JPH11234667A - Video coder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the video coder that conducts band reduction processing and pixel number conversion processing in response to a compression difficulty of an image. SOLUTION: The coder is provided with a pre-filter 14 that reduces a signal band of a video signal and a pixel number conversion section 15 that converts a pixel number of the video signal. The pixel number conversion section 15 applies pixel number conversion adaptively to a video signal so as to have a pixel number in response to a signal band reduced by the pre-filter 14. So that, a generated code quantity is reduced in the coding processing, the quantizationaccuracy is improved in the quantization processing and image quality deterioration is suppressed by the coding processing. Furthermore, the coder is provided with a sequence re-setting section 36 that revises a sequence set to the video signal, and the sequence is set again based on the pixel number conversion by the pixel number conversion section so as to attain pixel number conversion processing in real time in unit of frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order.

BACKGROUND OF THE INVENTION Prior Art (FIG. 4) Problems to be Solved by the Invention Means for Solving the Problems Embodiments of the Invention (FIGS. 1 to 3) Effects of the Invention

[0003]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video coding apparatus, and is suitably applied to, for example, a video signal coding apparatus used for digital broadcasting.

[0004]

2. Description of the Related Art In recent years, various compression / encoding methods have been proposed as methods for reducing the amount of video and audio information, and a typical one is MPEG2 (Moving Picture Experts Gr.).
There is a method called oup Phase 2). MPEG2
2. Description of the Related Art A digital broadcasting system has been started in which video and audio broadcast data are compression-encoded using a system and broadcast using terrestrial waves or satellite waves.

FIG. 4 shows a video signal encoding apparatus 50 as a whole.
The video signal D1 is input to the pre-filter 51 from a video signal supply device (not shown) such as a video tape recorder. The video signal D1 is subjected to band-limiting processing in the pre-filter 51 in accordance with the frequency characteristic control signal D55 supplied from the quantization rate control unit 55, whereby high-frequency components of the video signal are reduced, and the band-limited video signal D
The number 51 is output to the pixel number conversion unit 52. Here, the high-frequency component of the video signal represents a fine portion of the video, and the high-frequency component is reduced to omit the fine portion of the video, thereby reducing the influence on the entire video while reducing the influence on the entire video. Decrease bandwidth.

The pixel number conversion section 52 performs a pixel number conversion process on the input band-limited video signal D51. That is, assuming that the number of horizontal pixels of the video signal D1 input to the encoding device 50 is the number of horizontal pixels M, the pixel number conversion unit 52
The number of horizontal pixels of the band-limited video signal D51 obtained by band-limiting the video signal D1 is reduced to a reduced horizontal pixel number N where N <M, and is transmitted to the encoding unit 53 as a pixel number converted video signal D52. . Here, the number N of reduced horizontal pixels is set large according to the program content of the video signal D1 for programs requiring high image quality and small for programs not requiring high image quality.

[0007] The pixel-number-converted video signal D52 is supplied to the encoding unit 5
3, motion compensation processing, DCT (Discrete Cosine Tr)
Anisform, discrete cosine transform) processing, quantization processing, and VLC (Variable Length Coding) processing are compression-coded and sent to the buffer 54 as variable-length coded data D53. At this time, the encoding unit 53
Adjusts the quantization rate in the quantization processing according to the quantization control signal D56 supplied from the quantization rate control unit 55. The encoding unit 53 includes an encoding unit control circuit 5.
7, the coding unit control information D57 is supplied, and the coding unit 53 sets the coding timing and the motion vector search range in the motion compensation processing according to the coding unit control information D57.

Here, when the amount of motion of the video of the video signal D1 is large or when the video is complicated, the generated code amount of the variable length coded data D53 obtained by compression-coding the video signal D1 increases. A video signal having a large amount of code generated by such compression encoding is expressed as having a high degree of difficulty in compression. The degree of compression difficulty varies depending on the program content and scene of the video signal. Therefore, by controlling the quantization value of the quantization process in the encoding unit 53 and the band limitation in the pre-filter 51 based on the occupation amount of the variable-length encoded data D53 in the buffer 54, for example, the GOP
The generated code amount per (Group Of Pictures) is controlled to be constant.

That is, the quantization rate control unit 55 constantly monitors the accumulation state of the variable-length encoded data D53 in the buffer 54, and monitors the accumulation state with the occupancy rate information D5.
Obtained as 4. Then, the quantization rate control unit 55 generates a quantization control signal D56 and a frequency characteristic control signal D55 based on the occupation ratio information D54, and supplies them to the encoding unit 53 and the pre-filter 51, thereby performing variable-length encoding. The generated code amount of the data D53 per fixed period is controlled to be constant.

[0010]

By the way, in the video signal encoding device 50, while the band reduction width by the pre-filter 51 varies depending on the degree of difficulty of the compression of the video signal S1, the pixel number conversion unit 52 does not. The reduced horizontal pixel number N is constant according to the program content of the video signal D1. Therefore, the number of pixels N in the horizontal direction of the pixel number reduced video signal D52 is
May exceed the number of pixels in the horizontal direction necessary to represent the video of the band-limited video signal D51. in this case,
Pixels equal to or larger than the number of pixels required to represent the image of the band-limited video signal D51 are coded, and the quantization value in the quantization process is increased more than necessary, which causes a problem of deteriorating image quality. .

The present invention has been made in view of the above points, and it is an object of the present invention to propose a video signal encoding apparatus for performing a band reduction process and a pixel number conversion process according to the degree of difficulty in compressing an image.

[0012]

According to the present invention, there is provided a signal band reducing unit for reducing a signal band of a video signal, and a pixel number converting unit for converting the number of pixels of the video signal. The pixel number conversion means performs the pixel number conversion adaptively to the number of pixels according to the signal band reduced by the signal band reduction means.

Further, a coding unit resetting means for changing a predetermined coding unit set in the video signal is provided, and a break of the coding unit is changed based on the pixel number conversion by the pixel number converting means. I did it.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a video signal encoding apparatus 10 as a whole.
And an HDTV (High Definition Televisi) from a video signal supply device (not shown) such as a video tape recorder.
(On, high definition television) standard video signal D1 is input to the synchronizing signal generator 35 and the pre-filter 14.

The pre-filter 14 is a horizontal frequency low-pass filter, and reduces a high frequency component of the video signal D1 according to the frequency characteristic control signal D18 supplied from the quantization rate control unit 18 for the video signal D1. Perform bandwidth limiting processing to reduce the bandwidth of the video signal while omitting the fine parts of the video and reducing the effect on the entire video,
The signal is output to the pixel number conversion unit 15 as the band-limited video signal D2.

The number-of-pixels converter 15 converts the input band-limited video signal D2 into a horizontal-direction pixel count of the band-limited video signal D2 according to the pixel-number control signal D17 supplied from the pixel-number conversion determiner 17. And sends it to the encoding unit 20 as the pixel number converted video signal D3. For example, assuming that the number of pixels in the horizontal direction of the video signal D1 input to the encoding device 10 is 1920 pixels, the pixel number conversion unit 15 controls the horizontal direction of the band-limited video signal D2 obtained by band-limiting the video signal D1. The number of pixels is reduced to the number N of reduced horizontal pixels where N <1920.
This is sent to the encoding unit 20 as the pixel number converted video signal D3.

In this case, the pixel number conversion determining section 17 generates a pixel number control signal D17 according to the frequency characteristic control signal D18 sent from the quantization rate control section 18. First, based on the bandwidth after the high-frequency component reduction processing indicated by the frequency characteristic control signal D18, the pixel number conversion determination unit 17 determines a required horizontal pixel number, which is the number of horizontal pixels necessary to express the video of the band-limited video signal D2. Find the number N '. The bandwidth indicated by the frequency characteristic control signal D18 is F [Hz], and the band-limited video signal D
Assuming that the horizontal scanning time of No. 2 is Th [sec], N ′ = 2F ·
Th [pixel].

Next, the pixel number conversion determination unit 17 selects the smallest set horizontal pixel value Ns that satisfies the condition of N '<Ns from a plurality of set horizontal pixel values Ns set in advance. It is assumed that the number of reduced horizontal pixels is N. In this embodiment, the set horizontal pixel value Ns is 1440 pixels, 128 pixels.
Four types of 0 pixels, 1152 pixels, and 960 pixels are set. Then, the pixel number conversion determination unit 17 uses the identification number set corresponding to each set horizontal pixel value as the pixel number control signal D.
As 17, it is sent to the pixel number conversion unit 15 and the encoding unit control circuit 16 in synchronization with the synchronization signal D35 sent from the synchronization signal generation unit 35. Here, assuming that the type of the set horizontal pixel value is j types, the pixel number control signal D17 is k bits (j
≦ 2 ^k ).

Here, the synchronizing signal D35 is generated by the synchronizing signal generator 35 in synchronization with the frame period of the video signal D1. Thus, the band-limited video signal D2 is The number of pixels is converted in units of frames to a reduced horizontal pixel number N sufficient to represent D2, and the encoding unit 20 converts the pixel number into a pixel number converted video signal D3.
Sent to

When the identification number indicated by the pixel number control signal D17 is changed, the pixel number conversion determining unit 17 sends the sequence reset information D21 to the sequence resetting unit 36 in synchronization with the synchronization signal D35.

The encoding unit control circuit 16 outputs an encoding unit control signal D16 to the encoding unit 2 based on the pixel number conversion value D17.
Supply 0. The encoding unit 20 includes an encoding unit control signal D1
6, the pixel number converted video signal D
An encoding process according to the number of horizontal pixels of No. 3 is performed. That is,
The band-limited video signal D2 having the number of horizontal pixels M shown in FIG.
Are converted in the number of pixels by the number-of-pixels conversion unit 15, and FIG.
It is sent to the encoding unit 20 as a pixel number converted video signal D3 having the horizontal pixel number N shown in FIG. Here, the pixel number converted video signal D3 is not transmitted continuously,
After N pixels are continuously transmitted as shown in (B),
The transmission stops during a period corresponding to (MN) pixels. The encoding unit 20 performs an encoding operation during a period corresponding to N pixels according to the encoding unit control signal D16, and stops the encoding operation during a period corresponding to (M-N) pixels, thereby operating clock. While keeping the constant, the encoding process according to the horizontal pixel number of the pixel number converted video signal D3 is performed. Also, the encoding unit 20
Sets the motion vector search range in the motion compensation processing according to the coding unit control signal D16.

In the encoding section 20 (FIG. 1), the pixel number converted video signal D3 is input to the preprocessing section 21. First, the preprocessing unit 21 sets, for each frame image of the sequentially converted pixel number video signal D3, a sequence of a series of frame images having the same attribute, for example, the same number of pixels and the same aspect ratio. The sequence is data of the highest hierarchy of the data hierarchy defined by the MPEG2 standard. According to the MPEG2 standard, the number of pixels cannot be changed in frame units in the middle of a sequence, and the number of pixels cannot be changed only in sequence units.

Next, the pre-processing unit 21 determines which image type among three image types of I-picture, P-picture or B-picture according to the set sequence for each frame image of the pixel number converted video signal D3. After specifying whether or not to process the frame image, the frame image is rearranged in the encoding order according to the image type of the frame image, and the frame image corresponds to a luminance signal of 16 pixels × 16 lines and the luminance signal. The image data is divided into macroblocks constituted by color difference signals, and this is divided as macroblock data D4 into the arithmetic circuit 22 and the motion vector detector 3.
Feed to 1.

Here, when the sequence reset information D21 is input from the pixel number conversion judging section 17, the sequence resetting section 36 included in the encoding section control section 16 resets the sequence in synchronization with the sequence reset information D21. The signal D36 is sent to the preprocessing unit 21 included in the encoding unit 20. When receiving the sequence reset signal D36, the preprocessing unit 21 ends the set sequence and resets a new sequence for the pixel number converted video signal D3. At this time, re-designation of the image type is performed according to the reset of the sequence.

Thus, in response to a change in the number of pixels to be converted in the pixel number conversion process in the pixel number conversion unit 15, the pre-processing unit 21
By resetting the sequence in, the real-time pixel number conversion processing in frame units according to the band limitation processing in the pre-filter 14 is performed.

The motion vector detecting section 31 calculates a motion vector of each macro block of the macro block data D4 based on the macro block data D4 and the reference image data D28 stored in the frame memory 29. The motion compensator 30 and VL as D31
C (Variable Length Coding) section 25.

The arithmetic circuit 22 performs an intra mode, a forward prediction mode, and a backward prediction mode on the macroblock data D4 supplied from the preprocessing unit 21 based on the image type of each macroblock of the macroblock data D4. Alternatively, motion compensation is performed in one of the bidirectional prediction modes. Here, the intra mode is a method in which a frame image to be encoded is directly used as transmission data, and the forward prediction mode is a method in which a prediction residual between the frame image to be encoded and a past reference image is transmitted data. It is a method. In addition, the backward prediction mode is a method in which a prediction residual between a frame image to be encoded and a future reference image is used as transmission data, and the bidirectional prediction mode is
This is a method in which a prediction residual between a frame image to be encoded and an average value of two prediction images of a past reference image and a future reference image is used as transmission data.

First, the case where the macroblock data D4 is an I-picture will be described. In this case, the macro block data D4 is processed in the intra mode. That is, the arithmetic circuit 22 converts the macroblock of the macroblock data D4 into the DCT
(Discrete Cosine Transform, discrete cosine transform). The DCT unit 23 performs a DCT transform process on the operation data D5, converts the operation data D5 into DCT coefficients, and sends the result to the quantization unit 24 as DCT coefficient data D6. The quantization unit 24 performs a quantization process on the DCT coefficient data D6, and sends out the quantized DCT coefficient data D7 to the VLC unit 25 and the inverse quantization unit 26. At this time, the quantization unit 24 controls the generated code amount by adjusting the quantization value according to the quantization control signal D20 supplied from the quantization rate control unit 18.

The quantized DCT sent to the inverse quantization unit 26
The coefficient data D7 undergoes an inverse quantization process, and is sent to the inverse DCT unit 27 as DCT coefficient data D26. And D
The CT coefficient data D26 is output by the inverse DCT unit 27
After the CT processing, the arithmetic circuit 28
And stored in the frame memory 29 as reference image data D28.

Next, a case where the macroblock data D4 is a P-picture will be described. In this case, the arithmetic circuit 22 performs a motion compensation process on the macroblock data D4 in either the intra mode or the forward prediction mode.

When the prediction mode is the intra mode, the arithmetic circuit 22 sends the macroblock of the macroblock data D2 as it is to the DCT unit 23 as the arithmetic data D5, as in the case of the I-picture.

On the other hand, when the prediction mode is the forward prediction mode, the arithmetic circuit 22 outputs the macroblock data D4.
Is subtracted using the forward prediction image data D30F supplied from the motion compensation unit 31.

The forward prediction image data D30F is obtained by referring to the reference image data D28 stored in the frame memory 29.
Is calculated by performing motion compensation according to the motion vector data D31. That is, in the forward prediction mode, the motion compensator 30 reads the reference image data D28 by shifting the read address of the frame memory 29 according to the motion vector data D31, and uses the read reference image data D28 as the forward prediction image data D30F. 28. The operation circuit 22 subtracts the forward prediction image data D30F from the macroblock data D4 to obtain difference data as a prediction residual, and obtains the difference data as operation data D5 by the DCT unit 23.
To send to.

The operation circuit 28 is supplied with the forward prediction image data D30F from the motion compensator 30, and the operation circuit 28 adds the forward prediction image data D22F to the operation data D27 to obtain the reference image data. D2
8 (P picture) is locally reproduced and stored in the frame memory 29.

Next, a case where the macroblock data D4 of B picture is supplied from the preprocessing unit 21 to the arithmetic circuit 22 will be described. In this case, the arithmetic circuit 22 performs any one of the intra mode, forward prediction mode, backward prediction mode, and bidirectional prediction mode motion compensation processing on the macroblock data D4.

When the prediction mode is the intra mode or the forward prediction mode, the macroblock data D2 is subjected to the same processing as in the case of the P picture described above. However, since the B picture is not used as another predicted reference image, the reference image data D28 is not stored in the frame memory 29.

On the other hand, when the prediction mode is the backward prediction mode, the arithmetic circuit 22 outputs the macroblock data D4.
Is subtracted using the backward prediction image data D30B supplied from the motion compensation unit 30.

The backward predicted image data D30B is the reference image data D28 stored in the frame memory 29.
Is calculated by performing motion compensation according to the motion vector data D31. That is, in the backward prediction mode, the motion compensation unit 31 shifts the read address of the frame memory 29 in accordance with the motion vector data D31 to read the reference image data D28, and uses the read reference image data D28 as the backward prediction image data D30B. 28. The arithmetic circuit 22 subtracts the backward prediction image data D30B from the macroblock data D4 to obtain difference data as a prediction residual, and obtains the DCT unit 23 as the arithmetic data D5.
To send to.

The operation circuit 28 is supplied with the backward prediction image data D30B from the motion compensator 30, and the operation circuit 28 adds the backward prediction image data D30B to the operation data D27 to obtain the reference image data. D2
8 (B-picture) is locally reproduced, but since the B-picture is not used as another predicted reference image, the reference image data D28 is not stored in the frame memory 29.

When the prediction mode is the bidirectional mode, the operation circuit 22 calculates the motion compensator 3 from the macroblock data D4.
0 is subtracted from the average value of the forward prediction image data D30F and the backward prediction image data D30B to obtain difference data as a prediction residual, and DCT is used as operation data D5.
To the unit 23.

Further, the forward predictive image data D30F and the backward predictive image data D30B are supplied to the arithmetic circuit 28 from the motion compensator 30, and the arithmetic circuit 28 adds the forward predictive image data D30F and The reference image data D28 (B-picture) is locally reproduced by adding the average value of the backward predicted image data D30B. However, since the B-picture is not used as another predicted reference image, the reference image data D28 is stored in the frame memory 29. Is not remembered.

Thus, the pixel number converted video signal D3 input to the encoding device 20 undergoes motion compensation processing, DCT processing and quantization processing, and is supplied to the VLC section 25 as quantized DCT coefficient data D7.

The VLC unit 25 performs variable length coding on the quantized DCT coefficient data D7 and the motion vector data D31 based on a predetermined conversion table, and buffers the resulting data as variable length coded data D8. Send it to 19. In the buffer 19, the variable-length coded data D8 is temporarily stored and then read out sequentially as variable-length coded data D10.

The quantization rate control unit 18 includes a buffer 19
, The accumulated amount of the variable-length encoded data D8 is constantly monitored, and the accumulated amount is obtained as occupancy information D19.
Then, based on the occupation ratio information D19, the quantization rate control unit 18 controls the frequency characteristic control signal D18 and the quantization control signal D2.
By generating 0s and sending them to the pre-filter 14 and the quantization unit 24, the bandwidth in the band reduction process and the quantization value in the quantization process are adjusted.

Here, since the number-of-pixels converted video signal D3 has a smaller number of pixels than the video signal D1, a macroblock is obtained by dividing the image of the pixel-number converted video signal D3 into 16 pixels × 16 lines. The number of macro blocks in the data D4 also decreases. Since the total amount of motion vectors in the motion compensation processing is almost proportional to the number of macroblocks, when the number of macroblocks decreases, the total amount of motion vectors decreases accordingly. For this reason, the accumulation amount of the variable length coded data D8 obtained by performing the variable length coding on the DCT count data D7 and the motion vector data D31 also decreases.

Therefore, when the generated code amount of the variable length coded data D10 is fixed, the quantization rate control unit 18
By finely controlling the quantization value in the quantization unit 18 according to the decrease in the amount of variable-length encoded data D8 stored in the buffer 19, the generated code amount of the motion vector data D31 due to the decrease in the number of macroblocks is reduced. D
Since the CT count data D6 can be quantized with a finer quantization value, the quantization accuracy can be improved.

In the above configuration, the video signal D1 input to the video signal encoding device undergoes band reduction processing in the pre-filter 14, and is sent to the pixel number conversion unit 15 as a band-limited video signal D2. At this time, the quantization rate control unit 18 controls the amount of band limitation in the pre-filter 14 according to the degree of compression difficulty of the video signal D1.

The band-limited video signal D2 is supplied to the pixel number converter 1
In 5, the number of pixels is reduced to the minimum number of pixels necessary for expressing the band-limited video signal D2, and is transmitted to the encoding unit 20 as the reduced-pixels video signal D3. At this time,
As the number of pixels decreases, the number of macroblocks also decreases.

The video signal D3 with the reduced number of pixels is supplied to the encoding unit 20.
Receives a motion compensation process, a DCT transform process, a quantization process, and a variable length coding process, and outputs the data to the buffer 19 as variable length coded data D8. At this time, the quantization rate control unit 18 controls the quantization value of the quantization process in the encoding unit 20 according to the degree of compression difficulty of the video signal D1.

Here, the number of macroblocks of the pixel number reduced video signal D3 is smaller than that of the band limited video signal D2. Since the generated code amount of the motion vector by the motion compensation processing is almost proportional to the number of macroblocks, the generated code amount of the motion vector of the variable-length coded data D8 obtained by coding the video signal D3 with reduced number of pixels also decreases. Since the generated code amount of the motion vector is reduced, the DCT coefficient can be quantized with a finer quantization value, so that image quality deterioration can be avoided.

When the number of converted pixels is changed in the number-of-pixels conversion process in the number-of-pixels conversion unit 15, the preprocessing unit 21 of the encoding unit 20 sets the number-of-pixels converted video signal D3 according to the change. Ends the current sequence and resets the new sequence. At this time, the image type is specified again according to the resetting of the sequence. Thus, the real-time pixel number conversion processing is performed in frame units in accordance with the band limitation processing in the pre-filter 14.

According to the above arrangement, the pre-filter for reducing the signal band of the video signal and the pixel number converter for converting the number of pixels of the video signal are provided, and the signal reduced by the pre-filter in the pixel number converter is provided. By performing pixel number conversion adaptively to the number of pixels according to the band and encoding the minimum necessary pixels, it is possible to prevent the quantization value in the quantization process from becoming unnecessarily large, and the image quality by the encoding process Deterioration can be prevented.

Further, there is provided a sequence resetting means for transmitting a sequence resetting signal to the encoding section in response to a change in the number of pixels, and the encoding section resets the sequence in accordance with the sequence resetting signal. This makes it possible to perform real-time pixel number conversion processing in frame units.

In the above-described embodiment, the pixel number conversion determining unit 17 determines the pixel number control signal D in accordance with the frequency characteristic control signal D 18 sent from the quantization rate control unit 18.
17, but the present invention is not limited to this.
Pixel number conversion processing may be performed according to a control signal supplied from the outside. In FIG. 3, in which the same parts as those in FIG. 1 are assigned the same reference numerals, reference numeral 11 denotes a video signal encoding device 11 as a whole. Is supplied to Other configurations are the same as those of the video signal encoding device 10 shown in FIG. The pixel number conversion determination unit 13 sends a pixel number control signal to the pixel number conversion unit 15 in synchronization with the synchronization signal D35 sent from the synchronization signal generation unit according to the conversion control signal D13. Subsequent operations are the same as in the above embodiment.

In the above embodiment, the number of pixels in the conversion horizontal direction in the pixel number conversion process is 1440 pixels,
Although 1280 pixels, 1152 pixels and 960 pixels were used,
The present invention is not limited to this, and other horizontal pixel numbers may be used.

In the above embodiment, the video signal D1 is a video signal of the HDTV standard. However, the present invention is not limited to this, and a video signal of a standard other than the HDTV may be input.

Further, in the above-described embodiment, the process of reducing the number of pixels in the horizontal direction is performed according to the degree of difficulty in compressing the image. However, the present invention is not limited to this, and the number of pixels in the vertical direction, Alternatively, the number of pixels may be reduced in the vertical and horizontal directions, that is, the number of scanning lines and the number of pixels in the horizontal direction may be reduced at the same time.

[0059]

As described above, according to the present invention, a signal band reducing means for reducing the signal band of a video signal and a pixel number converting means for converting the number of pixels of the video signal are provided. In the means, the number of pixels is adaptively converted to the number of pixels corresponding to the signal band reduced by the signal band reducing means, thereby reducing the amount of codes generated by the encoding processing and the quantization in the quantization processing. Improve accuracy,
Image quality deterioration due to the encoding process can be suppressed. Further, a coding unit resetting means for changing a predetermined coding unit set in the video signal is provided, and the break of the coding unit is changed based on the pixel number conversion by the pixel number converting means. This makes it possible to perform real-time pixel number conversion processing in frame units.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a video signal encoding apparatus according to the present invention.

FIG. 2 is a schematic diagram illustrating pixel number conversion.

FIG. 3 is a block diagram showing a video signal encoding device according to another embodiment.

FIG. 4 is a block diagram showing a video signal encoding device.

[Explanation of Codes] 10, 11, 50 ... Video signal coding device, 13, 17
...... Pixel number conversion judging unit, 14, 51 ... Prefilter,
15, 52 ... pixel number conversion unit, 16, 57 ... coding unit control circuit, 18, 55 ... quantization rate control unit, 19,
54 ... buffer, 20, 53 ... coding unit, 35 ...
Synchronization signal generator, 36... Sequence resetter.

Claims (3)

[Claims] 1. A video encoding apparatus for compressing and encoding an input video signal for each predetermined unit and transmitting the same, comprising: a coding unit resetting means for resetting the coding unit set in the input video signal. A video encoding device characterized by the following. 2. A video encoding apparatus comprising: a signal band reducing unit configured to reduce a signal band of the input video signal; and a pixel number conversion unit configured to convert a pixel number of the input video signal based on the reduced signal band. 2. The video encoding apparatus according to claim 1, wherein the encoding unit resetting unit resets the encoding unit in accordance with a pixel number conversion process by the pixel number conversion unit. . 3. The coding unit resetting means, when the number of pixels of the input video signal is converted by the pixel number conversion means, sets the converted input video signal as a head of the coding unit. 3. The video encoding apparatus according to claim 2, wherein: