorated part, and detects the time / time. The position information is output to the memory 14 of the encoding device 1.

Next, referring to the flow chart of FIG.
The operation will be described. For example, when an image signal (original signal) associated with absolute time information is input to the device from a video camera or the like, the switch SW1 or SW2 is switched to select the terminal a1 or a2. Thus, the so-called real-time original signal captured by the video camera and the time information associated therewith are supplied to the encoding device 1 and the VTR 21. In the encoding device 1, the original signal or the time information input thereto is supplied to the encoder 11 or the delay circuit 13, respectively.

Then, in step S11, the original signal is encoded by the encoder 11, and the encoded data obtained as a result is output to the decoder 12, and at the same time, the VTR is transmitted.
At 21, the original signal is recorded together with the time information, and the process proceeds to step S12. In step S12, the encoder 11
The coded data from is decoded, and thereby the decoded image signal is output to the VTR 22.

On the other hand, the time information supplied to the delay circuit 13 is delayed by the time required for the encoding process in the encoder 11 and the decoding process in the decoder 12 and is output to the VTR 22.

That is, the decoded image signal or the time information is supplied from the decoder 12 or the delay circuit 13 to the delay circuit 13 in a state in which their phases are synchronized (the original signal supplied to the encoder 11 and the delay circuit 13). In the state where the same relationship as the corresponding time information is maintained), it is output to the VTR 22.

The VTR 22 records the decoded image signal and time information from the encoding device 1 (decoder 12 and delay circuit 13 respectively).

Thereafter, the process proceeds to step S13, and VTR2
At 1, the original signal and the time information associated with it (hereinafter appropriately referred to as original time information) are reproduced, and at the same time VT
In R22, the decoded image signal and the time information associated with it (hereinafter referred to as decoding time information) are reproduced.

The original signal or the decoded image signal is supplied to and displayed on the monitor 32 or 31, respectively. Further, the original time information and the decoding time information are supplied to the synchronizer 23. Note that the decoding time information is the synchronizer 2
3 is also supplied to the display 33.

In the synchronizer 23, the VTR 21 is arranged so that the original time information and the decoding time information are synchronized (matched).
And the playback operation of 22 is controlled (VTR21 and VT
R22 is controlled to operate in synchronization). As a result, when the monitor 32 displays the original signal of a certain frame, the monitor 31 displays the decoded image signal obtained by encoding and decoding the original signal of the frame.
That is, the decoded image signal or the original signal of the same frame is displayed on the monitor 31 or 32, respectively.

Then, in step S14, the monitor 3
The user determines whether the image quality of the decoded image signal displayed on the monitor 31 is deteriorated (extremely deteriorated) as compared with the original signal displayed on the screen 2. That is, the user first compares the decoded image signal displayed on the monitors 31 and 32 with the original signal, compares the decoded image signal with the original signal, and determines whether or not the decoded image signal has a deteriorated portion. Is determined subjectively (the decoded image signal is subjectively evaluated). Then, when there is a portion of the decoded image signal that is subjectively deteriorated, the user operates the operation unit 24 so as to specify the deteriorated portion. Operation part 2
When 4 is operated so as to specify the deteriorated portion, a deterioration point specifying signal indicating the position of the deteriorated portion is output from the display unit 33.

Here, if the VTRs 21 and 22 are kept in the normal reproduction state, the screen display progresses sequentially. Therefore, even if the user finds a deteriorated portion, the operation portion 24 is designated so as to designate that portion. It becomes difficult to operate. Therefore, by operating the operation unit 24 on the VTRs 21 and 22, for example, so-called slow reproduction, frame advance,
Special playback such as still playback can be performed.

Therefore, the user must first set, for example, VTR2.
Let 1 and 22 do normal reproduction, find the deteriorated part,
The operation unit 24 is operated so as to perform special reproduction in the vicinity thereof (frames in the vicinity thereof). Then, for example, by repeating special reproduction in the vicinity thereof, the frame including the deteriorated portion is specified, and thereafter, the operation unit 24 is operated so as to instruct the position of the deteriorated portion in the frame.

It is to be noted that the VTRs 21 and 22 are caused to repeat the special reproduction so that the video tape (the original signal or the decoded image signal in which the original signal or the decoded image signal is recorded together with the time information) is loaded on the video tape. Therefore, when the user finds a deteriorated part, V
It is possible to cause the TRs 21 and 22 to normally reproduce the vicinity thereof and store the reproduced image in, for example, a memory. In this case, when the vicinity of the deteriorated portion is repeatedly displayed on the monitors 31 and 32, the reproduced image stored in the memory is read and used to prevent the deterioration of the video tape set in the VTRs 21 and 22. be able to.

In step S14, it is judged that the image quality of the decoded image signal displayed on the monitor 31 is not deteriorated (not extremely deteriorated) as compared with the original signal displayed on the monitor 32. In the case, that is, when the deterioration point designation signal is not output from the operation unit 24, the encoder 1
By the encoding in No. 1, it is determined that the image quality of the decoded image signal does not extremely deteriorate, and the process ends. In this case, the encoded data output from the encoder 11 is
It is transmitted as it is through the transmission path or recorded in a recording medium.

On the other hand, in step S14, the monitor 3
When it is determined that the image quality of the decoded image signal displayed on the monitor 31 is deteriorated (extremely deteriorated) as compared with the original signal displayed on the screen 2, that is, from the operation unit 24. When the deterioration point designation signal is output, the decoding time information from the VTR 33 corresponding to the frame including the part (deteriorated part) of the decoded image signal indicated by the deterioration point designation signal is detected by the display unit 33, and further, The position information of the deteriorated portion indicated by the deterioration point designation signal is detected. And
These are output from the display device 33 to the memory 14 and stored as time / position information.

When the user is not satisfied with the image quality of the decoded image signal subjectively evaluated (operation unit 2
4 is operated to indicate the deteriorated portion), switch S
W1 or SW2 is switched from the terminal a1 or a2 side to the terminal b1 or b2 side, respectively. Then, proceeding to step S15, the VTR 21 is operated and the original signal and original time information recorded therein are reproduced. VTR
The original signal reproduced at 21 is the terminal b1 and the switch S.
It is supplied to the encoder 11 via W1. Similarly, V
The original time information reproduced by TR21 is supplied to the control unit 15 and the delay circuit 13 via the terminal b2 and the switch SW2.
Is supplied to.

At the same time, the time / position information stored in the memory 14 is read by the control unit 15, and step S
16, the encoder 11 under the control of the control unit 15
The original signal from VTR 21 is encoded again.

However, in this case, as in the case of the image coding apparatus of FIG. 1 described above, in the control unit 15, the original time information associated with the original signal is stored in the memory 14.
Of the encoder 11 so that the amount of code allocated to the original signal encoded by the encoder 11 at the timing matching the time / position information read from Parameterization is controlled.

Therefore, the deterioration of the image quality due to the encoding is reduced more than the previous time.

Also in this case, as in the case described above, the control unit 15 adjusts the generated code amount of the entire original signal or the coding rate near the deteriorated portion.
Further, when the minimum unit of the original signal indicated by the time / position information is smaller than that of the original time information, the processing speed of the encoder 11 is considered from the timing indicated by the original time information,
The timing indicated by the time / position information is calculated, and the encoding parameter of the encoder 11 is controlled so that the code amount assigned to the portion of the original signal encoded at that timing is increased.

After the encoding is performed as described above, the process returns to step S12, and the decoded image displayed on the monitor 31 is compared with the original signal displayed on the monitor 32 in step S14 described above. Until it is determined that the image quality of the signal has not deteriorated (not extremely deteriorated),
The processing of steps S12 to S16 is repeated.

Therefore, in this case, it is possible to prevent a portion where the image quality is extremely deteriorated from occurring in the decoded image obtained by decoding the finally obtained encoded data.

The case where the present invention is applied to an image coding apparatus for coding an image signal has been described above. However, the present invention can be applied to a coding apparatus for coding a voice signal and the like in addition to the above. It is possible.

In this embodiment, the time code is used as the time information, but it is not limited to this. That is, for example, a pulse indicating the start frame of the image signal is input to the encoding device 1 as time information, and the encoding device 1 generates a predetermined clock at the timing of the pulse,
It is possible to identify the deteriorated portion based on this clock. Further, as the time information, the same information as the above-mentioned time / position information can be used.

Further, in the present embodiment, the encoding device 1
The time information is delayed by the delay circuit 13 and output. However, in addition to this, for example, the time information is output together with the image signal.
The encoder 11 may be used for encoding, and the output thereof may be decoded by the decoder 12 and output. In this case, the delay circuit 13 need not be provided, so that the device can be made compact.

In this embodiment, the method of controlling the coding parameter of the encoder 11 so that the code amount to be allocated (assigned code amount) is not mentioned, but for example, the following method is used. , The allocated code amount can be increased. That is, for example, by making the quantization step fine, by setting the coding mode to intra coding, or by making the characteristics of the filter that filters the original signal pass through to a higher frequency band, the assigned code amount Can be increased.

Further, in the present embodiment, the deterioration is reduced by increasing the allocation code amount for the deteriorated portion, but the deterioration can be reduced by other methods. Is.

The encoding algorithm or the decoding algorithm in the encoder 11 or the decoder 12 is not limited to the above.

[0085]

As described above, according to the present invention, it is possible to perform encoding so that the decoded image will not be extremely deteriorated in image quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an image encoding device to which the present invention has been applied.

FIG. 2 is a flowchart illustrating the operation of the embodiment of FIG.

FIG. 3 is a block diagram showing a configuration of a second embodiment of an image encoding device to which the present invention has been applied.

FIG. 4 is a flowchart for explaining the operation of the embodiment in FIG. 3;

[Explanation of symbols]

 1 Encoder 2 Delay Circuit 3 S / N Comparator 11 Encoder 12 Decoder 13 Delay Circuit 14 Memory 15 Control Unit 21, 22 VTR (Video Tape Recorder) 23 Synchronizer 24 Operation Unit 30 Image Quality Evaluator 31, 32 Monitor 33 Display

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 7/32

Claims (6)

[Claims] 1. An encoding device for encoding time-series information associated with absolute time information, comprising: an encoding means for encoding the information; and a code output from the encoding means. Decoding means for decoding the decoded data, and detection for recognizing the deteriorated part of the decoded data output from the decoding means and detecting the deteriorated partial time information which is the time information corresponding to the part Means, storage means for storing the deteriorated partial time information detected by the detection means, and the deteriorated partial time information stored in the storage means when the information is encoded again by the encoding means An encoding apparatus, comprising: a control unit that controls the encoding unit so that deterioration of a corresponding portion of the decoded data is reduced. 2. The detecting means measures the S / N of the decoded data for the information, and based on the measurement result,
The encoding device according to claim 1, wherein a deteriorated portion of the decoded data is recognized. 3. The first or second recording / reproducing means for recording the information or the decoded data together with the time information, and reproducing the recorded information or the decoded data together with the time information, The information reproduced by the first recording / reproducing means,
The detecting means further comprises a supplying means for supplying the encoding means, the detecting means outputs the information or the decoded data reproduced by the first or second recording / reproducing means, and the output means. Compared to the information output by more, including a designating unit for designating a deteriorated portion of the decoded data, the portion of the decoded data designated by the designating unit is recognized, and The corresponding time information is detected as the deteriorated partial time information, and the control means supplies the information reproduced by the first recording / reproducing means to the encoding means by the supplying means, So that the deterioration of the decoded data corresponding to the deteriorated partial time information stored in the storage means is reduced when encoded again by the encoding means,
The coding apparatus according to claim 1, wherein the coding unit is controlled. 4. A coding method for coding time-series information associated with absolute time information, wherein the information is coded, the resulting coded data is decoded, and the result is obtained. Recognizing the deteriorated part of the decoded data to be detected, detecting the deteriorated partial time information which is the time information corresponding to the part, stores the deteriorated partial time information, and corresponds to the deteriorated partial time information An encoding method, characterized in that the information is encoded again so that deterioration of a portion of the decoded data is reduced. 5. S / N of decoded data for the information
Is measured, and the deteriorated portion of the decoded data is detected based on the measurement result. 6. The information is encoded, the information and the time information are recorded on a first recording medium, the encoded data is decoded, and the resulting decoded data is obtained. , The time information is recorded in a second recording medium, and the recorded information or the decoded data is reproduced from the first or second recording medium in synchronization with each other based on the recorded time information. Then, the reproduced information or the decoded data is output, the deteriorated portion of the decoded data is designated by comparing with the information, the designated portion of the decoded data is recognized, and the portion thereof is recognized. Detecting the time information corresponding to the degraded partial time information as the degraded partial time information, reproducing the information from the first recording medium, and reducing the degradation of the portion of the decoded data corresponding to the degraded partial time information. As is, the coding method according to claim 4, characterized in that the re-encoding the information reproduced.