JP2012010038A - Information processor and information processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information processor and an information processing method enabling use of a Box structure obtained by previously considering an edited data structure.SOLUTION: The information processor is equipped with: segmentation means for segmentation of data which has a data structure standardized by ISO14496 and is composed of meta data as the head of the data and medium data following the meta data; and replacement means which replaces a free box in the meta data equivalent to the head portion of the data segmented by the segmentation means, the free box being standardized by ISO14496, with SD Profile Box standardized by SD-Video standard.

Description

  Embodiments described herein relate generally to an information processing apparatus and an information processing method for editing MP4 data.

Ingenuity has been devised in the reproduction method of multimedia data such as MP4 data. For example, in Patent Document 1, information specifying a key frame in moving image data in multimedia data is generated as reproduction control data, and the reproduction control data is arranged at a predetermined position in the multimedia data. At the time of special reproduction, by using this reproduction control data, it is possible to easily identify, read out and reproduce a key frame used for random access or the like. By arranging the playback control data in an area of multimedia data that is ignored by conventional devices, file compatibility can be maintained. In this Patent Document 1, random access information is inserted into MP4 data and used for special reproduction.

Further, Patent Document 1 is a file conversion device, in which a free box is generated and placed in advance by an MP4 file generation device, and mdat copy processing is not required during file conversion. As a means, the increase in the moov size after editing is estimated in advance, and a free box is inserted before the moov.

On the other hand, there is a demand to reduce the working memory size at the time of editing by using a Box structure that takes into consideration the data structure after editing in advance, but means for realizing such a demand is not known.

JP 2006-74531 A JP 2003-173625 A

It is an object of the present invention to provide an information processing apparatus and an information processing method that can use a Box structure that takes into account a data structure after editing in advance.

In order to solve the above-described problem, according to the information processing apparatus of the embodiment, the data structure defined in ISO 14496 is used to cut out data including data top metadata and media data following the metadata. Replacing means for replacing the free box defined in ISO 14496 of the metadata corresponding to the head portion of the data clipped by the clipping means with an SD Profile Box specified in the SD-Video standard; Equipped with.

1 is a block diagram schematically showing the configuration of a television receiver according to an embodiment of the present invention. The figure which simplifies and shows the data structure of an ISO file format. The figure shown in order to demonstrate the Box structure row | line | column which considered cutting-out of embodiment. The figure which shows the data sequence after the cutout of the embodiment. The moov construction | assembly flowchart of the cut-out area used for the embodiment. The figure which shows the case where the free box is inserted in trak of the other form.

Embodiments of the present invention will be described below.
(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
The present invention can be applied to all digital media playback devices such as a digital television and a car navigation device having a video / audio content playback function.
(Configuration and operation of broadcast receiver)
First, a television receiver according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a block diagram showing an example of the configuration of a television receiver such as a digital broadcast receiver which is an embodiment of an information processing apparatus to which the system shown in FIG.

This television receiver can receive terrestrial analog broadcast waves, BS, CS, and terrestrial digital broadcast waves, and includes a microprocessor 10, a digital tuner 11, an analog tuner 12, a digital demodulator 13, and an analog demodulator. 14 and TS decoder 15 are provided.

BS, CS, and terrestrial digital broadcast waves are received by the antenna 1, and this received signal is supplied to the digital tuner 11. Similarly, the terrestrial analog broadcast wave is received by the antenna 1, and this received signal is supplied to the analog tuner 12. The digital tuner 11 and the analog tuner 12 employ a phase-locked loop (PLL) system, and select desired broadcast waves by designating reception parameters such as a center frequency and a bandwidth under the control of the microprocessor 10. Used for.

For example, in the case of Japanese terrestrial digital broadcasting, the received signal of the broadcast wave selected by the digital tuner 11 is sequentially supplied to an OFDM (orthogonal frequency division multiplexing) digital demodulator 13 and a TS decoder 15. Demodulated and decoded into digital video and audio signals. The received signal selected by the analog tuner 12 is supplied to an analog demodulator 14 where it is demodulated into an analog video signal and an audio signal.

The television receiver further includes a signal processing unit 16, a graphic processing unit 17, an OSD (on
screen display) signal generator 18, video processor 19, display 20, audio processor 21
A speaker 22, an operation panel 23, an infrared light receiver 24, a remote controller 25, a flash memory 26, a USB (Universal Serial Bus) connector 27, a card connector 28, and a network communication circuit 29. The signal processing unit 16 selectively performs predetermined digital signal processing on the digital video signal and the audio signal from the TS decoder 15 and outputs them to the graphic processing unit 17 and the audio processing unit 21, respectively. The signal processing unit 16 selectively digitizes the analog video signal and the audio signal from the analog demodulator 14, performs predetermined digital signal processing on the digitized video signal and audio signal, The data is output to the graphic processing unit 17 and the audio processing unit 21.

The graphic processing unit 17 applies OSD to the digital video signal output from the signal processing unit 16.
The OSD signal generated by the signal generator 18 is selectively superimposed and output. The video processing unit 19 performs conversion such as size adjustment for adapting to the display 20 with respect to the digital video signal output from the graphic processing unit 17. The display 20 displays a video corresponding to the video signal output from the video processing unit 19. The audio processing unit 21 performs conversion such as volume adjustment for adapting the digital audio signal output from the signal processing unit 16 to the speaker 22. The speaker 22 reproduces sound corresponding to the sound signal output from the sound processing unit 21.

The microprocessor 10 receives the operation information from the operation panel 23 or the operation information transmitted from the remote controller 25 and received by the infrared light receiver 24, and controls each component so that the operation content is reflected. Here, the operation panel or keyboard 23 and the remote controller 25 correspond to an operation module that functions as a user interface. FIG.
As shown, the microprocessor 10 is a central processing unit (CPU) that performs various processes and controls.
rocessing unit) 31, a ROM (read only memory) 32 for holding the control program of the CPU 31 and various initial data, a random access memory (RAM) 33 for providing a work area for temporarily storing input / output information of the CPU 31, It includes an interface 34 for inputting / outputting setting information and control information for each component via an I ² C bus or the like, and a clock circuit 35 which is corrected according to time information and date information acquired via a broadcast wave or a network.

The USB connector 27 is provided for connecting various USB devices. The card connector 28 is provided for connecting various media cards. The network communication circuit 29 is connected to the Internet directly or via a LAN (local area network). When the time information is acquired from the broadcast wave, the signal is received by the antenna 1, and when the basic data such as time information is acquired from the network, the time information is acquired by the microprocessor 10 from the network communication circuit 29.

The USB connector 27 and the card connector 28 can read a moving image, a photograph, and music data by connecting a USB device (memory or the like) or a media card from the outside.
The microprocessor 10 captures a video held as a file in a USB memory connected to the USB connector 27 or a media card connected to the card connector 28, and the signal processing unit 16, the graphic processing unit 17, and the video processing unit 19 Through this process, control is performed to display each image on the display 20.

In addition, regarding the following FIG. 1, although the description corresponding to the hard disk H is omitted, it may be provided as the USB device and constitute a storage medium.
FIG. 2 is a diagram showing a simplified data structure of the ISO file format.
As shown in FIG. 2, the ISO file format Box configuration usually includes moov 201 for storing metadata of media data such as management information of moving images and audio samples, and moving image and audio sample data. Mdat 202 for storing such actual media data.

The moov 201 includes a box 203 called trak corresponding to each piece of media data. Further, the media data in the mdat 202 is divided and stored in a set of a plurality of samples of continuous moving images and sounds called chunks.
An array of chunks is stored in the field. The size of the chunk and the number of included samples are not particularly limited, and a chunk having an arbitrary size and number of samples can be configured and stored according to the environment and situation.

In such an ISO file format, a data structure for specifying a random access point is defined as information for random access (special playback) processing.

Random access is performed mainly by using a child box included in stbl 204.
stts (time-to-sample) 205 indicates the time corresponding to the sample of the track. Use this Box to find the first sample before a given time.

Here, stts 205 is taken as an example, but even using a box called ctts (not shown), it is also possible to find the first sample before a given time.

However, since the found sample may not be a random access point, it is necessary to examine the following Box in order to find the nearest random access point.

stss (sync sample table) 206 indicates which sample is an actual random access point. Using this Box, the first sample number before a given time can be found. When there is no stss 206, it indicates that all samples are random access points, and therefore random access is facilitated.

At this point, the sample number to be used for random access could be found. Next, to determine which chunk this sample number is placed in, stsc (s
ample-to-chunk) 207.

Furthermore, stco (chunk offset) 208 is used to resolve where the chunk starts. Here, stco is taken as an example, but it is also possible to know the offset position of a chunk in the same manner by using a box called co64 (64-bit chunk offset) (not shown).

Starting from this offset, the size of each sample existing up to the position where the target sample is arranged in this chunk is obtained from stsz (sample size) 209, and the sum of the sizes is calculated. The position obtained by adding the total size to the target chunk offset position is the start position of the target sample.

The sample data used for random access can be specified from the mdat 202 using the sample start position and size obtained in this way.
Now, as an object of the present embodiment, for example, MP4 data is cut out so that a television program (MP4 format) recorded for a long time can be taken out on an SD card. For example, when this cut-out process is realized by software, the memory usage and the processing load are reduced as compared with a general method.

(Overview)
When creating a new MP4 data by extracting a section to be reproduced from the target MP4 data, it is a general method to select a reproduction section from the separated stream and perform re-multiplexing. mo
If ov is reconstructed, the information of the original data tends to be lost. However, if remultiplexing is performed while maintaining the information of the original data, the processing load and the memory usage during demultiplexing (demux) processing increase. m
The following procedure is required when extracting dat and creating MP4 data.

(1) Separate audio / video streams (≒ demux)
(2) Obtaining an audio / video stream in the clipping range (3) Re-multiplexing According to this procedure, detailed clipping is possible, but the memory size used is large and the processing load is high.
However, as a feature of this embodiment, the Medi is copied by copying the original data without re-multiplexing.
a Build moov after cutting out Data. That is, stbl b of each track without separating the streams
Recreate below ox. For other information, copy the original as much as possible and build moov. (However, table reduction processing and duration update below the stbl box of each trak (area storing information such as the size and offset of Media data)

FIG. 3 is a diagram for explaining the Box structure sequence in consideration of the cutout according to the embodiment.
Free boxes are lined up with trak as defined in ISO 14496. What is indicated by a broken line is the assumed reduced data of each audio / video trak (see FIG. 4).

SD Profile Box (sdvp) needs to be inserted when transferring data to the SD card, but 26 bytes in advance (when the original data is multiplexed) (when the size of User_data and Extra_data area is 0) Insert the free box.

FIG. 4 is a diagram illustrating a data string after extraction according to the embodiment.
The reduced data of trak indicated by the broken line is made available as a free area of sdvp.
(Explanation of flowchart)
FIG. 5 is a moov construction flow diagram of a cut-out section used in the embodiment. This flowchart shows a case where MP4 data multiplexed with the Box structure of FIG. 3 is cut out for an SD card. Hereinafter, details will be described in order from step S1-1 mainly controlled by the microprocessor 10.

<Preparation>
Step S1-1: Designate a range to be cut out in time units. (In this example, the time unit is specified, but any unit is acceptable as long as the extraction range can be detected on the stbl box)

Step S1-2: In MP4 data, samples are managed by serial numbers from the beginning, and in order to acquire the stbl box size after extraction, a sample number corresponding to the extraction range is acquired.

Step S1-3: The table size of each Box below the stbl box is estimated based on the sample number acquired in Step S1-2, and the cut out stbl box size is acquired.

(Decrease in size of stbl box after clipping) diff [bytes] is (original stbl box
(Size) minus (stbl Box size after cut out).

The above steps S1-2 to S1-3 are performed for all tracks, and diff obtained in step S1-3 is the total size for all tracks.
<Moov construction after cutting out>
Step S1-4: Copy from moov to the end of mvhd. (Note that duration and mod
Parameters that must be updated with the latest information, such as ification_time, are step S1
Correspond with -9. )

Step S1-5: Replace the prepared free box with sdvp box. Fr prepared in advance
Since ee box is for User_data_len = 0 and Extra_data_len = 0, step
The area for diff obtained in S1-3 is used for User_data or Extra_data.

The contents of the free box should be data that should be described as an sdvp box. This makes box typ
Only e and box size need be rewritten.

<Process for each trak>
Hereinafter (from step S1-6 to step S1-8, processing is performed for each inserted trak.
Step S1-6: Copy stbl box (just before child box) from trak.
Step S1-7: Based on the information obtained in Step S1-2 and Step S1-3,
Constructs a child box.
Step S1-8: Steps S1-6 to S1-7 are executed for all traks.
<Update required data>
Step S1-9: Update the size of each box of trak whose size is smaller than stbl box. In addition, duration, modifictaion_time, etc. are updated as necessary.

<End processing>
Step S1-10: If uuid etc. is inserted in moov, copy it as it is.
Step S1-11: Construction of moov is completed.
In the first embodiment described above, it is possible to obtain an effect simply by configuring a single free box that is the same as trak.
(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. 1 to 2 and FIG. Embodiment 1
A description of the same parts as those in FIG.
FIG. 6 is a diagram showing a case where a free box is inserted in trak.
Regarding the size of the stbl box after cutting, when the decrease is 9 [bytes] or more, it can be replaced with a free box (see Patent Publication No. P2009-239861 by the present inventor). fr
If you insert the ee box and keep it the same size as the original, you will not need to rearrange the trak. However, if the decrease is less than 9 [byte], it cannot be replaced with a free box.

Therefore, a free box with a box size of 9 [bytes] is inserted in advance at the end of each trak. As a result, even if the decrease is less than 9 [bytes], the free box inserted in advance
Can be absorbed.

Since trak is not demultiplexed as described above, the memory size required for software processing is small in this embodiment. This is particularly useful for long-time content editing.

(1) A free box is inserted assuming that a section to be reproduced is partially extracted from MP4 data and another MP4 data is created. When taking out the cut-out MP4 data on an SD card, replace the inserted free box header with an sdvp box for the SD card. This makes it possible to create new MP4 data by simple data replacement without re-multiplexing.

(2) When a section to be reproduced is partially extracted from MP4 data, information relating to reproduction of each track (data below the stbl box) is reduced. User_dat of the sdvp box
a or slide each track backwards for use as Extra_data, and User_ in the sdvp box
Prepare data or Extra_data area. This allows SD to remain moov size
Can meet MP4 specifications for cards.

That is, in the case of MP4 data having a Box structure in which mdat is present following moov, the storage destination offset value must be updated when the data size of moov changes. Even if Mdat is cut out, if the end position of moov is the same, there is no need to consider the data length of moov.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can implement in various modifications.
Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements according to different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 10 ... Microprocessor, 16 ... Signal processing part, 17 ... Graphic processing part, 18 ... O
SD signal generation unit, 19 ... Video processing unit, 20 ... Display, 23 ... Operation panel, 24 ... Infrared light receiving unit, 25 ... Remote control, 26 ... Flash memory, 27 ... USB connector, 28 ...
Card connector, 29... Network communication circuit, R.

Claims (4)

A cutout means for cutting out data in data having a data structure defined in ISO 14496 and consisting of metadata at the beginning of the data and media data following the metadata;
The IS of the metadata corresponding to the head portion of the data cut out by the cut-out means
SD that prescribes the free box specified in O14496 to the SD-Video standard
An information processing apparatus comprising replacement means for replacing with a Profile Box. The information processing apparatus according to claim 1, wherein the free box is lined up with trak defined in ISO 14496. The information processing apparatus according to claim 1, wherein the free boxes are arranged below a trak defined in ISO 14496. The cutout means has a data structure defined in ISO 14496, and executes cutout in data composed of metadata at the head of data and media data following the metadata,
The update means defines a free box defined in ISO 14496 of the metadata corresponding to the head portion of the data cut out by the cutout means in the SD-Video standard.
Information processing method to replace with Profile Box.

Images