JP3381630B2 - Data generation method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data generation method.
Especially for special reproduction of encoded data to be recorded.
Generate and record trick play information data, and record
Real-time recording of power coded data
A data generation method for causing the 2. Description of the Related Art An MPEG (Moving Picture Experts Group) is an international standard for compressing and encoding a video signal of a moving image and an audio signal related thereto. This MPEG was adopted in 1988 by the ISO / IEC
This is an abbreviation of the name of the organization that considers the moving picture coding standard established in JTC1 / SC2 (International Organization for Standardization / International Electrotechnical Commission Meeting Technical Committee 1 / Special Committee 2, current SC29). [0003] MPEG1 (MPEG phase 1)
A standard for storage media of about 1.5 Mbps, JPEG for the purpose of still image coding, and ISDN
H.264 for video compression for low transfer rates of video conferencing and video telephony of (Service Integrated Digital Network). 26
1 (CCITT SGXV, current ITU-T SG1
5 standardized) and introduced a new technology for storage media. These are 199
It was enacted as ISO / IEC 11172 in August 3rd. MPEG2 (MPEG Phase 2) is an ISO / IEC standard in November 1994 for the purpose of a general-purpose standard that can support various applications such as communication and broadcasting.
13818; 262. FIG. 4 is a block diagram of an example of a conventional encoding device using such MPEG, and FIG. 5 is a block diagram of an example of a decoding device. First, the encoding apparatus shown in FIG. 4 will be described. A video signal composed of a luminance signal and a chrominance signal is digitized and then rearranged according to a picture type.
Input to 0. This input image data is subtracted from the motion-compensated and predicted image data from the motion-compensated predictor 12 by the subtracter 11 to obtain differential image data with reduced temporal redundancy. [0005] There are three modes of the above prediction, the past, the future, and both. In addition, these are 16
Pixels can be switched and used in units of 16 × 16 macroblocks (MB), which are 16 pixels in the horizontal direction. The prediction direction is determined by the picture type given to the input image data. P-pictures have two modes of prediction from the past and independent encoding of the MB without prediction. B-pictures have four modes for prediction from the future, prediction from the past, prediction from both, and independent encoding. Then, it is the I picture that independently encodes all MBs. In the above-described motion compensation, the motion area is subjected to pattern matching for each MB, a motion vector is detected with half-pel accuracy, and the motion vector is predicted by shifting by the motion. The motion vector has a horizontal direction and a vertical direction, and is transmitted as additional information of the MB together with an MC (Motion Compensation) mode indicating where to predict the motion vector. A group of pictures (GOP) from an I-picture to a picture before the next I-picture is used, and when used in a storage medium or the like, about 15 pictures (frames) are generally used. In the case of an I picture, input image data is taken out as it is from the subtracter 11, and in the case of a P picture or a B picture, motion compensated difference image data is taken out and supplied to a DCT unit 13. Here, discrete cosine transform (DCT: Discrete Cosine Transform) is performed. This DCT is an orthogonal transform that discretely transforms an integral transform using a cosine function as an integral kernel into a finite space. In the MPEG, the MB is divided into four parts, eight pixels in the vertical direction and eight pixels in the horizontal direction.
Two-dimensional DCT is performed on the × 8 DCT block.
Generally, a video signal has many low-frequency components and few high-frequency components. Therefore, when DCT is performed, obtained coefficients are concentrated in low frequencies. [0008] DCT-processed image data (DCT coefficients)
Is supplied to a quantizer 14, where it is quantized. In this quantization, a value obtained by multiplying an 8 × 8 two-dimensional frequency called a quantization matrix by a visual characteristic and a value obtained by multiplying the whole by a value called a quantization scale for multiplying the whole by a scalar is used as a quantization width. This is performed by dividing by the quantization width. The quantized DCT coefficients are supplied to a variable length coder (VLC unit) 19 together with a motion vector from the motion compensation predictor 12 and a prediction mode indicating where to start prediction, and are subjected to variable length coding. . In the variable length coding, a DC (DC) component of the DCT coefficient is a DPCM (Differential Pulse Code Modulatio) which is one of predictive codings.
n), the alternating current (AC) component of the DCT coefficient is subjected to a zigzag scan from the low band to the high band, and the number of consecutive occurrences of zero and the effective coefficient value are regarded as one event. Huffman coding in which short codes are assigned is performed. The variable length coded data is temporarily stored in a buffer memory 20 and then output as coded data at a predetermined transfer rate. The generated code amount of the output coded data for each macro block is supplied to a code amount controller 21, and the error code amount between the target code amount and the generated code amount is fed back to the quantizer 14 to perform quantization. The code amount is controlled by adjusting the quantization scale. On the other hand, a P picture (inter-frame forward prediction coded image) and a B picture (bidirectional prediction coded image)
Needs to be used later as a reference screen for motion compensated prediction, the information quantized by the quantizer 14 is supplied to an inverse quantizer 15 and inversely quantized by multiplying by a quantized value. Furthermore, local decoding is performed by the inverse DCT performed by the inverse DCT unit 16, the added image is added to the predicted image data from the motion compensation predictor 12 by the adder 17, and the same image as the decoder is restored. Stored. The data extracted from the image memory 18 is supplied to the motion compensation predictor 12 and used as a reference image for the next motion compensation prediction. Next, a conventional decoder will be described with reference to the block diagram of FIG. In the figure, coded data input via an input terminal 23 is subjected to variable length decoding by a VLD unit 24 and then supplied to an inverse quantizer 25, where it is multiplied by a quantization width to obtain the original data. And then supplied to the inverse DCT unit 26 to obtain the inverse DCT coefficient.
Thus, local decoding is performed. The motion vector and the prediction mode extracted from the inverse quantizer 25 are supplied to the motion compensation predictor 27 together with the decoded data from the image memory 29, and the motion compensated image data is output. Let it. The adder 28 receives the data from the inverse DCT unit 26 and the motion compensation predictor 2
7, the data equivalent to the image data input to the encoder is decoded by adding the motion-compensated image data from No. 7 and supplied to the image memory 27 as decoded data while being output to the outside. . By using the above-described MPEG data encoding and decoding methods, fast forward and rewind reproduction of recorded encoded data from an optical disk or the like on which encoded data of video and audio signals are recorded. An apparatus has been proposed which records navigation data for navigating special reproduction data and reproduces the data so that the special reproduction can be performed (Japanese Patent Laid-Open No. 8-273304).
No.). That is, according to the conventional encoding method, decoding method and apparatus described in this publication, a plurality of packetized data packs are generated by compressing reproduced data such as video signals and audio signals by the MPEG method and packetizing them. A data unit is configured in units of a data pack sequence to be reproduced within a time range, and at the beginning of the data unit, reproduction information of the data pack and navigation information describing a relationship with other data units are stored. A plurality of data units provided with navigation packs are prepared, and these data units are recorded on a recording medium in a time-sequentially reproducible manner. This is to obtain a reproduced signal by converting it into a reproduced signal. However, in the above-described conventional encoding method, decoding method and apparatus, the generation of navigation information describing the reproduction information of a data pack and the relationship with other data units is not performed. After the completion of the MPEG encoding, it is necessary to observe the encoded data and calculate the desired special reproduction information such as the code amount and so on. That is, in the above-described conventional encoding method, decoding method and apparatus, since the encoded data by MPEG is basically a variable length code, the data is observed after all the encoded data have been prepared. Since the address of the data unit is calculated, the address of the data unit cannot be calculated until all the encoded data are collected, and there is a problem that the encoded data cannot be recorded in real time. The present invention has been made in view of the above points,
For special playback for special playback of encoded data to be recorded
Generate and record information data, and encode to be recorded
To enable real-time recording of data
It is an object of the present invention to provide a data generation method. According to the present invention, there is provided an image processing apparatus comprising:
Video encoded data obtained by encoding according to the MPEG system and audio encoded data obtained by encoding audio data are packed and multiplexed based on the MPEG system to generate encoded data. Multiplexing the encoded data with one or more of the video encoded data
GOP is unitized, and the unit is sequentially united for each unit.
In one unit, a predetermined number of pictographs for one unit
The audio for a certain time equivalent to the playing time of the tea
A structure that contains coded data, each time the unit is generated, the unit size of the generated units, unit playback time, and the N from the head of the unit
(N is a natural number less than or equal to the predetermined number) The three pieces of information of the data size information up to the end of the picture are calculated from the multiplexed coded data corresponding to the unit. And a data generation method for generating special reproduction information data having two pieces of information. Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows data generation according to the present invention.
Block diagram of one embodiment of the applied encoding apparatus of an embodiment of a method, FIG. 2 is recorded is generated by the encoding device
And one decoding apparatus for reproducing data from a recording medium
FIG. 2 shows a block diagram of an embodiment . 1, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted. First, a description will be given of a data encoding method and an encoding apparatus. In FIG. 1, image data is input to an input terminal 10, and as described with reference to FIG. In the case of a P picture or B picture, motion-compensated difference image data is subjected to DCT, quantization and variable length coding, respectively, and temporarily stored in the buffer memory 20 as video coded data. The generated code amount for each is supplied to the code amount controller 21. The processing in the code amount controller 21 will be described in further detail. The generated code amount for each macroblock is
The data is supplied from the buffer memory 20 to a comparator in the code amount controller 21, where it is compared with the target code amount, and the error code amounts thereof are input to a feedback quantization determiner in the code amount controller 21. The feedback quantization determiner accumulates the input error code amount for a predetermined period, for example, and when the generated code amount is larger, sets the quantization value to be larger in proportion to the error amount, and when the target code amount is larger. The quantizer 14 is controlled by setting the quantization value small in proportion to the error amount. Thus, each picture is controlled so that the generated code amount becomes the determined target code amount. On the other hand, audio data (speech data) obtained by digitizing the audio signal is supplied to an audio encoder 31 via an input terminal 30 and is supplied to an MP3.
It is fixed-length coded by EG, AC-3, or linear pulse code modulation (PCM) without compression. The video encoded data temporarily stored in the buffer memory 20 and the audio encoded data extracted from the audio encoder 31 are supplied to a multiplexer 32,
G2 is packed based on a known standard (ISO / IEC 13818-1), further added with information such as an ID for data identification and a time stamp indicating a display time, and then multiplexed in time series. It is coded data. The multiplexed encoded data extracted from the multiplexer 32 is recorded in real time on a recording medium 38 such as an optical disk by a known recording mechanism (not shown). The multiplexed encoded data extracted from the multiplexer 32 is also supplied to a logical unit generator 33 to be converted into a logical unit. For example, video data encoded by MPEG constitutes one GOP with 15 pictures,
Assuming that the data is unitized in GOP units, the logical unitizer 33 counts the number of pictures constituting one GOP of the video coded data in the multiplexed coded data, and
The OP boundary is detected, and a reset signal is supplied to the unit reproduction time calculator 34 and the data size calculator 35 at the time of the detection. It should be noted that the unit is not limited to one GOP, and may be a fixed playback time unit (a fixed number of pictures), but the head is set to an I picture. The unit reproduction time calculator 34 calculates the time during which the logical unit is reproduced from the multiplexed coded data. The unit playback time is obtained by counting the number of display pictures of video encoded data by observing the input encoded data, and reducing the number of pictures until the reset signal is input from the logical unitizer 33 by 1 /.
It can be calculated by multiplying by 29.97 seconds. The unit playback time calculated by the unit playback time calculator 34 is stored in the information memory 36. It is also conceivable that the playback time of the unit is fixed in advance. In this case, the reproduction time does not need to be calculated, and predetermined fixed reproduction time information is stored in the information memory 36. The data size calculator 35 calculates the data size from the time interval of the reset signal from the logical unit generator 33, and configures the logical unit for each logical unit from the multiplexed encoded data. The end addresses (EA) of the I picture and the P picture are calculated. For example, as shown in FIG.
5 is the end address (1EA) of the I picture from the point of input of the reset signal, the end address (2EA) of the P picture to be input next, and all or predetermined numbers in the logical unit in the same manner. , Each time a P-picture is input, the end addresses 3EA,. . . , TEA
Are calculated respectively. The data size and end address calculated by the data size calculator 35 in this way are also supplied to the information memory 36 and temporarily stored. The unit reproduction time, end address, and unit size stored in the information memory 36 are converted into a format shown in Table 1 and are recorded as special reproduction information data on a recording medium 38 by a known recording mechanism (not shown).
It is recorded in an area different from the recording area of the multiplexed coded data. [Table 1] As shown in Table 1, the information data for special reproduction includes a unit size, a unit reproduction time, a first REF for each unit.
The (reference) image data includes a set of information EA, the second REF image EA, and the third REF image EA. These data are sequentially synthesized in time series for all units. Here, as shown in FIG.
The F picture EA is the end address (1EA) of the I picture, the second REF picture EA is the end address (2EA) of the P picture next to the I picture, and the third REF picture E
A is the end address (3EA) of the next P picture. In Table 1, there is only the information up to the third REF image EA, but it goes without saying that the information may be more or less than this. By adding the unit addresses, the start address of the next unit can be calculated. [0028] Next, the data decoding method and decoding apparatus
One embodiment will be described with reference to FIG. In FIG. 2, a recording medium 3 on which encoded data and special reproduction information data are recorded in respective areas by the encoding apparatus of FIG.
8, the special reproduction information data is reproduced first by a reproducing mechanism (not shown) and stored in the information memory 41. Next, when an instruction signal for trick play is input to the pickup access address calculator 42 through an input terminal 40 by an interface (not shown), the pick-up access address calculator 42 accesses the information memory 41 to perform trick play. Fetching information data, selecting the end address of each unit according to the speed ratio indicated by the special reproduction instruction signal, calculating the read start address and the read end address based on the selected end address and unit size, These addresses are supplied to the optical disk controller 43. Optical disk controller 43
Performs read control of the pickup 44 based on the input read start address and read end address. This reading control is performed for each unit. The pickup 44 reproduces the multiplexed coded data and the address from the recording area of the multiplexed coded data of the recording medium 38 by a known method, and sets the reproduction address to the read start address input from the optical disk controller 43. Reproduction is performed by selecting a reproduction track position so as to be a read end address. The multiplexed coded data reproduced by the pickup 44 is supplied to a demultiplexer 45 and separated into video coded data and audio coded data. The video coded data is shown in FIG. The video data is supplied to the video decoder 47 having the configuration and decoded in the same manner as in the related art, and the encoded audio data is supplied to the audio decoder 46 and decoded. Thus, for example, when the special reproduction instruction signal instructs fast forward reproduction at 15 × speed, the pickup access address calculator 42 looks at the unit size of the special reproduction information data in Table 1 and checks the next unit. At the same time as calculating the start address (read start address) of
Here, since one GOP is composed of 15 pictures, it is necessary to detect the first REF image EA of the unit, calculate the end address as the read end address, and output it to the optical disk controller 43 for each unit. Do. Thereby, the pickup 44
Since only the first I picture of each unit in this case, in this case, of each GOP is reproduced from the recording medium 38 in order,
5x speed playback is possible. The present invention is not limited to the above embodiment. For example, the information memory 36 stores the special reproduction information data of each unit sequentially generated by the special reproduction information data formatter 37. If the data rate that can be recorded on the recording medium 38 is higher than the data rate of the encoded data to be recorded, the information memory 36 is not provided and the encoded data is not recorded. It is also possible to record information data for special reproduction at a time by time sharing. As described above, according to the present invention,
Convert image data composed of pictures into MPEG format
Video encoded data and audio data obtained by more encoding
And audio encoded data obtained by encoding
Encoded data packed and multiplexed based on the G method
With one or more of the video encoded data
GOPs are used as units, and the special reproduction information data is generated for each unit from the multiplexed coded data corresponding to each unit. Should multiplex
While the encoded data thus encoded is recorded on the recording medium in real time, the information data for special reproduction can be recorded on the same recording medium.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a data generation method according to the present invention.
1 is a block diagram of an embodiment of an encoding device according to the present invention. FIG. 2 shows data generated and recorded by the encoding apparatus shown in FIG .
FIG. 21 is a block diagram of an embodiment of a decoding device for reproducing data from a recording medium . FIG. 3 is an explanatory diagram of a reference image end address in the special reproduction information data. FIG. 4 is a block diagram illustrating an example of a conventional encoding device. FIG. 5 is a block diagram illustrating an example of a conventional decoding device. [Description of Code] 10 Image data input terminal 14 Quantizer (encoding means) 19 Variable length encoding (VLC) device (encoding means) 20 Buffer memory (encoding means) 21 Code amount controller (encoding means) 30) audio data input terminal 31 audio encoder (encoding means) 32 multiplexer 33 logical unitizer (special reproduction information data generating means) 34 unit reproduction time calculator (special reproduction information data generating means) 35 Data size calculator (special reproduction information data generation means) 36 Information memory (special reproduction information data generation means) 37 special reproduction information data formatter (special reproduction information data generation means) 38 recording medium 40 special reproduction instruction Signal input terminal 41 Information memory 42 Pickup access address calculator (access address generation means) 43 Option Critical A disk controller (pickup control means) 44 pickup 45 demultiplexing unit (decoding means) 46 Audio decoder 47 video decoder (decoding means)

Continuation of the front page (56) References JP-A-7-170488 (JP, A) JP-A-6-325553 (JP, A) JP-A-11-261962 (JP, A) JP-A-6-268969 (JP) , A) JP-A-8-273304 (JP, A) JP-A-10-74380 (JP, A) JP-A-2002-109860 (JP, A) WO 97/13361 (WO, A1) (58) Field (Int.Cl. ⁷ , DB name) H04N 5/85-5/956 H04N 7/24 G11B 20/10

Claims (1)

(57) [Claims 1] An image data composed of picture units is represented by M
Video encoded data obtained by encoding according to the PEG system and audio encoded data obtained by encoding audio data are packed and multiplexed based on the MPEG system to generate encoded data. Multiplexing the encoded data with one or more of the video encoded data
GOP is unitized, and the unit is sequentially united for each unit.
In one unit, a predetermined number of pictographs for one unit
The audio for a certain time equivalent to the playing time of the tea
A structure that contains coded data, each time the unit is generated, the unit size of the unit to which the generated, the unit reproduction time, and the unit leading from the N (N is the predetermined number or less natural number) th of The three pieces of information of the data size information up to the end of the picture are calculated from the multiplexed coded data corresponding to the unit, and the special reproduction information data including the three pieces of information for each unit is generated. A data generation method.