JP2007036705A - Video image storing/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video image storing/reproducing device which is capable of carrying out smooth fast forward reproduction avoiding still image display that is generated when intra-frame compressed frames cannot be detected while the fast forward reproduction of image streams of a coding system that uses both intra-frame compression and inter-frame compression is carried out. <P>SOLUTION: The video image storing/reproducing device stores storage positions of intra-frame compressed frames on display all the times, detects estimated positions of the following intra-frame compressed frames, reads out the video image streams from the stored storage position when the frames are not detected within a prescribed time, decoding and displaying them, and besides continuing detection processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a video storage / playback apparatus capable of storing and playing back video, and more particularly to detection of compressed data in a frame during fast-forward playback.

  The compression method using inter-frame compression within MPEG2, etc., is based on the premise that successive frames are sequentially decoded and displayed, so it is considered to play and display frames at regular intervals for high-speed playback. Not. Therefore, at the time of high-speed playback, a frame (hereinafter referred to as I picture) compressed by intra-frame compression decoded only by that frame is decoded and displayed.

In Patent Document 1,
The position of the I picture is stored during normal playback, and the I picture at that position is read out during fast forward playback.

The present invention is characterized by searching for the position of the I picture during fast-forward playback rather than after playback once.
Japanese Patent Laid-Open No. 8-77755 (Reproduced Image Information Reproducing Device Matsushita)

  When fast-forwarding and playing back the accumulated video of the compression encoding method using intra-frame compression and inter-frame compression, such as MPEG2 (Moving Picture Experts Group), display the I-frame that can be decoded independently. Yes. For that purpose, the accumulation position of the next I frame was estimated from the bit rate and GOP configuration (ratio of I frame, P and B frames), and reading of the stream was started from that position to detect the I frame. .

  When receiving a broadcast and recording / playback, if part of the stream is missing due to radio wave interference, or if the I-frame cannot be detected at the estimated position due to a GOP misalignment due to a scene change, etc. Must detect until an I frame is found.

  In that case, it was necessary to continue to display the displayed video frame, and it became a fast-forward playback video that stopped for a moment. In digital broadcasting, generally, I frames appear 2 frames per second, so that there is a problem that they remain stationary for up to 0.5 seconds.

  An object of the present invention is to remedy the drawbacks of the prior art, and when an I frame detection to be displayed in fast-forward playback cannot be found within a predetermined time, P and B frames following the currently displayed I frame. The purpose is to avoid the stop state of the reproduced video by reading out, decoding, and displaying.

  A device for accumulating and reproducing moving image data composed of intra-frame compressed data, inter-frame compressed data, and header information, random access means capable of reading moving image data from an arbitrary position; Analysis means for analyzing into a format, determination means for determining the analyzed data, storage means for storing the storage position and moving image header information of the compressed data in the frame, and the compressed data in the frame and the frame in the predetermined format Decoding means for decoding the intercompressed data and converting it into displayable frame data, display means for displaying the displayable frame data, and estimation means for estimating the position where the compressed data in the frame is accumulated from the header information An apparatus for storing and reproducing moving images, comprising: compressing the stored moving image data within a frame When performing fast-forward playback only by displaying data, the estimation unit estimates the position of the compressed data in the frame, reads the data by the random access unit, and analyzes the read data by the analysis unit. When the determination means is the intra-frame compressed data, the storage position is stored in the storage means, and the intra-frame compressed data is displayed by the decoding means and the display means. When the determination means is not compressed data within a frame, the random access means, the analysis means and the determination means are used to search the compressed data within the frame. From the position of the intra-frame compressed data stored in the storage means, until the intra-frame compressed data is found in the search by the random access means, the analysis means, the determination means, the decoding means, and the display means. It is characterized by continuing display processing of moving image data.

  In the fast-forward playback of the stored MPEG2 video stream, the present invention avoids a static screen display when an in-frame compressed frame (I picture) cannot be found within a predetermined time, and performs smooth fast-forward playback. There is an effect to realize.

  In digital television broadcasting, MPEG2 encoding using intraframe compression and interframe compression is used. MPEG2 does not have a structure particularly considered for fast-forward playback. The video storage / playback apparatus according to the present invention avoids still screen display when it takes time to detect an I picture (compressed frame within a frame) during fast-forward playback of a video signal received and stored by a digital television broadcast receiver. Is.

  The present invention is intended for fast-forward playback of a received and accumulated stream, not a pre-recorded encoded stream such as a movie title DVD, and therefore the present invention is applied because I pictures do not always appear constant. Preferred form.

  Hereinafter, the present invention will be described in detail with specific examples.

  FIG. 1 shows the configuration of a video storage / playback apparatus 22 having a function of receiving digital television broadcasts.

  In FIG. 1, an antenna 1 receives a digital television broadcast signal sent from a satellite. The antenna 1 generally includes a frequency converter, and supplies a received / frequency converted signal to the tuner 2. The tuner 2 extracts a signal of a specific frequency from the high frequency digital modulation signal including video / audio data. That is, a process of selecting one from a plurality of transponders for digital television broadcasting is performed. Further, the tuner 2 includes a deinterleave circuit, an error correction circuit, and the like, thereby demodulating the selected digital modulation signal and outputting a transport stream. The DEMUX circuit 3 separates the transport stream received from the tuner 2 into MPEG2 video transport packets, audio transport packets, and PSI (Program Specific Information). The DEMUX circuit 3 supplies the video transport packet and the audio transport packet to the analysis circuit 5, the video decoder 5 and the audio decoder 11, and supplies service information included in the PSI to the system controller 19. As described above, a plurality of channels are multiplexed in the transport stream, and the process for selecting an arbitrary channel from among the channels is determined based on which arbitrary channel from the PSI is included in the transport stream. It becomes possible by taking out data such as whether the packet ID is multiplexed. Further, selection of a transport stream (selection of a transponder) can also be performed based on PSI information. The analysis circuit 5 analyzes the video transport packet and the audio transport packet supplied from the DEMUX circuit 3, and sends the video transport packet and the audio transport packet to the storage device 4. The storage device 4 records at a predetermined position using management information for recording. The analysis circuit 5 analyzes the video transport packet and the audio transport packet recorded in the storage device 4 read at the time of reproduction, and supplies them to the video decoder 6 and the audio decoder 11, respectively. The video decoder 6 includes a video decoder that decodes the video transport packet, and the audio decoder 11 includes an audio decoder that decodes the audio transport packet. The video decoder 6 decodes the input variable length code to obtain a quantization coefficient and a motion vector, and performs inverse DCT transformation, motion compensation control based on the motion vector, and the like. The audio decoder 11 decodes the input encoded signal and generates audio data. The video data generated by the video decoder 6 is output to the video processing circuit 7, and the audio data generated by the audio decoder 11 is output to the audio processing circuit 12. The video processing circuit 7 receives the video data from the video decoder 6, performs D / A conversion, and converts it into, for example, a composite signal in the NTSC format. The audio signal processing circuit 12 receives the audio data output from the audio decoder 11, performs D / A conversion, and generates a right (R) sound analog signal and a left (L) sound analog signal. The video output circuit 9 and the audio output circuit 13 include an output resistor, an amplifier, and the like. The NTSC composite signal output from the video output circuit 9 is displayed on the monitor 10 through a video output terminal (not shown). The sound analog signal output from the audio output circuit 13 is output as audio from the speaker 14 through left and right audio output terminals (not shown). The OSD (On Screen Display) display circuit 21 outputs bitmap data based on the character information instructed to be output from the system controller 19 to the adder 8. The adder 8 performs processing for incorporating the bitmap data into the video signal output from the video processing circuit 7. The OSD display circuit 21 realizes an EPG (Electronic Program Guide) screen display based on the service information included in the PSI received by the system controller 19 and enables setting of a recorded program by EPG, as well as an operation guide screen. Etc. can also be displayed. The remote control transmitter 15 is a transmitter for sending a command to the video storage device 22. When a key (not shown) provided on the remote control transmitter 15 is operated, signal light (remote control signal) indicating a command corresponding to the key is transmitted from a light emitting unit (not shown). The remote control light receiver 16 receives the signal light, converts it into an electrical signal, and supplies it to the system controller 19. The timer 20 notifies the system controller 19 that the designated time has been reached when the program recording is reserved. The nonvolatile memory 17 stores a program for controlling the video storage / playback device 22 and is transferred to the volatile memory and executed at the time of activation. The volatile memory 18 has a structure as shown in FIG. 9, and the program execution area 200, the video decoding work area 201, the audio decoding work area 202, and the last I picture for storing the position of the storage medium of the last detected I picture. The position 203, the current picture position 204 indicating the position of the next picture data, and various work areas for operating the video storage device 22 are assigned.

  Next, FIG. 2 shows a digital image data encoding method according to MPEG2. That is, in MPEG2, encoding is performed by dividing one sequence of digital image data into GOPs (Group Of Pictures) composed of a plurality of frames (pictures).

  This GOP does not have time difference information but has only one frame of information for one frame (Irta coded) picture (intra-frame coded image) and temporal movement such as motion in this I picture. This is the information added with the change, P (Predictive Coded) picture (inter-coded image) generated by predicting from the previous frame in time and 2 frames preceding and following in time It is composed of a combination with a generated B (bi-directionally coded) picture (inter-frame encoded image). In other words, an I picture is digital image data created from a screen of one frame, and a corresponding image can be reproduced by performing decoding processing as it is. The P picture is digital image data including only the difference from the preceding I picture or the preceding P picture. By using the preceding I picture or the preceding P picture, An image can be reproduced. Furthermore, the B picture is digital image data including only the difference between the I picture and the P picture or the P picture 2 screen, and the image is reproduced by using both the I picture and the P picture or the P picture 2 screen. Is something that can be done. Since the P picture and the B picture include only difference information, the amount of data is small. However, even if digital image data of only the P picture or only the B picture is received, the image cannot be reproduced.

  FIG. 3 shows a data transmission format in MPEG2. The digital image data of each picture is not broadcast as it is, but is broadcast with a header code added. In FIG. 3, picture data includes digital image data of each picture. The picture header contains attribute information indicating what the picture is.

  FIG. 4 shows the contents of the GOP header.

  FIG. 5 shows the contents of the sequence header. For example, horizontal size value (12 bits) represents the number of horizontal pixels of the image, and bit rate value represents the bit rate.

  FIG. 6 shows the format of the picture header. Of these, picture coding type is as defined in Fig. 7. “001” indicates an I picture, “010” indicates a P picture, and “011” indicates a B picture.

In the above configuration,
In the case of program recording, as described above, the digital television broadcast signal is received / frequency converted by the antenna 1, and the tuner 2 is used to transcode the recorded program from among a plurality of high frequency digital modulation signals including video / audio data. Is de-interleaved and error-corrected to demodulate it into a transport stream. The DEMUX circuit 3 separates the transport stream into MPEG2 video transport packets and audio transport packets, and analyzes the packets. To be supplied.

  The analysis circuit 5 analyzes the content of the video transport packet and obtains the bit rate from the sequence header. Further, the number of frames constituting the GOP can be obtained by detecting the GOP header and the picture header. Video transport packets and audio transport packets are stored in the storage device 4 in the configuration shown in FIG.

  The storage device 4 stores and manages video transport packets and audio transport packets in physical units (head, cylinder, sector). Reference numeral 130 denotes a storage medium in the storage device, which indicates that video transport packets and audio transport packets are stored with a plurality of sectors as one block.

  The storage medium management map 100 manages the used blocks and unused blocks of the storage medium 130 and manages them by turning on / off the bits corresponding to the blocks.

  The recorded program table 110 records a start block number 111 indicating from which position in the storage medium 130 the recorded program is recorded, a block number 112 indicating the number of recorded blocks, a program name, a recording date and time, and the like. It consists of program information 113, GOP configuration frame number 114, stream bit rate 115, and a plurality of them are prepared in succession. At the initial (unused) time, the start block number is set to -1, and -2 indicates the end.

  Storage media management map 100 and recorded program table 110 Storage media fixed position of storage device 4, for example, 0 head, 0 cylinder, 0 sector to N head, N cylinder, N sector (N is storage media in the case of from the beginning) (Vary depending on the capacity and the number of recorded programs).

  Next, when the recorded program is normally reproduced, the program information 113 of all the recorded program tables 110 being recorded is sequentially read out to create a display screen by the OSD display circuit, and the monitor 10 is added via the adder 8 and the video output circuit 9. A screen for selecting a recorded program playback is displayed. Although the user selects a recorded program to be played back using the remote control transmitter 15, the operation method is not closely related to the present invention, and thus a detailed description is omitted. Now, assuming that a recorded program to be reproduced is selected, a video transport packet and an audio transport packet stored from the block of the storage medium 130 corresponding to the start block 111 of the recorded program table 110 corresponding to the selected recorded program. Are sequentially read and supplied to the video decoder 6 and the audio decoder 11, and the video on the monitor 10 is displayed and the audio is output from the speaker 14. The recorded program is normally reproduced by performing the processing as described above. be able to.

  Next, when fast-forwarding the recorded program, the program information in the recorded program table 110 being recorded is displayed on the monitor 10 in the same way as the normal playback of the above-mentioned recorded program. This is performed when instructed by the transmitter 15.

  The recorded program table 110 corresponding to the recorded program to be played back in fast forward is taken out. Since the recorded program table 110 stores the number of GOP constituent frames 114 and the bit rate 115, it is possible to estimate the GOP interval, that is, the interval at which the I picture appears. Since digital broadcasting displays 30 frames per second, an I picture appears at a bit interval expressed by the following equation.

(GOP configuration frame number / 30) x (bit rate) (Equation 1)
The video transport packet is read from the block of the storage medium 130 corresponding to the start block 111, and the GOP header is searched for by the analysis circuit 5 according to the data transmission format in MPEG2 described above. If the GOP header is found, the picture header is searched next. In the case of an I picture, the position of the picture header in the storage medium 130 (head, cylinder, sector, number of bits from the head of the sector) is stored in the last I picture position 203 in the volatile memory 18, and the next picture header The read data is supplied to the read video decoder 6 while analyzing the above. That is, only the data of the I picture is supplied, and the I picture is displayed on the monitor 10 by the processing after the video decoder 6. Further, the current picture position 204 in the volatile memory 18 stores the position of the picture header in the storage medium 130 (head, cylinder, sector, number of bits from the head of the sector), and the timer 20 is slightly shorter than 1/30 second. Set to time. Since the screen to be displayed is updated at 30 frames per second, the slightly shorter time is the time taken from reading one frame from the storage medium 130 to outputting it to the monitor 10. Next, in order to display the next I picture, the storage medium 130 is read from a position slightly before the position obtained by adding (GOP configuration frame number / 30) × (bit rate) to the last I picture position 203. The next I picture is searched for, but it is assumed that the I picture is searched from a certain amount in advance in consideration of a failure at the time of reception or a case where the position is shifted due to some problem. Thus, fast-forward playback is realized by sequentially detecting, decoding and displaying the I picture, but when the I picture is not found and detected, the detection of the I picture is continued from that position. In FIG. 10, the I picture is detected at the position A, decoded and displayed, the I picture is detected at the position B in the interval of the position S of the next I picture obtained by Equation 1, and decoded and displayed. When the I picture cannot be detected at the position C at the interval S, the detection of the I picture is continued until the next position D. Therefore, the timer 20 is started at the position B and the position C is started. When detection of the I picture starts and the timer 20 has reached the set time, the position of b0 is stored in the current picture position 204, so b0 is read, the current picture position 204 is updated, and the video decoder 6 is updated. Then, the display process is performed, 1 / 30- (time from reading to display) is set in the timer 20 as described above, the detection of the I picture from the position C is continued, and the timer is similarly set. When -20 reaches the set value, the picture at the position 204 is again read and displayed. When this process is repeated and an I picture is detected from the position C, the timer 20 is stopped, the last I picture position 203 is updated, and the normal fast-forward playback process is switched.

  FIG. 11 is a flowchart of program recording in this embodiment.

  In the figure, in step 300, the recorded program table 110 corresponding to the program to be recorded is found and an unused block of the storage medium is secured. At this time, the largest unused block is secured and set to the start block number. In step 301, the digital television broadcast signal is received / frequency converted by the antenna 1, and in step 302, the transponder of the recorded program is selected from the plurality of transponders of the high-frequency digital modulation signal including video / audio data by the tuner 2, and vice versa. Interleave and error correction are performed and demodulated into a transport stream. In step 303, the DEMUX circuit 3 separates the transport stream into MPEG2 video transport packets and audio transport packets, and supplies the packets to the analysis circuit 5.

  In step 304, the analysis circuit 5 analyzes the content of the video transport packet, obtains the bit rate from the sequence header, sets it to the bit rate 115 of the recorded program table 110, detects the GOP header and the picture header, and constitutes the GOP. The number is obtained, and the number of GOP constituent blocks 114 of the recorded program table 110 is set. In step 305, the video transport packet and the audio transport packet are stored in the storage media block secured in step 300. In step 306, it is determined from the program information 113 in the program recording table 110 whether or not the recording is finished. If not completed, the process returns to step 301 and steps 301 to 306 are repeated. When the program recording is finished, the process proceeds to step 307, and the corresponding bit of the storage medium management table 100 is set to 0 indicating that it is not used in order to release the unused storage medium block secured in step 300. End program recording.

  FIG. 12 is a flowchart of fast-forward playback according to this embodiment.

  In the figure, in step 401, a recorded program table 110 corresponding to a recorded program to be reproduced by fast-forwarding is taken out. In step 402, the I picture appearance interval is obtained based on the number of GOP constituent frames 114 and the bit rate 115 of the recorded program table 110. In step 403, the video transport packet is read from the block of the storage medium 130 corresponding to the start block 111. In step 404, the analysis circuit 5 searches for a GOP header. In step 405, the picture header is searched to determine whether it is an I picture. Step 405 is repeated until an I picture is found. In step 406, the position of the I picture is stored in the last I picture position 203. In step 407, the read data is supplied to the read video decoder 6 while analyzing up to the next picture header. In step 408, the next position where the storage medium is read in step 407 is stored in the current picture position 204. In step 409, the timer 20 is set to 1 / 30- (time from reading to display). In step 410, the video decoder 6 decodes, and in step 411, the video signal is converted into a video signal by the video processing circuit 7 and displayed on the monitor 10. In step 412, the position of the storage medium is read by adding the appearance interval of the I picture obtained in step 402 to the last I picture position stored in step 406. In step 413, the read video transport packet is analyzed by the analysis circuit 5 to determine whether it is an I picture. If it is an I picture, the process returns to step 406. If it is not an I picture, the process proceeds to step 414 to determine whether the timer 20 is set. If it is not the set value, the next position of the storage medium is read to detect the picture header, and the process returns to step 413. If the timer is the set value, the process proceeds to step 416, and the read data is supplied to the read video decoder 6 while analyzing from the current picture position 204 to the next picture header. In step 417, the next position where the storage medium is read in step 416 is stored in the current picture position 204. In step 418, 1 / 30- (time from reading to display) is set in the timer 20. In step 419, the video decoder 6 performs decoding. In step 420, the video processing circuit 7 converts the video signal into a video signal, which is displayed on the monitor 10, and returns to step 413.

FIG. 3 is a block diagram showing a configuration of a video storage / playback device 22. The block diagram of the digital image data by MPEG. The figure which shows the transmission format of the data in MPEG. The figure which shows the format of a sequence header. The figure which shows the format of a GOP header. The figure which shows the format of a picture header. The figure which shows a picture code type. The block diagram which shows the storage device 4. FIG. The figure which shows the structure of a volatile memory. The figure which shows the detection of I picture. The figure which shows the flowchart of a program recording. The figure which shows the flowchart of fast-forward reproduction | regeneration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Tuner 3 DEMUX circuit 4 Storage device 5 Analysis circuit 6 Video decoder 7 Video processing circuit 8 Adder 9 Video output circuit 10 Monitor 11 Audio decoder 12 Audio processing circuit 13 Audio output circuit 14 Speaker 15 Remote control transmitter 16 Remote control light receiver 17 Nonvolatile memory 18 Volatile memory 19 System controller 20 Timer 21 OSD display circuit 22 Digital television broadcast receiver 100 Storage media management table 110 Recorded program table 111 Start block number 112 Number of blocks 113 Program information 114 Number of GOP configuration frames 115 Bit rate 200 Program execution area 201 Video decoding work area 202 Audio decoding work area 203 Last I picture position 204 Current picture Catcher position 205 other work area

Claims (1)

  A device for accumulating and reproducing moving image data composed of intra-frame compressed data, inter-frame compressed data, and header information, random access means capable of reading moving image data from an arbitrary position; Analysis means for analyzing into a format, determination means for determining the analyzed data, storage means for storing the storage position and moving image header information of the compressed data in the frame, and the compressed data in the frame and the frame in the predetermined format Decoding means for decoding the intercompressed data and converting it into displayable frame data, display means for displaying the displayable frame data, and estimation means for estimating the position where the compressed data in the frame is accumulated from the header information Comprising video storage / playback apparatus, the compressed data within the frame of the stored moving image data When performing fast-forward playback only by display, the estimation unit estimates the position of the compressed data in the frame, reads the data by the random access unit, analyzes the read data by the analysis unit, and determines the determination. If it is the intra-frame compressed data by the means, the storage position is stored by the storage means, and the intra-frame compressed data is displayed by the decoding means and the display means. When the determination means is not compressed data within a frame, the random access means, the analysis means and the determination means are used to search the compressed data within the frame. From the position of the intra-frame compressed data stored in the storage means, until the intra-frame compressed data is found in the search by the random access means, the analysis means, the determination means, the decoding means, and the display means. A video storage / playback apparatus characterized by continuing display processing of moving image data.

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