JPH05292458A - Video signal store and reproducing device for stored media - Google Patents

Abstract

PURPOSE:To perform normal reproducing and special reproducing by generating the two kinds of coded data in the case of coding image signals, storing those data in a write/read enabling stored medium such as an HDD (hard disk) or the like and selecting which coded data are read in the case of reading them from the stored medium. CONSTITUTION:For the image signals inputted to an input terminal 1, coded data for normal reproducing are generated by a discrete cosine transformation (DCT) part 3, quantizing part 4 and variable length encoding part 5 and stored in a storage medium 14. Coded data for special reproducing are sub-sampled by a spatial filter 10, generated by a DCT part 11, quantizing part 12 and variable length encoding part 13 while reducing the number of picture elements into 1/4, and stored in the storing medium 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal accumulating / reproducing apparatus capable of performing special reproduction when a video signal is encoded, accumulated in a storage medium and reproduced.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open No. 2-295287 discloses a method of decoding accumulated video coded data and performing high speed reproduction or high speed reverse reproduction. This is because when a frame is coded, the frame is composed of general image data (reduced data) and difference data, coded and stored. At the time of decoding (reproduction), it has a step means to the position to be decoded, and at the time of high speed reproduction, skips to the position of the frame to be reproduced and decodes only the schematic image data (reduced data) to perform high speed reproduction or high speed reverse reproduction. You can do things.

Next, the operation will be described. 3 is a block diagram showing a conventional example, FIG. 4 is an example of a coded data string when hierarchical intraframe coding of the conventional example is performed, and FIG. 5 is a block diagram for implementing the conventional coding method. 6 shows an example of encoded data according to the encoding method of FIG. 5, and FIG. 7 shows an example of a configuration for implementing a decoding method corresponding to the encoding method of FIG.

In FIG. 3, 22 is an input terminal, 23 is an encoding device, 24 is an image storage device, 25 is a decoding device, and 26 is an output terminal. The image input from the input terminal 22 is hierarchically encoded by the encoding device 23 and stored in the image storage device 24. At the time of reproduction, the image stored in the image storage device 24 is decoded by the decoding device 25 and output through the output terminal 26.

FIG. 4 is a basic conceptual diagram showing an example of a coded data string when hierarchical intra-frame coding is applied, and the head data of each frame is a minimum reading unit such as a CD. Is at the beginning of the track. Of the intra-frame coded data A1, only the part of the data a1 representing the schematic image is decoded, and subsequently, the part of the data a2 of the next intra-frame coded data A2 is decoded. (High-speed forward reproduction →→ ○ 3 in FIG. 4) If the data reading speed is constant and the skip time is sufficiently small, only a1 part, which is a very small amount of data, is read compared to reading all data A1. Therefore, a general image of several frames can be obtained at the time of decoding one frame for normal reproduction. Reverse reproduction can be realized by decoding a1 and then skipping in the reverse direction (high-speed reverse reproduction ◯ 1 → ○ 2 → ○ 3 in FIG. 4).

FIG. 5 shows an example of the structure for implementing the encoding method. In the figure, 27 is a low-pass filter (Fi).
l), 28 is a sub-sample unit (↓), 29 is a discrete cosine transform unit (DCT), 30 is a quantizer (Q), 31 is a variable length coding unit (VLC), 32 is a quantization controller,
Reference numeral 33 is an inverse quantization unit (Q ^-1 ), 34 is an inverse discrete cosine transform unit (IDCT), 35 is an interpolation enlargement unit (INTP), 36
Is a subtraction unit (-), 37 is a discrete cosine transform unit (DC
T), 38 is a quantization unit (Q), 39 is a variable length coding unit (VLC), 40 is a quantization controller, 41 is an inverse quantization unit (Q ^-1 ), and 42 is an inverse discrete cosine transform (IDC).
T), 43 is an addition unit (+), 44 is a frame memory (FM), 45 is a motion compensation processing unit (MC), 46 is a variable length coding unit (VLC), S5 and S6 are in-frame and in-frame This is an interlocking switch for switching inter-coding. Others are the same as those having the same reference numerals in FIG.

Next, the operation will be described. The video signal is input from the input terminal 22 and is input to the low pass filter 27 at the time of intraframe coding. The signal from which the high frequency components have been removed is subsampled in the horizontal and vertical directions by the subsampling unit and is discrete cosine transformed by the discrete cosine transform unit 29. The transform coefficient is quantized by the quantizing unit 30, variable-length coded by the variable-length coding unit 31, and then stored in the image storage device 24. In the case of quantization and variable length coding, the quantization controller 3 keeps the code amount constant for each frame.
The quantization step width is defined by 2 and used. The step size used is also coded as it is needed for decoding.

The signal quantized by the quantizer 30 is inversely quantized by the inverse quantizer 33, and the inverse discrete cosine transform unit 34.
Inverse discrete cosine transform is performed to obtain a decoded reduced image. The decoded reduced image is interpolated and enlarged by the interpolating and enlarging unit 35 to become a roughly decoded image, and the subtraction unit 36 obtains the difference from the original image. The differential image is discrete cosine transformed by the discrete cosine transform unit 37, quantized by the quantization unit 38, variable length coded by the variable length coding unit 39, and then stored in the image storage device 24. At that time, the quantization step is determined by the quantization controller 40 so that the predetermined data amount is obtained, and the used quantization step is also encoded. The signal quantized by the quantization unit 38 is inversely quantized by the inverse quantization unit 41, and inverse discrete cosine transform is performed by the inverse discrete cosine transform unit 42 to form a decoded difference image. The decoded difference image becomes a decoded image added to the rough decoded image by the adder 43. Since the decoded image is used for interframe coding of the next frame, the frame memory 44
Stored in.

At the time of inter-frame coding, the motion compensation processing unit 45 performs motion compensation processing between the decoded image of the previous frame stored in the frame memory 44 and the original image,
A motion prediction image is generated. The subtraction unit 36 subtracts the difference between the original image and the motion prediction image to form a motion difference image. The motion difference image is discrete cosine transformed by the discrete cosine transform unit 37, quantized by the quantization unit 38, and variable length coded by the variable length coding unit 39. At that time, the quantization step is determined by the quantization controller 40 so that the predetermined data amount is obtained, and the used quantization step is also encoded. The quantized signal is inversely quantized by the inverse quantization unit 41, and inverse discrete cosine transform is performed by the inverse discrete cosine transform unit 42 to obtain a decoded motion difference image. The decoded motion difference image is a decoded image added to the motion prediction image by the adder 43. The decoded image is stored in the frame memory 44 because it is used for interframe coding of the next frame. Since the motion vector used in the motion compensation processing is used in the decoder, it is variable-length coded in the variable-length encoder 46 and then stored in the image storage device 24.

FIG. 6 shows an example of image coded data when intra-frame coding is performed once every three frames by the coding method of FIG. For example, if the code amount in the intra-frame portion is four times as large as that in the inter-frame portion, 1/2 of the data in the frame is assigned to the reduced image encoding, and the rest to the differential signal encoding. If it is allocated, the code amount of the reduced image becomes 1/3 of the sum of the code amounts of three frames, and if only the encoded data portion of the reduced image is skipped, triple speed high-speed reproduction becomes possible.

FIG. 7 shows an example of the structure for realizing a decoding method for the encoding method of FIG. In the figure, 47 is a coded data reading unit (READ), 48 is a read controller (CONT), and 49 is a variable length decoding unit (VLC).
D), 50 is an inverse quantization unit (Q ^-1 ), 51 is an inverse discrete cosine transform unit (IDCT), and 52 is an interpolation enlargement unit (INT).
P), 53 is an addition unit (+), 54 is a frame memory (FM), 55 is a motion compensation processing unit (MC), S7, S
8 and S9 are interlocking switches which interlock in the direction a or b. Others are the same as those having the same reference numerals in FIG.

The operation of FIG. 7 will be described. The encoded data reading unit 47 reads the encoded data stored in the image storage device 24. At this time, the memory address to be read is controlled by the read controller 48, and in the normal reproduction, it follows the order of the data series, and in the high-speed reproduction, it skips to the head position of the hierarchical coding portion in each frame, and codes the reduced image. Control to read only the encoded data. The data read by the encoded data reading unit 47 is decoded by the variable length decoding unit 49, and then the transform coefficient portion is returned to the image signal by the inverse quantization unit 50 and the inverse discrete cosine transform 51. Further, of the output of the variable length decoding unit 49, the portion related to the quantization step width is sent to the inverse quantization unit 50, and the portion related to the motion vector is sent to the motion compensation processing unit 55. Inverse discrete cosine section 51
If the output of is a decoded reduced image, the interlock switch S7,
S8 and S9 are tilted in the a direction, enlarged by the interpolating and enlarging section 52, and sent to the frame memory 33 as they are. During high speed reproduction, the decoded reduced image is output from the output terminal 26 to reproduce the image. At the time of normal reproduction, the encoded data for the difference image and the motion difference image is also decoded, and when the output of the inverse discrete cosine unit 51 is the decoded difference data, the addition unit 53 displays the image reduced screen stored in the frame memory 54. And the decoded image is generated. When the output of the inverse discrete cosine transform unit 51 is the decoded motion difference signal, the interlocked switches S7, S8, S9 are tilted in the b direction, and the motion compensation processing unit 55 displays the decoded image of the previous frame stored in the frame memory. The sum of the motion predicted image generated by rearranging the motion vectors according to the motion vector is obtained, and the sum is output from the output terminal 5 as a reproduced image.

[0013]

In the prior art, since the frame encoded by the hierarchical encoding is intra-frame encoded, the high efficiency encoding method cannot be used. In addition, when the inter-frame coding method is used to improve efficiency, the frame cannot be hierarchically coded and therefore cannot be used for high-speed reproduction or high-speed reverse reproduction.

The present invention has been made in order to solve the above-mentioned problems, and by preparing two kinds of encoded data for normal reproduction and special reproduction, the encoding for normal reproduction is improved. An object of the present invention is to obtain a video signal storage / playback device for storage media that can perform efficient coding and that can perform high-speed playback at variable speed and high-speed reverse playback.

[0015]

According to a first aspect of the present invention, there is provided a video signal storing / reproducing apparatus for a storage medium, wherein the video signal storing / reproducing apparatus includes a writable and readable storage medium.
There is provided encoded data generating means for generating two types of encoded data of forward variable speed reproduction and backward variable speed reproduction when the video signal is encoded, and the storage medium is generated by the encoded data generating means. It stores the two types of encoded data.

According to a second aspect of the present invention, there is provided a video signal storage / playback apparatus for storage media, wherein the video signal storage / playback apparatus is provided with a writable / readable storage medium, and a request is issued when coded data is read from the storage medium and decoded. According to the present invention, there is provided means for performing forward variable speed reproduction or reverse variable speed reproduction by decoding one of two types of encoded data of forward variable speed reproduction and reverse variable speed reproduction.

[0017]

According to the first aspect of the present invention, the storage medium video signal storage / playback apparatus generates coded data by using two types of coding methods for the same input signal and stores the coded data in the storage medium.

According to a second aspect of the present invention, there is provided a video signal storing / reproducing apparatus for a storage medium, which reads out one of two types of coded data stored in the storage medium according to a request, and performs forward variable speed reproduction or reverse direction variable reproduction. Perform speed playback.

[0019]

EXAMPLES Example 1. FIG. 1 is a block diagram showing an embodiment of a video signal storage device of the present invention, in which 1 is an input terminal, 2 is a subtraction unit (-), and 3 is a discrete cosine transform unit (D).
CT), 4 is a quantizer (Q), 5 is a variable length encoder (V
LC), 6 is an inverse quantizer (Q ⁻¹ ), 7 is an inverse discrete cosine transform (IDCT), 8 is an adder (+), 9 is a frame memory (FM), and 10 is a spatial filter (FIL). ), 1
Reference numeral 1 is a discrete cosine transform unit (DCT), 12 is a quantization unit (Q), 13 is a variable length decoding unit (VLC), 14 is a storage medium, and S1 is a switch for switching between intraframe coding and interframe coding. is there.

Next, the operation will be described. 1. Regarding generation of encoded data for normal reproduction, the image signal input from the input terminal 1 is subjected to intraframe encoding with the frame memory 9 when performing interframe encoding at S1 in the subtraction unit 2. Takes the difference from "0",
Difference data is generated. Discrete cosine transform unit 3 generates the discrete cosine transform coefficient for the difference data. The discrete cosine transform coefficient is quantized by the quantization unit 4, converted into a variable length code by the variable length coding unit 5, and the variable length data is stored in the storage medium 14. In addition, the quantized data generated by the quantizer 4 is inversely quantized by the inverse quantizer 6 to obtain a difference in the next frame, inversely discrete cosine transformed by the inverse discrete cosine transformer 7, and added by the adder. 8 in frame memory 9
The present frame data is stored in the frame memory 9 again by taking the sum with the previous frame data stored in. Here, the interframe difference + discrete cosine transform is used as the encoding method, but another high efficiency encoding method may be used.

2. Regarding the generation of special reproduction coded data, the image signal input from the input terminal 1 is subjected to horizontal and vertical sub-sampling by the spatial filter 10 to reduce the number of pixels to 1/4 and reduce the amount of information. A discrete cosine transform coefficient is generated from the output of the spatial filter 10 by the discrete cosine transform unit 11. The discrete cosine transform coefficient is quantized by the quantizer 12, converted into a variable length code by the variable length coding unit 13, and the variable length data is stored in the storage medium 14. Here, in order to reduce the amount of information, sub-sampling is performed to reduce the number of pixels to 1/4, but sub-sampling may not be performed depending on the required image quality, or the reduction amount may be 1/4 or more.

By storing the above-mentioned two types of encoded data in the storage medium 14 which can be accessed the same or simultaneously, a video signal storage device for storage medium can be constructed.

Example 2. 2 is a block diagram showing another embodiment of the video signal reproducing apparatus of the present invention. In FIG.
Is a storage medium, 15 is a variable length decoding unit (VLD), 1
6 is an inverse quantizer (Q ⁻¹ ), 17 is an inverse discrete cosine transform (IDCT), 18 is an adder (+), 19 is a frame memory (FM), 20 is a spatial filter (FIL), 21
Is an output terminal, S2 and S3 are switches for switching between normal reproduction and special reproduction, and S4 is a switch for switching between intraframe encoding and interframe encoding during normal reproduction.

Next, the operation will be described. 1. The reproduction method during normal reproduction, S2 and S3, is set to a (normal reproduction). The normal reproduction coded data is continuously read from the storage medium 14 in the order in which they are stored,
The variable length decoding unit 15 decodes it, the inverse quantization unit 16 performs inverse quantization, and the inverse discrete cosine transformation unit 17 performs inverse cosine transformation. The transform coefficient is added by the adder unit 18 to the data in the frame memory 19 when the coded data is interframe coded and "0" when the coded data is intraframe coded, and is output from the output terminal 21. To be done.

2. The reproduction method during special reproduction, S2 and S3, is set to b (special reproduction). The special reproduction coded data is read from the storage medium 14, decoded by the variable length decoding unit 15, dequantized by the inverse quantization unit 16, and inverse cosine transformed by the inverse discrete cosine transform unit 17. Since the special reproduction coded data is intra-frame coded data, the conversion coefficient is added to "0" by the adder 18 to generate a decoded screen. Pixels are interpolated by the spatial filter 20 that performs sub-sampling at the time of encoding to reduce the pixels to 1/4, and the output terminal 2
It is output from 1.

When the special reproduction is read out, if the encoded data is continuously read out in the order in which they are stored, the image quality deteriorates as compared with the normal reproduction, but the normal reproduction can be performed. Further, if reading is performed for each frame in the order of writing, double speed reproduction in the forward direction can be performed, and if reading for each frame is opposite to the order of writing, double speed reproduction in the reverse direction can be performed. By changing the reading order in this way, it becomes possible to perform forward and backward reproduction at a variable speed.

If the relation between the normal reproduction coded data and the special reproduction coded data is known, the normal reproduction is performed halfway and the forward double speed reproduction is performed to find the necessary screen. , It is possible to perform the reproduction that returns to the normal reproduction.

If dedicated reproducing devices are prepared for normal reproduction and special reproduction, respectively, special reproduction is performed during normal reproduction to find a necessary scene in advance, and two kinds of reproduced images are reproduced. It is also possible to combine them and display them on one display.

[0029]

The present invention has the following effects. The video signal storage / playback apparatus for storage media according to claim 1, wherein the video signal storage / playback apparatus is provided with a writable and readable storage medium, when the video signal is encoded, the forward variable speed playback and the backward variable speed playback are performed. The storage medium is provided with encoded data generating means for generating two types of encoded data, and the storage medium is configured to store the two types of encoded data generated by the encoded data generating means. Encoding can be performed.

According to another aspect of the present invention, there is provided a video signal storage / playback apparatus for storage media, wherein the video signal storage / playback apparatus is provided with a writable and readable storage medium, and when the encoded data is read from the storage media and decoded, According to the configuration, a unit for performing forward variable speed reproduction or reverse variable speed reproduction is provided by decoding one of the two types of encoded data of forward variable speed reproduction and reverse variable speed reproduction. Two types of encoded data are read out from the storage medium as necessary and reproduced, so that forward variable speed reproduction and reverse variable speed reproduction can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a video storage / playback apparatus for storage media according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a video storage / playback apparatus for storage media according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional example.

FIG. 4 is a diagram showing an example of a coded data string in the case of performing hierarchical intraframe coding in the conventional example.

FIG. 5 is a configuration diagram for implementing a conventional encoding method.

FIG. 6 is a diagram showing an example of encoded data according to the encoding method of FIG. 5 of a conventional example.

7 is a configuration diagram for implementing a decoding method corresponding to the encoding method of FIG. 5 of the conventional example.

[Explanation of symbols]

1 Input Terminal 2 Subtractor 3 Discrete Cosine Transform 4 Quantizer 5 Variable Length Coding 6 Inverse Quantizer 7 Inverse Discrete Cosine Transform 8 Adder 9 Frame Memory 10 Spatial Filter 11 Discrete Cosine Transform 12 Quantizer 13 variable-length coding unit 14 storage medium 15 variable-length decoding unit 16 inverse quantization unit 17 inverse discrete cosine transform unit 18 adder unit 19 frame memory 20 spatial filter 21 output terminal S1 switching between intraframe coding and interframe coding Switch S2 Switch for switching between normal playback and special playback S3 Switch for switching between normal playback and special playback S4 Switch for switching between intraframe coding and interframe coding

Claims (2)

[Claims] 1. A video signal storage / reproduction device equipped with a writable and readable storage medium, when encoding a video signal, two kinds of encoded data of forward variable speed reproduction and reverse variable speed reproduction are provided. A video signal storing / reproducing apparatus for a storage medium, comprising: encoded data generating means for generating; wherein the storage medium stores two types of encoded data generated by the encoded data generating means. 2. A video signal storage / reproduction device equipped with a writable and readable storage medium, in which forward variable speed reproduction and reverse variable speed reproduction are performed in response to a request when reading and decoding encoded data from the storage medium. Play 2
A video signal storage / playback apparatus for storage media, characterized by comprising a procedure of performing forward variable speed playback or reverse variable speed playback by decoding any one of encoded data of different types.