JP3185594B2 - Digital compressed data reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reproduces multiplexed digital data obtained by time-division multiplexing digital compressed image data with reproduction time information and digital compressed audio data with reproduction time information recorded on an optical disk or the like. More particularly, the present invention relates to a digital compressed data reproducing apparatus suitable for application to a still image file system.

[0002]

2. Description of the Related Art ISO / IEC13818-1 is a method for recording digitally compressed image data and compressed audio data on a recording medium such as an optical disk in a time multiplexed manner.
Standard methods are known. An outline of a time axis multiplexing method for digital compressed image data and compressed audio data in this method will be briefly described below. First, digital compressed image data and compressed audio data are each divided into units called access units. The access unit is
In the case of image data, it is in image frame units, and in the case of audio data, it is in audio frame units. Next, each successive access unit of image data and audio data is divided into units called packets, and if each packet contains the first digital data of the access unit of image data and audio data, the access unit PTS (Presenta
The signal called “Action Time Stamp” is added. The time axis is multiplexed using this packet as a minimum unit.

[0003]

When digital multiplexed data recorded on an optical disk is reproduced using such a method, the PTS indicates a reproduction time of an access unit belonging to a packet to which the data is added. Therefore, when both image signals and audio signals such as movie files are sequentially reproduced in frame units, there is no problem because there are access units corresponding to the signals of all image frames. When reproducing a still image file in which only audio signals are temporally sequentially reproduced in a state in which the compressed image data is recorded only for one frame period, the compressed image data for one frame of the still image is simply recorded. Cannot be played back, so the compressed image data for the necessary frames during the still Narazu, recording efficiency of the optical disk may be reduced.

In view of the above, the present invention records compressed image data for one frame when an image signal such as a still image file is stationary and only an audio signal is sequentially reproduced temporally. It is an object of the present invention to provide a digital compressed data reproducing apparatus which can be realized only by performing the above operations.

[0005]

In order to achieve the above object, the present invention extracts, from time-division multiplexed digital data, reproduction time information relating to digital compressed image data and compressed audio data, and obtains a still image file. During playback, the output of the playback image signal is controlled to freeze until the time described in the playback time information on the new image data is reached in accordance with the playback time information.

Further, at the time of reproducing a still image file, the data reading is stopped immediately before the time described in the reproduction time information on the new image data is reached, and the next data is read until a standby release signal is input from the outside. This is a configuration in which reading is controlled to be on standby.

[0007]

According to the present invention, when reproducing a still image file, the present invention can be realized only by recording one frame of digital compressed image data.

Further, the user can operate the still image file in a desired time unit, and the interactivity can be improved.

[0009]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a digital compressed data reproducing apparatus according to Embodiment 1 of the present invention.

Reference numeral 101 denotes an image information extracting circuit for extracting reproduction time information relating to digital compressed image data from the multiplexed digital data sequence, and selecting and outputting only the digital compressed image data. An audio information extraction circuit for extracting reproduction time information relating to digital compressed audio data from among them and selecting and outputting only digital compressed audio data.
03, an image decoding circuit for decoding digital compressed image data; 104, a PTSv delay unit for delaying image reproduction time information by a time required for processing of the image decoding circuit 103;
Reference numeral 05 denotes a voice decoding circuit for decoding digital compressed voice data. Reference numeral 106 denotes a PTSa delay unit for delaying voice reproduction time information by a time necessary for processing of the voice decoding circuit 105.
Reference numeral 07 denotes an image signal output control circuit for controlling the output of a reproduced image signal, and reference numeral 108 denotes a counting circuit in which a signal from the delay unit 106 is set at a predetermined cycle, and otherwise counts at a predetermined frequency.

The operation will be described in detail with reference to FIG.
The input terminal 100 has, for example, ISO / IEC13818.
An MPEG program stream time-division multiplexed according to the -1 standard is reproduced from an optical disk or the like and input. FIG. 2 schematically shows an example of this stream.

FIG. 2 (a) shows a video and audio access unit multiplexed on a time axis, and shows a movie file portion and a still image file portion connected to each other. I,
B and P denote access units for digital compressed image data, respectively, which are ISO / IEC1381.
Based on the 8-2 standard, it indicates an access unit that has been subjected to intra-coding, an access unit that has been subjected to bidirectional prediction coding, and an access unit that has been subjected to unidirectional prediction coding. A indicates an access unit for digital compressed audio data. The number added to each indicates the order of the reproduction time for each image and sound. Figure 2
When the packets are packetized in units as shown in (b) (the number indicates the packet number), the P of the image data and the audio data is obtained.
The TS will be stored in the stream at a location as shown in FIGS. 2 (c) and 2 (d). PTS is stored reproduction time information of the access unit shown by arrow, PTS existent access unit, such as B ₂ and B ₅ may be present. Therefore, in this embodiment, FIG.
As shown in FIG. 2, the description will be made on the assumption that the PTS is always added only to the access unit (the access unit indicated by I in FIG. 2A) that has been subjected to intra-coding.

The MPEG program stream is input to an image information extraction circuit 101 and an audio information extraction circuit 102. The image information extraction circuit 101 extracts, from the MPEG program stream, reproduction time information (hereinafter, abbreviated as PTSv) for each access unit in which in-screen encoding of digitally compressed image data has been performed, and extracts this PTSv.
In addition to the output to the v delay unit 104, only the digitally compressed image data is output to the image decoding circuit 103. Similarly, the audio information extraction circuit 102 extracts reproduction time information (hereinafter abbreviated as PTSa) for each packet of digital compressed audio data from the MPEG program stream,
This is output to the PTSa delay unit 106, and only the digital compressed audio data is output to the audio decoding circuit 105. The image decoding circuit 103 decodes the bit stream that has been compression-encoded using the MPEG2 method, and outputs a reproduced image signal to the image signal output control circuit 107.
On the other hand, the PTSv is necessary for processing up to decoding and reproduction of the access units (I ₃ , I ₇ , I _{8 in} FIG. 2) that have been subjected to in-screen encoding of the image decoding circuit 103 by the PTSv delay unit 104. The signal is delayed by the time and input to the image signal output control circuit 107. Also, the audio decoding circuit 105
Decodes the bit stream that has been compression-encoded using the AC3 method, and outputs it to the output terminal 110. On the other hand, P
TSa is an access unit (FIG. 2) to which the PTS of the audio decoding circuit 105 is added by the PTSa delay unit 106.
A ₁ , A ₃ , A ₅ , and A ₇ ) are input to the counting circuit 108 after being delayed by a time necessary for decoding and reproduction. The counting circuit 108 sets P every predetermined period.
The counter is set to the value of PTSa output from the TSa delay unit 106, and in the other periods, is constituted by a counter that counts up every 90 kHz, and the counter value (hereinafter, abbreviated as PTSm) is an image signal output control circuit. 1
07.

An image signal output control circuit 107 outputs an image signal obtained by decoding the access unit I ₃ when PTSm becomes equal to PTS ₃ output from the PTSv delay unit 104 during reproduction of the movie file portion of FIG.
, And thereafter, an image signal obtained by decoding the access units B ₄ , B ₅ , and P ₆ is output to the output terminal 109 at a frame period. The image signal obtained by decoding the access units B ₁ and B ₂ is output to the output terminal 109 before the image signal obtained by decoding the access unit I ₃ . On the other hand, FIG.
When the still image file portion is reproduced, the PTSv delay unit 10
The image signal decoded access units I ₇ when the PTS ₇ is PTSM becomes equal outputted from 4 outputting to the output terminal 109, PTSM freezes until it equals the PTS _8. Moreover, until PTSm is equal to PTS _7, the image signal obtained by decoding the access unit P ₆ is frozen. That is, when the decoded image signal of the access unit that has been subjected to intra-picture encoding is reproduced next, P
The frame being output is frozen until TSm becomes equal to the value output from the PTSv delay unit 104.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram of a digital compressed data reproducing apparatus according to Embodiment 2 of the present invention.

Reference numeral 301 denotes an optical disk on which multiplexed digital data is recorded; 302, an optical head for irradiating a semiconductor laser to convert reflected light into an electric signal; 303, rotation of the optical disk; A drive control circuit 304 for controlling the dynamic operation is a reproduction signal processing circuit for processing a reproduction signal from the optical system head 302.

The operation will be described in detail with reference to FIGS. The multiplexed digital data recorded on the optical disc 301 is read by the optical system head 302 and input to the reproduction signal processing circuit 304. The reproduction signal processing circuit 304 performs necessary processing on the reproduction signal such as reproduction of a clock signal necessary for internal processing and error correction from the reproduction signal input from the optical system head 302, and then converts only the MPEG program stream into image information. Output to the extraction circuit 101 and the audio information extraction circuit 102. Hereinafter, in the blocks other than the image signal output control circuit 107, the same processing as that described in the first embodiment is performed.

The image signal output control circuit 107, the access unit I ₃ the output terminal 109 an image signal obtained by decoding when the PTS ₃ is PTSm becomes equal output from PTSv delay unit 104 during reproduction of the movie file portion of FIG. 2
, And thereafter, an image signal obtained by decoding the access units B ₄ , B ₅ , and P ₆ is output to the output terminal 109 at a frame period. The image signal obtained by decoding the access units B ₁ and B ₂ is output to the output terminal 109 before the image signal obtained by decoding the access unit I ₃ . On the other hand, FIG.
When the still image file portion is reproduced, the PTSv delay unit 10
The image signal decoded access units I ₇ when the PTS ₇ is PTSM becomes equal outputted from 4 outputting to the output terminal 109, with PTSM freezes until it equals the PTS _8, PTSM equals PTS ₈ The drive standby signal is output to the drive control circuit 303 immediately before. Upon receiving this drive standby signal, the drive control circuit 303 controls the operations of the optical disk 301 and the optical system head 302, and waits immediately before the multiplexed digital data of the packet number 10 shown in FIG. Data reading is stopped until a standby release signal is input from the input terminal 305. When the standby release signal is input from the input terminal 305, the drive standby signal is reset, and then the multiplexed digital data of the packet number 10 is read. During the reproduction period of the still image file, the above-described processing is repeatedly performed.

In the first and second embodiments, the determination as to whether the file is a movie file or a still image file is made according to the ISO code indicating how the access unit is encoded.
The decoding can be performed by the image decoding circuit 103 by decoding the information defined by the / IEC13818-2 standard. However, information indicating the reproduction mode of the still image file is externally supplied to the image signal output control circuit 107. May be entered.

[0020]

As described above, according to the present invention, when the decoded image signal of the access unit subjected to intra-picture encoding is reproduced next, the reproduction time of the access unit subjected to intra-picture encoding is reproduced. In order to control the output so that the frame being output is frozen until, the still image file is still, and only the audio signal is reproduced sequentially in time. It is not necessary to record the compressed image data for one frame, and this can be realized only by recording the compressed image data for one frame, and the recording efficiency of a recording medium such as an optical disk can be improved.

Further, when the decoded image signal of the access unit which has been subjected to intra-picture encoding is reproduced next, data is read from the optical disk immediately before the reproduction time of the access unit which has undergone intra-picture encoding. The optical disc drive mechanism is controlled and stopped at that position until the stand-by signal is input from the outside until the stand-by release signal is input, so that the user can operate the still image file in a desired time unit and has a high interactivity. An optical disk reproducing device can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital compressed data reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an MPEG program stream.

FIG. 3 is a block diagram of a digital compressed data reproducing apparatus according to a second embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 101 image information extraction circuit 102 audio information extraction circuit 103 image decoding circuit 104 PTSv delay unit 105 audio decoding circuit 106 PTSa delay unit 107 image signal output control circuit 108 counting circuit 301 optical disk 302 optical system head 303 drive control circuit 304 reproduction signal Processing circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956 G11B 20/10

Claims (4)

(57) [Claims] 1. An apparatus for reproducing multiplexed digital data obtained by time-multiplexing digital compressed image data having reproduction time information and digital compressed audio data having reproduction time information, comprising: Means for extracting first reproduction time information relating to the digital compressed image data; means for extracting second reproduction time information relating to the digital compressed audio data from the multiplexed digital data; Image decoding means for decoding to obtain a reproduced image signal; audio decoding means for decoding the digital compressed audio data to obtain a reproduced audio signal; and applying the first reproduction time information to the processing of the image decoding means.
A first delay unit for delaying a required time, and the second reproduction time information for processing by the audio decoding unit.
A second delay unit for delaying a required time; a value of the audio reproduction time information set at predetermined intervals according to the audio reproduction time information output from the second delay unit; A counting means for performing counting in step (c), and comparing the count value Tm output from the counting means with the image reproduction time information Tv output from the first delay means, until the Tm becomes equal to the value of Tv. An image signal output control means for controlling an output of a reproduced image signal obtained before by the decoding means to be frozen, the digital compressed data reproduction apparatus comprising: 2. An apparatus for reading and reproducing multiplexed digital data obtained by time-multiplexing digitally compressed image data with reproduction time information and digitally compressed audio data with reproduction time information from a recording medium such as an optical disk. Means for extracting first reproduction time information relating to the digital compressed image data from the multiplexed digital data, and means for extracting second reproduction time information relating to the digital compressed audio data from the multiplexed digital data Image decoding means for decoding the digital compressed image data to obtain a reproduced image signal; audio decoding means for decoding the digital compressed audio data to obtain a reproduced audio signal; In the processing of the image decoding means
A first delay unit for delaying a required time, and the second reproduction time information for processing by the audio decoding unit.
A second delay unit for delaying a required time; a value of the audio reproduction time information set at predetermined intervals according to the audio reproduction time information output from the second delay unit; Comparing the count value Tm output from the counting means with the image reproduction time information Tv output from the first delay means, and immediately before the Tm becomes equal to the value of Tv, the optical disc. Means for stopping the reading of the multiplexed digital data from the optical disk and waiting for the reading mechanism of the optical disk at the reading stop position until a stop release signal is input from the outside; and a count value Tm output from the counting means, The image reproduction time information Tv output from the first delay means is compared with the reproduction time information Tv obtained by the image decoding means until Tm becomes equal to the value of Tv. Compressed digital data reproduction apparatus characterized by comprising an image signal output control means for freezing the output of the image signal. 3. The digital compressed data reproducing apparatus according to claim 1, wherein said image signal output control means operates based on a mode signal specified externally. 4. A mode signal designated from the outside is a signal indicating reproduction information of a still image file, and is based on the signal.
Claims, characterized in that controlling the output of the image signal Zui
Item 3. A digital compressed data reproducing apparatus according to Item 3.