JP2010016618A - Video reproducing device and video reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reproducing device, capable of performing multi-display reproduction in a reproduction form optimal to a user even though a decoder or a tuner is insufficient to the number of videos, when a plurality of videos are decoded and are multi-displayed. <P>SOLUTION: The reproduction device 1 receives or acquires a plurality of video streams and reproduces them. The reproduction device 1 is provided with: a decoding part 104 for decoding the plurality of video streams, adjusting parts 105 and 106 for adjusting the video streams input to the decoding part 104 and decoded video output from the decoding part 104; a control part 110 for dynamically controlling the operations of the adjusting parts 105 and 106 and the decoding part 104; and a composition part 108 for compositing multi-display video images. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a video playback apparatus and a video playback method for playing back a video such as a real-time video obtained through broadcasting or communication and an on-demand video obtained through communication or storage.

  The so-called multi-video display interface, which receives a plurality of video streams and simultaneously displays a moving image on one screen, is one of the most intuitive and easy-to-understand video interfaces now capable of handling a large amount of video. For example, by switching the selected video one after another and combining it with a zapping interface that searches the video you want to watch while checking the video content in order, the display time of each video can be lengthened and compared with other videos Now you can search for the video you want to watch more efficiently. As a zapping interface, toggle channel selection operations such as channel up / down buttons are familiar on current televisions.

  If the number of decoders (decoders) or the number of tuners (demodulators) at the time of broadcasting are sufficient for multi-display video streams, it is easy to receive and play back individual video streams. is there. However, it costs more.

On the other hand, when the number of decoders and tuners is insufficient, it is not possible to simply play back all video streams. Therefore, in the display system described in Patent Document 1, when the number of decoders is insufficient, a system is adopted in which a plurality of video streams are input in a time division manner and decoded by one decoder. Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of time-division receiving channel images other than during channel selection with one tuner when the number of tuners is insufficient.
JP-A-10-155123 JP 2001-309255 A

  By the way, when multi-video display is used in the zapping interface, the degree of emphasis on the multi-displayed video (that is, the multi-display is shown) between users who tend to quickly switch channels one after another and users who do not tend to see the previous video. The degree of emphasis on each video is different). Further, even for the same user, the degree of emphasis between images displayed in a multi display is different between the time immediately after channel switching and the time after a certain amount of time has elapsed since switching. Note that the difference in the degree of importance regarding each video that is displayed in a multi display is not limited to a scene where multi video display is performed for zapping purposes, but a scene where normal multi video display for continuously watching a plurality of videos simultaneously is performed. Can also occur.

  On the other hand, both the method described in Patent Document 1 corresponding to the shortage of the number of decoders and the method described in Patent Document 2 corresponding to the shortage of the number of tuners differ depending on the user as described above, or from the channel switching. Considering the importance level (video priority) for each video that varies depending on the elapsed time, processing for relatively improving the image quality of a video with higher priority has not been performed.

  Further, in the conventional video reproduction technology including the techniques described in Patent Document 1 and Patent Document 2, in order to speed up the video reproduction at the time of switching the input source (channel, etc.), one or a plurality of input sources currently being reproduced. Even if a technology for buffering a video stream of an input source different from that in advance is used, it is only possible to read out the video stream and start decoding immediately after switching the input source. Unless it is executed, video playback when the input source is switched cannot be started any faster.

  Also, in the technique described in Patent Document 2, a single tuner receives a plurality of channel videos in a time-division manner. However, since the received time is different for each channel and a stream is lost in an unreceived part, the video of each channel is directly received. There is also a problem that unnatural reproduction occurs when decrypted and displayed. This problem can also arise from the need for decimation caused by an insufficient number of decoders.

  Further, in the conventional video reproduction technologies including the techniques described in Patent Document 1 and Patent Document 2, depending on operations other than the direct switching operation, normal reproduction for displaying one video and multi-display for displaying a plurality of videos are performed. Cannot switch between playback.

  The present invention has been made in view of the above-described circumstances, and when multi-display is performed for zapping applications or the like, when the number of decoders and / or tuners is insufficient, the multi-display is performed according to the operation tendency or timing. It is an object of the present invention to provide a video playback apparatus and a video playback method that can change the priority of each video and can display a plurality of videos in the form that is best for the user.

  Also, the present invention provides a technique for buffering an input source video stream that is not currently being reproduced in preparation for switching of the input source. It is another object of the present invention to provide a video playback method and a video playback method capable of quickly starting playback.

  The present invention also provides a video playback method and a video playback method capable of smoothly playing back a video of a stream in which a missing section is generated due to a lack of the number of tuners and / or the number of decoders when performing multi-display for zapping applications or the like. To provide other purposes.

  In addition, the present invention provides a video playback method and a video playback method capable of switching between normal playback for displaying one video and multi-display playback for displaying a plurality of videos without performing a direct switching operation. To do other purposes.

  In order to solve the above-described problems, a first technical means of the present invention includes a stream acquisition unit that acquires a video stream from an input source, and a decoding unit that decodes the video stream to generate a video, A video playback apparatus capable of combining and outputting each of a plurality of playback videos by a video stream in a predetermined arrangement on the screen, wherein the plurality of playback videos to be reproduced on one screen in the predetermined arrangement When each video stream is input and synthesized, switching means for switching the processing method of the stream acquisition unit and / or decoding unit for each video stream, and each predetermined arrangement obtained by a user operation on the video playback device Switching control means for controlling the switching of the processing method by the switching means according to the priority relating to the image quality between. That.

  According to a second technical means, in the first technical means, the switching of the processing method by the switching means changes a ratio of a code amount input from the stream acquisition unit to the decoding unit for each of the plurality of video streams. The switching control means, for each video stream to be decoded in order to obtain a playback video corresponding to each predetermined arrangement, the ratio of the code amount according to the priority between the predetermined arrangements The switching means is controlled so as to change.

  According to a third technical means, in the first or second technical means, the switching of the processing method in the switching means changes a decoding processing level in the decoding unit for each of the plurality of video streams. And the switching control means changes the decoding processing level in accordance with the priority between the predetermined arrangements for each video stream to be decoded in order to obtain a reproduced video corresponding to the predetermined arrangements. Further, the switching means is controlled.

  According to a fourth technical means, in any one of the first to third technical means, the switching of the processing method in the switching means may be performed by setting an input source of a video stream to be acquired in the stream acquisition unit as the plurality of videos. Switching between the input sources corresponding to the streams in a time-sharing manner, wherein the switching control means is configured for each predetermined source for each input source of the video stream to be input in order to obtain a reproduced video corresponding to each predetermined arrangement. The switching unit is controlled to change the stream acquisition time according to the priority between the arrangements.

  According to a fifth technical means, in any one of the first to fourth technical means, the priority is determined based on a tendency of a user's input source switching operation.

  According to a sixth technical means, in any one of the first to fifth technical means, the priority is determined based on an elapsed time from a user input source switching operation.

  According to a seventh technical means, in any one of the first to fourth technical means, the priority is obtained from a setting content obtained by a prior priority setting operation by a user.

  According to an eighth technical means, in any one of the first to seventh technical means, the stream acquisition unit obtains and buffers in advance a video stream of an input source different from the input source of the video currently being reproduced. The decoding unit detects an I picture from the video stream during the buffering or immediately after the end of the buffering.

  Ninth technical means in the first to eighth technical means is the target to be combined in the predetermined arrangement by switching control of the processing method according to the priority by the switching control means. When there is a missing section in the playback video corresponding to each of a plurality of video streams, a playback speed adjustment unit is provided that compensates by adjusting the playback speed so that the missing section does not exist. .

  According to a tenth technical means, in any one of the first to ninth technical means, a multi-display reproduction mode for combining and outputting each of the plurality of reproduction videos in a predetermined arrangement on the screen, and one reproduction picture Is switched by the mode switching unit according to the priority relating to the image quality obtained by the switching operation of the input source of the user to the video reproduction device. And a mode switching control means.

  An eleventh technical means provides a plurality of playback videos by a plurality of video streams in a video playback device including a stream acquisition unit that acquires a video stream from an input source, and a decoding unit that decodes the video stream into a video. Is a video reproduction method for combining and outputting each of the above in a predetermined arrangement on the screen, wherein the stream acquisition is performed according to a priority relating to image quality between the predetermined arrangements obtained by a user operation on the video reproduction apparatus. Each of a plurality of video streams to be reproduced on one screen with the predetermined arrangement while switching the processing method in the switching step. And a step of synthesizing.

  According to the present invention, when the number of decoders and / or tuners is insufficient when performing multi-display for zapping applications or the like, the priority of each video displayed in multi-display is changed according to the operation tendency or operation timing, It is possible to display a plurality of images in a multi-display manner in the best form for the user. This also makes it possible to perform zapping by multi-video display without stress while compensating for the shortage of the number of decoders and the number of tuners, and the user can efficiently find a desired video.

  According to another aspect of the present invention, in a technique for buffering an input source video stream that is not currently being reproduced in preparation for input source switching, the buffer is provided immediately after channel switching without providing a dedicated decoder. It is possible to quickly start playback of the ringed video stream.

  Further, according to another aspect of the present invention, it is possible to smoothly reproduce the video in the section in which the stream is missing due to the lack of the number of tuners and / or the number of decoders by adjusting the reproduction speed. Accordingly, it is possible to avoid unnatural reproduction of each video, and to reduce the user's stress at the time of zapping operation by multi-display.

  Further, according to another embodiment of the present invention, it is possible to switch between normal reproduction for displaying one video and multi-display reproduction for displaying a plurality of videos without performing a direct switching operation.

  Various video playback apparatuses and video playback methods according to embodiments of the present invention will be described below with reference to the drawings. Hereinafter, the video playback device and the video playback method according to the present invention are simply referred to as “playback device” and “playback method”, respectively.

  A playback apparatus according to the present invention includes a stream acquisition unit that acquires a video stream (compressed video signal stream) from an input source, and a decoding unit that decodes the video stream to obtain video, and includes a plurality of video streams. It has a function (multi-display function) for combining and outputting each of a plurality of reproduced videos in a predetermined arrangement on the screen. And the reproducing | regenerating apparatus concerning this invention shall be equipped with the following switching means and switching control means as the main characteristics. When the switching means inputs and synthesizes each of a plurality of video streams to be reproduced on one screen in the predetermined arrangement, the switching means processes the stream acquisition unit and / or the decoding unit for each video stream (that is, Switch operation method, usage method). The switching control means performs processing in the switching means according to the priority relating to the image quality between the predetermined arrangements (image quality priority between reproduced videos to be reproduced in each predetermined arrangement) obtained by a user operation on the reproduction apparatus. Control method switching.

  The playback method according to the present invention is a method of combining and outputting each of a plurality of playback videos by a plurality of video streams in a predetermined arrangement on a screen in a playback device including the stream acquisition unit and the decoding unit. It is. The reproduction method according to the present invention includes the following switching step and combining step as main features. In the switching step, the processing method of the stream acquisition unit and / or the decoding unit is switched according to the priority regarding the image quality between the predetermined arrangements obtained by the user operation on the playback device. The synthesizing step inputs and synthesizes each of a plurality of video streams to be reproduced on one screen with the predetermined arrangement while switching the processing method in the switching step.

  The playback apparatus and playback method according to the present invention provides an on-demand playback video whether the number of decoders, the number of tuners, the multi-display video is a real-time received video, or the number of multi-display videos. Depending on whether it is, the configuration requirements are different. In the following embodiments, a case where the number of decoders is insufficient and a case where the number of tuners is insufficient will be described as separate embodiments, but these may be implemented in combination. That is, various means (/ processes) constituting the playback device (/ playback method) of each embodiment can be arbitrarily combined. The reproduction method according to the present invention can be interpreted as various processing procedures in the reproduction apparatus described below.

  Throughout all of the following embodiments, each video to be switched is referred to as “channel” or “channel video”. The playback processing according to the present invention can also be applied as a playback target such as video distributed on-demand video, video stored on a portable or installation type recording medium, and in this case, the on-demand video and stored video to be selected are Although it is not exactly “channel” or “channel video”, the description is unified in “channel” or “channel video” in the embodiment for the sake of simplicity. For this reason, when implementing the present invention for on-demand video distribution, stored video acquisition, etc., “channel” or “channel video” is appropriately replaced with “selected video” for interpretation. Further, this “channel” has a one-to-one correspondence with the “input source”. Here, in a broad sense, the input source includes a transmission path such as broadcasting and communication, a recording / playback device medium, and the like, but the term “input source” in this specification can be selected (tuned). It is used in a narrow sense such as the source. Accordingly, the video of each broadcast program (that is, the selected video) and each selected video are handled as video from different input sources.

  In addition, functional blocks that receive a video stream from a transmission path such as broadcasting or communication and store it in a cache memory are collectively referred to as a “tuner”. This broadly defined “tuner” includes IP (Internet Protocol) broadcast tuners (actually demultiplexers), TV broadcast demodulators, on-demand video distribution receiving applications, and recording media for recording and playback devices. Drives are also included. This “tuner” in a broad sense corresponds to the stream acquisition unit that acquires a video stream from an input source. In the following, the case where the tuner means a broadcast demodulator is specified with a special note. On the other hand, those not specifically noted are interpreted as the above-mentioned “tuner” in a broad sense.

  Further, through all the following embodiments, for the sake of simplicity of explanation, the number of videos to be multi-displayed (that is, the number of channels) is set to 3, and the number of streams acquired in advance for high-speed channel switching is Two images are displayed before and after the image being displayed. These are only limitations on description provided for the sake of simplicity of explanation, and the number of videos displayed in multiple on one screen is not limited to 3, and any number other than 3 is related to the embodiment of the present invention. Various playback devices and playback methods can be applied. Also, the number of channel images to be prefetched for high-speed channel switching is not limited to two in the front and rear, but may be any number other than two, and may be increased or decreased according to the number of channels to be handled. In an extreme case, the configuration may be such that all channel images that can be selected (tuned) are prefetched.

  In addition, audio and other data handled together with video data are not directly related to the effects of the present invention, and thus are not particularly mentioned in the embodiment. Of course, video and audio data are multiplexed. Needless to say, even with multiplexed data, video data is separated, and various playback apparatuses and playback methods according to embodiments of the present invention can be similarly applied.

(First embodiment)
In the playback apparatus according to the first embodiment of the present invention, the switching of the processing method in the switching means as the main feature of the present invention is that the ratio of the code amount input from the stream acquisition unit to the decoding unit is a plurality of videos. Including changes for each stream. Further, the switching control means as the main feature of the present invention is characterized in that for each video stream to be decoded in order to obtain a reproduced video corresponding to each predetermined arrangement, the code amount according to the priority between the predetermined arrangements The switching means is controlled so as to change the ratio. Hereinafter, the playback apparatus according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a functional block diagram showing a schematic configuration example of a playback apparatus 1 according to the first embodiment of the present invention. The playback apparatus 1 includes a tuner unit 101, a decoding buffer unit 102 including decoding buffers (cache memories) 102-1 to 102-5, a decoding unit 103, a decoding unit 104, an adjustment unit 105, an adjustment unit 106, and a synthesis buffer 107-1. ˜107-2, the synthesis buffer unit 107, the synthesis unit 108, the selection unit 109, and the control unit 110 are included. The control unit 110 controls each operation of the adjustment unit 105, the decoding unit 104, the adjustment unit 106, and the synthesis buffers 107-1 to 107-2 for dynamic control which is a main feature of the present invention. Hereinafter, such dynamic control is referred to as “dynamic control of image quality” because the image quality is controlled as a result. A control signal from a main control unit (not shown) is input to the tuner unit 101, the decoding buffer unit 102, the selection unit 109, and the control unit 110. The control signal from the main control unit will be described later in the description of each unit 101-110.

  The playback apparatus 1 according to the present embodiment is a playback apparatus that assumes that the number of decoders is insufficient with respect to the number of video streams to be multi-displayed (one decoding unit 104 for three display streams). . In addition, the tuner exemplified by the tuner unit 101 has the capability of simultaneously allocating the input multi-stream to the respective decoding buffers exemplified by the decoding buffers 102-1 to 102-5. Such a playback apparatus corresponds to a television broadcast receiving device provided with a tuner (demodulator) for the number of channels, and an IP broadcast receiving device distributed via a network. In FIG. 1 and the following description, the playback apparatus 1 will be mainly described as an IP broadcast receiving device connected to a network.

  The playback apparatus 1 according to the present embodiment shown in FIG. 1 switches between normal playback (playback of one video) and zapping multi-display playback (hereinafter simply referred to as “multi-display playback”) with the selection unit 109 for display. It has a configuration that can be done.

  FIG. 2 shows an example of multi-display reproduction. In this embodiment, when switching from normal playback to multi-display playback, the currently selected video (reduced video) is in the center, the previous channel video with respect to the selected video is on the left, the next Suppose a multi-screen with multiple channel images displayed on the right. In this specification, the selected video is “MAIN channel” or “MAIN video”, the next channel video is “NEXT channel” or “NEXT video”, and the previous channel video is “PREV channel” or “PREV”. This is called “video”. In the present invention, it is assumed that each multi-displayed video is displayed as a moving image. Note that the arrangement and size of each video are not limited to those shown in FIG. 2, and the ordering is clearly defined, for example, the vertical orientation (up and down), the arrangement on the curve, the arrangement on the three dimensions, etc. Any arrangement can be used. It is possible to display the MAIN channel larger than the NEXT channel and PREV channel, and to emphasize that the channel is being selected.

  FIG. 3 schematically shows the transition of the display screen at the time of channel switching. When the channels have the order relationship shown in FIG. 3A, switching as shown in the upper part of FIG. 3B is possible in normal reproduction. In other words, in normal playback, the display video is changed to Ch.A → Ch.B → Ch.C → Ch.D → Ch.E → Ch by selecting the next channel (such as pressing the NEXT (+) button). Switch in order of .A. Similarly, the display image is changed from Ch.A → Ch.E → Ch.D → Ch.C → Ch.B → Ch.A by selecting the previous channel (such as pressing the PREV (–) button). Switch.

  When the display mode switching operation (operation such as pressing the MODE button) is accepted in the normal playback state, the selection unit 109 switches to multi-display playback. The display modes mentioned here include a normal playback mode that is a display mode for performing normal playback and a multi-display playback mode that is a display mode for performing multi-display playback. Switching from one to the other is possible according to the control signal.

  More specifically, the main control unit that has received the display mode switching operation transmits a display mode switching instruction to the selection unit 109 and the control unit 110. In accordance with the display mode switching instruction, the selection unit 109 selects an output, and when the control unit 110 is in the multi-display reproduction mode, the adjustment unit 105, the decoding unit 104, the adjustment unit 106, the synthesis buffer unit 107, In addition, control is performed so that the composite unit 108 functions to generate a video for multi-display playback, and the units 104 to 108 are controlled not to function in the normal playback mode. In this example, it is assumed that the synthesis unit 108 automatically performs synthesis based on input from the synthesis buffer unit 107 and does not require control from the control unit 110. In addition, the decoding unit 103 may function only in the normal playback mode. Since either one of the outputs is selected by the selection process in the selection unit 109, for example, decoding in the decoding unit 103 is also executed in the multi-display playback mode, for example, generation of a video other than the display mode being executed is also executed. However, there is no problem if power consumption is not taken into consideration.

  The lower part of FIG. 3B shows an example in which mode switching is performed during channel selection of Ch. B in normal playback. At this time, Ch.B being selected is displayed in the center, and Ch.A and Ch.C before and after (PREV channel, NEXT channel) are displayed on both sides. In the present invention, each multi-displayed video is displayed as a moving image.

  When an operation for selecting the next channel (operation such as pressing the NEXT (+) button) is performed in the multi-display playback (Ch.A-Ch.B-Ch.C) state shown in Fig. 3 (B) (Ch.A-Ch.B-Ch.C) → (Ch.B-Ch.C-Ch.D) → (Ch.C-Ch.D-Ch.E) → (Ch. D-Ch.E-Ch.A). In addition, when a multi-channel playback (Ch.A-Ch.B-Ch.C) state shown in FIG. 3B is performed, an operation for selecting the previous channel (operation such as pressing the PREV (-) button) is performed. , (Ch.A-Ch.B-Ch.C) → (Ch.E-Ch.A-Ch.B) → (Ch.D-Ch.E-Ch.A) → ( (Ch.C-Ch.D-Ch.E).

  The playback apparatus 1 according to the present embodiment also provides a means for performing such channel switching at high speed, the NEXT channel during normal playback, the PREV channel, and the NEXT channel during multi-display playback, A configuration for prefetching the channel video stream immediately preceding the PREV channel is provided. As a configuration for such prefetching, the playback apparatus 1 shown in FIG. 1 includes a tuner unit 101 and decoding buffers 102-1 to 102-5, and these operations will be described later.

Hereinafter, the operation of each functional block of the playback apparatus 1 shown in FIG. 1 will be described.
The tuner unit 101 separates each video stream received via the transmission path and outputs the video streams to the decoding buffers 102-1 to 102-5. In the IP broadcast tuner (substantially demultiplexer) assumed in the present embodiment, IP packets storing each video stream received through the network are sorted for each stream by looking at the packet ID. It caches in each decoding buffer 102-1 to 102-5. Channel selection (MAIN channel selection) is basically performed by a user's UP / DOWN (NEXT / PREV) channel selection operation or a channel selection operation designating a channel. The tuner 101 transmits the channel selection signal, and based on the channel selection signal, the tuner unit 101 selects the MAIN channel, that is, acquires the video stream of the MAIN channel. In addition, the tuner unit 101 performs channel selection for the MAIN channel, and in the normal playback mode, can also perform channel selection for the previous and next channel, and in the case of the multi-display playback mode. It is also possible to perform channel selection for the two channels before and after the second channel. Which of the two display modes is functioning may be determined by a signal from the main control unit. However, when applying display mode automatic switching, which will be described later, the tuner unit 101 is notified of the display mode switching result by the control unit 110.

  Here, the playback device 1 includes a decoding unit 103 for normal playback and a decoding unit 104 for multi-display playback in order to easily switch between normal playback and multi-display playback. Further, as described above, in order to be able to immediately switch and display the received channel, the previous video, A plurality of decoding buffers 102-1 to 102-5 are provided for receiving and buffering a subsequent video stream together with the video being displayed.

  In IP broadcasting, there is a delay between selecting a channel and issuing a request on the network until the IP packet of that channel is received. The time varies depending on the network environment, but it is expected to take several seconds. Also, in digital television broadcasting, when performing demodulation, it takes about several seconds to several seconds from reception to use as a stream in order to perform deinterleaving processing of digital data. Further, in any case, since the stream is started by searching for an I picture that can be decoded from the stream, for example, in the case of a compressed video stream in which the I picture is encoded at intervals of 0.5 seconds, the maximum In 0.5 seconds, decoding is not started and video is not output. In MPEG (Moving Picture Experts Group) -2 used for broadcasting, I pictures are usually stored at intervals of 0.5 seconds corresponding to GOP (Group Of Picture) size. In this way, video is not output for the time required for stream acquisition and decoding start, and for a few seconds immediately after channel switching (assuming Td seconds).

  In order to eliminate the period Td seconds in which the display video is interrupted immediately after the switching, the playback device 1 pre-reads the streams to be played back for Td seconds (or more than Td seconds) for the switching destination channel and decodes the buffers 102-2 to 102-. 5, the stream buffered in advance at the time of channel switching is immediately decoded and reproduced. Such a configuration that loses the display image interruption period Td is the principle of the high-speed channel switching described above.

  Each decoding buffer of the decoding buffer unit 102 will be described. The decoding buffer 102-1 is a buffer for storing a channel video stream being selected. In normal reproduction, the currently selected video stream temporarily stored in the decoding buffer 102-1 is sent to the decoding unit 103, decoded and reproduced, and displayed on the screen through the selection unit 109.

  Decoding buffers 102-2 and 102-3 are decoding buffers for storing the next video and the previous channel video stream for the channel video being selected. In normal playback, the video streams stored in the decoding buffers 102-2 and 102-3 are pre-read data (video data for Td seconds or more) for high-speed switching, and are not decoded in that state, and the channel is switched. Decoding starts immediately when the channel is selected. In that case, the decoding unit 103 is used for decoding. Further, in the case of real-time reception such as IP broadcasting and television broadcasting, the video stream stored in the decoding buffers 102-2 and 102-3 without being decoded is discarded with the old stream data as time elapses. It is assumed that stream data for the latest Td length (or more) is always held by storing data.

  In order to shorten the time until detection of the I picture and to start decoding / playback more immediately, it is preferable to execute in advance until the detection of the I picture position at the time of buffer storage. In order to perform such detection, the playback apparatus of the present invention may include detection means for detecting the position of the I picture before the stream data is stored in the decoding buffer. For example, in the playback device 1 of FIG. 1, this detection means controls the decoding unit 103 to detect the I picture position from the data in the target decoding buffer for the decoding buffer that has started data storage. Can be implemented. Even when control is performed such that the decoding buffer that has completed data storage is the target decoding buffer and the position of the I picture is detected when the data storage is completed, decoding can be started immediately at the time of channel switching. Here, the decoding buffers to be subjected to the prior detection of the I picture position may be the decoding buffers 102-2 and 102-3. It should be noted that when the decoding buffers 102-4 and 102-5 are used even in the normal reproduction mode, they may be subject to prior detection. Further, depending on the usage status of the decoding unit 103, there is a case where the current video reproduction may be affected. Therefore, it is preferable to perform control so that this detection is performed by the decoding unit 104 that is not used.

  In FIG. 1, the data stored in the decoding buffer 102-2 or 102-3 is represented as if it moved to the decoding buffer 102-1 at the time of channel switching (decoding buffers 102-1 and 102-2, 102). -1 and 102-3 are connected to each other), but in actual implementation, reference is made again so that the data stored in the decoding buffers 102-2 and 102-3 is used as the data in the decoding buffer 102-1. It is implemented in such a way that no data movement occurs. This re-referencing can be realized by the main control unit controlling each decoding buffer of the decoding buffer unit 102 according to which channel is selected and which display mode it is in. However, when the display mode automatic switching described later is applied, the decoding buffer unit 102 is similarly controlled by the control unit 110.

  Also, when the mode is shifted to the zapping mode (multi-display playback mode), decoding / playback is immediately started. In this case, decoding and playback of the streams stored in the decoding buffers 102-2 and 102-3 are started using the decoding unit 104. At this time, the decoding unit 104 also starts decoding the stream stored in the decoding buffer 102-1. That is, in the multi-display playback state (the zapping interface execution state by multi-display), the video stream stored in the decoding buffers 102-2 and 102-3 is combined with the video stream stored in the decoding buffer 102-1, and the decoding unit 104. Is decrypted.

  The decoding buffers 102-4 and 102-5 are decoding buffers for storing a video stream two after the selected video and a video stream two before the selected channel in the multi-display playback state, respectively. That is, it is the next channel video and the previous channel video for the channel video (MAIN / NEXT / PREV channel) displayed in the multi-display playback state. The stream data stored in these buffers is read-ahead data for performing high-speed channel switching in the multi-display playback state. In this state, the stream data is not decoded and the channel is switched and the channel to be displayed (NEXT channel or PREV channel). At this point, decoding and display are started. Decoding is performed by the decoding unit 104.

  Here, by detecting the I picture at the time of buffering as described above, decoding / reproduction can be started immediately even when the channel is switched in the zapping mode. The above-described detection means in the multi-display playback mode in the playback apparatus 1 of FIG. 1 is switched, for example, by the adjustment unit 105 described later to a target decoding buffer (a decoding buffer that starts data storage), and the decoding unit 104 It can be implemented by controlling to detect the position of the I picture from the data. Here, the decoding buffers to be subjected to the prior detection of the I picture position in the multi-display playback mode may be the decoding buffers 102-4 and 102-5. Further, depending on the usage status of the decoding unit 104, there may be an effect on the reproduction of the current video. Therefore, it is preferable to perform control so that this detection is performed by the decoding unit 103 that is not used.

  In FIG. 1, the data stored in the decoding buffer 102-4 is moved to the decoding buffer 102-2 or the data stored in the decoding buffer 102-5 is moved to the decoding buffer 102-3 at the time of channel switching. Although notated (the lines connecting the decoding buffers 102-4 and 102-2 and 102-5 and 102-3 respectively correspond thereto), in actual implementation, the data stored in the decoding buffers 102-4 and 102-5 Is re-referenced so as to be the data of the decoding buffers 102-2 and 102-3, respectively, so that the data is not moved. As described above, the re-reference is performed by the main control unit controlling each decoding buffer of the decoding buffer unit 102 according to which channel is selected and which display mode is selected. realizable. However, when the display mode automatic switching described later is applied, the decoding buffer unit 102 is similarly controlled by the control unit 110.

  Further, as described as a preferred example, in the present invention, the detection means described above for the normal playback mode and the multi-display playback mode is not essential. Furthermore, such a stream management technique that performs in advance until the detection of the I picture position at the time of buffer storage adopts “switching control of processing method according to priority”, which is the main feature of the present invention. Nevertheless, it is a useful technique.

  Explaining this stream management technology excluding this switching control of the present invention, the stream acquisition unit acquires and buffers in advance a video stream of an input source different from the input source of the currently reproduced video, The decoding unit detects an I picture from the video stream during buffering or immediately after the end of buffering. In such a technique, in the technique of buffering an input source video stream that is not currently being played in preparation for switching of the input source, the buffered video stream is immediately after channel switching without providing a dedicated decoder. Playback can be started quickly. Further, not only in the multi-display playback mode and the normal display playback mode, it may be determined whether or not zapping is performed based on the user's operation tendency, and this detection may be performed only when it is determined that zapping is performed. . This determination may be determined to be zapping, for example, when an operation for selecting the next channel or the previous channel is performed a predetermined number of times in succession.

  Next, the adjustment unit 105, the decoding unit 104, and the adjustment unit 106 will be described. The adjustment unit 105 performs input control of a stream to be input to the decoding unit 104 when the video stream stored in the decoding buffers 102-1 to 102-3 is decoded by one decoding unit 104. Correspondingly, the adjustment unit 106 controls output of the video decoded by the decoding unit 104.

  The decoding unit 104 decodes and outputs the input video stream. At this time, it is assumed that a plurality of video streams are input to the decoding unit 104 by time division, and the decoding unit 104 decodes them by time division and individually reproduces them while securing them in the reference frame memory. At that time, in the playback apparatus 1 according to the present embodiment, the adjusting unit 105 is provided, and when the total amount of the code amount of the input stream exceeds the range that can be processed by the decoding unit 104, the adjusting unit 105 preliminarily decodes the decoding unit. Control is performed so as to limit the stream input to 104.

  The stream input restriction process performed by the adjustment unit 105 will be described in detail with reference to FIGS. In the multi-display playback state (zapping interface execution state by multi-display), as already explained in FIG. 2, the channel video being selected (MAIN channel) is centered, and the previous and subsequent channel video (PREV channel, NEXT channel) ) Is displayed on the left and right. In the multi-display zapping interface, the user mainly looks at the central MAIN video and determines whether to select this video. For this reason, it is desirable that the central MAIN video is reproduced smoothly. On the other hand, since it is only necessary to determine whether or not to select the next channel (displayed in the center) for the videos at both ends, the image quality can be reduced to some extent.

  For this reason, the adjustment unit 105 inputs all the video streams from the decoding buffer 102-1 to the decoding unit 104 so that detailed decoding processing can be performed on the currently selected video (MAIN channel). On the other hand, the video before and after the selected video (PREV channel, NEXT channel) has a lower priority than the MAIN video, and the video stream from the decoding buffers 102-2 and 102-3 can be decoded. This is thinned out and input to the decoding unit 104. As a decimation method, it is possible to decimate to a GOP unit which is a decoding unit of an MPEG stream, or to extract and input only an I picture signal.

  FIG. 4 shows an example schematically showing the relationship between the input / output (stream) of the adjustment unit 105 when thinned out in GOP units and the multi-display playback video at that time. In the figure, M1 to M6, N1 to N6, and P1 to P6 represent GOPs constituting the MAIN channel, NEXT channel, and PREV channel video streams, and are multiplexed in GOP units via the adjustment unit 105. FIG. 4A shows a state where there is no thinning. If the processing capability of the decoding unit 104 is sufficient to simultaneously decode three streams, the state shown in FIG. FIG. 4B shows a state where thinning is performed for each of the NEXT channel and the PREV channel. When the processing capability of the decoding unit 104 is not sufficient, such a state is taken, and the decoding process of the NEXT channel and the PREV channel is partially reduced so that smooth decoding is performed. At this time, the displayed video of the NEXT channel and PREV channel is a video that has deteriorated by the amount of missing data. When thinning out in units of the GOP, the playback of the thinned section is stopped and discontinuous playback is performed.

  Further, the adjustment unit 105 checks the operation tendency at the time of zapping of the user in addition to the priority determined by the MAIN channel or the PREV / NEXT channel, that is, the priority determined by the arrangement to be displayed (for convenience, default priority). Adjustment is performed to change the weight of the channel and the NEXT channel (that is, the priority regarding the image quality between the arrangements). Actually, the control unit 110 stores a history of operations received from the main control unit (only the latest history may be stored) in, for example, a memory or cache memory in the control unit 110, and the user's The operation tendency is analyzed, and the priority (priority related to the image quality between the arrangement of each video) is determined according to the operation tendency. Subsequently, the control unit 110 determines the ratio of the code amount input to the decoding unit 104 for each channel (for each video stream) according to the priority, and adjusts the ratio to be determined for each channel. The unit 105 is controlled. Such code amount ratio control corresponds to an example of the processing method switching described above. As described above, the priority used for switching the processing method may be determined based on the tendency of the user to perform the channel switching operation. The priority according to the operation tendency may be changed so as to raise or lower the default priority by a predetermined level, or the priority determined according to the operation tendency without using the default priority. You may make use of it.

  For example, it may be desirable for a user who tends to repeat channel switching to the next channel one after another to confirm the NEXT channel video earlier. For this reason, the control unit 110 decodes more (preferentially) the stream of the NEXT channel than the stream of the PREV channel when it is determined as a user operation tendency that the postponement is continuously performed in a short time. Control to input to the unit 104. On the other hand, if there is a tendency to go back and forth, such as checking the next channel or checking the previous channel (that is, for users who tend to do this) Since both the PREV channel and NEXT channel images are useful, it is better to assign acquisition evenly and to play both images with some quality.

  As a method of determining the operation tendency, for example, when the control unit 110 monitors the time interval when the NEXT button is pressed in the multi-display playback state, and is operated repeatedly at a predetermined interval Tw or less and a predetermined number of times Nw or more. Because of the tendency to postpone, the priority of the NEXT channel video is increased. Similarly, the time interval at which the PREV button is pressed is monitored, and when the operation is repeated for a predetermined number of times Nw or less within a predetermined interval Tw, the PREV channel video priority is increased because there is a tendency to forward. These priorities also monitor whether the NEXT button and PREV button are pressed, and the PREV button is pressed while the NEXT button is continuously pressed less than Nr times, or the PREV button is pressed continuously less than Nr times. Canceled when the NEXT button is pressed. Of course, the procedure for setting and canceling the priority is not limited to this, and may be performed using other appropriate means capable of determining the operation tendency.

  FIG. 5 shows an example schematically showing the relationship between the input / output (stream) of the adjustment unit 105 thinned out in GOP units and the multi-display playback video at that time. 5A shows the relationship when the NEXT channel is prioritized, and FIG. 5B shows the relationship when the priority is equal. Here, it is assumed that the decoding unit 104 has a processing capability capable of decoding 3/2 GOPs per unit time, and 4 GOPs are thinned out while 4 GOPs are input to each of the MAIN, NEXT, and PREV channels (12 GOPs in total). To do. At this time, in FIG. 5A, since the priority of the NEXT channel is higher than that of the PREV channel, three GOPs of the PREV channel are thinned out with respect to one GOP of the NEXT channel. As for the playback video, the picture quality of the PREV channel video is lowered, while the NEXT channel video is not deteriorated so much. That is, PREV has a longer playback stop period due to missing GOP than NEXT, resulting in more discontinuous playback. A user who tends to switch channels one after another can easily check the video of the NEXT channel by such reproduction. In FIG. 5B, in order to equalize the priority of the NEXT channel and PREV channel, 2 GOPs are thinned out for each of the NEXT channel and PREV channel. The playback video is deteriorated to the same extent as the NEXT channel and PREV channel, and users who tend to repeatedly go back and forth check the video on both the NEXT channel and PREV channel with a certain level of image quality. Determine whether to switch channels.

  The thinning ratio is not limited to the above, and an appropriate ratio can be set. Of course, the input control is not necessarily performed in units of GOPs. The stream is mechanically divided into time divisions and input to the decoding unit 104. The stream for B picture is thinned out or the data stream for I picture is extracted. For example, the data may be input to the decoding unit 104. For example, when the total input to the decoding unit 104 is 1, the allocation is determined as MAIN video 0.5, PREV video, and NEXT video each 0.25, and the time division is performed. This is a process such as switching the input stream by the switch with the allocated time length.

  In addition, apart from user operation trends, in the state immediately after channel switching, the newly displayed PREV or NEXT video is more important to the user than the PREV or NEXT video that was the MAIN video before switching (attention) Degree) is high. For this reason, during a certain period immediately after switching, the newly displayed PREV or NEXT video stream may be decoded and reproduced with priority. That is, the control unit 110 performs switching control on the adjustment unit 105 so that the video stream newly synthesized immediately after the channel switching operation is output with high image quality preferentially. In that case, after a certain period, each channel video may be displayed with a priority according to the operation tendency. As described above, the priority used for switching the processing method may be determined based on the elapsed time from the channel switching operation of the user instead of or based on the tendency of the channel switching operation described above.

  Furthermore, apart from the user's operation tendency, an input interface for setting the priority in advance by the user is provided, and the control unit 110 inputs the MAIN / NEXT / PREV channel according to the priority set in advance by the input interface. The output (that is, the reproduction image quality of the reproduction image) may be controllable. For example, the priority of the newly displayed NEXT video or PREV video is provisionally set to be higher than MAIN, and the newly displayed NEXT video or PREV video is controlled to have the highest image quality for a certain period immediately after switching. It is also possible to do so. Of course, it is also possible to set the priority to be fixed and to always fix the ratio of MAIN / NEXT / PREV. Thus, the priority used for switching the processing method may be obtained from the setting content obtained by the prior priority setting operation by the user. Thereby, the change from the default priority mentioned above is attained.

  In addition, as an operation to switch the display mode from normal playback to multi-display playback or from multi-display playback to normal playback, an operation method in which the user intentionally switches the mode, such as pressing the MODE button, has been described. is not. For example, it may be detected that the user has started an operation of switching channels one after another, and may be automatically switched to the multi-display playback mode by interpreting that zapping has started. In the normal playback mode, the zapping determination process monitors the time interval when the NEXT (or PREV) button is pressed in the same manner as the operation tendency determination process described above, and is repeated for a predetermined number of times Nm at a predetermined interval Tm or less. When it is done, it may be determined that zapping has started. Conversely, in the multi-display playback mode, the time interval for pressing the NEXT or PREV button is monitored. An image may be displayed.

  The fact that zapping has started can be regarded as starting to view each video regardless of the image quality, and as a result, it can be understood that the priority of the image quality has been changed. Conversely, the fact that zapping has been completed can also be regarded as changing the priority of image quality. Therefore, the display mode conversion process based on such zapping determination can be realized with the following configuration. That is, the playback device 1 not only includes mode switching means for switching between the multi-display playback mode and the normal playback mode, but also switches the mode according to the priority regarding the image quality obtained by the user's channel switching operation on the playback device 1. Mode switching control means for performing switching control by means is provided.

  In this way, it is possible to switch between normal playback for displaying one video and multi-display playback for displaying a plurality of videos without performing a direct switching operation. That is, the user can perform zapping by multi-display only by operating the channel switching button, and it becomes unnecessary to press the MODE button for zapping, so that the convenience of the user at the time of viewing is improved. The predetermined number of times Nm may be 1. In an extreme case, pressing the NEXT button may always switch to the zapping mode (multi-display playback mode). In addition, it is possible to add control for automatically shifting to the normal playback mode, which also improves user convenience.

  In addition, as described as a preferred example, in the present invention, mode switching that automatically switches the display mode between the normal playback mode and the multi-display playback mode according to the situation of the user's channel switching operation as described above. Technology is not essential. This mode switching technique can also be applied to other embodiments described later although not described. Further, this mode switching technique is a useful technique regardless of whether or not the “processing method switching control according to priority” which is the main feature of the present invention is adopted. Explaining this mode switching technique excluding the processing method switching control of the present invention, the playback apparatus can display in both display modes, and only needs to include the mode switching means and the mode switching control means.

  Next, the synthesis buffer unit 107 will be described with reference to FIG. The synthesis buffers 107-1 and 107-2 reproduce each video (that is, output timing) in order to display the PREV channel video and the NEXT channel video output from the decoding unit 104 and separated by the adjustment unit 106 together with the MAIN video. ) Is controllable. Control of holding / output in each of the synthesis buffers 107-1 and 107-2 is performed by the control unit 110.

  The reproduced video of the stream without thinning becomes a continuous smooth video as indicated by reference numeral 6a in FIG. On the other hand, as described above, for example, a video obtained by directly reproducing a stream that has been thinned out in units of GOP has a certain period in which data is thinned out and a period during which the reproduced video is not output. When the GOP is periodically thinned, such a period is periodically generated as indicated by reference numeral 6b in FIG. 6B. Therefore, the synthesis buffers 107-1 and 107-2 have a reproduction time Tx of the section Xn (n = 1, 2,...) From which the stream is obtained, as indicated by reference numeral 6c in FIG. The section video is thrown at Tx / (Tx + Ty) double speed so as to cover the playback time (presumed playback time of the unacquired stream) Ty of the playback video of the missing stream section (section from which a stream of another channel is acquired) Yn It is preferable to reproduce (that is, to delay the output timing of the frame sequentially). By such slow playback, the slow playback video of the section Xn can be connected to the section video of the section Xn + 1, and smooth playback without a stop point is possible.

  In other words, the playback device 1 preferably includes the following playback speed adjustment means. This playback speed adjustment means is missing when a missing section occurs in the playback video corresponding to each of a plurality of video streams to be combined at the time of multi playback display by switching control of the processing method according to the priority by the switching control means. Compensate by adjusting the playback speed so that there is no section. With such a configuration, the playback of both the NEXT channel and the PREV channel is smooth, and the user's stress caused by watching discontinuous playback during zapping can be reduced. In other words, since the video of the period lost due to the lack of the number of decoders is compensated by adjusting the playback speed, it is avoided that each video is played back unnaturally, and the user's stress at the time of zapping operation by multi-display is avoided. Can be reduced.

  Further, as described as a preferred example, the playback speed adjusting means described above in the present invention is not essential. Further, this reproduction speed adjustment technique can be incorporated not only in the present embodiment and the third embodiment described later, but also in the second embodiment. Furthermore, even if the “control method switching according to priority” of the present invention is not adopted, a missing section is generated in a playback video corresponding to each of a plurality of video streams to be displayed on one screen at the same time. This is a useful technique in such cases. Explaining this playback speed adjustment technique excluding the processing method switching control of the present invention, a section that is missing in a playback video corresponding to each of a plurality of video streams to be simultaneously displayed on one screen occurs in the playback device. In such a case, it is only necessary to provide a reproduction speed adjusting means for adjusting the reproduction speed so that there is no missing section. However, it is useful in a scene where the number of tuners is insufficient or a scene where the number of decoders is insufficient as described above, that is, a scene where a stream is lost. In that respect, it is particularly useful to apply to the present invention. Further, it is also useful for a playback apparatus that controls the processing method of the stream acquisition unit even if it is not control according to priority. As described above, by providing the playback speed adjusting means, it is possible to smoothly play the video in the section where the stream is lost due to the lack of the number of decoders or the number of tuners, and each video is played unnaturally. Can be avoided.

  The processes from the decoding unit 104 to the synthesis buffers 107-1 to 107-2 described above are executed in association with each other. Accordingly, the control unit 110 receives at least a user operation signal related to the priority determination including the channel selection signal (particularly the UP / DOWN signal) from the main control unit, and controls the operations of the units 104 to 107 in an integrated manner. . That is, the control unit 110 determines the priority of each video to be displayed in a multi-number based on the user's operation tendency during zapping, and instructs the adjustment unit 105 to perform input control according to the priority. At the same time, the control unit 110 instructs and manages the switching of the decoding process in the decoding unit 104 that occurs in response thereto, instructs and manages the output control in the adjustment unit 106, and performs the synthesis buffers 107-1 to 107-2. Instruct and manage speed (output timing) control.

  Next, the synthesis unit 108 and the selection unit 109 will be described. The synthesizing unit 108 synthesizes (multi-displays) the MAIN video output from the decoding unit 104 and the adjusting unit 106 with the PREV video and the NEXT video whose reproduction has been adjusted through the synthesis buffers 107-1 and 107-2. In this example, the synthesizing unit 108 automatically synthesizes by input from the synthesizing buffer unit 107. At this time, if necessary, each image is resized according to the display size, and each image is arranged and combined according to the multi-display screen arrangement. The combined multi-display video is output and displayed through the selection unit 109.

  1, the MAIN channel video is decoded through the decoding unit 103 in the normal playback mode, and the MAIN channel video decoded by the decoding unit 104 is used in the multi-display playback mode. The reproducing apparatus according to the first embodiment of the invention may adopt another configuration as shown in FIG. FIG. 7 is a functional block diagram showing another schematic configuration example of the playback apparatus according to the first embodiment of the present invention. The playback apparatus 1a illustrated in FIG. 7 has a configuration in which the stream of the MAIN channel does not pass through the decoding unit 104, and the output of the decoding unit 103 is input to the synthesizing unit 108 and displayed in multiple. That is, the playback device 1a can also use the MAIN channel video decoded by the decoding unit 103 in the multi-display playback mode. The operation of each functional block of the playback device 1a is the same as that of each function block of the playback device 1 (the adjustment units 105a and 106a have different input / output numbers from the adjustment units 105 and 106, but the internal operation is the same). Therefore, the description is omitted. Such a change in configuration can be similarly applied to a second embodiment to be described later.

  In addition, the playback device 1 of FIG. 1 includes a normal playback decoding unit 103 and a multi-display playback decoding unit 104 separately, each of which can be independently decoded, so that the selection unit 109 performs high-speed playback. Although the screen can be switched, the playback apparatus according to the first embodiment of the present invention may employ another configuration as shown in FIG. FIG. 8 is a functional block diagram showing another schematic configuration example of the playback apparatus according to the first embodiment of the present invention. The playback apparatus 1b illustrated in FIG. 8 does not include the decoding unit 103 for normal playback and the selection unit 109 for switching between normal playback and multi-display playback. It has a configuration to output playback video. With this configuration, the playback device 1b can reduce the device configuration to a smaller scale than the playback device 1. Such a change in configuration can be similarly applied to second and third embodiments described later.

  In the playback device 1b, during normal playback, only the stream in the decoding buffer 102-1 is selected and input by the adjustment unit 105b, decoded by the decoding unit 104, and sent to the synthesis unit 108b through the adjustment unit 106b. The synthesizing unit 108b outputs the decoded video in a normal playback display format (for example, full screen display). Since the operation of each of the other functional blocks including the operation at the time of multi-display reproduction is the same as that of each functional block of the reproducing apparatus 1, description thereof will be omitted. Note that the synthesizing unit 108 receives a control signal indicating how the synthesis is to be performed from a main control unit (not shown), thereby enabling synthesis according to normal reproduction and multi-display reproduction.

  Furthermore, in the above description regarding the playback device according to the first embodiment of the present invention, it is assumed that the video acquired via the transmission path is real-time received video such as IP broadcast or television broadcast. However, the playback apparatus and playback method of the present invention can be applied to on-demand playback video such as VOD (Video On Demand) video distribution over the network, in addition to real-time reception. Further, the present invention may be applied to playback of video stored in a recording / playback device (that is, local on-demand playback). Note that the stored video of the recording / playback device is not limited to the stored video inside the recording / playback device configured as the playback device of the present invention, but also the video stored in a device such as an externally connected recording / playback device or home server, Can be a target of playback.

  In the real-time received video, all of the multi-displayed videos are on-time videos that are currently being broadcast. On-demand playback videos may be played back at different times based on the requested time. For this reason, in the real-time received video and the on-demand playback video, as shown in FIG. 9, the decoding buffers 102-2 and 102-3 at the normal playback, and the decoding buffers 102-4 and 102-5 at the multi-display playback, Different streams are prefetched and stored for high-speed channel switching.

  In the reproduction of the real-time received video, as shown in FIG. 9A, the stream accumulated in the past is discarded, and the stream data for always supplementing the latest delay time Td is buffered. On the other hand, in the playback of on-demand playback video, as shown in FIG. 9B, after buffering a stream for the delay time Td based on the video playback start time Ts, the buffering is paused and played back. Wait for subsequent buffering until is started. This playback start time Ts stores the beginning of the video or the user's arbitrary time, stores how far the video has been played in normal playback or multi-display playback, and holds the last playback end time. Then, it may be used as the start time Ts at the start of the next reproduction. It is assumed that the reproduction start time Ts of each channel image is stored in a memory (not shown) and the tuner unit 101 performs buffering using the start time information. Even such a playback device for on-demand playback includes synthesis buffers 107-1 and 107-2 and a control unit 110 from the decoding unit 104 according to the first embodiment of the present invention described above. Dynamic control of image quality during multi-display playback is applicable. If the transmission side cannot be instructed to pause due to restrictions on the communication protocol for on-demand playback, a transmission request from time (Ts + Td) is periodically generated after buffering for Td is completed, and pseudo It is also possible to reproduce the pause state at the time (Ts + Td).

  As described above, in the playback device and playback method according to the first embodiment, when the number of decoders is insufficient or when zapping is performed by multi-video display, the user's operation tendency, operation timing, and setting contents are viewed between channels. And the ratio of the time division input to the decoder of the video stream of the preceding and succeeding channels is adaptively changed. As a result, for users who switch channels one after another, the priority of the stream of the switch-destination channel is increased, more streams are acquired, and the switch-destination channel can be played more smoothly. For example, the user is equally weighted to make it easier to see both channels. In this way, since multi-image display is possible in the best form for the user, zapping by multi-image display can be performed without stress, and the user can efficiently find a desired image. The overall efficiency related to video selection increases. Also, immediately after the channel switching, the priority of the newly displayed channel video is provisionally increased so that it is displayed smoothly. As a result, the multi-video display can be performed in a form that is best for the user such that a new switching destination channel can be quickly and preferentially confirmed. Similarly, the efficiency of video selection in multi-display zapping can be increased.

(Second Embodiment)
In the playback apparatus according to the second embodiment of the present invention, unlike the first embodiment, the switching of the processing method in the switching means as the main feature of the present invention is a plurality of input to the decoding unit. This includes changing the decoding processing level in the decoding unit for each of the video streams. The switching control means as the main feature of the present invention is different from the first embodiment in that each predetermined arrangement is provided for each video stream to be decoded in order to obtain a reproduced video corresponding to each predetermined arrangement. The switching means is controlled so as to change the decoding processing level in accordance with the priority between. Hereinafter, the playback apparatus according to the present embodiment will be described with reference to FIGS.

  FIG. 10 is a functional block diagram showing a schematic configuration example of a playback apparatus according to the second embodiment of the present invention. The playback apparatus 10 includes a tuner unit 101, a decoding buffer unit 102 including decoding buffers (cache memories) 102-1 to 102-5, a decoding unit 103, a decoding unit 1004, an adjustment unit 1005, an adjustment unit 1006, a synthesis unit 108, and a selection unit. The unit 109 and the control unit 1010 are included. The control unit 1010 controls each operation of the decoding unit 1004, the adjustment unit 1005, and the adjustment unit 1006 for dynamic control of image quality, which is a main feature of the present invention.

  Among the constituent elements of the playback apparatus 10, the same functional blocks as those of the playback apparatus 1 in FIG. That is, the playback apparatus 10 according to the second embodiment has a decoding unit 1004, an adjustment unit 1005, an adjustment unit 1006, instead of the decoding unit 104, the adjustment unit 105, the adjustment unit 106, the synthesis buffer 107, and the control unit 110. And the point provided with the control part 1010 differs from the reproducing | regenerating apparatus 1 of 1st Embodiment. Therefore, hereinafter, the reproducing apparatus 10 according to the present embodiment will be described focusing on differences from the reproducing apparatus 1 of the first embodiment. The main control unit (not shown) is the same as that in the first embodiment.

  Similar to the playback device 1 according to the first embodiment, the playback device 10 according to the second embodiment has an insufficient number of decoders with respect to the number of video streams to be multi-displayed (3 display streams). On the other hand, the playback apparatus is assumed to have one decoding unit 1004). The tuner exemplified in the tuner unit 101 is assumed to have the capability of distributing the input multi-stream to the respective decoding buffers exemplified by the decoding buffers 102-1 to 102-5 at the same time. That is, the assumed playback device is an IP broadcast receiving device or the like, as in the first embodiment.

  In the playback apparatus 1 according to the first embodiment, the adjustment unit 105 thins out the stream, and the decoding unit 104 decodes the thinned video stream. On the other hand, in the playback device 10 of the second embodiment, the adjustment unit 1005 does not perform the thinning process, the decoding unit 1004 simplifies the decoding process, and the decoding process of each stream is reduced according to the priority. To do.

  The adjustment unit 1005 takes out the video streams of the respective channels stored in the decoding buffers 102-1 to 102-3, and time-divides them to send them to the decoding unit 1004. At this time, the adjustment unit 1005 of this embodiment does not perform stream thinning, and sends the entire video stream stored in each decoding buffer to the decoding unit 1004.

  The decoding unit 1004 is a functional block having the ability to simplify the processing at the decoding stage. The decoding unit 1004 receives an instruction from the control unit 1010 for each input video stream, and simplifies the low-priority stream at the decoding stage.

  FIG. 11 shows an example of a stream to be decoded, and FIG. 12 shows an example of simplification of the decoding process for the stream. For simplification, as shown in FIG. 12A, a DCT coefficient size to be subjected to inverse DCT (Discrete Cosine Transform) is limited and a reduced size decoded image is output, or as shown in FIG. There is a method of selectively decoding a decoding process of a B picture and a P picture and outputting a decoded image at a low frame rate. In any case, the processing amount can be reduced by omitting the decoding operation (motion compensation calculation etc.) of the B picture and the P picture in which the calculation of the inverse DCT of the high frequency component is omitted, and the decoding unit 1004 Even when there is not sufficient ability to decode three streams at the same time, appropriate decoding processing can be performed by simplifying the decoding processing of several streams. In order to suppress such simplification to some extent, the above-described reproduction speed adjusting means can be incorporated.

  The control unit 1010 determines the priority of each video to be multi-displayed according to the operation tendency when the user performs multi-display zapping, and instructs the decoding unit 1004 to apply simplification according to the priority.

  For example, for users who tend to repeat channel switching to the next channel one after another, the degree of simplification of the NEXT channel image is reduced so that the NEXT channel image will have higher image quality. Apply simplification with high reduction effect. The example shown in FIGS. 12A and 12B corresponds to this example. On the other hand, for users who tend to repeatedly move back and forth, such as confirming the next channel or confirming the previous channel, the middle simplification is applied equally to NEXT and PREV. A method similar to that of the first embodiment can be used as a method of determining the operation tendency.

  Further, immediately after switching, the priority of newly displayed video may be increased for a certain period immediately after switching. That is, the simplification with a high reduction effect may be applied to the channel video (other than the MAIN channel) displayed before switching by reducing the degree of simplification for the newly displayed channel video.

  As described above, in this embodiment, as described in the first embodiment, the priority used for switching the processing method may be determined based on the tendency of the user's channel switching operation. Alternatively, or at the same time, it may be determined based on the elapsed time from the user's channel switching operation. Furthermore, the priority used for switching the processing method may be obtained from the setting content obtained by the prior priority setting operation by the user.

  Also in this embodiment, I-picture pre-detection can be applied, and may be executed by the decoding unit 1004 or the decoding unit 103. Furthermore, when I picture data is extracted from the stream and simplified decoding is performed as shown in FIG. 12B, the decoding process for I picture data requires a larger amount of processing than the decoding process for other P pictures and B pictures. Further, an additional process may be added such that the decoding is performed with the decoding timing shifted so as not to overlap with the decoding process of the I picture of another stream. This process is extremely limited by monitoring the fluctuation in the decoding processing amount of the channel video with a low degree of simplification (main channel video without simplification), and at the timing when the decoding processing amount decreases, It may be a process of executing the decoding process of the channel video.

  The adjustment unit 1006 outputs the decoded video of each channel in response to the input of the adjustment unit 1005 and the decoding process of the decoding unit 1004. The synthesizer 108 synthesizes the decoded video output from the adjustment unit 1006 to form a multi-display video. At this time, even when the size of the decoded video is different as illustrated in FIG. 12A due to the simplification of the decoding unit 1004, necessary resize processing is performed to form a multi-display video.

  As described above, in the playback device and playback method according to the second embodiment, when the number of decoders is insufficient, when zapping is performed by multi-video display, the user's operation tendency, operation timing, and setting contents are used to check the channel. And the simplification level (decoding process level) of the decoding process of the video stream of the preceding and succeeding channels is adaptively changed. This reduces the degree of simplification of the switching destination channel for users who switch channels one after another, and makes the switching destination channel appear more smooth, while for users who go back and forth between channels. Is equally weighted to make it easier to see bidirectional channels. In this way, since multi-image display is possible in the best form for the user, zapping by multi-image display can be performed without stress, and the user can efficiently find a desired image. The overall efficiency related to video selection increases. Immediately after the channel switching, the priority of the newly displayed channel video is provisionally increased so that it is displayed smoothly. As a result, the multi-video display can be performed in a form that is best for the user such that a new switching destination channel can be quickly and preferentially confirmed. Similarly, the efficiency of video selection in multi-display zapping can be increased.

(Third embodiment)
In the playback apparatus according to the third embodiment of the present invention, unlike the first and second embodiments, the processing method switching in the switching means as the main feature of the present invention is the acquisition in the stream acquisition unit. This includes switching the channel of the target video stream in a time division manner between channels corresponding to a plurality of video streams. The switching control means as the main feature of the present invention differs from the first and second embodiments in that each input source of a video stream to be input in order to obtain a playback video corresponding to each predetermined arrangement. In addition, the switching unit is controlled so that the stream acquisition time is changed according to the priority between the predetermined arrangements. Hereinafter, the playback apparatus according to the present embodiment will be described with reference to FIGS.

  FIG. 13 is a functional block diagram showing a schematic configuration example of the playback apparatus 3 according to the third embodiment of the present invention. The playback apparatus 3 includes a tuner unit 301, a tuner unit 302, a decoding buffer unit 303 including decoding buffers (cache memories) 303-1 to 303-5, a decoding unit 304, a decoding unit 305, and decoding units 306-1 to 306-2. The combination buffer unit 307 including the combination buffers 307-1 to 307-2, the combining unit 308, the selection unit 309, and the control unit 310 are configured. The control unit 310 performs operations of the tuner unit 302, the decoding units 306-1 to 306-2, and the synthesis buffers 307-1 to 307-2 in order to perform dynamic control of image quality, which is a main feature of the present invention. Control. The main control unit (not shown) is basically the same as that in the first embodiment except that the tuner unit 302 is controlled to be switched by the control unit 310.

  In the playback device 3 according to the third embodiment, the number of tuners is insufficient with respect to the number of video streams to be multi-displayed (in addition, the number of reception channels including channels pre-received for high-speed switching). This is a playback device that assumes (one tuner unit 302 for four reception channels). As illustrated in the decoding units 305 and 306-1 to 306-2, the decoder is prepared so as to be able to decode all the videos to be displayed in multi display. As such a reproducing apparatus, a television broadcast receiving device, a recording / reproducing device, and the like equipped with a plurality of tuners (demodulators) are assumed. For example, a receiving device, a recording / playback device, and the like that are provided with two tuners (demodulators) for viewing a back program and recording a video recording separately. In this embodiment, for simplicity of explanation, a plurality of decoding units 305 and 306-1 to 306-2 are illustrated as shown in FIG. 13, but instead of these, (the second embodiment) The playback apparatus 3 may be configured to include one decoding unit capable of simultaneously decoding three streams (as shown in the embodiment).

  The playback device 3 includes a selection unit 309 for switching between normal playback and multi-display playback, and switches the display. The tuner unit 301 receives the channel video being selected, and supplies the received video stream to the decoding buffer 303-1. The stream held in the decoding buffer 303-1 is supplied to the decoding unit 304. In the normal playback state, the video output from the decoding unit 304 is displayed via the selection unit 309.

  The tuner unit 302 is a tuner for receiving several channels before and after the channel being selected. Assuming that the tuner is a demodulator in a broadcasting device in this embodiment, a video stream of one channel is obtained by tuning to one frequency at any one time (provided that multiple channels are multiplexed at one frequency) Therefore, only one channel can be received by one tuner. Therefore, in a playback apparatus that performs multi-display as in the present invention, the number of tuners is insufficient with respect to the number of videos to be displayed. From this, the tuner unit 302 of the playback apparatus 3 of the present embodiment obtains the video stream of each channel (illustrated by channels A to D) in a time division manner as shown in FIG. Each stream is stored in each decoding buffer 303-2 to 303-5.

  Alternatively, not only in a demodulator of a broadcast receiving device, but also in a broad-sense tuner of a device that reads and reproduces a plurality of video streams from an on-demand video distribution application or a media drive, the video stream of each channel is time-divisioned as described above. If an environment to acquire (as described later, an environment in which an acquisition operation is limited and it is assumed that a part of the stream cannot be acquired at the time of acquisition) is assumed, the present embodiment is similarly applied. . For example, even when there is no technical restriction, it is conceivable to construct such a video distribution application that imitates a real-time reception environment by intentionally providing such a restriction.

  The decoding buffers 303-2 and 303-3 are buffers that store the video stream of the next channel and the previous channel with respect to the channel being selected. In the normal playback state, these are prefetch buffers for high-speed channel switching control. In this state, the stream is not decoded and played back, and decoding and display start at the time of channel switching or switching to multi-display playback. Is done. On the other hand, in the multi-display playback state, the video streams of the MAIN channel, NEXT channel, and PREV channel stored in the decoding buffers 303-1 to 303-3 are decoded via the decoding units 305 and 306-1 to 306-2. Played.

  The decoding buffers 303-4 and 303-5 are buffers that store the video stream of the second channel and the second previous channel with respect to the channel being selected. These are look-ahead buffers used for high-speed channel switching. The MAIN / NEXT / PREV channel displayed during multi-display playback is one channel after the NEXT channel and one channel before the PREV channel. Video stream. They are not decoded and played back as they are, and any video stream corresponding to the newly displayed channel is decoded and displayed when the channel is switched in the multi-display mode.

  Note that in order to enable decoding to start immediately at the time of switching, the decoding start positions (I picture The head position of data) is detected and held at the time of buffer storage. In addition, the prefetch data may be stored in the decoding buffers 303-4 and 303-5 at the time of normal reproduction. In this manner, the I picture pre-detection may also be executed by the decoding units 304, 305, 306-1, and 306-2.

  Here, when considering real-time reception such as television broadcasting, a stream of each channel that is time-divisionally received is not received while other channels are being received. Accordingly, as shown in FIG. 14, each video stream is stored in the decoding buffer in a state where a part thereof is missing. For this reason, if they are reproduced as they are, the image quality of the reproduced video is deteriorated by the missing amount.

  When considering use in the zapping interface for multi-display playback, the priority is not fixed for the video to be displayed or the video that will be displayed next by channel switching. For example, for users who tend to zap by switching channels one after another, it is more important to quickly check the channels that are displayed one after the other, so channel images in the channel switching direction (the next switchable channel is also Including) has a higher priority. On the other hand, for users who tend to check the channel back and forth and select the channel each time, the priority of the previous and next channels is almost equal, and the user wants to check the displayed video in detail. Prioritize the currently displayed channel over the channel that can be switched to.

  FIG. 15 is a schematic diagram showing the required operation of the time division tuner in these situations. FIG. 15 (A) shows a case where a user who tends to change the channel one after another in the direction of the next channel (NEXT channel) assumes the NEXT channel (Ch. + 1) and the next channel (Ch. + 2). An example is shown in which a large number of division acquisition times are allocated. On the other hand, FIG. 15B shows that the NEXT channel (Ch. + 1) and PREV channel (Ch.-1) are equal, and the next channel (Ch. + 2) of the NEXT channel and the PREV channel one before. This is an example in which more time-division acquisition times are assigned to the NEXT and PREV channels (Ch. + 1, Ch.-1) with respect to the channel (Ch.-2). The degree of allocation of acquisition time with respect to priority can be arbitrarily set. In an extreme case, control may be performed so that acquisition of a channel with a low priority is stopped and only a stream of a channel with a high priority is acquired. Note that a method similar to that of the first embodiment can be used as a method of determining the operation tendency.

  In addition, apart from user operation trends, in the state immediately after channel switching, the newly displayed PREV or NEXT video is more important to the user than the PREV or NEXT video that was the MAIN video before switching (attention) Degree) is high. For this reason, during a certain period immediately after switching, the newly displayed PREV or NEXT video stream may be decoded and reproduced with priority. In that case, after a predetermined period, each channel image is displayed with a priority according to the operation tendency.

  As described above, in this embodiment, as described in the first embodiment, the priority used for switching the processing method may be determined based on the tendency of the user's channel switching operation. Alternatively, or at the same time, it may be determined based on the elapsed time from the user's channel switching operation. Further, the priority used for switching the processing method may be obtained from the setting content obtained by the prior priority setting operation by the user.

  The decoding units 305, 306-1, and 306-2 decode the streams of the respective channels supplied and held to the decoding buffers 303-1, 303-3, and 303-2 as described above, and synthesize the decoded video. The data is input to the synthesis unit 308 via 307-1 and 307-2.

  As described with reference to FIG. 6 in the first embodiment, the synthesis buffers 307-1 and 307-2 adjust the playback speed of the decoded video to compensate for the missing portion of the stream and the short section video, This is a buffer for playback speed control (decoding frame output timing control) provided to smooth the playback video of the NEXT channel.

  In response to the time division reception processing in the tuner unit 302, the decoding processing in the decoding units 306-1 and 306-2 and the speed adjustment processing in the synthesis buffers 307-1 and 307-2 are performed. A control unit 310 is provided that controls them in an integrated manner. That is, according to the priority reflecting the user's operation tendency, the control unit 310 instructs the tuner unit 302 to perform the time-division reception ratio, and performs the decoding process corresponding to the stream lost in the time-division reception. 1 and 306-2 are instructed and managed, and the playback speed of the decoded video is instructed and managed in the synthesis buffers 307-1 and 307-2.

  The synthesizing unit 308 synthesizes the reproduced video including necessary resize processing to form a multi display screen. The formed multi-display image is output and displayed through the selection unit 309.

  Although not shown in FIG. 13, unlike the playback apparatuses 1 and 10 of the first and second embodiments, the playback apparatus 3 of the present embodiment uses a switching candidate channel ( That is, the stream of the NEXT channel and the PREV channel for the MAIN channel in the multi-display is already thinned out by time division reception when it is stored in the decoding buffers 303-2 and 303-3. On the other hand, all the streams are stored in the decoding buffers 303-2 and 303-3 of the playback apparatuses 1 and 10, respectively. For this reason, in the playback apparatuses 1 and 10 of the first and second embodiments, when channel selection is performed from NEXT / PREV as the MAIN channel, the stream stored in the buffer at the time of switching is always at that point. In the playback apparatus 3, when the NEXT / PREV channel is selected as the MAIN channel at a timing when it is not being received in time division, the stream is already buffered. Since the stream stored in is an earlier stream in time, after the video slightly before the switching time (Td seconds) is played back, the video after switching (at the switching time + Td seconds) is played back. The The same applies when the NEXT and PREV candidate channels (decoding buffers 303-4 and 303-5) are switched to the NEXT and PREV channels (decoding buffers 303-2 and 303-3) and the ratio of time division reception changes. Adjustments are made.

  As described above, in the playback device and playback method according to the third embodiment, when the number of tuners is insufficient, when zapping is performed by multi-video display, the user's operation tendency, operation timing, and setting contents are viewed between channels. Priority is determined, and the ratio of time-division reception of the previous and next channel images is adaptively changed. As a result, for users who switch channels one after another, a large number of destination channel streams are acquired so that the switching destination channel looks smoother, and for users who move back and forth between channels. Equally weighted to make it easier to see bidirectional channels. In this way, since multi-image display is possible in the best form for the user, zapping by multi-image display can be performed without stress, and the user can efficiently find a desired image. The overall efficiency related to video selection increases. Also, immediately after the channel switching, the priority of the newly displayed channel video is provisionally increased so that it is displayed smoothly. As a result, the multi-video display can be performed in a form that is best for the user such that a new switching destination channel can be quickly and preferentially confirmed. Similarly, the efficiency of video selection in multi-display zapping can be increased.

(Other)
In the playback device and the playback method of each embodiment of the present invention, an example in which dynamic control of the image quality of multi-display playback is performed in combination with channel selection operation by zapping has been shown, but the multi-display shown in each embodiment Needless to say, the dynamic image quality control of reproduction itself can be similarly applied to multi-display reproduction other than the zapping purpose.

  That is, for a plurality of videos to be displayed in multiple display, past selection operation history and user's operation / viewing habits (for example, there is a tendency to watch the video on the upper left on the multi display screen), When different priorities are given for each multi-display position (arrangement) by active setting or the like, the input stream to the decoding unit (first embodiment), the decoding level (second embodiment), the stream By limiting and controlling the acquisition (Embodiment 3), it is possible to realize the optimum multi-display reproduction corresponding to the decoding capability (the number of decoders) and the tuner capability (the number of tuners). This process is performed every time a plurality of different videos are displayed in a multi-display by switching the multi-display screen, and the image quality of the displayed multi-display video changes as the priority changes.

  As a configuration of the playback apparatus, a prefetch buffer for zapping (buffers for adjacent non-display channels. That is, the decoding buffers 102-4 and 102- in FIGS. 5 and the decoding buffers 303-4 and 303-5) of FIG. 13 are omitted. Since the user can check each video that is displayed in multiples with the image quality according to the priority that the user has explicitly or potentially has, the video that the user often wants to watch / view more even when the decoding capability and / or the tuner capability are insufficient Can be viewed with high image quality, and stress when viewing a multi-display screen can be reduced.

  In addition, a configuration that switches between normal playback (normal single-screen playback) and normal multi-display playback without zapping, and a configuration that switches between normal playback, normal multi-display playback, and zapping multi-display playback are adopted. May be.

  In addition, the playback apparatus according to the present invention exemplified in each embodiment may be configured entirely by hardware, but a part of the playback apparatus may be configured by software (including firmware). As an example for realizing such a configuration, when a computer such as a microcomputer is used, hardware including a tuner, a CPU, a memory, a bus, an interface, a peripheral device, and the like, and on these hardware Executable software (including a decryption program) can be mentioned. The CPU controls the other hardware by executing this software. Specifically, the software stored in the ROM is expanded on the memory, and the expanded program is sequentially executed to process, store, and output data on the memory and data input via the interface. Thus, the functions of the respective parts are realized. The processing in each embodiment described above can be realized by incorporating and executing a program for causing the CPU to execute the processing procedure as the software. Also, other combinations are possible, such as a hardware configuration with the decoding unit as a decoder and no decoding program included in the software.

  As mentioned above, it should be thought that embodiment disclosed by this specification is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a functional block diagram showing a schematic configuration example of a playback device according to a first embodiment of the present invention. It is the figure which showed the example of a display screen of the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. It is the figure which showed the example of a screen transition of the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. FIG. 2 is a diagram illustrating an example of a video image that is multi-displayed by the playback apparatus of FIG. 1 together with a stream adjustment process. FIG. 10 is a diagram illustrating another example of video displayed in a multi display by the playback apparatus of FIG. 1 together with stream adjustment processing. It is the figure which showed the example of a process for reproducing | regenerating smoothly the image | video which is multi-displayed by the reproducing | regenerating apparatus of FIG. It is the functional block diagram which showed another schematic structural example of the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. It is the functional block diagram which showed another schematic structural example of the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. It is the figure which showed the difference of the process of real-time reception and on-demand reproduction | regeneration with the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. It is the functional block diagram which showed the example of schematic structure of the reproducing | regenerating apparatus concerning the 2nd Embodiment of this invention. FIG. 11 is a diagram illustrating an example of a video stream that is multi-displayed by the playback device of FIG. 10. FIG. 12 is a diagram illustrating an example of adjustment processing performed on the video stream of FIG. 11 by the playback device of FIG. 10. It is the functional block diagram which showed the example of schematic structure of the reproducing | regenerating apparatus concerning the 3rd Embodiment of this invention. It is the figure which showed the video stream acquired by the reproduction | regeneration apparatus of FIG. 13 by time division. It is the figure which showed the difference in the video stream acquired by a time division according to a priority with the reproducing | regenerating apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Playback apparatus 102 ... Decoding buffer part 103 ... Decoding part 104 ... Decoding part 105 ... Adjustment part 106 ... Adjustment part 107 ... Composition buffer part 108 ... Composition part 109 ... Selection part 110 ... Control Department.

Claims (11)

A stream acquisition unit that acquires a video stream from an input source; and a decoding unit that decodes the video stream to generate a video, and synthesizes each of a plurality of playback videos from the plurality of video streams in a predetermined arrangement on the screen. A video playback device capable of outputting
Switching means for switching the processing method of the stream acquisition unit and / or the decoding unit for each video stream when the video streams to be reproduced on one screen in the predetermined arrangement are input and combined; ,
Switching control means for controlling the switching of the processing method in the switching means according to the priority relating to the image quality between each predetermined arrangement obtained by a user operation on the video playback device;
A video reproducing apparatus comprising: The switching of the processing method in the switching means includes changing a ratio of a code amount input from the stream acquisition unit to the decoding unit for each of the plurality of video streams,
The switching control means changes the ratio of the code amount according to the priority between the predetermined arrangements for each video stream to be decoded in order to obtain a reproduced video corresponding to the predetermined arrangements. The video reproduction apparatus according to claim 1, wherein the switching unit is controlled. The switching of the processing method in the switching means includes changing a decoding processing level in the decoding unit for each of the plurality of video streams,
The switching control unit changes the decoding processing level according to the priority between the predetermined arrangements for each video stream to be decoded in order to obtain a reproduced video corresponding to the predetermined arrangements. The video playback apparatus according to claim 1, wherein the switching unit is controlled. The switching of the processing method in the switching means includes switching the input source of the video stream to be acquired in the stream acquisition unit in a time division manner between the input sources corresponding to the plurality of video streams,
The switching control means changes the stream acquisition time in accordance with the priority between the predetermined arrangements for each input source of the video stream to be input in order to obtain a reproduced video corresponding to the predetermined arrangements. The video playback device according to claim 1, wherein the switching unit is controlled.   The video playback apparatus according to claim 1, wherein the priority is determined based on a tendency of a user's input source switching operation.   The video playback device according to claim 1, wherein the priority is determined based on an elapsed time from a user input source switching operation.   The video playback apparatus according to claim 1, wherein the priority is obtained from setting contents obtained by a prior priority setting operation by a user.   The stream acquisition unit acquires and buffers in advance a video stream of an input source different from the input source of the currently playing video, and the decoding unit performs the buffering during the buffering or immediately after the end of the buffering. The video reproduction apparatus according to claim 1, wherein an I picture is detected from the video stream.   When a missing section occurs in the playback video corresponding to each of the plurality of video streams to be combined in the predetermined arrangement by switching control of the processing method according to the priority by the switching control unit, 9. The video playback apparatus according to claim 1, further comprising playback speed adjustment means that adjusts the playback speed to compensate for a missing section. Mode switching means for switching between a multi-display playback mode for combining and outputting each of the plurality of playback videos in a predetermined arrangement on the screen, and a normal playback mode for outputting one playback video on the screen;
Mode switching control means for performing switching control in the mode switching means according to the priority relating to the image quality obtained by the user's input source switching operation on the video playback device;
The video reproduction apparatus according to claim 1, further comprising: In a video playback apparatus comprising a stream acquisition unit that acquires a video stream from an input source, and a decoding unit that decodes the video stream into video, each of a plurality of playback videos by a plurality of video streams is predetermined on the screen. A video playback method of combining and outputting in the arrangement of
Switching the processing method of the stream acquisition unit and / or the decoding unit according to the priority related to the image quality between each predetermined arrangement obtained by a user operation on the video playback device;
Inputting and synthesizing each of a plurality of video streams to be reproduced on one screen in the predetermined arrangement while switching the processing method in the switching step;
A video reproduction method characterized by comprising:

Images