JP5493564B2 - Movie output device, movie output method and program - Google Patents

Description

  The present invention relates to a moving image output apparatus, a moving image output method, and a program, and more particularly, to a moving image output apparatus, a moving image output method, and a program that perform output after buffering moving image data.

  As described in Patent Documents 1 and 2, in the video compression method used for digital broadcasting or the like, the amount of encoded information increases or decreases depending on the content of video or audio to be displayed. Data buffering is performed to synchronize video and audio. Since the buffer is used at the time of channel switching, a waiting time is required until an image is actually displayed. Therefore, in the receiving apparatuses and digital television broadcast receivers of Patent Documents 1 and 2, a technique for shortening the waiting time is described. ing.

  In Patent Document 1, when changing the channel of digital TV broadcasting using radio waves, the video signal is output when the channel is changed by outputting the first decoded video signal without waiting for the display time of the video / audio received and output by the tuner. The time is shortened.

  In Patent Document 2, when a channel of digital TV broadcasting is changed, playback is started at a lower playback speed than the normal playback speed, and after the channel switching process is stabilized, the normal playback speed is set, so that video switching output at the time of channel change is performed. The time is shortened.

  In recent years, video stream distribution services using the Internet have increased, and among them, IPTV (Internet Protocol TeleVision) broadcasts and VOD (Video On Demand) broadcasts that use NGN (Next Generation Network) to perform IP retransmission of terrestrial digital broadcasts. ) Streaming of multi-channel video streams such as broadcasting is increasing. On the receiver side of such a moving image stream distribution service, moving image data is buffered in consideration of the quality of the transmission path (data delay, fluctuation, loss, retransmission, etc.).

  FIG. 8 is a diagram showing a change in the buffer amount of video data and audio data and a data output timing in the moving image stream receiving apparatus. As shown in the figure, video data and audio data buffering is started from the occurrence of a channel viewing request from the user, and synchronized playback of video and audio is performed when the buffer amounts exceed predetermined values (thv0, tha0), respectively. Has started.

  In Patent Document 3, a moving image stream received from a communication network is accumulated in a buffer, read out from the buffer at a predetermined reading interval, and reproduced and output so that the viewer does not notice when the buffer amount falls below a lower threshold. There is disclosed a stream data receiving / reproducing device that suppresses deterioration of reproduction quality due to underflow or overflow of a reproduction buffer by widening the interval and narrowing the reading interval when the buffer amount exceeds an upper limit threshold.

JP 2005-12310 A JP 2001-292181 A JP 2008-211131 A

  The digital television receiver of Patent Document 1 displays only a still image of a video signal when switching channels, and normally reproduces video and audio after data is accumulated in a buffer to some extent. There is a problem that only a still image without sound is outputted during the accumulation of the data. Further, the receiving apparatus of Patent Document 2 reproduces video at a speed slower than the normal reproduction speed until the input signal is stabilized, and the sound is muted (silent state) as in Patent Document 1.

  Thus, in the method of outputting only the video first, there is a possibility that the viewer may suspect a failure. Further, paragraph 0047 of Patent Document 2 states that “an audio signal may be decoded at a low decoding processing speed as in the case of a video signal”, but decoding is performed at a low decoding processing speed as in the case of a video signal. In this case, there is a problem that the output sound is extended and the contents are difficult to hear.

  Even in a video stream distribution service that uses an IP network or the like instead of radio waves, as described in Patent Document 3, a certain amount of buffer is considered in consideration of the quality of the transmission path (data delay, fluctuation, loss, retransmission, etc.). Since a ring is necessary, there is no change in the situation that it takes time until an image is displayed.

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is to provide a user who makes a viewing request to a device that performs output after buffering the moving image data and waits for the start of reproduction. Another object of the present invention is to provide a configuration that allows a user to view an uncomfortable voice together with an image.

According to the first aspect of the present invention, a buffer that separates and stores video data received from a distribution source into video data and audio data, and starts after the buffer amount of the video data reaches a predetermined value. Before normal playback, the video data being stored is used to output a still image or video data at a lower speed than the playback speed during normal playback, and at least a predetermined value asynchronously with the playback of the video data. of a control unit which outputs the audio data at a reproduction speed, a moving picture output device Ru comprising a further audio level detection for detecting a silent section of the audio data according to whether it is audio level below a predetermined And a moving image output apparatus that executes a process of extending the silent section at a predetermined rate .

According to the second aspect of the present invention, the step of storing the video data received from the distribution source separately into video data and audio data and starting after the buffer amount of the video data reaches a predetermined value Before normal playback, the video data being stored is used to output a still image or video data at a lower speed than the playback speed during normal playback, and at least a predetermined value asynchronously with the playback of the video data. a of the step of outputting the audio data at a reproduction speed, the including vie output method further includes the steps of detecting a silent section of the audio data according to whether it is audio level below a predetermined, wherein And a method of extending a silent section at a predetermined rate . This method is linked to a specific machine called a moving image output device that outputs moving image data received from a distribution source.

According to the third aspect of the present invention, the process of storing moving image data received from a distribution source separately into video data and audio data and starting after the buffer amount of the video data reaches a predetermined value. Before normal playback, the video data being stored is used to output a still image or video data at a lower speed than the playback speed during normal playback, and at least a predetermined value asynchronously with the playback of the video data. A program for causing the computer to execute the process of outputting the audio data at a reproduction speed of , and further, a process of detecting a silent section of the audio data based on whether or not the audio level is lower than a predetermined level, and the silence There is provided a program for causing the computer to execute a process of extending a section at a predetermined rate . This program can be recorded on a computer-readable storage medium. That is, the present invention can be embodied as a computer program product.

  According to the present invention, it is possible to provide a sound that does not feel uncomfortable in addition to an image to a user who makes a viewing request to an apparatus that performs output after buffering moving image data and waits for the start of output.

It is a figure for explaining the outline of the present invention. It is a block diagram showing the structure of the 1st Embodiment of this invention. It is a flowchart showing operation | movement of the 1st Embodiment of this invention. It is a figure showing the transition of the buffer amount of video data and audio | voice data, and the output timing of data in the 1st Embodiment of this invention. It is a block diagram showing the structure of the 2nd Embodiment of this invention. It is a flowchart showing operation | movement of the 2nd Embodiment of this invention. It is a figure showing the transition of the buffer amount of video data and audio | voice data, and the output timing of data in the 2nd Embodiment of this invention. It is the figure showing the transition of the buffer amount of video data and audio | voice data, and the output timing of data in the moving image stream receiver mentioned as background art.

  FIG. 1 is a diagram showing an outline of the invention. The moving image output apparatus 3a according to the present invention includes a buffer 102/105 that stores moving image data received from a distribution source separately into video data and audio data, and after the buffer amount of the video data reaches a predetermined value. Before starting normal playback, the stored video data is used to output still image or video data at a lower speed than the playback speed during normal playback, and asynchronously with the playback of the video data. And a control unit 109 that outputs the audio data at a reproduction speed equal to or higher than the value.

  Specifically, when an operation for requesting the start of viewing is performed on the operation input unit 111 in FIG. 1, the moving image data receiving unit 100a starts receiving moving image data, and the video data buffer unit 102 and the audio data buffer unit In 105, video data and audio data are temporarily stored.

  The control unit 109 monitors the buffer amount of each of the buffer units 102/105, and before the video buffer amount reaches the specified amount thv0 for normal playback, the video buffer unit 102 sends video to the video decoding unit 103. Instructs to take out data and output still image or low-speed output.

  Simultaneously with the output of the video data, the control unit 109 instructs the audio decoding unit 106 to extract the audio data from the audio buffer unit 105 and output it at a predetermined reproduction speed.

  The audio output speed from the audio decoding unit 106 is asynchronous with the video output, and is slower than the normal reproduction speed but does not give the viewer a sense of incongruity (a predetermined value less than 1 × speed). To do. Thereafter, when the time information of the video data to be output and the time information of the audio data coincide with each other, the process proceeds to normal playback in which the audio data is synchronously played back at the same speed as the video data.

  Thus, according to the present invention, it is possible to provide an image with sound in a manner that does not give a sense of incongruity to a user who has performed a viewing request operation in a short time.

[First Embodiment]
Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a block diagram showing the configuration of the first exemplary embodiment of the present invention. Referring to FIG. 2, a video stream distribution device 1 that distributes a video stream, a network 2, and a video stream reception device 3 that receives a video stream via the network 2 are illustrated.

  The moving image stream distribution device 1 is a device that distributes a moving image stream to the moving image stream receiving device 3 by multicast communication, and corresponds to, for example, an IP broadcast server that redistributes an IPTV (Internet Protocol TeleVision).

  The video stream receiving device 3 includes a video stream receiving unit 100, a video stream separating unit 101, a video data buffer unit 102, a video decoding unit 103, a video output unit 104, an audio data buffer unit 105, and an audio decoding unit. 106, an audio output unit 107, a control unit 109, a moving image stream request unit 110, and an operation input unit 111.

  The moving image stream receiving unit 100 receives the moving image stream from the moving image stream distribution device 1 via the network 2 and outputs the received moving image stream to the moving image stream separating unit 101.

  The video stream separation unit 101 separates the multiplexed video stream into video data, audio data, and other data, and outputs them to the video data buffer unit 102 and the audio data buffer unit 105, respectively.

  The video data buffer unit 102 accumulates video data and provides it to the video decoding unit 103.

  The video decoding unit 103 performs a decoding process on the encoded video data so as to be played back at the playback speed specified by the control unit 109, and outputs the decoded video data to the video output unit 104.

  The video output unit 104 has a function of outputting the decoded video data.

  The audio data buffer unit 105 accumulates audio data and provides it to the audio decoding unit 106.

  The audio decoding unit 106 performs a decoding process on the encoded audio data so that reproduction is performed at the reproduction speed specified by the control unit 109, and outputs the decoded audio data to the audio output unit 107.

  The audio output unit 107 has a function of outputting the decoded audio data.

  The control unit 109 issues a stream viewing start request instruction to the video stream request unit 110 in accordance with the user instruction received by the operation input unit 111. The control unit 109 has a function of monitoring the amount of video data stored in the video data buffer unit 102 and instructing the video decoding unit 103 on the playback speed of the video data based on the result.

  The control unit 109 also monitors the amount of data stored in the audio data buffer unit 105 and, based on the result and an instruction to reproduce the video data to the video decoding unit 103, the audio data reproduction rate to the audio decoding unit 106. Has a function of instructing.

  The video stream request unit 110 has a function of making a video stream distribution request to the video stream distribution device 1 based on an instruction from the control unit 109.

  The operation input unit 111 has a function of accepting a viewing request from the user and notifying the control unit 109 by an operation button on the main body of the remote controller or the moving picture stream receiving device 3.

  Next, the operation of this embodiment will be described in detail. When a video viewing start operation is given to the operation input unit 111, the control unit 109 instructs the video stream request unit 110 to start viewing the specified video stream.

  The video stream request unit 110 that has received the instruction requests the video stream distribution apparatus 1 to distribute the instructed content via the network 2.

  FIG. 3 is a flowchart showing an operation after the moving picture stream requesting unit 110 of the moving picture stream receiving apparatus 3 requests content distribution.

  Referring to FIG. 3, the moving image stream receiving unit 100 of the moving image stream receiving device 3 receives the moving image stream distributed from the moving image stream distributing device 1 and inputs the received moving image stream to the moving image stream separating unit 101 (step S100).

  The moving image stream separation unit 101 separates the input moving image stream into video / audio and other data, and stores them in the video data buffer unit 102 and the audio data buffer unit 105, respectively (step S101).

  At the time of the separation, the moving picture stream separation unit 101 analyzes the header information of the separated video data, and extracts video reproduction time information (time stamp) and video coding information (step S102). Similarly, for the audio data, the moving image stream separation unit 101 analyzes the header information of the separated audio data, and extracts audio reproduction time information (time stamp) (step S107).

  The control unit 109 monitors the video encoding information in the video data stored in the video data buffer unit 102, and determines whether or not low-speed playback of video data can be started or is started (step S104). . For example, when video data (I frame; Intra-coded Frame) that has undergone intra-screen coding processing exists in the video data buffer unit 102, it is determined that low-speed playback is possible, and the playback speed during low-speed playback before normal playback is performed. Sv (Sv> 0) is calculated (step S105). Even if there is no intra-coded video data (I-frame; Intra-coded Frame), if the playback speed Sv is 0 or higher, the low-speed playback has already started, so the playback speed Sv is calculated. (Step S105).

  The playback speed Sv calculated in step S105 may be any slower than the normal playback speed Sn, and may be determined according to the amount of video data stored in the video data buffer unit 102, the storage speed, and the like. . Of course, the reproduction speed Sv in the period before the normal reproduction may be a predetermined fixed value.

  When video data sufficient for normal playback is stored in the video data buffer unit 102, the playback speed Sv calculated in step S105 is set to the speed Sn during normal playback. Thereby, normal reproduction is realized.

  The video decoding unit 103 decodes the video data, and outputs the decoded video data to the video output unit 104 according to the set reproduction speed Sv (step S106).

  On the other hand, if there is no intra-screen encoded video data in the video data buffer unit 102 and the playback speed Sv is 0 in step S104, the process returns to step S100 to continue the subsequent video stream reception process ( No in step S104).

  When the output of the video data is started, the control unit 109 calculates the reproduction speed Sa (Sv ≦ Sa ≦ Sn) of the audio data output together with the video data (step S110). Here, the reproduction speed Sa is a value not less than the reproduction speed Sv calculated in the step S105 and not more than the normal reproduction speed Sn, and satisfies Sv ≦ Sa ≦ Sn. In step S109, if video playback has not started, the process returns to step S100, and the subsequent video stream reception process is continued (No in step S109).

  The playback speed Sa calculated in step S110 is slower than the normal playback speed Sn, but may be a speed that does not give the viewer a sense of incongruity. The amount of audio data accumulated in the audio data buffer unit 105 And may be determined according to the accumulation speed. Of course, the reproduction speed Sa in the period before the normal reproduction may be a predetermined fixed value. Alternatively, the audio reproduction speed Sa may be increased as time passes.

  The audio decoding unit 106 decodes the audio data and outputs the decoded audio data to the audio output unit 107 in accordance with the set reproduction speed Sa (step S111).

  Further, after the video data playback speed Sv calculated in step S105 is set to the normal playback speed Sn, the audio data playback speed Sa is set to the normal speed when the video playback time information Tv matches the audio playback time information Ta. The playback speed Sn is set. As a result, normal playback in which video and audio are synchronized is performed thereafter.

  FIG. 4 is a diagram showing the transition of the buffer amounts of the video data and audio data and the data output timing in the moving picture stream receiving apparatus 3 described above. Low-speed playback of video data and audio data is started at the timing of the start of video output and the start of audio output in FIG. After that, when the video playback speed is set to Sn at the start timing of normal video playback in FIG. 4, the video and audio transition to a synchronized state at the start timing of synchronized playback.

  As is clear from comparison between FIG. 4 and FIG. 8, in this embodiment, it is possible to output video and audio without a sense of incongruity earlier than the video / audio output timing of FIG. 8.

  As described above, according to the present embodiment, video data and audio data are quickly played back when a video stream viewing start operation or a channel change operation (including channel zapping) is performed. Is possible. As a result, the user can quickly grasp the contents of the video stream, and if the program does not like the operation, the user can perform an operation of switching to another channel without waiting for buffer accumulation (start of audio / video synchronized playback). It can be carried out.

[Second Embodiment]
Next, a second embodiment obtained by changing the above-described first embodiment will be described in detail with reference to the drawings. FIG. 5 is a block diagram showing the configuration of the second exemplary embodiment of the present invention. The difference between the present embodiment and the first embodiment is that an audio level detection unit 108 is added in the moving picture stream receiving device 3 and an extension process of the silent section detected by the audio level detection unit 108 is performed. Is a point. Hereinafter, the configuration and operation of this embodiment will be described focusing on the differences.

  The voice level detection unit 108 in FIG. 5 has a function of monitoring the voice output level decoded by the voice decoding unit 106 and notifying the control unit 109 of the result.

  FIG. 6 is a flowchart showing an operation after the moving picture stream requesting unit 110 of the moving picture stream receiving device 3 according to the second embodiment of the present invention requests distribution of contents. Each process from step S100 to step S110 in FIG. 6 is the same as that in FIG.

  After calculating the audio playback speed Sa in step S110, the control unit 109 extracts the video data and audio data stored in the video data buffer unit 102 and the audio data buffer unit 105, and sets the video playback time information ( The time stamp) and the audio reproduction time information (time stamp) are compared (step S112).

  As a result of the comparison, when the video playback time information is advanced, the audio data decoding process is performed by the audio decoding unit 106 at the audio reproduction speed Sa calculated in step S110 as in the first embodiment ( Step S111).

  On the other hand, as a result of the comparison, if the audio reproduction time information is advanced, the control unit 109 causes the audio decoding unit 106 to perform the audio data decoding process, and a silence state is included in the audio data subjected to the decoding process. If there is, a silent section extending process for extending the time at a predetermined rate is executed. As a result, the advancement of the audio playback time information can be delayed, and the time until the start of video / audio synchronized playback after the buffer amount of the video data buffer unit 102 reaches the specified amount thv0 can be shortened. Note that the silent section can be determined based on whether or not the voice level input from the voice level detector 108 is equal to or lower than a preset level.

  FIG. 7 is a diagram showing transition of the buffer amounts of the video data and audio data and the data output timing in the moving picture stream receiving device 3 described above. The low speed reproduction of the video data and the audio data is started at the timing of the video output start and the audio output start in FIG. In the meantime, for the voice, the above-described process of extending the silent section according to the voice level is appropriately performed. Then, when the video playback speed is set to Sn at the video normal playback start timing in FIG. 7, the video and audio are synchronized when the video playback time information matches the audio playback time information. (Video / audio synchronized playback start).

  Note that, instead of the above-described process of extending the silent section, a process of reducing the audio reproduction speed Sa of the silent section by a predetermined value or a predetermined ratio may be performed.

  As described above, according to the present embodiment, as compared with the first embodiment, even when the audio reproduction speed Sa is set to a high value, only the sound does not advance too far. Is obtained.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments are possible without departing from the basic technical idea of the present invention. Can be added. For example, in the above-described embodiment, an example in which the present invention is applied to a moving image stream receiving device has been described. However, the present invention can be applied to a moving image output device that outputs moving image data received by radio waves after being buffered. is there.

  Further, for example, in the above-described embodiment, it has been described that low-speed reproduction is performed before normal reproduction at normal speed. However, the present invention can also be applied to a case where still image output is performed as in Patent Document 1. Even in this case, by performing the extension process of the silent period as in the second embodiment described above, the time until the start of the video / audio synchronous reproduction after the buffer amount to the video data buffer unit 102 reaches the prescribed amount thv0. Time can be shortened.

  In the above-described embodiment, the example of the moving image stream receiving device including the moving image stream receiving unit has been described. However, the moving image data may be received from another device.

DESCRIPTION OF SYMBOLS 1 Movie stream delivery apparatus 2 Network 3 Movie stream receiver 3a Movie output device 100 Movie stream receiver 100a Movie data receiver 101 Movie stream separator 102 Video data buffer 103 Video decoder 103 Video output 105 Audio data buffer 106 Audio decoding unit 107 Audio output unit 108 Audio level detection unit 109 Control unit 110 Movie stream request unit 111 Operation input unit

Claims (7)

A buffer that stores video data received from a distribution source separately into video data and audio data;
Before normal playback that starts after the buffer amount of the video data reaches a predetermined value, the video data being accumulated is used to output still image or output video data at a lower speed than the playback speed during normal playback. performs the a moving picture output device Ru and a control unit which outputs the audio data at a predetermined value or more playback speed asynchronously, the reproduction of the video data,
Furthermore, the moving image output apparatus includes a voice level detection unit that detects a silent section of the voice data depending on whether or not the voice level is equal to or lower than a predetermined voice level, and executes a process of extending the silent section at a predetermined rate.   2. The moving image output apparatus according to claim 1, wherein, when performing the low-speed playback output of the video data using the stored video data, the audio data is output at a speed higher than the playback speed of the video data before the normal playback.   The moving image output apparatus according to claim 1 or 2, wherein the reproduction speed of the sound is increased with the passage of time. As a process of extending the silent section at a predetermined rate,
In case of output the video data and audio data before the previous SL normal reproduction, compares the time stamp added to the audio data and appended timestamp to the video data retrieved from the buffer was removed from the buffer 4. The moving image output apparatus according to claim 1, wherein when the time stamp of the audio data is advanced, a process of extending the silent section detected by the audio level detection unit at a predetermined rate is executed. . A video stream separator that separates the video stream received from the distribution source into video data and audio data;
A video data buffer unit for storing the separated video data;
An audio data buffer for storing the separated audio data;
In accordance with an instruction from the control unit, a video decoding unit that extracts and decodes video data from the video data buffer unit;
Wherein in response to an instruction from the control unit, the audio data buffer unit 4 any one of the video output device from claim 1, further comprising a speech decoder for decoding taken out audio data, from. Storing the video data received from the distribution source separately into video data and audio data;
Before normal playback that starts after the buffer amount of the video data reaches a predetermined value, the video data being accumulated is used to output still image or output video data at a lower speed than the playback speed during normal playback. performs, and a step of outputting the audio data at a predetermined value or more playback speed asynchronously with the reproduction of the video data a including vie output method,
Furthermore, detecting a silent section of the audio data depending on whether or not it is below a predetermined audio level;
Extending the silent section at a predetermined rate. Processing to store video data received from the distribution source separately into video data and audio data;
Before normal output that starts after the buffer amount of the video data reaches a predetermined value, the video data being accumulated is used to output still image or output video data at a lower speed than the playback speed during normal playback. And a program for causing a computer to execute a process of outputting the audio data at a reproduction speed equal to or higher than a predetermined value asynchronously with reproduction of the video data ,
Furthermore, a process of detecting a silent section of audio data depending on whether or not it is below a predetermined audio level;
A program for causing the computer to execute a process of extending the silent section at a predetermined rate.

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