JP2755116C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk for recording or reproducing data obtained by band-compressing a digitized video signal in each sector. 2. Description of the Related Art When recording and reproducing a moving image signal as digital data on an optical disk, it is very difficult to record and reproduce in real time because the amount of information is very large. For example, an NTSC composite signal is sampled at a sampling frequency of 4 fsc (
When fsc is quantized with 8 bits (color subcarrier frequency), a transfer rate of about 120 Mbps is required. However, it is technically very difficult to realize a recording / reproducing system that achieves a transfer rate of 120 Mbps, depending on the characteristics between the optical disk and the recording / reproducing head and the operating performance of the electric circuit system. Therefore, when recording and reproducing information at a high transfer rate on an optical disk, the processing speed in one processing system is reduced by using a plurality of recording / reproducing heads and a plurality of electric circuits, so that the entire apparatus can be processed in real time. Processing was possible. However, even if the real-time processing is enabled as described above, the recording and reproducing time is constant as long as the total capacity of the optical disk does not change. Therefore, in a device for recording or reproducing a digitized moving image signal, the moving image signal is compression-encoded to such an extent that the information of the original signal is not conspicuously degraded, recorded on an optical disk, and decoded during reproduction. A method has been considered in which a recording process is performed to facilitate real-time processing of recording and reproduction, and at the same time, to lengthen the recording and reproduction. As a compression encoding method, data of several frames (or fields) is stored in one frame.
One group (group), at least one frame (or field) of data is subjected to compression coding in a frame (or field) with a relatively low compression ratio, and the remaining frames (or fields) are compared. Compression coding between frames (or between fields) having a high dynamic compression ratio. By combining the intra-frame and inter-frame (or intra-field and inter-field) compression encoding processing in this manner, it is possible to improve the overall compression ratio and relatively suppress image degradation. When recording or reproducing the compressed and encoded data on an optical disk, a single recording / reproducing processing system is used to compress and encode the compressed and encoded data within the frame (or within the field) and between the frame (or between the fields). ), The data encoded by compression is arranged in chronological order, the compressed encoded data is divided into sectors each having a fixed capacity, and recording and reproduction are performed while recognizing the addresses of the sectors. [0006] However, in the above-mentioned conventional recording or reproducing method, for example, when performing special reproduction for reproducing only the compression-coded data in a frame (or in a field) at the time of reproduction, it is difficult to perform special reproduction in the frame. It is necessary to provide a correspondence table indicating in which sector the compression-encoded data is recorded (or in the field). Conventionally, the correspondence table is stored in an area on the optical disc which is different from the area where the compression-encoded data is recorded and in another area. I was recording. [0007] For this reason, the recording cannot be performed simultaneously with the recording of the compression-encoded data, and must be recorded in another area on the optical disk after the recording of the compression-encoded data is completed. There has been a problem that a correspondence table cannot be created, for example, when the power of the recording / reproducing apparatus itself has been turned off. The present invention solves the above-mentioned drawbacks, and creates a correspondence table indicating in which sector the in-frame (or in-field) compression-encoded data is recorded when the recording / reproducing apparatus or the optical disk is inconvenient. It is an object of the present invention to provide an optical disk capable of performing special reproduction for reproducing only compression-encoded data in a frame (or in a field) by solving the problem that the optical disc cannot be reproduced. [0009] To achieve this object, the present invention provides a method for transmitting an image in a frame.
(Or in the field) At least several groups of sector addresses in which the head data and the last data of the compression-encoded data are stored are grouped into another sector existing in the same area as the sector in which the compression-encoded data is recorded. The configuration is recorded as needed. [0010] Alternatively, the addresses of the sectors in which the start addresses and the end addresses of the data of the compression-encoded data in the frame (or in the field) for several groups are stored are collected together to form another address. This is a configuration recorded in a sector. The present invention recognizes in which sector compression-coded data in a frame (or in a field) exists by reproducing the sector recorded in this manner, and based on that data, the frame This makes it possible to reproduce only the compression-encoded data within (or within the field). An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a format of an optical disc in which one sector for recording a sector address in which head data and last data of intra-frame coded data are stored for every n groups in one embodiment of the present invention. FIG. 2 shows a sequence of six consecutive image frames according to one embodiment of the present invention.
The first and seventh frames of the first frame are set as intra-frame compression-coded frames, and the second, third, fifth, and sixth (8, 9, 11, 12) frames are bidirectionally predicted inter-frame compression codes. FIG. 10 is a schematic diagram showing that a modified frame and a fourth (10) frame are set as compression frames between forward prediction frames. FIG. 3 is a schematic block diagram of a compressed image reproducing apparatus according to one embodiment of the present invention. As shown in FIG. 1, A1, A2,..., An and B1, B2,.
, Bn and C1, C2,..., Cn are one group including the compression-coded data of the intra-frame compression-coded frame, the bidirectionally predicted inter-frame compression-coded frame, and the forward predicted inter-frame compression-coded frame, respectively. It is. The sector addresses at which the first data and the last data of the intra-frame coded data of each group are stored in sectors a, b, and c. That is,
The sector addresses where the first data and the last data of the intra-frame encoded data indicated by the group B1 are stored are x1 and xm, respectively. As shown in FIG. 3, the optical disc 1 is read by the optical pickup 2 during reproduction.
The signal reproduced from is transmitted to the reproduction processor 3 and subjected to processes such as binarization, digital demodulation and error correction. As for the data processed by the reproduction processor 3, only the compression-encoded data is sent to the reception buffer 4. For example, consider the case of reproducing only the intra-frame encoded data of the optical disk 1 of FIG. 3 recorded in the format shown in FIG. 1 during the special reproduction in which only the intra-frame compressed encoded data is reproduced. If the optical pickup 2 reproduces a sector on the optical disc 1 in FIG. 3, for example, the sector b in FIG. 1, the groups B1, B2,.
The sector address where the first data and the last data of the intra-frame coded data in Bn exist can be known. Therefore, the reproduction is sequentially performed from the x1 sector in the group B1, and when the reproduction is completed up to the xm sector in which the last data of the intra-frame coded data is present, the sector in which the head of the intra-frame coded data of the group B2 exists is known in advance. Therefore, the optical pickup 2 is moved to the sector. Thereafter, by performing the same operation up to the groups B3, B4,..., Bn, it is possible to continue to reproduce only the intra-frame encoded data. When the operation up to the group Bn is completed, if the c sector is reproduced next, the groups C1, C2,.
, Cn, the start address and the end address of the intra-frame encoded data are located. If the same operation is continued thereafter, it is possible to continuously reproduce only the intra-frame encoded data. The intra-frame coded data is sent from the reception buffer 4 to the compression / decoding processor 5. The image signal data decoded by the compression decoder 5 based on the transmitted data is sent to the frame memory 6 and then transferred from the frame memory 6 at a constant transfer rate to Y, U, V. The signals are read out in synchronization with the signals, and are output to the outside as analog image signals through the D / A converters 7, 8, and 9. The reading speed is A at the time of recording.
The Y signal is 13.5 MHz and the U and V signals are 6
. 75 MHz. In some cases, data read from the frame memory 6 is directly output to the outside as digital data. It should be noted that the processing in units of frames of the image may be performed in units of fields. The addresses of the sectors a, b, and c in which the start addresses and the end addresses of the end data of the compression-encoded data in the frame (or in the field) for several groups are collectively recorded. Further, the configuration may be such that the information is collectively recorded in another sector. As described above, according to the present invention, at least several groups of sector addresses storing the first data and the last data of compression-encoded data within a frame (or within a field) are grouped together and compressed. Since it is recorded as needed in another sector in the same area as the area where the encoded data is recorded, it is possible to record the encoded data without accessing another area while recording the compressed encoded data. The correspondence table can be recorded at any time, and there is no possibility that the correspondence table cannot be created at all, such as when the power of the recording / reproducing apparatus itself is turned off due to some inconvenience during data recording. It is possible to reliably recognize the sector address where the compression-encoded data exists (in the field), and within the frame (or Special reproduction, such as high-speed reproduction, in which only the compression-encoded data (in the field) is reproduced, is reliably realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an optical disc in which one sector for recording a sector address for storing head data and last data of intra-frame encoded data is provided for each n groups in one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a format.
The frames are intra-frame compression-coded frames, the fourth and tenth frames are compression-coded frames between forward prediction frames, the second, third, fifth, sixth and eighth, nine, eleven, and twelve.
FIG. 3 is a schematic diagram showing that a frame is a bidirectionally predicted inter-frame compression encoded frame. FIG. 3 is a schematic block diagram of a reproducing apparatus according to an embodiment of the present invention. Buffer 5 Compression decoder 6 Frame memory 7, 8, 9 D / A converter

Claims (1)

1. An optical disk having a sector structure and storing image signals, wherein the image signals are grouped by collecting a plurality of continuous image frames or field signals into a plurality of frames or a plurality of fields. A first image signal obtained by band-compressing at least one frame or one of the grouped image frames or fields by an intra-frame or intra-field compression encoding method;
The remaining grouped frames or fields are composed of a second image signal which is band-compressed by an inter-frame or inter-field compression encoding method using a time axis correlation, and the first image signal is stored. Combining sector location information for multiple groups
A plurality of groups of stored sectors are used for the first image signal and the second image signal.
An optical disc, which is provided adjacent to a sector for storing the data . 2. The position information of the sector in which the first image signal is stored is the position information of the sector in which the first data of the first image signal is stored and the position information of the sector in which the last data is stored. And at least one of them.
An optical disc as described. 3. The system according to claim 1, wherein a plurality of pieces of sector position information in which the position information of the sector in which the first image signal is stored are collectively stored for a plurality of groups are stored. Optical disk.