JP2012105194A - Moving image reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which reduces memory consumption in reproduction of moving image.SOLUTION: A moving image reproduction device reproduces a moving image by decoding moving image data subjected to differential encoding. The moving imaging data comprises: a referred frame; a difference frame indicating difference information on difference from the referred frame; and frame information indicating the positions of the referred frame and the difference frame on a medium. The image reproduction device extracts, from the moving image data, the frame information indicating the position of not the difference frame but the referred frame, reads the frame information onto memory, reads the moving image data on the basis of the frame information on the memory, and decodes and reproduces the moving image.

Description

  The present invention relates to a technique for reproducing a differentially encoded moving image file.

  The moving image file includes header information, actual data, and frame information (index). When the moving image file is reproduced, the index is expanded on the memory, and the actual data is read and decoded from the position indicated by the index selected by the user operation or the like, and the moving image is reproduced.

Japanese Patent Laid-Open No. 10-312650

In recent years, with the advancement of functions such as mobile phones and car navigation systems, more and more can reproduce moving images. When a moving image is played back by an embedded microcomputer, such as a mobile phone or a car navigation system, there is a problem in that the amount of memory used is not sufficient, leading to tight use of the memory. Especially in the case of devices that play videos in parallel with main functions (telephone functions, navigation functions, etc.), such as mobile phones and car navigation systems, the amount of memory that can be allocated for video playback is limited. There is a tendency to run out of free memory.
Therefore, simply increasing the memory leads to an increase in the size of the apparatus and the number of parts.

  In view of the above problems, an object of the present invention is to reduce the amount of memory used when reproducing a moving image.

The video playback device of the present invention is
Decoding differentially encoded moving image data having a referenced frame, a difference frame indicating difference information between the referenced frame, and frame information indicating positions of the referenced frame and the difference frame on the medium; A video playback device for playing back video,
A frame management unit that extracts frame information indicating a position of a referenced frame that is not a difference frame from the moving image data, and reads the frame information on a memory;
A decoding unit that reads the moving image data from the medium based on the frame information on the memory, decodes the reproduced moving image data, and reproduces the moving image.

In addition, the moving image playback method of the present invention includes:
Decoding differentially encoded moving image data having a referenced frame, a difference frame indicating difference information between the referenced frame, and frame information indicating positions of the referenced frame and the difference frame on the medium; A video playback device that plays back video
Extracting frame information indicating a position of a referenced frame that is not a difference frame from the moving image data and reading the frame information on a memory;
Reading the moving image data from the medium based on the frame information on the memory, decoding and reproducing the moving image.

  In order to solve the above problem, the present invention may be a moving image reproduction program for causing a computer to execute the moving image reproduction method. Further, the moving image reproduction program may be stored in a computer-readable storage medium. The function can be provided by causing the computer to read and execute the program of the storage medium.

  Here, the computer-readable storage medium refers to a storage medium that stores information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read from the computer. . Examples of such storage media that can be removed from the computer include a flexible disk, a magneto-optical disk, a CD-ROM, a CD-R / W, a DVD, a DAT, an 8 mm tape, and a memory card.

  Further, there are a hard disk, a ROM (read only memory) and the like as a storage medium fixed to the computer.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which reduces the memory usage at the time of moving image reproduction can be provided.

Schematic configuration diagram of video playback device Illustration of MPEG file format Illustration of AVI file format Illustration of video playback method The block diagram which shows the structure of the AVN integrated machine which employ | adopted the moving image reproducing device of this invention

  FIG. 1 is a schematic configuration diagram of a moving image reproducing apparatus according to the present embodiment. The moving image playback apparatus 10 of this embodiment includes a CPU 1, a main memory 2, an input / output interface 3, an input unit 4, an output unit 5, and an auxiliary storage device 6.

The input unit 4 is means for inputting moving image data to the CPU 1, and is, for example, a DVD drive, a memory card reader, a TV tuner, or the like. Further, the input unit 4 includes an operation unit that inputs instructions such as reproduction, stop, fast forward, rewind, and scene movement of a moving image by a user operation.
The output unit 5 is a means for outputting a moving image, for example, a display device and a speaker.

The main memory 2 is a main storage device that exchanges data such as data, programs, and instructions with the CPU 1 and temporarily stores the information.
The auxiliary storage device (nonvolatile memory) 6 is a nonvolatile storage means for storing data and programs.

  The CPU 1 is an arithmetic processing unit that executes processing according to a program. In the present embodiment, the CPU 1 also functions as a data acquisition unit, a frame management unit, a decoding unit, and an output control unit.

  The data acquisition unit acquires data of the moving image from the medium when the reproduction of the moving image is instructed. The media from which the moving image data is acquired is a broadcast medium or a broadcasting station via a moving image data transmitted from another computer in addition to a storage medium such as a DVD, an HD (hard disk), or a memory card. Also good.

The frame management unit extracts the frame information (index) of the referenced frame from the moving image data and reads it onto the main memory. In the moving image data of the present embodiment, the frames constituting the moving image are differentially encoded, the difference frame indicating difference information between the referenced frame and the referenced frame, and the positions of the referenced frame and the difference frame. Frame information. For example, FIG. 2 is a diagram showing an MPEG4 file format, and FIG. 3 is a diagram showing an AVI file format.

  As shown in FIG. 2, an MPEG4 moving image file is composed of data blocks called BOX or ATOM, ftyp storing information indicating a standard to which the moving image file complies, moov storing frame information, It has mdat that stores the actual data of video and audio.

  The moov box 91 has a nested structure including a box storing an index of audio data and an index of moving image data. For example, the moov box 91 includes a BOX 92 in which a video header and a video index are stored. As the index, a BOX (stss) 93 that stores a randomly accessible position (frame number) or a BOX (frame size) that stores a frame size (frame number). stsz) 94 is included.

  The stss box stores the number of a randomly accessible frame, that is, the number of a referenced frame (I frame). Therefore, the frame management unit reads out the frame size corresponding to the key frame No. from the stsz box and obtains the offset of the key frame from the frame size before the key frame, for example, the data size from the beginning of the file to the key frame. The offset and the frame size are read out as a key frame position on the memory.

  Also, as shown in FIG. 3, the AVI moving image file includes a moving image file header 81, actual data 82, and an index 83.

  This index 83 is a key frame position such as a key frame position and its sound position 83A, a difference frame position and its sound position 83B, a difference frame position and its sound position 83C, a key frame position and its sound position 83D. And the difference frame position. The frame management unit extracts the key frame position and the sound position thereof, and reads them onto the main memory.

  The moving image data is not limited to an MPEG4 file or an AVI file, but may be any data including frame information such as an ASF file or a DMF file.

  The key frame position extraction method may be a method of selectively reading a key frame with reference to information indicating whether it is a frame type, that is, a referenced frame (key frame), or periodically storing the key frame position. In this case, the key frame position may be selectively read onto the main memory in accordance with this cycle.

  At this time, not only the key frame is selected, but both the key frame position and the difference frame position are once read on the main memory, and the difference frame position is selectively deleted to leave the key frame position on the main memory. Things can be used. Also, not only reading all key frame positions, but reading key frame positions every predetermined number, or when the matching degree is less than a predetermined value by comparing key frames (for example, when there is a scene change) Alternatively, the key frame position may be read out.

The decoding unit (decoder) reproduces the moving image by decoding the differentially encoded moving image data. For example, when resume playback, fast forward, frame advance, rewind, or the like is selected by the user's operation, and the frame management unit sends the index of the frame to start playback to the decoding unit, the decoding unit executes the actual data after the position indicated by the index. Data is acquired from the input unit 4 and decoded. Here, the decoding unit decodes not only image data but also audio data.

  The output control unit (renderer) generates a video signal in a format suitable for the display device of the output unit 5 based on the moving image data decoded by the decoding unit, sends the video signal to the display device for display, and based on the moving image data An audio signal is generated and sent to the speaker of the output unit 5 to output the audio.

  A moving image playback apparatus 10 shown in FIG. 1 is a computer in which the CPU 1 executes processing in accordance with a program (software). By this processing, functions of a frame management unit and a decoding unit are realized, and so-called software decoding is performed. However, the present invention is not limited to this, and a device that performs so-called hardware decoding in which functions such as a frame management unit and a decoding unit are realized by dedicated hardware may be used.

Here, the hardware is, for example, FPGA [Field Programmable Gate Array], AS.
A circuit such as an IC [Application Specific Integrated Circuit] or an LSI [Large Scale Integration] may be provided. The hardware may include basic circuits such as an IC [Integrated Circuit], a gate array, a logic circuit, a signal processing circuit, and an analog circuit.

  As the logic circuit, for example, an AND circuit (logical product circuit), an OR circuit (logical sum circuit), a NOT circuit (negative circuit), a NAND circuit (negative logical product circuit), a NOR circuit (negative logical sum circuit), There are flip-flop circuits and counter circuits. The signal processing circuit may include a circuit that performs, for example, addition, multiplication, division, inversion, product-sum operation, differentiation, and integration on the signal value. The analog circuit may include, for example, a circuit that performs amplification, addition, multiplication, differentiation, and integration on the signal value.

FIG. 4 is an explanatory diagram of a moving image reproducing method by the moving image reproducing apparatus having the above configuration.
A user sets a storage medium such as a DVD or a memory card in the moving image playback apparatus 10, or selects and plays back a moving image file (moving image data) stored in a storage medium such as a hard disk or a semiconductor main memory in the moving image playback apparatus 10. Is issued, the moving image reproducing apparatus 10 starts the moving image reproducing process of FIG. 4, and the moving image data is acquired from the storage medium by the data acquisition unit (step S1).

  Next, the frame management unit reads a header from the acquired moving image file (step S2), and determines whether or not it is a previously reproduced moving image (step S3). Note that the frame management unit stores in advance the identification information such as the ID of the video that was played last time in the nonvolatile memory 6 in advance, compares this with the identification information of the header read in step S2, and the video that was played last time. It is determined whether or not. The identification information stored in advance may be stored not only the previous time but also a predetermined number, and it may be determined whether or not the video is stored.

  As a result of the comparison in step S3, if it is not the previously reproduced moving image, the frame management unit extracts the frame information of the referenced frame included in the index of the moving image file, that is, the position of each key frame from the index, and stores it on the main memory 2. (Step S4). The frame management unit also stores the read key frame position in the nonvolatile memory 6 for the resume function. If the resume function is not used, the storage in the nonvolatile memory 6 may be omitted and the main memory 2 may be used.

  Then, the frame management unit reads the key frame position according to the instruction from the main memory 2 and sends it to the decryption unit (step S5). Here, since the instruction in step S2 is a reproduction instruction and is not a previously reproduced moving image file, the first key frame position is sent to the decoding unit.

  The decoding unit sequentially reads the actual data at the key frame position received from the frame management unit, that is, the key frame at the position and the subsequent frames from the storage medium, decodes the decoded moving image data (video data and audio data) Is sent to the output control unit. The output control unit converts the moving image data into an output format, sends it to the output means, and causes the output means to output a moving image (step S6). Specifically, the output control unit converts the video data into a video signal and sends it to the display device to display the video, and converts the audio data into a voice signal and sends it to the speaker to output the voice.

  Then, when playback stop is instructed by a user operation or the like, each unit stops playback processing and stops output of the moving image, and the frame management unit sets the position of the last played key frame at the time of stop to the last key frame The position is stored in the nonvolatile memory 6 (step S7).

  Next, when the reproduction of the moving image is instructed, the frame management unit reads the header from the acquired moving image file (step S2), and determines whether or not it is the previously reproduced moving image (step S3), as described above.

  As a result of the comparison in step S3, if it is a previously reproduced moving image, the frame management unit reads out the last key frame position stored in step S7 from the nonvolatile memory 6 and sends it to the decoding unit (step S8). Further, the key frame information stored in step S4 is read out from the nonvolatile memory 6 onto the main memory 2.

  The decoding unit sequentially reads and decodes the actual data at the last key frame position received from the frame management unit from the storage medium, sends the decoded moving image data to the output control unit, and the output control unit outputs the moving image data to the output format. And the moving image is output by the output means (step S6).

  By holding the last key frame in this way, even after the reproduction is stopped, when the reproduction is instructed again, the reproduction can be performed from the stopped position.

  When special playback such as frame advance, 30-second advance, fast-forward (X playback), movement to the next or previous scene, or rewind (reverse playback) is instructed, the frame management unit The frame position is read from the main memory and sent to the decoding unit. For example, when an instruction to send 30 seconds is received, the key frame position 30 seconds after the currently reproduced frame is read from the main memory and sent to the decoding unit. Also, if the key frame position at the beginning of each scene is set in advance and the movement to the next scene is instructed, the frame management unit reads the key frame position at the beginning of the next scene from the main memory. To the decryption unit.

  As described above, according to the present embodiment, by holding the key frame position on the main memory, it is possible to reproduce a moving image, and the difference frame position is not held on the main memory, so that the main memory usage can be reduced. .

  Next, an in-vehicle audio / visual navigation integrated machine (hereinafter referred to as an AVN integrated machine) that employs the moving picture reproducing apparatus of the present invention will be described.

FIG. 5 is a block diagram showing a configuration of an AVN integrated machine that employs the moving image playback apparatus according to the present embodiment.
100 inputs each part of the AVN integrated machine, or a signal from a connected external device, an operation instruction signal from each operating part based on the user's operation, etc., and each part of the AVN integrated machine based on these signals, or A control unit that comprehensively controls external devices, which is configured by, for example, a microcomputer and operates according to a program stored in a memory such as a ROM.

  Reference numeral 101 denotes an external storage medium playback unit (semiconductor audio), a data acquisition circuit (data acquisition unit) that reads data from a memory connected to a connector, and a frame of a reference frame when the data is moving image data A frame management circuit (frame management unit) that extracts information and reads it onto the memory, and a decoding circuit (decoding unit) that decodes moving image data based on the frame information.

  Reference numeral 102 denotes a radio receiver that selectively receives a broadcast wave having a specific frequency from broadcast waves received by an antenna, demodulates and outputs an audio signal of the broadcast, and includes a tuning circuit, a demodulation / decoding circuit, and the like Is done. The radio receiving unit 102 is controlled by a control signal from the control unit 100 to perform various operations such as on / off of the radio receiving unit 102 and reception frequency selection (tuning).

  Reference numeral 103 denotes a television (TV) receiver that selectively receives a broadcast wave of a specific frequency from broadcast waves received via the selector 113, demodulates it, and outputs an audio signal and an image signal of the broadcast. A demodulation circuit (data acquisition unit), a frame management circuit, a decoding circuit, and the like. Various operations such as ON / OFF of the TV receiver 103 and selection of a reception frequency (channel selection) are controlled by a control signal from the controller 100.

A disk playback unit 104 reads data stored on the disk with a pickup and outputs an audio signal and an image signal (for example, in the case of a DVD or BD (Blu-ray Disc)) based on the read data. It includes a pickup (data acquisition unit), a pickup / disk drive mechanism, a control circuit for the pickup / disk drive mechanism, a frame management circuit, a decoding circuit, and the like. The disc playback unit 104 is controlled by the control signal from the control unit 100 to perform various operations such as on / off and designation of the reading position.

  Reference numeral 105 denotes a hard disk (HD), which is a magnetic storage medium, which stores music data such as MP3 files, image data such as JPEG files, moving picture data such as MPEG4, map data for navigation, and the like from various stored data. Is an HD playback unit that reads and outputs the data, and includes an HD drive, a data acquisition circuit that reads data from the HD drive, a frame management circuit, a decoding circuit, and the like. The HD playback unit 105 is controlled by the control signal from the control unit 100 to perform various operations such as on / off and selection of data to be read.

  130 displays the position of the host vehicle and the route to the destination on the map, and provides direction guidance such as a right or left turn by voice or the like at an intersection or the like, and traffic information, GPS information from the VICS information receiving unit 106 described later A navigation unit that obtains and displays vehicle position information from the receiving unit 107 and provides route guidance to a destination. A hard disk (HD) that stores map information used for navigation, various arithmetic processes And a memory such as a RAM for storing data for various processes. The on / off and various operations are controlled according to a control signal from the control unit 100.

  A VICS information receiving unit 106 receives traffic information related to the traffic information communication system (VICS (registered trademark)) and outputs the received traffic information. A receiver (FM reception) receives data from the traffic information communication system. Machine, radio beacon receiver, optical beacon receiver), decoding circuit for decoding received data, and the like. Reference numeral 107 denotes a GPS information receiving unit that detects the position of the vehicle based on a GPS signal from a GPS (registered trademark) satellite and outputs the detected current location information. A GPS signal receiving circuit that receives the GPS signal; It is comprised from the calculating part which calculates the own vehicle position based on it.

  Reference numeral 119 denotes a camera that captures an image of the surroundings of the vehicle and inputs moving image data (video data and audio data) via the external audio / video input unit 118. Video data photographed by the camera 119 is displayed on the display unit 113 via the distribution circuit 108, the image adjustment circuit 109, and the image output unit 112, and is used for parking assistance or the like. The moving image data shot by the camera 119 may be stored in the HD drive or the memory 115 in the HD playback unit 105 via the distribution circuit 108 for a drive recorder or the like.

  Reference numeral 108 denotes various sources (external storage medium playback unit 101, radio reception unit 102, TV reception unit 103, disc playback unit 104, HD playback unit 105, navigation unit) designated to be output by the control signal of the control unit 100. 130) a distribution circuit that outputs the audio signal and the video signal to the audio adjustment circuit 110 and the image adjustment circuit 109, and includes a switch group including an electronic circuit such as a relay or a switching transistor.

  Reference numeral 109 denotes an image adjustment circuit that adjusts brightness, color tone, contrast, and the like of an input image signal according to a control signal of the control unit 100, and outputs each adjusted image signal. A memory that stores image data, an image It is composed of an arithmetic circuit such as a digital signal processor for arithmetic processing of data.

  Reference numeral 110 denotes a sound adjustment circuit that adjusts the volume and sound of an input sound signal according to a control signal of the control unit 100 and outputs the adjusted sound signal. A memory for storing sound data and arithmetic processing of image data It consists of an arithmetic circuit such as a digital signal processor, an amplification / attenuation circuit composed of transistors, resistors, capacitors, coils, etc., a resonance circuit, and the like. Reference numeral 111 denotes a speaker that outputs the audio signal input by the audio adjustment circuit 110 as audio.

  112 receives a video signal input from the image adjustment unit and a display image signal to be displayed on the display unit from the control unit 100 and performs processing such as image synthesis, and the display unit based on the processed image signal 113, for example, an image ASIC that is an arithmetic processing circuit specialized for an image that performs image processing by arithmetic processing, a video memory that stores image data for image processing / output, and an image output It is composed of an image driving circuit for driving the display unit based on image data stored in the video memory.

  The display unit 113 includes a touch panel 131, a liquid crystal panel 132, and a backlight 133. A video is drawn on the liquid crystal panel 132 by a video signal from the image output unit 112, and a video such as a moving image is displayed by the backlight 133 illuminating from behind. The display unit 113 displays an operation menu or the like on the liquid crystal panel 132, detects an operation selected by the user by touching the operation menu on the touch panel 131 superimposed on the liquid crystal panel 132, and detects the detected operation signal. Enter 100.

  The display unit 113 may be a flat panel display other than a liquid crystal panel, such as an organic EL display panel, a plasma display panel, a cold cathode flat panel display, or the like.

Reference numeral 114 denotes an operation unit for the user of the apparatus to perform various operations, and includes, for example, a push button switch, a rotation operation switch, a joystick, and the like. Reference numeral 115 denotes a memory (storage medium) that stores various types of data and control programs, and includes, for example, an HDD (Hard Disk Drive), a rewritable flash memory, and the like.

116 is installed in a place away from the AVN integrated machine main body installed on the instrument panel or the like in the automobile, for example, near the armrest between the driver seat and the passenger seat, or in the steering wheel, and outputs the operation state of the input operation by the user. In this example, a rotation operation, tilting operation, and pressing operation of the operation unit are detected by the remote operation unit (remote control). Such a remote control unit includes a rotary encoder that outputs a signal corresponding to the rotation operation amount and direction, a tilt sensor such as a joystick that includes a pressure sensor and outputs a signal corresponding to the tilt operation direction, and a pressing operation. It consists of a push switch whose on / off state changes. The operation signal detected by the remote control 116 is sent to the remote control transmission / reception unit 117 and input to the control unit 100.

Reference numeral 120 denotes an ETC vehicle-mounted device that automatically pays a fee by communicating with a terminal on the ETC lane side in an ETC (registered trademark: Electronic Toll Collection) system.
Reference numeral 121 denotes a communication unit that communicates with other devices via a communication line. The communication unit 121 may include a data acquisition circuit, a frame management circuit, a decoding circuit, and the like, and may reproduce the moving image data acquired via the communication line and display it on the display unit 113.

  The external storage medium playback unit 101, the TV reception unit 103, the disk playback unit 104, the HD playback unit 105, and the communication unit 121 each include a data acquisition circuit, a frame management circuit, a decoding circuit, and the like. Similar to the apparatus, when reproducing moving image data, the frame information of the referenced frame is extracted and read out on the memory, and the moving image data is decoded based on this frame information to reproduce the moving image.

  As a result, the external storage medium playback unit 101, the TV reception unit 103, the disk playback unit 104, the HD playback unit 105, and the communication unit 121 can play back video from any position based on the frame information (key frame position). However, it is possible to reduce the amount of memory used during the reproduction of the moving image.

10 Movie playback device 1 CPU
2 Main memory 3 Input / output interface 4 Input unit 5 Output unit 6 Auxiliary storage device

Claims (9)

Decoding differentially encoded moving image data having a referenced frame, a difference frame indicating difference information between the referenced frame, and frame information indicating positions of the referenced frame and the difference frame on the medium; A video playback device for playing back video,
A frame management unit that extracts frame information indicating a position of a referenced frame that is not a difference frame from the moving image data, and reads the frame information on a memory;
A decoding unit that reads the moving image data from the medium based on the frame information on the memory, decodes and reproduces the moving image;
A video playback device comprising:   The moving image reproducing apparatus according to claim 1, wherein frame information of a predetermined number of referenced frames is extracted from a plurality of the referenced frames included in the moving image data and is read onto the memory.   When the reproduction of the moving image is stopped, the extracted frame information of the referenced frame is stored in a nonvolatile memory, and when the moving image is reproduced again, the frame information of the referenced frame is stored in the memory from the nonvolatile memory. The moving image reproducing device according to claim 1 or 2, wherein the moving image reproducing device is read out. Decoding differentially encoded moving image data having a referenced frame, a difference frame indicating difference information between the referenced frame, and frame information indicating positions of the referenced frame and the difference frame on the medium; A video playback device that plays back video
Extracting frame information indicating a position of a referenced frame that is not a difference frame from the moving image data and reading the frame information on a memory;
Reading the moving image data from the medium based on the frame information on the memory, decoding and reproducing the moving image;
How to play video.   The moving image reproducing method according to claim 4, wherein frame information of every predetermined number of referenced frames is extracted from a plurality of the referenced frames included in the moving image data and read onto the memory.   When the reproduction of the moving image is stopped, the extracted frame information of the referenced frame is stored in a nonvolatile memory, and when the moving image is reproduced again, the frame information of the referenced frame is stored in the memory from the nonvolatile memory. The moving image reproducing method according to claim 4 or 5, wherein the moving image reproducing method is read out. Decoding differentially encoded moving image data having a referenced frame, a difference frame indicating difference information between the referenced frame, and frame information indicating positions of the referenced frame and the difference frame on the medium; On the computer that plays the video,
Extracting frame information indicating a position of a referenced frame that is not a difference frame from the moving image data and reading the frame information on a memory;
Reading the moving image data from the medium based on the frame information on the memory, decoding and reproducing the moving image;
A video playback program for running   The moving image reproduction program according to claim 7, wherein frame information of every predetermined number of referenced frames is extracted from a plurality of the referenced frames included in the moving image data and read onto the memory. When the reproduction of the moving image is stopped, the extracted frame information of the referenced frame is stored in a nonvolatile memory, and when the moving image is reproduced again, the frame information of the referenced frame is stored in the memory from the nonvolatile memory. The moving image reproducing program according to claim 7 or 8, wherein the moving image reproducing program is read out.
Clarified that difference frames are not extracted. This is the difference from the previous point in that the amount of memory is reduced.

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