JP2010016506A - Reproducing device for reproducing encoded stream, and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reproducing device capable of starting section reproduction at a high speed without decoding a reference frame to be needed in decoding of the start frame of the section reproduction when starting the optional section reproduction of a stream. <P>SOLUTION: In order to reproduce the optional section of the stream, a PlayList registering the position information of a start frame and a stop frame for performing the section reproduction and the position information of a reference frame to be needed in decoding of the start frame, and the reference frame to be needed in decoding of the start frame, are stored in a storage medium. When starting the section reproduction, by using the position information of the reference frame to be needed in the decoding of the start frame registered in the PlayList, acquiring the reference frame from the storage medium, and referring to it, decoding is performed from the start frame without performing the decoding of a reference frame to be needed in the decoding of the start frame, and the section reproduction is started at a high speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a playback apparatus and method for playing back a stream encoded by intraframe predictive coding and interframe predictive coding. In particular, the present invention relates to a technique for starting arbitrary section reproduction at high speed.

  As a method for compressing and encoding a moving image, a method using a correlation between frames is known. The MPEG (Moving Picture Expert Group) system, which is an international standard, is one of such methods. FIG. 1 is a diagram showing a data format encoded by intra-frame prediction and inter-frame prediction. As shown in FIG. 1, the MPEG data structure is composed of an I frame, a P frame, and a B frame. I frames are encoded with intra-frame prediction. The P frame is encoded by forward inter-frame prediction with reference to the I frame or the P frame. The B frame is encoded by bidirectional inter-frame prediction with reference to the I frame or the P frame. GOP (Group Of Pictures) is a set of frames from I frame to I frame.

When performing arbitrary section reproduction, PlayList may be used. FIG. 2 is a diagram showing the configuration of a table when storing a conventional playback section. For example, as shown in FIG. 2, PlayList registers and manages the order of a plurality of streams to be reproduced. In addition, a start frame and a stop frame are registered and managed for each stream to be reproduced. FIG. 3 is a diagram showing a configuration of a reference table described in Patent Document 1. There is provided a first reference table for storing position information of a frame to start reproduction. Further, a second reference table that stores reference frame position information is provided for one frame. The first reference table and the second reference table are linked. Therefore, the header analysis is performed from the I frame that is the head of the GOP for the position information of the reference frame necessary for decoding the frame to be reproduced and the position information of the reference frame necessary for decoding the reference frame. If it is not a reference frame, decoding is skipped. Thus, it is not necessary to sequentially repeat the process of performing header analysis of the next frame, and it can be obtained at high speed. However, it is necessary to decode a reference frame necessary for decoding a frame to be reproduced.
JP 2000-175143 A

  As described above, the MPEG system is composed of I frames, P frames, and B frames, and only I frames can be decoded independently. FIG. 4 is a diagram for explaining a section reproduction method in the prior art. As shown in FIG. 4, when playback is started from the B11 frame registered in the PlayList, the I0 frame is first decoded. Subsequently, the P3 frame is decoded with reference to the I0 frame. In order, the P6, P9, and P12 frames are decoded. After decoding the P9 and P12 frames, the B11 frame is decoded and playback is started. Therefore, it is necessary to decode the I0, P3, P6, P9, and P12 frames and a plurality of reference frames before decoding the B11 frame, and there is a problem that it takes time until the reproduction display of the B11 frame is started. .

  In addition, when seamless playback is performed without segmental playback of each stream registered in the PlayList, it is necessary to decode a plurality of reference frames until the start frame of subsequent segment playback is switched by switching between segment playbacks. There is also a problem that the display cannot be switched to the start frame of the subsequent section reproduction without interruption.

  The present invention has been made to solve the above-described problem, and when starting playback of an arbitrary section of a stream, without performing decoding of a reference frame necessary for decoding of a start frame of section playback, The present invention provides a playback method and apparatus that can perform playback start of segment playback registered in advance and display switching of seamless playback at high speed.

  In order to achieve the above-mentioned object, the present invention provides a start frame and a stop frame of a section in order to reproduce a stream encoded by intra-frame predictive coding and inter-frame predictive coding in an arbitrary section. It has a means that can accept the designation, analyzes the position information on the stream from the designated frame, the position information of the start frame and stop frame of the section, and the reference frame necessary for decoding the start frame Storage means for registering position information in the management information and storing the management information in the storage medium, and storage means for storing the reference frame necessary for decoding the start frame in the storage medium as a decoded frame It is characterized by that.

  As described above, the present invention extends PlayList (hereinafter, management information is expressed as PlayList) as management information to be registered for reproducing an arbitrary section. Necessary for decoding the start frame of section playback when starting playback of any section registered in PlayList for a stream encoded by intra-frame prediction encoding and inter-frame prediction encoding, such as MPEG. It is possible to perform decoding from the start frame without decoding the reference frame. For this reason, it is possible to start reproduction of pre-registered section reproduction at high speed. Furthermore, when a plurality of segment reproductions are registered in the PlayList and seamless reproduction is performed without interruption, display switching can be performed at high speed.

  For example, in the conventional method, the decoding time of the reference frames I0, P3, P6, P9, and P12 in the time required for starting the reproduction and display of the start frame B11 registered in the PlayList in FIG. The decoding time of B11 which is the start frame is required. Therefore, the display is not switched for the decoding time, and the screen appears to be stopped.

  In the present invention, in FIG. 4, without decoding the reference frames I0, P3, P6, P9, and P12 up to the start frame B11 registered in the PlayList, and by eliminating the decoding time of the reference frame, the start frame B11 Reproduction display can be started only with the decoding time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 5 is a diagram showing the configuration of the playback apparatus of the present invention.

  When the decoding unit 100 performs playback using an SD movie or a DVD player, a stream encoded by intraframe predictive coding and interframe predictive coding is input. The encoded stream is MPEG or the like stored in a flash memory or an optical disk. Further, the decoding unit 100 decodes encoded data that is an input stream. Here, the encoded data includes a reference frame corresponding to a time lag between frame decoding and display. Then, the decoding unit 100 outputs the decoded decoded frame to the display unit 101. Further, the decoded reference frame is held in the frame memory as a decoded frame until the display unit 101 finishes displaying the decoded frame.

  In addition, the decoding unit 100 determines that the PTS (Presentation Time Stamp) of the encoded data that is an input stream reaches the PTS of the start frame of the section reproduction registered in the PlayList stored in the storage medium 103. Skip the decryption process. The PlayList stored in the storage medium 103 is created by a user operation or the like. Decoding is started after the PTS of the input encoded data reaches the PTS of the start frame of the interval reproduction, and the decoding is performed up to the PTS of the stop frame of the interval reproduction. When decoding the input encoded data, the start frame of the interval reproduction is decoded without decoding the reference frame. Specifically, the reference frame registered in PlayList is acquired from the storage medium 103 using the head address of the reference frame on the storage medium 103, and the reference frame is written to the frame memory for reference.

  The display unit 101 displays the decoded frame input from the decoding unit 100. In addition, in an SD movie or the like, the display unit 101 is set to a touch panel or the like, so that a frame that is displayed even when a stream is being played is confirmed while a start frame and a stop frame of segment playback by a user operation are confirmed. The specification can be accepted.

  When the frame designation unit 104 designates the start frame for section playback, the management information control unit 102 registers the PTS of the decoded frame specified as the start frame in the PlayList as the section playback start frame. The PlayList is stored in the storage medium 103. Further, the reference frame necessary for decoding the frame designated as the start frame is analyzed for position information on the stream, and the reference frame is decoded. Then, the decoded reference frame is stored in the storage medium 103 as a decoded frame. When the stream is being reproduced, the decoded reference frame is acquired from the frame memory of the decoding unit 100 and stored in the storage medium 103 as a decoded frame. The head address of the reference frame stored in the storage medium 103 is registered in the PlayList. When the decrypted frame is already stored in the storage medium 103, the head address is registered in the PlayList. When the stop frame for the section playback is specified by the frame specifying unit 104, the PTS of the frame specified as the stop frame is registered in the PlayList as the stop frame for the section playback.

  The storage medium 103 stores PlayList. The PlayList includes a start frame and a stop frame PTS for section reproduction, and a reference frame start address necessary for decoding the start frame. Further, a reference frame necessary for decoding the start frame registered in the PlayList is decoded and stored as a decoded frame.

  The storage medium 103 can be either a nonvolatile memory such as an HDD, SD, flash memory, or optical disk, or a volatile memory such as a ROM. Further, when a PlayList and a decoded frame are stored in a flash memory, an optical disc, or the like together with a stream to be reproduced, it can be carried. Therefore, the playback of the section playback can be started at high speed using this playback device.

  The frame designation unit 104 can accept designation of a start frame and a stop frame for section reproduction. The designation of a frame can be performed by a user operation while checking the frame displayed on the display unit 101 even when the stream is being reproduced. In addition, the user can determine the start frame and the stop frame of the section playback of the input stream by designating the information of the section that the user wants to play the stream in advance. When a frame is designated, the frame designation unit 104 notifies the management information control unit 102 of information on the designated frame.

  FIG. 6 is a flowchart when storing the playback section in the playback apparatus of the present invention. The playback section is a section indicated by PlayList by a start frame and a stop frame of the section playback.

  First, the decoding unit 100 decodes the encoded data and outputs it to the display unit 101 (step S100). Next, the display unit 101 displays the decoded frame input from the decoding unit 100 (step S101). Next, it is checked whether or not the decoded frame displayed on the display unit 101 is designated as the start frame of the segment reproduction by the frame designation unit 104 by a user operation or the like (step S102).

  When the decoded frame is designated as the section reproduction start frame (S102: Yes), the management information control unit 102 registers the PTS of the decoded frame as the section reproduction start frame in the PlayList and stores it in the storage medium 103. Store (step S104). When the stream is being reproduced, the decoded referenced frame is acquired from the frame memory of the decoding unit 100. The acquired reference frame is a frame referred to when decoding the frame specified as the start frame. Then, the acquired reference frame is stored in the storage medium 103 as a decoded frame (step S105). The head address of the reference frame stored in the storage medium 103 is registered in the PlayList and stored in the storage medium 103 (step S106).

  Next, when the decoded frame is not designated as the start frame for the section reproduction (S102: No), or after the registered PlayList is stored in the storage medium 103 (step S106), the decoding displayed on the display unit 101 is performed. It is checked whether the framed frame has been designated as a stop frame for section playback by the frame designation unit 104 by a user operation or the like (step S103).

  When the decoded frame is designated as the stop frame for section playback (S103: Yes), the management information control unit 102 registers the PTS of the decoded frame in the PlayList as the stop frame for section playback. And it memorize | stores in the storage medium 103 (step S107). If the frame designating unit 104 determines that it is not designated as a stop frame for section reproduction (S103: No), the process returns to the first process.

  FIG. 7 is a flowchart when the section playback is performed in the playback apparatus of the present invention. First, the PTS of the encoded data that is the input stream is compared with the PTS of the start frame of the section reproduction (step S200). When the PTS of the encoded data that is the input stream is less than the PTS of the start frame of the section reproduction (S200: No), the decoding unit 100 skips the decoding process of the encoded data (step S206). Next, when the PTS of the encoded data has reached the PTS of the start frame of the section reproduction (S200: Yes), the address of the reference frame on the storage medium 103 is acquired (step S201). The reference frame is a frame necessary for decoding the start frame of the section reproduction registered in the PlayList.

  Next, the decoded frame stored in the storage medium 103 is acquired using the acquired head address of the reference frame, and is written in the frame memory of the decoding unit 100 (step S202). Next, the decoded data is decoded with reference to the decoded frame written in the frame memory by the decoding unit 100 (step S203). Next, the decoded frame is output to the display unit 101 (step S204). Next, it is checked whether the decoded frame output to the display unit 101 is a stop frame for section reproduction (step S205). If it is the stop frame for the section playback (S205: Yes), the section playback is stopped (step S207). If the decoded frame output to the display unit 101 is not a section reproduction stop frame (S205: No), the process returns to S203.

  FIG. 8 is a diagram for explaining a section reproduction method according to the embodiment of the present invention. Specifically, in a state where a stream is being played back, it is a diagram showing a state when the start frame for section playback is registered in the B11 frame and the stop frame is registered in the B14 frame.

  When the encoded data is input, the decoding unit 100 sequentially decodes the I0 frame and outputs the decoded data to the display unit 101. When the B11 frame is displayed on the display unit 101 and the B11 frame is designated as the section playback start frame by the frame designation unit 104, the management information control unit 102 sets the PTS of the B11 frame as the section playback start frame in the PlayList. sign up. Then, it is stored in the storage medium 103. Further, the P9 and P12 frames referred to for decoding the B11 frame are acquired from the frame memory of the decoding unit 100 and stored in the storage medium 103 as decoded frames. Then, the address 1000 of the P9 frame and the address 2000 of the P12 frame stored in the storage medium 103 are registered in the PlayList and stored in the storage medium 103. When the B14 frame is displayed on the display unit 101 and the B14 frame is designated as the stop playback frame for the frame specification unit 104, the management information control unit 102 sets the P14 of the B14 frame as the stop playback frame for the PlayList. Register and store in the storage medium 103.

  The playback procedure from the start frame B11 to the stop frame B14 of the section playback registered in the PlayList stored in the storage medium 103 will be described.

  When the encoded data is input, the decoding unit 100 skips the decoding process until the PTS of the encoded data reaches the PTS of the section reproduction start frame B11 registered in PlayList. Decoding is started when the PTS of the encoded data reaches the PTS of the B11 frame. For the decoding of the B11 frame, the reference frames P9 and P12 which are reference frames stored in the storage medium 103 are obtained by using the addresses 1000 and 2000 of the reference frame P9 registered in the PlayList. The data is written into the frame memory of the decoding unit 100 for reference. The encoded data is sequentially decoded and output to the display unit 101. Since the P12 frame already exists in the storage medium 103, it is written from the storage medium 103 to the frame memory, and is output to the display unit 101 without being decoded. Decoding is performed up to the stop playback frame B14 registered in the PlayList and output to the display unit 101.

  Since it is not necessary to decode the I0, P3, P6, P9, and P12 frames and the plurality of reference frames before the start frame B11 is decoded, the reproduction can be started at high speed.

  In the present application, it is also possible to perform seamless reproduction without interruption in a plurality of sections. The process is shown below.

  FIG. 9 is a diagram for explaining a method when seamless playback is performed without interruption in a plurality of sections. For example, after the first encoded data is reproduced from the start frame B11 to the stop frame B14, the second encoded data is reproduced from the start frame B7 to the stop frame B10.

  After decoding the first encoded data up to the stop frame B14, the decoding unit 100 outputs the B14 frame to the display unit 101, and stops the decoding of the first encoded data. Thereafter, the second encoded data is decoded. In the second encoded data, since the PTS of the start frame of the interval reproduction is designated as the B7 frame, the decoding unit 100 skips the decoding process up to the B7 frame. For decoding the B7 frame, the decoding frames 100 and P9 stored in the storage medium 103 are acquired using the addresses 3000 and P9 of the reference frame P6 registered in the PlayList, and the decoding unit 100 Export to frame memory for reference. After decoding the B7 frame, it is output to the display unit 101. It decodes to the stop frame B10 of the section reproduction registered in the PlayList, and outputs it to the display unit 101.

  By seamlessly decoding the stop frame B14 of the first encoded data and the start frame B7 of the second encoded data and outputting them to the display unit 101, the display of seamless playback can be switched at high speed. Is possible.

  As described above, the playback apparatus according to the present invention is necessary for decoding the start frame of section playback when performing playback of an arbitrary section of a stream encoded by intraframe prediction encoding and interframe prediction encoding. Therefore, it is possible to perform decoding from the start frame without decoding the reference frame, and to start the section reproduction at high speed.

  In addition, when seamless playback is performed without interruption for a plurality of segment playbacks, decoding can be performed from the start frame of subsequent segment playback by switching between segment playbacks, and the display of seamless playback can be switched at high speed.

Diagram showing the data format encoded by intra-frame prediction and inter-frame prediction The figure which showed the structure of the table when memorize | storing the conventional reproduction area The figure which showed the composition of the reference table in patent documents The figure for demonstrating the method to reproduce the area in a prior art The figure which showed the structure in the reproducing | regenerating apparatus of this invention Flowchart when storing a playback section in the playback apparatus of the present invention Flowchart when section playback is performed in the playback apparatus of the present invention The figure for demonstrating the system which reproduces | regenerates in the embodiment of this invention The figure for demonstrating the method of seamless reproduction | regeneration in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Decoding part 101 Display part 102 Management information control part 103 Storage medium 104 Frame designation | designated part

Claims (4)

In order to reproduce a stream encoded by intraframe predictive encoding and interframe predictive encoding in an arbitrary section, it has means capable of accepting designation of the start frame and stop frame of the section,
The position information on the stream is analyzed from the designated frame, and the position information of the start frame and stop frame of the section and the position information of the reference frame necessary for decoding the start frame are registered in the management information. Storage means for storing the management information in a storage medium;
A playback apparatus comprising storage means for storing a reference frame required for decoding the start frame as a decoded frame in a storage medium. When a designation of a start frame for performing section reproduction is received, a reference frame necessary for decoding the start frame is obtained from a frame memory of a decoding means in a state where the stream is being decoded, and a storage medium The playback apparatus according to claim 1, wherein the playback apparatus is stored. The position information of the start frame and the stop frame for performing the interval reproduction is registered in the management information as the time stamp, and the position information of the reference frame necessary for decoding the start frame is registered in the management information as the start address of the reference frame on the storage medium. The playback apparatus according to claim 1. When performing the interval reproduction from the start frame to the stop frame registered in the management information, the decoding means stores the reference frame position information necessary for decoding the start frame registered in the management information. Obtaining a reference frame from the medium, writing to the frame memory of the decoding means and referring to it, decoding from the start frame, displaying from the decoded start frame,
The playback apparatus according to claim 1, wherein decoding is performed up to a stop frame, and display is performed up to the decoded stop frame.

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