JP3773892B2 - Digital recording / reproducing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital recording / reproducing apparatus having a function of generating a special reproduction stream.
[0002]
[Prior art]
FIG. 1 shows a conventional digital recording / reproducing apparatus disclosed in Japanese Patent Laid-Open No. 2001-16546 and its peripheral devices.
[0003]
The tuner device 101 transfers the received video broadcast as MPEG2-TS data to the digital recording / reproducing device 102 via the 1394 serial bus 111. The digital recording / reproducing device 102 records the MPEG2-TS data transferred from the tuner device 101 on a storage medium such as an HDD or a DVD-RAM.
[0004]
The digital recording / reproducing apparatus 102 transfers the MPEG2-TS data recorded on the storage medium to the digital TV (decoding apparatus) 103 via the 1394 serial bus 112. The digital TV 103 performs decoding (decoding) of the MPEG2-TS data transferred from the digital recording / reproducing apparatus 102 and displays the decoded image on the screen.
[0005]
The digital recording / reproducing apparatus 102 has special reproduction functions such as fast-forward reproduction and reverse (rewind) reproduction. When performing special reproduction, only I pictures are extracted from the MPEG2-TS data (TS stream) recorded on the storage medium, and display time information (PTS: Presentation Time Stamp) and decoding time information (DTS: Decode Time Stamp) are extracted. ) Is generated, and a special reproduction stream is generated and sent to the digital TV 103.
[0006]
In the conventional digital recording / reproducing apparatus 102, since the picture sending cycle is lengthened, no consideration is given to the fact that no picture is sent within the sending cycle. On the other hand, in order to perform high-quality special reproduction, it is necessary to increase the number of pictures transmitted per second. However, if the number of picture transmissions per second is increased, transmission may not be completed within an output period depending on the picture.
[0007]
[Patent Document] Japanese Patent Application Laid-Open No. 2001-16546
[Problems to be solved by the invention]
In the present invention, even when picture transmission is not completed within a predetermined output cycle due to factors such as an increase in the number of pictures transmitted per second or a temporary delay in reading operation, An object of the present invention is to provide a digital recording / reproducing apparatus capable of performing special reproduction operations such as rewinding reproduction.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the digital recording / reproducing apparatus having a function of generating a special reproduction stream, the stream data to be externally output is read from the storage medium based on the index information generated at the time of recording. 1 means, 2nd means for extracting picture data from the read stream data, 3rd means for updating display time information and decoding time information for the extracted picture data for the special reproduction stream, 4th for packetizing the picture data And a fifth means for externally outputting packetized picture data based on a preset picture transmission period. The picture transmission period is set in advance to a constant value that is an integral multiple of the frame period or the field period. The third means calculates the display time information and the decoding time information by adding the display time offset value and the decoding time offset value respectively to the system reference time at the picture transmission start timing determined by the picture transmission cycle. The display time offset value and the decoding time offset value are set to an integral multiple of the frame period or field period.
[0010]
According to a second aspect of the present invention, in the digital recording / reproducing apparatus according to the first aspect, the decoding time offset value is preset to the same value as the picture transmission cycle .
[0011]
According to a third aspect of the present invention, in the digital recording / reproducing apparatus according to the first or second aspect, when a picture requiring a transmission time longer than a preset picture transmission cycle is transmitted, or a read operation from a storage medium is performed. In the case of temporary stagnation, there is provided means for extending the picture transmission cycle in frame cycle units or field cycle units.
[0012]
According to a fourth aspect of the present invention, in the digital recording / reproducing apparatus having a function of generating a special reproduction stream, the stream data to be externally output is read from the storage medium based on the index information generated at the time of recording. 1 means, 2nd means for extracting picture data from the read stream data, 3rd means for updating display time information and decoding time information for the extracted picture data for the special reproduction stream, 4th for packetizing the picture data Means, and fifth means for outputting packetized picture data to the outside based on a preset picture transmission cycle. The picture transmission period is set to an integral multiple of the frame period or the field period. Furthermore, when sending a picture that requires a sending time longer than the preset picture sending period or when the reading operation from the storage medium is temporarily delayed, the picture sending period is extended by the frame period unit or the field period unit. It is characterized by having the means to make.
[0013]
According to a fifth aspect of the present invention, in the digital recording / reproducing apparatus according to the fourth aspect , the third means is a system reference time at a picture transmission start timing determined by a picture transmission period or an extended picture transmission period. And a means for calculating display time information and decoding time information by adding the display time offset value and the decoding time offset value, respectively .
[0014]
According to a sixth aspect of the present invention, in the digital recording / reproducing apparatus according to the fifth aspect, the display time offset value and the decoding time offset value are set to an integral multiple of a frame period or a field period .
[0015]
A seventh aspect of the present invention is the digital recording / reproducing apparatus according to any one of the first to sixth aspects, further comprising means for changing the setting of the picture transmission cycle at an arbitrary timing. The picture sending cycle is changed to the picture sending cycle after the setting change when external output of the picture to be externally output first is started .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described below with reference to FIGS.
[0017]
[1] Description of the configuration of a special reproduction stream generating circuit provided in the digital recording / reproducing apparatus.
FIG. 2 shows a configuration of a special reproduction stream generating circuit provided in the digital recording / reproducing apparatus.
[0019]
Reference numeral 1 denotes storage media in which TS streams are stored. 2 is a buffer. Reference numeral 3 denotes a picture extraction unit. Reference numeral 4 denotes a PES (Packetized ES) unit. Reference numeral 5 denotes a TS unit. 6 is a switch. Reference numeral 7 denotes a multiplexing unit. Reference numeral 8 denotes a serial bus I / F.
[0020]
Reference numeral 10 denotes a CPU. Reference numeral 11 denotes a memory. Reference numeral 12 denotes a remote controller. Reference numeral 13 denotes a remote control I / F. Reference numeral 14 denotes a timing generation unit. Reference numeral 15 denotes a reference time generation unit. Reference numeral 16 denotes a PTS / DTS calculator. Reference numeral 17 denotes a PCR packet generator. Reference numeral 18 denotes a PSI packet generator.
[0021]
The memory 11 stores index information generated by the CPU 10 during recording. The index information includes position information (start position and end position) of each picture stored in the storage medium 1, picture type information (I picture, B picture, P picture) and the like.
[0022]
[2] Description of processing of the CPU 10 during special playback
FIG. 3 shows the processing procedure of the CPU 10 during special playback.
[0024]
When a special reproduction instruction is issued from the user (step 1), the CPU 10 acquires index information stored in the memory 11 (step 2). Based on the acquired index information, a picture to be transmitted first is determined according to special reproduction, and the picture is set as a processing target picture D (n) (step 3).
[0025]
The CPU 10 obtains position information, picture type information, and the like of the processing target picture D (n) (step 4). The CPU 10 reads the stream of the area including the data of the picture D (n) from the storage medium 1 to the buffer 2 based on the position information, picture type information, etc. of the picture D (n) to be processed (step 5). .
[0026]
Further, the CPU 10 sets the TS packet ID (TS PID) representing the video and the picture position information (picture start position and picture end position) in the picture extraction unit 3, the display time offset value PTSoffs _i, and the decoding time offset value DTSoffs. _i is set in the PTS / DTS calculator 16 (step 6).
[0027]
When the data reading and the setting in step 6 are completed in this way, the CPU 10 instructs the timing generation unit 14 that the picture transmission preparation is completed (step 7). At the time of the start of special playback, the timing generator 14 sends T_Tf (90 kHz accuracy), which is a value corresponding to a frame period for controlling transmission timing or a field period, and T_Ts (frame period accuracy, Or field period accuracy).
[0028]
Thereafter, the picture D (n) to be processed is sent out as follows. That is, the picture extraction unit 3 cuts out a TS stream to be processed from the TS stream stored in the buffer 2 based on the picture position information (picture start position and picture end position) set by the CPU 10, and the CPU 10 The PES payload part is extracted from the TS packet having the TS packet ID set by, thereby obtaining picture data.
[0029]
The obtained picture data (PES payload part) is sent to the PES converting part 4. The PES converting unit 4 generates a PES header including the display time information PTS and the decoding time information DTS calculated by the PTS / DTS calculating unit 16, and then converts the PES payload portion sent from the PES header and the picture extracting unit 3 into the PES header. Send sequentially. The PES converting unit 4 may encode only PTS and may encode both PTS and DTS, but the PES header format is different between the two.
[0030]
The PES packet composed of the PES header and the PES payload portion sent from the PES conversion unit 4 is sent to the TS conversion unit 5. The TS unit 5 generates a TS packet from the sent PES packet. At this time, the payload-unit-start-indicator is set to “1” only for the TS packet including the head of the PES packet. Also, coutinuity-counter will be updated sequentially. The TS packet generated by the TS unit 5 is sent to the multiplexing unit 7 via the switch 6 at a predetermined transmission start timing.
[0031]
The multiplexing unit 7 includes a TS packet sent from the TS unit 5 via the switch 6, a PCR packet sent from the PCR packet generation unit 17, and a PSI packet sent from the PSI packet generation unit 18. Are transmitted to the serial bus I / F8. The PCR packet includes information for reproducing the system reference time STC by an MPEG2-TS decoder (not shown). The PSI packet includes control information such as program configuration information.
[0032]
When picture transmission is completed in this way, a picture transmission completion signal is input (interrupted) from the TS unit 5 (step 8). Then, it is determined whether or not a special playback end instruction has been input (step 9). If the special playback end instruction has not been input, the picture D (n) to be processed is changed to the picture D (n + 1) to be transmitted next (step 10), and the process returns to step 4. If an instruction to end special reproduction is input, special reproduction is terminated (step 11).
[0033]
[3] Description of the operation of the timing generator 14 and the PTS / DTS calculator 16
The timing generation unit 14 determines the transmission start timing of one picture as follows. As shown in FIG. 4, the transmission start timing is determined based on a period generated based on T_Tf (90 kHz accuracy) which is a value corresponding to the frame period. Then, transmission control for one picture is repeated according to a transmission cycle (output cycle) generated based on T_Tf and T_Ts. That is, transmission of one picture is started at the timing of T_Tf × T_Ts. However, as will be described later, the sending cycle may be automatically extended.
[0035]
When the transmission start timing comes, the timing generation unit 14 turns on the switch 6 and sends a transmission start timing signal to the reference time generation unit 15. When receiving the transmission start timing signal from the timing generator 14, the reference time generator 15 sends the system reference time STC _{i at} that time to the PTS / DTS calculator 16. The reference time STC is constantly sent from the reference time generation unit 15 to the PCR packet generation unit 17. The PCR packet generation unit 17 generates a PCR packet including the reference time and sends it to the multiplexing unit 7. The switch 6 is turned off when the TS generation unit 5 generates an interrupt signal indicating completion of picture transmission.
[0036]
A method of calculating PTS and DTS by the PTS / DTS calculation unit 16 will be described. Let STC _i be the system reference time at the start of sending the i-th picture determined by the picture sending cycle (T_Tf × T_Ts) or the sending cycle automatically extended as described later. The PTS / DTS calculation unit 16 calculates the display time information PTS _i by adding the system reference time STC _i to the PTS offset value PTSoffs _i set by the CPU 10, and also calculates the DTS offset value DTSoffs _i set by the CPU 10. Decoding time information DTS _i is calculated by adding the system reference time STC _i .
[0037]
That is, the display time information PTS _i and the decoding time information DTS _i are expressed by the following equations (2) and (3).
[0038]
PTS _i = STC _i + PTSoffs _i (2)
DTS _i = STC _i + DTSoffs _i (3)
STC _i : Reference time at the start of sending the i-th PES
PTS _i : Display time information PTS encoded in the i-th PES header
DTS _i : Decoding time information encoded in the i-th PES header DTS
PTSoffs _i : Time from the start of sending the i-th PES to the expected display timing
DTSoffs _i : Time from the transmission start time of the i-th PES to the expected decoding timing
As the offset values PTSoffs _i and DTSoffs _i , a fixed value such as a picture transmission cycle (T_Tf × T_Ts) is usually set. However, when the picture size is larger than a predetermined value, the value is determined based on the picture size (picture position information). However, the offset values PTSoffs _i and DTSoffs _i are set to be an integral multiple of T_Tf. As a result, PTS _i and DTS _i are each updated at an integral multiple of the frame period. If PTSoffs _i and DTSoffs _i are equal, DTS _i is not encoded. When a B picture is included in the transmitted picture, the display order is also taken into consideration and PTSoffs _i is set.
[0040]
For example, when T_Tf = 3003 (90 kHz) and T_Ts = 5 and I-pictures that are continuous in the time axis direction are read out, triple-speed special reproduction with 6 frames per second can be obtained.
[0041]
By the way, when there is a picture that requires a transmission time longer than the set picture transmission cycle (T_Tf × T_Ts), or when reading from the storage medium 1 is temporarily delayed, the transmission start timing is automatically set. Extended by T_Tf.
[0042]
FIG. 5 shows an example of transmitting a picture that requires a transmission time equal to or longer than the set picture transmission cycle (T_Tf × T_Ts).
[0043]
In the example of FIG. 5, since the transmission of picture 1 has not been completed within the transmission cycle (T_Tf × T_Ts), the transmission timing cycle is automatically extended twice in units of T_Tf.
[0044]
The process of extending the transmission timing period is performed by the timing generation unit 14. That is, after receiving the picture transmission completion signal, the CPU 10 prepares for sending the next picture according to steps 4 to 6 in FIG. 3, and then completes preparation for sending the next picture as shown in step 7 in FIG. This is notified to the timing generation unit 14. When the transmission preparation completion signal for the next picture is not notified from the CPU 10 before the transmission cycle (T_Tf × T_Ts) for the currently transmitted picture is completed, the timing generation unit 14 transmits the transmission timing in units of T_Tf. Extend the cycle automatically. If the CPU 10 is not notified of a transmission preparation completion signal for the next picture before the extended transmission timing cycle is completed, the transmission timing cycle is automatically extended in units of T_Tf.
[0045]
Even when the reading operation from the storage medium 1 is temporarily delayed, the transmission preparation completion signal for the next picture is sent to the CPU 10 before the transmission cycle (T_Tf × T_Ts) for the currently transmitted picture is completed. Is not notified to the timing generation unit 14, so that the transmission timing period is automatically extended.
[0046]
When the automatic extension is performed, the timing generation unit 14 notifies the CPU 10 to that effect. When notified that the automatic extension has been performed, the CPU 10 performs processing such as skipping a picture to be read so that the reproduction magnification is not greatly affected.
[0047]
T_Ts defining the picture transmission cycle (T_Tf × T_Ts) can be set and changed at an arbitrary timing based on an instruction from the user. When such a setting change is made, as shown in FIG. 6, a new picture transmission cycle is reflected at the transmission start timing of the first picture after the setting change.
[0048]
【The invention's effect】
According to the present invention, even when picture transmission is not completed within a certain output cycle due to factors such as an increase in the number of pictures transmitted per second or a temporary delay in reading operation, fast-forward playback, Special playback operations such as reverse (rewind) playback can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a conventional digital recording / reproducing apparatus and its peripheral devices.
FIG. 2 is a block diagram showing a configuration of a special reproduction stream generating circuit provided in the digital recording / reproducing apparatus.
FIG. 3 is a flowchart showing a processing procedure of a CPU 10 during special playback.
FIG. 4 is a time chart for explaining a method for determining a transmission start timing of one picture by a timing generation unit;
FIG. 5 is a time chart showing an example in the case of transmitting a picture that requires a transmission time equal to or longer than a set picture transmission cycle (T_Tf × T_Ts).
FIG. 6 is a time chart showing an example when the setting of the picture transmission cycle (T_Tf × T_Ts) is changed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Storage media 2 Buffer 3 Picture extraction part 4 PES part 5 TS part 6 Switch 7 Multiplexer 8 Serial bus I / F
10 CPU
11 Memory 12 Remote control 13 Remote control I / F
14 Timing generator 15 Reference time generator 16 PTS / DTS calculator 17 PCR packet generator 18 PSI packet generator

Claims (7)

In a digital recording / reproducing apparatus having a function of generating a special reproduction stream,
First means for reading out stream data to be externally output from the storage medium based on the index information generated at the time of recording;
A second means for extracting picture data from the read stream data;
Third means for updating the display time information and the decoding time information for the extracted picture data for the special reproduction stream;
A fourth means for packetizing picture data;
A fifth means for externally outputting packetized picture data based on a preset picture transmission cycle;
The picture transmission period is preset to a constant value that is an integer multiple of the frame period or field period,
The third means calculates the display time information and the decoding time information by adding the display time offset value and the decoding time offset value respectively to the system reference time at the picture transmission start timing determined by the picture transmission cycle,
A digital recording / reproducing apparatus, wherein the display time offset value and the decoding time offset value are set to an integral multiple of a frame period or a field period. 2. The digital recording / reproducing apparatus according to claim 1, wherein the decoding time offset value is preset to the same value as a picture transmission cycle. Means for extending the picture sending cycle in frame cycle units or field cycle units when sending a picture that requires a sending time longer than a preset picture sending cycle or when the reading operation from the storage medium is temporarily delayed The digital recording / reproducing apparatus according to claim 1, further comprising: In a digital recording / reproducing apparatus having a function of generating a special reproduction stream,
First means for reading out stream data to be externally output from the storage medium based on the index information generated at the time of recording;
A second means for extracting picture data from the read stream data;
Third means for updating the display time information and the decoding time information for the extracted picture data for the special reproduction stream;
A fourth means for packetizing picture data;
And a fifth means for externally outputting packetized picture data based on a preset picture transmission cycle,
The picture transmission period is set to an integral multiple of the frame period or field period,
Furthermore, when sending a picture that requires a sending time longer than the preset picture sending period or when the reading operation from the storage medium is temporarily delayed, the picture sending period is extended by the frame period unit or the field period unit. A digital recording / reproducing apparatus characterized by comprising: The third means adds the display time offset value and the decoding time offset value to the system reference time at the picture transmission start timing determined by the picture transmission cycle or the extended picture transmission cycle, respectively, thereby displaying the display time information and 5. The digital recording / reproducing apparatus according to claim 4 , further comprising means for calculating decoding time information. 6. The digital recording / reproducing apparatus according to claim 5 , wherein the display time offset value and the decoding time offset value are set to an integral multiple of a frame period or a field period. A means for changing the setting of the picture sending cycle at an arbitrary timing is provided, and when the external output of the first externally output picture after the setting change is started, the picture sending cycle becomes the picture sending cycle after the setting change. digital recording and reproducing apparatus according to any one of claims 1, characterized in that it is changed 6.

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