JP3223631B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus used for recording or transmitting a video signal with high efficiency encoding.

[0002]

2. Description of the Related Art As a method for reducing the data amount of a video signal, a method using high efficiency coding is known. High-efficiency coding is a coding method that removes the redundancy of a video signal to reduce the amount of data.

As a high-efficiency encoding method, a method is often used in which adjacent pixels are collected to form a block, and each block is compressed using an orthogonal transform or the like. A block that performs this orthogonal transformation is called an orthogonal transformation block. Such orthogonally transformed data is usually encoded or recorded or transmitted for each orthogonal transform block using variable length encoding in order to improve compression efficiency.

[0004] For moving images, there is known a method of improving the compression ratio using correlation between frames. In this method, a difference value is obtained between adjacent frames, and only the difference signal is encoded and recorded. Further, a method of further reducing the information amount of the difference signal by calculating and correcting the amount of motion with respect to the frame whose difference is to be calculated when calculating the difference value and executing the difference is also being studied.

[0005]

However, since variable length coding is used in the above configuration, if an error occurs during recording / reproduction, the variable length code cannot be decoded and cannot be reproduced. Was. On the other hand, there has been proposed a method of recording address information indicating which orthogonal transform block is related to the data around the data every fixed recording data period. By this method,
Even if the code synchronization of the variable length code is lost due to a transmission line error,
Code synchronization and orthogonal transformation block synchronization can be restored using the address information.

However, in order to record the address information, it is necessary to record data that is not related to the video information, which degrades the compression efficiency of the high-efficiency coding. Further, in order to execute high-speed reproduction with a VTR or the like, it is desirable that the position of recorded data and the position of data on the screen have a one-to-one correspondence, but since variable-length coding is used, , The relationship between the recording position and the position on the screen becomes undefined. For this reason, the image quality during high-speed reproduction is greatly deteriorated.

In particular, when high-efficiency encoding is performed using information between a plurality of frames, high-speed encoded data using data only in a frame is required during high-speed reproduction or error correction. However, in the conventional method, it is difficult to use the data generated based on the information only in the frame because the position on the tape is indefinite.

An object of the present invention is to solve the problem of such a conventional recording apparatus that performs high-efficiency encoding between a plurality of frames.

[0009]

According to a first aspect of the present invention, input moving image signals are collected for K (K is a natural number of 2 or more) frames, and are encoded with high efficiency in units of K frames to obtain a high efficiency of the K frames. Efficiency encoded data is represented by L (L is a natural
A recording apparatus for recording by dividing the number) number of tracks, the first frame a predetermined frame in the K frame
Is defined as, for the first frame is high-efficiency coding using only information within the frame, except the first frame
In frame or frame for K-1 frame
Has a high-efficiency encoding means for high-efficiency encoding using the information between, when the high-efficiency encoding means for high-efficiency encoding the information of the first frame, one frame data of n Blocking means for dividing into compressed blocks; and n recording blocks at specific positions in the L tracks, corresponding to each of the n compressed blocks, and wherein in is high-efficiency encoding first
The data of the compressed block of the frame is recorded in the corresponding recording block, and the encoded data overflowing from the next corresponding recording block still has free space even after the data is recorded in the compressed block of the first frame. The data is recorded in the recording block corresponding to the first frame, and if there is surplus data of the compressed block for the first frame even after all the recording blocks have been filled, n of the L tracks The data of the remaining compressed block is recorded in a portion other than the recording block, and the information on the K-1 frame other than the first frame is added to the remaining portion after recording the remaining compressed data on the L track. A recording apparatus characterized in that the recording is performed with efficiency coding.

[0010] Further, the recording apparatus of the second invention has a first recording device.
This is a recording apparatus in which K = 2 .

[0011]

With the above arrangement, in the recording apparatus according to the first aspect of the present invention, the data of n compressed blocks, which are highly efficient encoded only with the data in the frame within the L tracks, are fixed n data blocks. Since the data is recorded in the recording block, and at the time of high-speed reproduction, if the n recording blocks are reproduced so as to be sequentially scanned, it is possible to sequentially reproduce the reproduction data composed only of the frame. As a result, a smooth reproduced image can be reproduced even during high-speed reproduction.
In addition, even when a transmission path error occurs and the code synchronization of the variable length coding is lost, the variable length coding is reset in the above n recording blocks, so that there is no influence of the error. In this way, it is possible to minimize the influence of a transmission path error on data composed only in a frame important for reproduction.

In the recording apparatus according to the second aspect of the present invention, in a recording method for performing high-efficiency encoding in two frames, information for highly efficient encoding in a frame is recorded for recording data for two frames. Recording is performed preferentially on the first n tracks of the 2n tracks. As a result, as in the first aspect, high-speed reproduction and correction at the time of a transmission path error can be performed. Further, in the second invention, since most of the information of the first frame can be reproduced only by the first n tracks, the second n tracks (the data of a part of the first frame and the data of the second frame are Recorded), new video information can be recorded. This enables editing in units of one frame in spite of the two-frame compression.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Here, an example in which the present invention is applied to a TV signal transmitted by the 525/60 system will be described. In the present embodiment, it is assumed that a video signal is independently encoded and recorded with high efficiency for each K frame, and that a luminance signal of one frame is composed of 720 horizontal pixels and 480 vertical lines. The orthogonal transformation block is composed of data consisting of 64 pixels of 8 horizontal pixels and 8 vertical lines. As a result, the number of orthogonal transform blocks of the luminance signal per frame becomes 5,400.

Each of the two color difference signals (RY signal and BY signal) constitutes one orthogonal transform block by pixels included in the same area on the screen as the orthogonal transform block of four adjacent luminance signals. I do. In addition, a total of six orthogonal transform blocks including four orthogonal transform blocks of luminance signals and one RY signal block and one BY signal block at the same position on the screen are referred to as one macro block. . Therefore, one frame is composed of 1350 macroblocks. In this embodiment, one compressed block is composed of one macroblock for the first frame in the K frame, and this compressed block is recorded in the corresponding recording block. Therefore, the number of compression blocks and recording blocks in the K frame is 1350.

FIG. 1 is a block diagram in one embodiment of the first invention. In FIG. 1, 1 is an input unit, 2 is a frame RAM, 3 is a differentiator, 4 is a high-efficiency encoding unit, and 5 is a first
The frame recording unit 6 is an i-th frame recording unit (1
<I ≦ K), 7 is a magnetic tape.

The video information of the first frame input from the input unit 1 is input to the frame RAM 2 and also to the high-efficiency encoding unit 4 at the same time. The data that has been highly efficient encoded by the high efficiency encoding unit 4 is recorded on a magnetic tape 8 by a magnetic head 7 according to a recording format in a first frame recording unit 5.

In the recording format of the present embodiment, information of a macroblock unit which has been highly efficient coded is first recorded in a corresponding compressed block from visually important data. The surplus data that could not be recorded in the corresponding compressed block in each macroblock is recorded in another recording block in which there is still a gap. In this way, the entire recording area in the recording block prepared for the first frame is used. If the data of the first frame still remains after the recording in the recording block is completed, the data is recorded in a recording area other than the recording block.

Next, video information of the second and subsequent frames input from the input unit 1 (hereinafter referred to as video information of the i-th frame (1 <i ≦ K)) is sent to the frame RAM 2 and the high-efficiency encoding unit 4. Is entered. At the same time, the difference between the input video information after the i-th frame and the video information of the previous frame output from the frame RAM 2 is calculated by the differentiator 3 and input to the high-efficiency encoding unit 4. The high-efficiency coding unit 4 selects one of the video information of the i-th frame and the difference information between the i-th frame and the previous frame and performs high-efficiency coding.

The video information of the i-th frame which has been encoded with high efficiency is recorded on the magnetic tape 8 by the i-th frame recording section 6 based on a recording format. The data after the second frame is sequentially recorded in the remaining recording area where the first frame is recorded.

In this embodiment, at the time of input, a difference value from the input video signal delayed by one frame is obtained.
It is also possible to use a difference value between the frame-delayed and highly efficient coded and reproduced video signal. Further, it is also possible to use not only one frame before but also a plurality of adjacent frames including a frame that is one frame or more behind for calculating the difference.

FIG. 2 is an explanatory diagram of a recording format according to the first invention. FIG. 2 shows a format for recording six consecutive frames of data on 20 tracks on a magnetic tape. In FIG. 2, the first 10 tracks of the 20 tracks are used as recording blocks for the first frame, and the last 10 tracks are used for recording the data of the first frame and the data of the second to sixth frames that could not be recorded in the recording block. Used as a recording area for recording. As the recording block, a block formed by dividing each track into 135 is used.

With this configuration, the visually important data of the first frame is recorded in the fixed recording block, so that the influence of the transmission path error can be minimized. Also, since the data of the first frame can be reproduced independently in recording block units, the VTR
High-speed playback is also possible. In particular, by focusing the recording blocks on the positions scanned by the magnetic head during high-speed reproduction, it is possible to improve the high-speed reproduction image quality.

Further, in the configuration shown in FIG. 2, it is possible to record information of one frame, which is highly efficient coded only with intra-frame information, in a recording block of 10 tracks. Therefore, when reducing the circuit scale of the high-efficiency coding, it becomes possible to perform the high-efficiency coding on all the frames within the frame and to allocate 10 tracks at a time. However, in this case, the compression ratio is reduced to 1/3 of the example of FIG. In FIG. 2, six frames of data are recorded on 20 tracks. However, other configurations such as recording of four frames of data on 20 tracks are possible.

Next, an embodiment of the second invention will be described. First
In this embodiment, one macroblock constitutes one compressed block. In this embodiment, two macroblocks constitute one compressed block. As a result, the number of compressed blocks and recording blocks becomes 675.

FIG. 3 is a block diagram showing an embodiment of the second invention. In FIG. 3, 8 is an input unit, 10 is a frame RAM, 11 is a differentiator, 12 is a high-efficiency encoding unit, 1
3 is a first frame recording unit, 14 is a second frame recording unit,
Reference numeral 15 denotes a magnetic head, and 16 denotes a magnetic tape.

The video information of the first frame input from the input unit 9 is input to the high efficiency encoding unit 12. The data that has been highly efficient encoded by the high efficiency encoding unit 12 is transmitted to the magnetic head 1 according to the recording format by the first frame recording unit 13.
5 is recorded on the magnetic tape 16. The data of the first frame, which has been highly efficiently coded by the high efficiency coding unit 12, is decoded and input to the frame RAM 10.

In the recording format of the present embodiment, information of a macroblock which has been encoded with high efficiency is first recorded in a corresponding compressed block from visually important data. The surplus data that could not be recorded in the corresponding compressed block in each macroblock is recorded in a recording block having a gap in another recording block. In this way, the entire recording area in the recording block prepared for the first frame is used. If the data of the first frame still remains after the recording in the recording block is completed, the data is recorded in a recording area other than the recording block.

Next, the video information of the second frame input from the input unit 9 is input to the high-efficiency encoding unit 12. At the same time, the input video information of the second frame is stored in the frame RAM 1
The difference from the video information of the previous frame output from 0 is calculated by the differentiator 11 and input to the high-efficiency encoding unit 11.
In the high-efficiency encoding unit 12, the video information of the second frame and
Either one of the difference information between the second frame and the first frame is selected and subjected to high efficiency coding.

The highly efficient encoded video information of the second frame is recorded on the magnetic tape 16 by the second frame recording section 14 based on the recording format. The data of the second frame is sequentially recorded in the remaining recording area where the first frame is recorded.

FIG. 4 is an explanatory diagram of a recording format according to the second invention. FIG. 4 shows a format for recording two consecutive frames of data on ten tracks on a magnetic tape. In FIG. 4, the first five tracks of the ten tracks are used for the recording block for the first frame, and the latter five tracks are used for the recording areas of the first frame data and the second frame data that could not be recorded in the recording block. Used. As the recording block, a block formed by dividing each track into 135 is used.

With such a configuration, the visually important data of the first frame is recorded in the fixed recording block, so that the influence of the transmission path error can be minimized. Also, since the data of the first frame can be reproduced independently in recording block units, the VT
High-speed reproduction of R is also possible.

Further, in the configuration shown in FIG. 4, it is possible to record information of one frame, which is highly efficient coded only with intra-frame information, in a recording block of five tracks. Therefore, when reducing the circuit scale of the high-efficiency coding, it becomes possible to perform the high-efficiency coding on all the frames within the frame and to allocate the tracks by 5 tracks. As described above, in the configuration of FIG. 4, any five tracks can be assigned to a recording block. Therefore, even when high-efficiency encoding in units of two frames is used, compression in units of one frame can be performed.

Also, in the embodiment of FIG.
Although a macro block is recorded and 10 frames are used in 2 frames, it is also possible to record 1 macro block in a recording block and record using 10 tracks in 1 frame. Also in this case, all frames are compressed using information only in the frames. However, in this case, the compression ratio is reduced to half that of the embodiment of FIG. Further, in FIG. 4, two frames are recorded on ten tracks, but other configurations are also possible.

As described above, the first and second inventions have been described using the embodiments. However, these inventions can be applied to video signals other than 525 TV signals, and various high-efficiency coding methods can be applied. is there. It is also possible to use a motion compensation technique with the above-mentioned inter-frame difference. Further, the present invention can be realized by a configuration other than the above-described embodiment, and the same function can be realized by software.

[0035]

As described above, in the recording apparatus according to the first aspect of the present invention, the data of n compressed blocks, which are highly efficient coded only with the data in the frame within the L tracks, are fixed n data.
Since the n recording blocks are recorded in a plurality of recording blocks, if the n recording blocks are reproduced so as to be sequentially scanned at the time of high-speed reproduction, it is possible to sequentially reproduce the reproduction data constituted only in the frame. As a result, a smooth reproduced image can be reproduced even during high-speed reproduction. In addition, even when a transmission path error occurs and the code synchronization of the variable length coding is lost, the variable length coding is reset in the above n recording blocks, so that there is no influence of the error. As described above, according to the first aspect, it is possible to minimize the influence of a transmission path error on data constituted only in a frame important for reproduction.

In the recording apparatus according to the second aspect of the present invention, in the recording method for performing the high-efficiency encoding within two frames, the highly-encoded information within the frame is used to record data for two frames. Since recording is performed preferentially on the first n tracks of the 2n tracks, high-speed reproduction and correction at the time of a transmission path error can be performed as in the first invention. Further, in the second invention, since most of the information of the first frame can be reproduced only by the first n tracks, the second n tracks (first
New video information can be recorded from the data of a part of the frame and the data of the second frame. As a result, despite the two-frame compression, 1
Editing on a frame basis is also possible.

According to the first and second aspects of the present invention, all frames can be highly efficiently coded using substantially the same recording format using information only in the frames, so that the circuit scale can be reduced. . However, in this case, the compression ratio may decrease.

According to the present invention, the coding efficiency of high-efficiency coding is not degraded at all, and the disadvantage of high-efficiency coding between a plurality of frames can be solved with a relatively simple configuration. The effect is very large.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment according to a recording apparatus of the first invention.

FIG. 2 is an explanatory diagram of a recording format according to the recording apparatus of the first invention.

FIG. 3 is a block diagram of one embodiment according to the recording apparatus of the second invention;

FIG. 4 is an explanatory diagram of a recording format according to the recording apparatus of the second invention.

[Explanation of symbols]

 2, 10 frame RAM 3, 11 differentiator 4, 12 high efficiency coding unit 5, 13 first frame recording unit 6 i-th frame recording unit 14 second frame recording unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/782 H04N 5/91-5/956 H04N ^7/ 24-7/68

Claims (3)

(57) [Claims] An input moving image signal is represented by K (K is 2 or more).
Natural number) collected frames, in the K above with high-efficiency encoding on a frame basis has been high-efficiency encoding of the K frames data L (L is a recording apparatus for recording by dividing into two or more natural number) tracks A predetermined file in the K frame.
A frame is defined as a first frame, and
There are the highly efficient coding using only information within the frame,
For K-1 frames other than the first frame,
It has a high-efficiency encoding means for high-efficiency encoding using the information between over arm or in the frame, the high efficiency coding means before
The information of the serial first frame when high-efficiency encoding, block for dividing data of one frame into n compression blocks
And means, the L to a specific position in a track constitutes the n recording blocks so as to correspond to each of the n compression blocks and the block is first high efficiency encoding by the high efficiency coding means the data of the compressed block of the first frame is recorded in the corresponding recording block, then the encoded data overflowing from the recording blocks corresponding still empty after recorded data in the compressed block of the first frame When the data of the compressed block corresponding to the first frame having a space is recorded in the recording block corresponding to the first frame and the remaining data of the compressed block for the first frame remains even after all the recording blocks are filled, the L track of the L track is used. After recording the data of the remaining compressed block in a portion other than the n recording blocks, and finally recording the remaining compressed data on the L track, Tsu part in other than the first frame
A recording apparatus for recording information on a K-1 frame after encoding it with high efficiency. 2. The recording apparatus according to claim 1, wherein n recording blocks are concentrated on the first half of the L tracks. 3. A process according to claim 1 K is which is a 2
The recording device as described in the above .