JP2010258489A - Video display device, reception device, transmission and reception system, and video display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a user may have a sense of discomfort when viewing and listening, due to the occurrence or the like of the break of video or audio, when processing for securing the amount of data in a buffer by returning a buffer capacity to an original size is not performed by a suitable manner or timing, in a method of making display switching to a selected channel fast by adjusting the buffer capacity after discarding data in a reception-side and/or transmission-side buffer during channel selecting operation and returning the buffer capacity to the original size after a certain time. <P>SOLUTION: When processing for increasing in the buffer capacity and storing data in the buffer is performed, a slight delay time for securing a buffering time is intentionally inserted, and the processing for storing the data is carried out. The delay time is inserted bit by bit in such timing that the user is hard to notice the insertion, for example, when scene is switched or the like. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The technical field relates to a receiver and a video display device.

  Japanese Patent Laid-Open No. 2004-228867 has an issue of “reducing the delay time generated when switching the TV channel on the receiving side when performing real-time transmission of the video signal”. A channel selection unit 212 that selects a channel and generates selection information, a data reception unit 213 that receives the data from the transmission side, a reception buffer 201 that temporarily stores received data, and a temporary buffer in the reception buffer 201 Packet data reading means 202 for reading the accumulated data, decoding means 204 for reading and decoding the packet data from the read data and generating a video signal, and the reception buffer based on the control information Receiving buffer control means 211 for controlling, the receiving buffer control means 211 controls the control information. Upon receiving the input, it erases the packet data that has been temporarily stored in the data receiving buffer 201 changes the storage capacitor "that have been described (see Patent Document 1 Summary).

JP 2003-46582 A

  Japanese Patent Application Laid-Open No. 2004-133830 describes a method for reducing video failure at the time of decoding due to the influence of the speed and bandwidth of a communication line (hereinafter referred to as a communication environment) in a video transmission device and a video reception device connected to a network. When using the buffer memory, the problem is that the display switching time to the selected channel becomes longer due to the delay due to the data storage waiting time in the buffer. To solve the problem, the receiving side and / or transmission at the time of channel selection operation By adjusting the buffer capacity after discarding the data in the buffer on the side, the display switching to the selected channel is made faster, and the buffer capacity is returned to the original size after a certain period of time to return to normal operation. A method of returning is disclosed.

  However, Patent Document 1 does not describe details of processing for returning the buffer capacity to the original size and securing the data amount in the buffer. Therefore, when this process is not performed with an appropriate method or timing, there is a possibility that the user may feel uncomfortable during viewing such as interruption of video or audio.

  In order to solve the above-described problem, an embodiment of the present invention provides buffering when performing processing for increasing buffer capacity and accumulating data in the buffer, for example, in a configuration for adjusting the capacity of the buffer in the data transmission path. A process for accumulating data is performed by intentionally inserting a slight delay time for securing time. The delay time is inserted little by little at a timing that is difficult for the user to notice, such as when the scene changes. When selecting a channel, the buffer capacity is minimized to shorten the buffer data retention time. During continuous viewing, the buffer capacity is increased and the buffering time is inserted at a timing that is difficult for the user to notice. .

  According to the above means, for example, when a network such as a LAN is configured and the broadcast received by the receiver is acquired / selected by the video display device and viewed, the channel selection time of the program viewed by the video display device is shortened, In addition, there is an advantage that a method that enables stable data reception / viewing during long-time viewing can be realized without causing the user to feel uncomfortable.

The figure which shows an example of the system configuration | structure of Example 1. The figure which shows an example of a structure of the video display apparatus 101 in Example 1. FIG. FIG. 3 is a diagram illustrating an example of the configuration of the network interface unit 203 inside the video display apparatus 101 in the first embodiment. FIG. 3 is a diagram illustrating an example of the configuration of the receiver 104 according to the first embodiment. The figure which shows an example of a process of the video display apparatus 101 in Example 1. FIG. The figure which shows an example of a process of the receiver 104 in Example 1. FIG. The figure which shows an example of the buffer control processing in Example 1. The figure which shows an example of a structure of the video display apparatus 101 in Example 2. FIG. The figure which shows an example of the buffer control processing in Example 2. The figure which shows an example of a structure of the video display apparatus 101 in Example 3. FIG. The figure which shows an example of the buffer control processing in Example 3. The figure which shows an example of a structure of the video display apparatus 101 in Example 4. FIG. The figure which shows an example of the buffer control processing in Example 4. FIG. 10 is a diagram illustrating an example of the configuration of the receiver 104 according to the fifth embodiment. FIG. 10 is a diagram illustrating an example of the configuration of the network interface unit 401 inside the receiver 104 according to the fifth embodiment. FIG. 10 is a diagram illustrating an example of processing of the video display device 101 and the receiver 104 in the fifth embodiment. The figure which shows an example of a structure of the video display apparatus 101 in Example 6. FIG. The figure which shows an example of a structure of the network interface part 203 inside the video display apparatus 101 in Example 6. FIG. The figure which shows an example of a structure of the network interface part 401 inside the receiver 104 in Example 6. FIG. The figure which shows an example of a process of the video display apparatus at the time of communication interruption in Example 6 The figure which shows an example of the process of the receiver at the time of communication interruption in Example 6 2 is a diagram illustrating an example of a hardware configuration of a video display device 101 according to Embodiments 1 to 6. FIG. FIG. 10 is a diagram illustrating an example of a hardware configuration of the receiver 104 according to the first to sixth embodiments.

  Examples will be described below. However, the present invention is not limited to this embodiment.

In recent years, video devices received from broadcast stations and video data downloaded via the Internet are stored in a storage device of the recording device, and the recording device stores the data via a home network such as a LAN (Local Area Network). Recording devices and video display devices compliant with the DLNA (Digital Living Network Alliance) standard are beginning to spread for the purpose of viewing videos from other than the above (video display devices in a remote room, etc.). DLNA is a standardization standard for device interconnection required when sharing content such as video and music stored in video devices and personal computers on a home network. DLNA supports not only distribution of accumulated content but also distribution of live broadcast video (distributing received broadcasts to other devices via a network) and cooperation with mobile terminals.
In the basic configuration of DLNA, digital content encoded according to, for example, the MPEG (Moving Picture Experts Group) standard is stored as video in an apparatus (server) that stores content such as video and audio. Information on the genre (genre, description, recording time, etc.) is also stored.

  As an example, a system configuration will be described in which a receiver (server) storing received broadcast data and a video display device (client) at a different location are connected to a network and viewed by the client. When the user operates the client to access the server, the client obtains a list of information about the content from the server. The client displays the ordered list on the screen, and the user selects the content to be reproduced from the list.

  The selected information is transmitted from the client to the server via the network, and in response to this, encoded data of the designated content is transmitted from the server to the client via the network. The client decrypts the received data and provides it to the user as video / audio. With the above mechanism, content stored in other devices can be viewed via the network.

  As another example, a case where the server includes a broadcast receiving unit and a live broadcast being received by the broadcast receiving unit is redistributed from the server to the client will be described. For example, the server uses information obtained from the electronic program guide as information related to the content, and when the user makes a list inquiry from the client in the same procedure as described above, the server transmits the program information to the client.

  When the user selects from a program list displayed on the client screen or designates a desired program by remote control operation, the designated information is transmitted from the client to the server via the network. When the server controls the tuner to receive the designated program and changes the channel, the server extracts the encoded data of the corresponding program and transmits it to the client via the home network. Then, as in the case of the above-mentioned stored content, the client decrypts the data received via the home network and provides it to the user as a live broadcast. With the above-described mechanism, a live broadcast received by another device via a network can be viewed.

  MPEG2-TS (Transport Stream) will be briefly described as an example of the data format handled in the present embodiment. MPEG2-TS can configure multiple programs in one stream and can perform powerful error code correction processing, so it can be used in environments where data transmission errors such as broadcasting and networks can occur. Because it is suitable for transmission, it is used for terrestrial digital broadcasting.

  In MPEG2-TS, video data, audio data, and other data are divided into streams each having an appropriate length called a packet, and additional information such as a header is added as appropriate. The packets are grouped as packets called Packetized Elementary Stream) and further subdivided into TS packets each composed of 188 bytes, and this TS packet is used as one unit for data transmission.

  Also, when transmitting TS packets over a network, unlike transmission from a broadcast station, data may not reach the receiving side at the intended timing on the transmitting side due to the influence of the communication environment such as the bandwidth. By adding a time stamp to the beginning of the packet and buffering it on the receiving side, if it is transmitted from the buffer to the decoder at the time based on the time stamp, decoding can be performed at the timing intended by the transmitting side as in the case of broadcasting.

  Next, as an example, the operation of the video display apparatus when reproducing content encoded in MPEG2-TS will be briefly described. In MPEG2-TS, a time information value program clock reference (PCR) referred to by a receiver is multiplexed and transmitted so that video and audio can be reproduced in synchronization by the receiver as intended by the transmission side.

  First, a program association table (PAT) / program map table (PMT) is acquired from a transport stream (TS) input to the receiver, and a target program identifier (PID) is determined. A TS packet having the found PID is acquired and separated into video data, audio data, and PCR.

  Next, after setting the PCR obtained above as the initial value of the count value of the system time clock (STC) counter, the count value of the counter is increased, and the decoding time information (DTS) attached to each video data Is decoded (decoded) at the time corresponding to the counted value, and is reproduced (displayed) at the time when the reproduction output time information (PTS) attached to the video or audio data is matched. Through the above processing, data in the MPEG2-TS format can be reproduced.

  Next, an example of a system configuration diagram in the present embodiment is shown in FIG. Here, the receiver 104 is a device that can receive a broadcast wave by the tuner and transmit it to the network (here, the LAN 103), and the broadcast wave data received by the receiver 104 is acquired and displayed via the network. Is a video display device 101. Hereinafter, the reference numerals in FIG. 1 will be described.

  The video display device 101 is connected to the LAN 103 and accepts an operation by the remote controller 102. The receiver 104 includes an antenna 105 that is connected to the LAN 103 and can receive broadcast waves. In this configuration, the program data obtained from the broadcast wave received by the antenna 105 can be distributed by the receiver 104, and the program data can be received and viewed by the video display device 101 connected to the LAN 103. The channel selection request is transmitted to the receiver 104 via the LAN 103 by making the video display device 101 using the remote controller 102.

  FIG. 2 shows an example of the configuration of the video display device 101. The video display device 101 includes a remote controller 102, a user interface unit 201, a channel selection control unit 202, a network interface unit 203, a setting storage unit 204, a separation unit 205, a PCR acquisition unit 206, an STC counter 207, a video / audio decoding unit 208, A scene switching detection unit 209, a video output unit 210, an audio output unit 211, a control unit 212, and a VCXO 213 are provided, and each functional block is connected by a system bus 214.

  Among these, FIG. 3 shows an example of the internal configuration of the network interface unit 203. The network interface unit 203 includes a reception buffer 301, a reception buffer control unit 302, a packet analysis unit 303, a packet generation unit 304, and a network control unit 305, which are connected by a system bus 306. The system bus 306 of the network interface unit 203 is connected to the system bus 214 of the video display device 101.

  In this example, the control unit 212 controls each functional block other than the network interface unit 203 in the video display device 101. The network control unit 305 controls each functional block in the network interface unit 203 and communicates with the control unit 212 through the network interface unit system bus 306 and the system bus 214. With the above configuration, the video display apparatus 101 is controlled. However, not limited to the above, the control unit 212 may control all functional blocks including the network interface unit 203 using the system bus 214 and the network interface unit system bus 306.

  An example of a hardware configuration diagram of the video display apparatus 101 is shown in FIG. 22 and correspondence with the system configuration diagram of FIG. 2 will be described. 22 includes the functions of the channel selection control unit 202, the separation unit 205, the PCR acquisition unit 206, the STC counter 207, the video / audio decoding unit 208, and the control unit 212 shown in FIG. The network control LSI 2202 corresponds to the network interface unit 203. The remote control light receiving unit 2203 corresponds to the user interface unit 201. The oscillator 2204 corresponds to the VCXO 213 and supplies a necessary clock to each block. The memory 2205 is used as a storage device by each block as necessary. A panel 2206 corresponds to the video output unit 210. The speaker 2207 corresponds to the audio output unit 211. A system bus 2208 corresponds to the system bus 214.

  The basic operation of each functional block of the video display apparatus 101 will be described below with reference to FIGS. In the video display device 101, the user interface unit 201 acquires a channel selection instruction from the remote controller 102, and the channel selection control unit 202 acquires the channel selection information. The channel selection control unit 202 transmits channel selection information to the network interface unit 203.

  In the network interface unit 203 illustrated in FIG. 3, the packet generation unit 304 controlled by the network control unit 305 converts the channel selection information transmitted from the channel selection control unit 202 into a packet that can be transmitted over the network. By sending this packet to the LAN 103, channel selection information is transmitted to the receiver 104 connected to the LAN 103.

  Based on the channel selection information transmitted by the video display device 101, the receiver 104 transmits video / audio data and playback control data (hereinafter collectively referred to as distribution data) from the received data to the video display device 101. . The receiver 104 will be described later with reference to FIG.

  When the video display apparatus 101 receives the distribution data transmitted by the receiver 104, the received data is acquired by the packet analysis unit 303 inside the network interface unit 203, and a network such as a TCP (Transmission Control Protocol) header is obtained from the acquired data. Data necessary only at the time of transmission is removed, and only distribution data is stored in the reception buffer 301. The packet analysis unit 303 is controlled by the network control unit 305.

  The data stored in the reception buffer 301 is transmitted to the separation unit 205 by the network control unit 305. The separation unit 205 separates video / audio data and reproduction control data such as PCR. Among these, the video / audio data is transmitted to the video / audio decoding unit 208, and the reproduction control data is transmitted to the PCR acquisition unit 206.

  The PCR acquisition unit 206 acquires the PCR in the reproduction control data, and corrects the STC counter 207. The STC counter 207 performs a count operation with the clock of the VCXO 213. Based on the STC counter 207, the video / audio decoding unit 208 decodes the reproduction data. The video / audio decoding unit 208 transmits the video data / audio data obtained by the decoding to the video output unit 210 / audio output unit 211 and outputs it.

  Next, functional blocks necessary for the video display apparatus 101 will be described. These add functions to the basic operations described above.

  A scene change detection unit 209 is connected to the video / audio decoding unit 208 and notifies the reception buffer control unit 302 in the network interface unit 203 that a scene change has been detected from the result of the decoding operation. The reception buffer control unit 302 controls the capacity of the reception buffer 301.

  The setting storage unit 204 holds a setting value such as the size of the buffer capacity in advance, and the reception buffer control unit 302 can control the capacity of the buffer based on the value held in the setting storage unit 204. A new value can be set in the setting storage unit 204. In this embodiment, it is assumed that the system control LSI 2201 in FIG. 22 has the function of the scene switching unit 209 and the memory 2205 in FIG. 22 corresponds to the setting storage unit 204.

  A diagram illustrating an example of the configuration of the receiver 104 is illustrated in FIG. The receiver 104 includes a network interface unit 401, a channel selection control unit 402, a tuner unit 403, an antenna 105, a separation unit 404, and a control unit 405, and is connected via a system bus 406.

  An example of a hardware configuration diagram of the receiver 104 is shown in FIG. 23, and correspondence with the system configuration diagram of FIG. 4 will be described. 22 includes the functions of the channel selection control unit 402, the separation unit 404, and the control unit 405 of FIG. The network control LSI 2302 corresponds to the network interface unit 401. The tuner unit 2303 corresponds to the tuner unit 403. The oscillator 2304 supplies a necessary clock to each block. The memory 2305 is used as a storage device by each block as necessary. A system bus 2306 corresponds to the system bus 406.

  Hereinafter, the basic operation of the receiver 104 will be described with reference to FIG. The receiver 104 receives channel selection information from the video display device 101 connected to the LAN 103 by the network interface unit 401. The channel selection control unit 402 causes the tuner unit 403 to perform a channel selection operation based on the channel selection information, and transmits information necessary for separating distribution data to the separation unit 404. The tuner unit 403 acquires the broadcast wave received by the antenna 105 as data that can be handled by the separation unit 404.

  The separation unit 404 separates the distribution data from the data acquired by the tuner unit 403 based on the information transmitted from the channel selection control unit 402 and transmits the distribution data to the network interface unit 401. The network interface unit 401 converts the distribution data into a packet in a format corresponding to the LAN 103 and sends it out.

  Next, FIG. 5 shows an example of processing when the video display apparatus 101 reproduces distribution data from the receiver 104. The video display apparatus 101 starts processing by establishing a connection with the receiver 104 connected via the LAN 103, and transitions to step 501 (hereinafter, "step" is abbreviated as "S").

  In S501, if there is a channel selection instruction from the remote controller 102, the process proceeds to S502. If there is no channel selection instruction in S501, the process proceeds to S503. In S502, the packet generation unit 304 converts the channel selection information into a packet format that can be transmitted over the network, and then transmits the packet information to the network interface unit 401 of the receiver 104 connected via the LAN 103, and the process proceeds to S503.

  In S <b> 503, distribution data based on the channel selection information is transmitted to the video display apparatus 101 by the operation of the receiver 104. An example of the processing of the receiver 104 is shown in FIG. 6, and details will be described later. In S504, it is monitored whether or not distribution data from the receiver 104 has been received. If data has been received, the process proceeds to S505.

  If no data is received in S504, the process proceeds to S507. In step S <b> 505, it is confirmed whether the received data amount reaches the reception buffer capacity upper limit value of the reception buffer 301 (that is, the state where reception data is written in the entire reception buffer area). If the reception buffer capacity upper limit has been reached, the process proceeds to S506. If the received data amount has not reached the reception buffer capacity upper limit value in S505, the operation of the receiver in S503 is waited for until the data is accumulated in the receive buffer 301 to the upper limit value.

  In S <b> 506, the control unit 212 transfers the distribution data stored in the reception buffer 301 to the video / audio decoding unit 208 via the separation unit 205, performs decoding, and outputs the decoded data through the video output unit 210 and the audio output unit 211. I do. Since the above process is repeated unless the connection with the receiver 104 is disconnected, the process proceeds to S501 again when the connection is not disconnected in S507, and ends when the connection is disconnected.

  Next, FIG. 6 shows an example of processing when the receiver 104 sends distribution data based on a channel selection request from the video display device 101. The receiver 104 starts processing upon establishment of a connection with the video display apparatus 101, and the process proceeds to S601.

  In step S <b> 601, the network interface unit 401 receives a channel selection request from the video display device 101. If there is a channel selection request, the process proceeds to S602. In S602, program data corresponding to the channel selection information is separated and acquired by the separation unit 404 from the broadcast data acquired by the operations of the channel selection control unit 302 and the tuner unit 403, and the process proceeds to S604.

  When there is no channel selection request from the video display apparatus 101, the process proceeds from S601 to S603, and the program data selected by the channel selection control unit 402 at that time is continuously acquired. In step S <b> 604, the network interface unit 401 acquires the program data obtained in step S <b> 604, converts it into a distribution data format for transmission to the LAN 103, and proceeds to step S <b> 605.

  In S605, the distribution data is transmitted to the video display apparatus 101, and the process proceeds to S606. Since the above process is repeated unless the connection with the video display apparatus 101 is disconnected, if the connection is not disconnected in S606, the process proceeds to S601 again, and the process ends when the connection is disconnected.

  In the present embodiment, in the configuration described above, by changing the capacity of the reception buffer 301 of the video display device 101, both the speed of channel selection time and the reduction of the occurrence of video failure are compatible. When a channel selection instruction is issued, the reception buffer capacity is set to a minimum state (for example, a size corresponding to one frame of video / audio data) that can store a minimum amount of data necessary for decoding. This shortens the data retention time in the reception buffer and shortens the channel selection time. In addition, after watching for a certain period of time (that is, when there has been no channel selection operation for a while), it is determined that the user will continue to watch the program, and when the scene changes (including when switching to commercials), the time is short. By increasing the reception buffer capacity by the size of data that can be stored within that time, and performing buffering for the increased amount, the data can be received more stably during subsequent viewing. To do. Hereinafter, the above process is referred to as reception buffer control.

  In this embodiment, the reason for performing the reception buffer control at the time of scene switching detection is that the video / audio is not continuous before and after the scene switching, and therefore the delay time caused by the reception buffer control (decoding stop period and buffer for the increased size) This is because it is difficult for the user to recognize the ringing time).

  An example of a specific procedure of reception buffer control in the video display apparatus 101 is shown in FIG. The buffer control process corresponds to the internal process of S501 in FIG.

  When a channel selection instruction is issued to the video display apparatus 101, the process proceeds from S701 to S702, and the storage capacity of the reception buffer 301 of the video display apparatus 101 is set to the minimum value. For the minimum buffer capacity, an initial value corresponding to the connection environment or the decoding performance of the video / audio decoding unit 208 is stored in the setting storage unit 204 in advance, and the value is used. After minimizing the reception buffer capacity, the process ends.

  When the user continues to watch the program after the channel selection operation, the channel selection instruction is not performed during the viewing, so the process proceeds from S701 to S703. Here, the time when the channel selection instruction is not performed is defined as the continuous viewing time. The video display apparatus 101 monitors the continuous viewing time in S703, and when the preset threshold (Th) is exceeded, the video display device 101 is continuously viewing the channel that the user is viewing at that time ( Hereinafter, the state is referred to as “continuous viewing state”), and the process proceeds from S703 to S704.

  If the continuous viewing time is equal to or less than the threshold Th, the reception buffer is not operated until a channel selection request is made in S701 or the continuous viewing time reaches Th. This is because when the user performs an operation of frequently switching channels such as so-called zapping, the reception buffer is always minimized and the channel selection time is shortened.

  In S704, when the scene switching detection unit 209 detects that a scene switching has occurred, the process proceeds to S705. A specific method of detecting scene switching in S704 will be described later. If no scene switching has occurred in S704, the process proceeds to S701, where it is determined whether there is a channel selection request.

  In S705, the decoding process is temporarily stopped, and the process proceeds to S706. The pause of the decoding process in S705 means that the video / audio output is stopped, the video / audio decoding unit 208 is requested to pause (the data stored in the buffer in the decoder is not deleted but held), the video / A series of processes of interrupting data transfer to the audio decoding unit 208. At this time, the value of the STC counter serving as a reference for the decoding timing is temporarily stored in the setting storage unit 204.

  In S706, the reception buffer control unit 302 increases the reception buffer capacity by an increment value set in advance in the setting storage unit 204, and the process proceeds to S707. At this time, since the video / audio decoding unit 208 is in a paused state, the accumulated data in the reception buffer is not consumed, and the amount of accumulated data in the reception buffer increases by receiving new data. To do. A method for determining the increment value of the reception buffer capacity in S706 will be described later.

  In S707, the decoding process in the paused state is resumed, and the process proceeds to S708. The restart of the decoding process in S707 is a series of processes of releasing the temporary stop of the video / audio decoding unit 208, restarting the data transfer to the video / audio decoding unit 208, and restarting the video / audio output. At this time, the value held in S705 is used as the STC counter value.

  In S708, it is determined whether the buffer capacity increase amount has reached a predetermined increase upper limit value by the buffer capacity increase process in S706. The increase amount upper limit value is determined by setting an appropriate value in the setting storage unit 208 in advance, reading it, and comparing it with the increase amount up to that point. If the increase amount upper limit has been reached, it is determined that the video display device 101 has sufficient buffer capacity for stable reproduction, and it is not necessary to further increase the buffer capacity, so the processing ends.

  If the scene change is not detected in S704, the channel selection request is made in S701, or the buffer operation is not performed until the scene change is detected, and the processes of S701, S703, and S704 are repeatedly waited.

  If a channel selection instruction is issued in S701 from the state in which the buffer capacity has increased by the processing in S706, the process proceeds to S702, where the buffer capacity is reset to the minimum capacity, and at the same time, the previous channel accumulated in the buffer is reset. Discard the data. By this process, data of a new channel starts to be accumulated immediately in the buffer, so that the buffering time can be shortened. The reception buffer capacity is controlled by the above processing. Note that the above reception buffer control always operates during viewing according to the present configuration, so even after the processing in FIG. 7 is finished, if the buffer capacity does not reach the upper limit of increase due to the channel selection operation, etc. The process is resumed.

  As a method for determining the threshold value Th for determining the continuous viewing state, for example, there is a method of acquiring program information being viewed and empirically determining it based on the configuration of the program. For example, if the broadcast time and the program genre are acquired from the program information and it is determined that the drama is being viewed, it can be estimated that the drama is continuously viewed from the CM to the CM, so the continuous viewing time threshold Th is The value is shorter than the interval from CM to CM (for example, for a one-hour drama, the interval from CM to CM is assumed to be 15 minutes, and Th is 3 minutes shorter than that).

  As another method, the channel switching time interval when the user frequently performs channel switching operation (zapping) is recorded in the setting storage unit 204 or the like, and the latest number of channel switching times is recorded. There is also a method in which an average channel switching time interval is calculated, and a time longer than that time (for example, about twice as long) is defined as the threshold Th. In this method, even when the user repeats zapping and continuous viewing, the number of reception buffer controls can be increased. However, the method for determining the continuous viewing time threshold Th is not limited to the above.

  As a detection method for switching scenes, for example, there is a method of detecting a change in an audio mode (for example, a stereo / monaural distinction or an audio multiplexing method). In general broadcasting, since the audio mode changes when switching between CMs, this method is often used for CM detection. When this change is detected, it is determined that the scene is switched.

  Another method is to use video luminance information such as a luminance histogram from decoded video data. This method uses the fact that the luminance histogram changes gently at a location where scenes are continuous, and changes abruptly when the scene is switched. Specifically, the threshold value of the luminance histogram change amount is appropriately set, and the transition of the luminance histogram is sequentially referred to, and before and after the video data having the change amount exceeding the threshold value is determined as the scene switching time. However, the scene change detection method is not limited to the above.

  The increment value of the buffer capacity for each scene change is set taking into consideration the bit rate of the received data, etc., and as a guide, the amount of time that the user does not feel the decoding stop period long at the scene change . For example, a decoding stop period for a time corresponding to one frame of video display, that is, 33 ms is provided, and a buffering time for that amount is secured. However, the buffer capacity increment value setting method is not limited to the above.

  In the first embodiment, the buffer amount is increased by the reception buffer control when the scene is switched. However, in the present embodiment, the buffer amount is increased even when a video displayed on the video display device 101 is broken. This is because when there is a video failure, there is a high possibility that the received data is missing, and it can be determined that stable display cannot be performed with the buffer amount.

  In addition, there is an advantage that it is difficult for the user to notice the temporary stop of the video accompanying the buffer control at the timing when the video failure occurs. FIG. 8 shows an example of a configuration in the present embodiment. 8 with the same reference numerals as those in FIG. 2 are omitted.

  In FIG. 8, a video failure detection unit 801 is connected to the video / audio decoding unit 208, detects the occurrence of video failure during decoding, and notifies the reception buffer control unit 302 of the network interface unit 203 of the occurrence of video failure.

  An example of reception buffer control processing in this embodiment is shown in FIG. In FIG. 9, the description of the same reference numerals as those in FIG. 7 is omitted. As in the first embodiment, after exceeding the threshold Th of the continuous viewing time in S703, the process proceeds to S901, where the video / audio decoding unit 208 indicates that a video failure, that is, a decoding error has occurred during decoding. When the failure detection unit 801 detects, the process proceeds to S705, and buffer control is performed similarly to the first embodiment.

  When the buffer control according to the present embodiment is performed, it is considered that a video failure has occurred due to the buffer capacity that was initially set. Therefore, the initial value of the minimum buffer capacity set in the storage setting unit 204 is changed again. You may make it reset appropriately.

  As a video failure detection method in this embodiment, for example, the video / audio decoding unit 208 detects an error related to decoding, and determines a video failure occurrence when an error during decoding is detected.

  Since the video failure detection in this method is performed at the timing based on the DTS, depending on the display timing of the data in which the failure has occurred (timing based on the PTS), the failure may occur regardless of the state in which the user cannot see the video failure. Will be detected. In this case, if the reception buffer control is performed in accordance with the timing of detecting the occurrence of video failure, the delay time due to the reception buffer control occurs at a timing different from the visual failure that can be seen.

  That is, the display is suddenly stopped temporarily from the normal display state while the user is viewing. Therefore, the reception buffer control in the present embodiment is performed in accordance with the PTS of the failed data, that is, at the timing when the failed video is displayed, so that the video is paused when normally displayed. Can be prevented. However, the video failure detection method is not limited to the above. Further, it may be implemented in combination with the reception buffer control at the time of scene switching shown in the first embodiment.

  As a method of performing the reception buffer control by means other than the above-described embodiment, for example, there is a method of performing when the still image is continuously displayed while the image is displayed on the image display apparatus 101. The still image in the present embodiment refers to an image that has no change in luminance value on the display screen and does not move on the screen. If still images are being displayed, there is an advantage that the user is less likely to notice video pauses during the decoding stop period.

  FIG. 10 shows an example of a configuration in the present embodiment. 10 with the same reference numerals as those in FIG. 2 will not be described. In FIG. 10, the video still state determination unit 1001 is connected to the video / audio decoding unit 208, determines whether the video obtained by decoding is in a still state, the video is in a still state, and the still state duration time. Exceeds the preset threshold (sh), the reception buffer control unit 302 of the network interface unit 203 is notified. In this embodiment, the system control LSI 2201 in FIG. 22 has the function of the video still state determination unit 1001.

  An example of reception buffer control processing in this embodiment is shown in FIG. In FIG. 11, the description of the same reference numerals as those in FIG. 7 is omitted. Similarly to the first embodiment, when there is no channel selection request in S701, the process proceeds to S1101, and it is determined whether the video is stationary. If it is in a stationary state, the process proceeds to S1102. If it is determined in S1101 that the video is not stationary, the process proceeds to channel selection request reception in S701.

  In S1102, it is determined whether or not the still video state duration exceeds the threshold Sh. If the threshold exceeds Sh, the process proceeds to S705, and thereafter, reception buffer control is performed as in the first embodiment. If it is determined in S1102 that the still video state continuation time does not exceed the threshold value Sh, the process proceeds to the still video state determination in S1101 again, and is repeated until the still video state is lost or the duration exceeds Sh.

  As a method for discriminating still images, for example, there is a method of using video luminance information such as a luminance histogram from decoded video data. When a still image continues, the fact that there is no change in the value indicating the luminance histogram is used. The video still state determination unit 1001 periodically acquires a luminance histogram, and when it is the same value a plurality of times, it determines that still video is being displayed and performs reception buffer control at that timing.

  The above example uses the video still state determination unit 1001 to determine the still state. However, as another method, the same effect can be obtained by determining the video still state by processing of software operated by the control unit 212. Can be obtained. Note that still image discrimination in the present embodiment is not limited to the above. Further, it may be implemented in combination with the first embodiment and / or the second embodiment.

  As a method of performing reception buffer control by means other than the above-described embodiment, for example, there is a method of temporarily stopping decoding at a periodic timing and performing reception buffer control during the paused time. FIG. 12 shows an example of the configuration of this embodiment. 12 with the same reference numerals as those in FIG. 2 will not be described.

  In FIG. 12, the buffer control cycle determination unit 1201 is connected to the video / audio decoding unit 208, measures the decoding processing time, and when the processing time coincides with a preset buffer control cycle (Bp), the network interface Notify the reception buffer control unit 302 of the unit 203. In the present embodiment, the system control LSI 2201 in FIG. 22 has the function of the buffer control cycle determination unit 1201.

  An example of reception buffer control processing in this embodiment is shown in FIG. In FIG. 13, the description of the same reference numerals as those in FIG. 7 is omitted. As in the first embodiment, when there is no channel selection request in S701, the process proceeds to S1301, and it is determined whether the decoding processing time matches the buffer control period Bp. If it matches Bp, the process proceeds to S705, and thereafter, receive buffer control is performed in the same manner as in the first embodiment. In S1301, if the decoding processing time does not match Bp, the process proceeds to channel selection request determination in S701, and channel selection is performed, or channel selection is not performed and the process proceeds to S1301, and the decoding processing time matches Bp. Repeat until.

  As a set value of the buffer control cycle Bp, for example, there is a method of setting a decoding processing time for each GOP (Group Of Pictures) unit in the video stream. The GOP is a screen group structure including a plurality of screen data and including at least one intra-frame encoded screen. In the MPEG2 encoding method, screen data that refers to previous and subsequent screen data exists, so that one piece of screen data is not complete information, and this GOP is equivalent to one unit. The cycle for decoding 1 GOP is set to Bp, and each time 1GOP processing is completed, the decoder is paused for a short time (for example, the time that can process one frame of video), and the buffer capacity is controlled during that time by controlling the reception buffer. Increase buffering time.

  By simultaneously performing this method and the method described in the first, second, or third embodiment, the buffer capacity and the amount of stored data can be increased in a short time after channel selection. In the above example, the buffer control cycle determination unit 1201 is used to compare the decoding processing time and the buffer control cycle Bp. As another method, the decoding processing time and the buffer control are processed by software processing executed by the control unit 212. A similar effect can be obtained by comparing the periods Bp. The method for setting the buffer control period in the present embodiment is not limited to the above.

  Although each of the above embodiments controls the reception buffer, the transmission buffer of the receiver 104 may be controlled. FIG. 14 shows an example of the configuration of the receiver 104 in the present embodiment. 14 with the same reference numerals as those in FIG. 4 will not be described. The receiver 104 in this embodiment includes a network interface unit 401, a channel selection control unit 402, an antenna 105, a control unit 405, a tuner unit 1201, a tuner unit 1401, a tuner A 1402 and a tuner B 1403, a separation unit A 1404 and a separation unit B 1405, A back channel setting unit 1406 (the definition of the back channel will be described later) is provided and is connected by the system bus 406. In this embodiment, the system control LSI 2301 in FIG. 23 has the function of the back channel setting unit 1406.

  FIG. 15 shows an example of the configuration of the network interface unit 401 of the receiver 104. The network interface unit 401 includes a packet analysis unit 1501, a transmission buffer A 1502, a transmission buffer B 1503, a transmission buffer switching unit 1504, a packet generation unit 1505, and a network control unit 1506. Each block is connected by a system bus 1507.

  In this example, the control unit 405 controls each functional block other than the network interface unit 401 in the receiver 104. Each function block in the network interface unit 401 is controlled by the network control unit 1506, and communicates with the control unit 405 through the network interface unit system bus 1507 and the system bus 406. With the above configuration, the receiver 104 is controlled. However, the present invention is not limited thereto, and the control unit 405 may control all functional blocks including the network interface unit 401 using the system bus 406 and the network interface unit system bus 1507.

  In the network interface unit 401 illustrated in FIG. 15, channel selection information data transmitted from the video display apparatus 101 via the LAN 103 is acquired by the packet analysis unit 1501 and transmitted to the channel selection control unit 402 of the receiver 104. The channel selection control unit 402 notifies the current channel selection information to the tuner unit 1401, the back channel setting unit 1406, the separation unit 1404, and the separation unit 1405.

  The tuner unit 1401 operates the tuner 1402 and the tuner 1403 based on the channel selection information of the channel selection control unit 402 and the back channel setting unit 1406, receives broadcast data, and transmits the broadcast data to the separation unit 1404 and the separation unit 1405.

  The separation unit 1404 and the separation unit 1405 separate the distribution data necessary for each channel, and transmit the data to the transmission buffer A 1502 and the transmission buffer B 1503 inside the network interface 401, respectively.

  The transmission buffer switching unit 1504 switches the transmission buffer based on the current channel selection information held by the channel selection control unit 402, and the network control unit 1505 transmits the distribution data in the transmission buffer to the packet generation unit 1504. The packet generation unit 1504 converts the packet into a TCP packet that can be transmitted over the network and transmits the packet to the video display apparatus 101 via the LAN 103.

  An example of processing of the receiver 104 and the video display device 101 in this embodiment is shown in FIG. In the configuration using two tuners and two transmission buffers, the receiver 104 shown in FIG. 14 receives data (hereinafter referred to as program data) including a program of a channel which is one tuner, and is separated by the other tuner. It is assumed that each program data is received and each program data is stored as distribution data in two transmission buffers.

  Here, a channel capable of receiving program data based on channel selection information is defined as a front channel, and a channel capable of receiving program data different from the front channel is defined as a back channel. The receiver 104 starts processing by establishing a connection with the video apparatus 101, and transitions to S1601 and S1603.

  The processing from S1601 to S1602 and the processing from S1603 to S1604 are performed in parallel. In S1601, the channel currently selected by the receiver 104 (hereinafter referred to as channel A) is set as a front channel, and the process proceeds to S1602.

  In S1602, channel A is selected by the first tuner 1402 (hereinafter referred to as tuner A), distribution data is separated from the received program data, and the first transmission buffer (hereinafter referred to as transmission buffer A) is selected. ). The capacity of the transmission buffer A is assumed to be a sufficient capacity so as not to cause video failure due to a change in the communication environment.

  In parallel with the above process, the process proceeds to S1603 after the process starts. In S1603, a back channel is selected / designated from channels not currently selected, and the process proceeds to S1604. The back channel designation method will be described later.

  In S1604, the receiver 104 selects a channel different from the front channel (hereinafter referred to as channel B) by the second tuner 1403 (hereinafter referred to as tuner B), and separates the distribution data from the received program data. And stored in the second transmission buffer (hereinafter referred to as transmission buffer B). Assume that the capacity of the transmission buffer B is sufficient to prevent video corruption due to changes in the communication environment, as with the transmission buffer A.

  Further, every time the transmission buffer A / B reaches the buffer capacity limit value, data with a long residence time in the buffer (old data) is sequentially discarded, and the latest distribution data in the transmission buffer is always accumulated. A ring buffer structure may be used.

  After S1602 and S1604, the process proceeds to S1605, where it is determined whether there is a channel selection request from the video display apparatus 101. If there is no channel selection request in S1605, the process proceeds to S1606, and the distribution data of the front channel in the transmission buffer A, that is, the distribution data of Channel A is transmitted to the video display apparatus 101.

  When the video display apparatus 101 notifies the channel selection request in S1605, the process proceeds to S1607, and the data in the reception buffer in the video display apparatus 101 is discarded. Thereafter, the process proceeds to S1608, where it is determined whether the requested channel is a back channel.

  If the channel selection request is for the back channel (channel B in this example), since the distribution data has already been accumulated in the transmission buffer B, the process proceeds to S1610, where the transmission buffer switching unit 1504 changes the transmission buffer A1502 to the transmission buffer. Switching to B1503, the distribution data of channel B stored in the transmission buffer B is immediately transmitted to the video display apparatus 101.

  The amount of data to be transmitted is determined so that the transmission buffer B does not underflow and increases as much as possible (that is, the data rate of the network temporarily becomes higher than when no channel selection request is made). The reception buffer capacity of the video display apparatus 101 on the receiving side needs only to be large enough to store the entire amount of data transmitted from the receiver 104 by the above method. Set in advance.

  After the first buffered data is transmitted, the received program data is continuously transmitted to the video apparatus 101 sequentially (with minimum buffering). The video display apparatus 101 accumulates the transmitted data in the reception buffer and starts decoding sequentially.

  In S1608, if the requested channel is other than the back channel (for example, channel C), the data of channel C, which is the requested channel, is newly accumulated in the transmission buffer B, the process proceeds to S1610, and the accumulation amount upper limit is reached. As soon as the transmission buffer B is switched, the data is transmitted.

  After S1610, it is determined whether the connection is disconnected. If it is not disconnected, the processes of S1601 and S1603 are started in parallel in the same manner as when the process is started. The above processing is repeated, and the distribution data for the front channel and the back channel are respectively stored in the transmission buffers A / B.

  According to this embodiment, the channel selection time between the two channels can be shortened by receiving and buffering two different channels at the receiver 104 on the transmission side. In addition, the distribution data accumulated in the transmission buffer of the receiver 104 is transmitted and stored in the reception buffer of the video display device 101 at a time until the data in the reception buffer is completely processed even if the communication environment changes. There is an advantage that video failure due to data loss does not occur.

  As a back channel designation method, for example, a channel up / channel down (a method of switching a program to be watched in ascending / descending order of channel numbers) is recorded, and a channel considered to be selected next is predicted and designated. There is a way.

  For example, if channel selection operation continues with channel up, it can be predicted that the current channel will change to the next channel in ascending order, so the next channel in the ascending order from the current channel (front channel) is designated as the back channel. To do. With this method, when the next channel is selected in ascending order as predicted, the data is already buffered in the transmission buffer B and can be transmitted immediately, so that the tuning time can be shortened. . Similarly, in the case of channel down, it is predicted that the channels will be selected in descending order, and the back channel is designated.

  The transmission buffer control timing, the back channel designation method, the number of tuners and buffers in this embodiment are not limited to the above.

  In each of the above embodiments, either the reception buffer of the video display device 101 or the transmission buffer of the receiver 104 is controlled. However, both buffers may be controlled. In a configuration in which broadcast data received by the receiver 104 is transmitted to the video display device 101 via the network and decoded / displayed by the video display device 101, the communication environment deteriorates due to a decrease in the network bandwidth or the like, and communication is temporarily performed. A method of reducing the influence on the video display by buffer control when the interruption occurs will be described.

  FIG. 17 is a diagram showing an example of the configuration of the video display apparatus 101 in this embodiment, and FIG. 18 is a diagram showing an example of the configuration of the network interface unit 203 in FIG. 17 having the same reference numerals as those in FIG. 2 and those having the same reference numerals as those in FIG. 3 in FIG.

  In FIG. 17, the reception buffer control information generation unit 1701 performs buffer control on the reception buffer control unit 302 in the network interface unit 203 by the method described in the first, second, third, or fourth embodiment, or a combination thereof. Notify instructions. In this embodiment, the system control LSI 2201 in FIG. 22 has the function of the reception buffer control information generation unit 1701.

  In FIG. 18, the communication state monitoring unit 1801 monitors the communication state by the LAN 103 and notifies the reception buffer control unit 302 when communication is interrupted.

  The receiver 104 in the present embodiment is the same as the diagram (FIG. 4) showing an example of the configuration in the first embodiment. FIG. 19 shows an example of the configuration of the network interface unit 401 inside the receiver 104 in this embodiment. In FIG. 19, those having the same reference numerals as those in FIG.

  The transmission buffer 1901 temporarily stores the distribution data generated by the separation unit 402. The transmission buffer control unit 1902 changes the transmission buffer capacity. The communication status monitoring unit 1903 monitors the communication status of the LAN 103 and notifies the transmission buffer control unit 1902 when communication is interrupted. The setting storage unit 1904 stores setting values such as the initial value and increment of the transmission buffer capacity in advance, and the transmission buffer control unit 1902 controls the transmission buffer 1901 using these values.

  The processing of the video display apparatus 101 when the communication environment in this embodiment is good (normal time) is the same as in FIG. 5, and the processing of the receiver 104 is the same as in FIG. At normal times, the video display apparatus 101 performs reception buffer control by the method shown in the first, second, third, or fourth embodiments, or a combination thereof, and sequentially increases the reception buffer capacity.

  In addition, the receiver 104 sets the transmission buffer as small as possible and transmits distribution data with minimum buffering. Whenever the buffer capacity limit value is reached, the transmission buffer and reception buffer are sequentially discarded from the data with long residence time (old data) in the buffer, and the ring buffer in which the latest distribution data is always accumulated in the transmission buffer. It is good also as a structure.

  An example of processing in the video display apparatus 101 when communication interruption occurs in this embodiment is shown in FIG. 20, and an example of processing in the receiver 104 is shown in FIG.

  When the communication state monitoring unit 1801 detects that the data cannot be received due to communication interruption, the video display apparatus 101 on the receiving side transitions to S2001, and determines whether the increase in the reception buffer area is the upper limit value. . If it is the upper limit value, the process proceeds to S2003.

  If the increase amount of the reception buffer is not the upper limit value in S2001, the process proceeds to S2002, and the reception buffer capacity is immediately increased. At this time, new distribution data cannot be received due to communication interruption, so buffering is not performed for the increased amount of the buffer, but only the storage area used as the buffer is expanded. The increment of the reception buffer capacity of the video display apparatus 101 is preferably set to a value sufficiently larger than the maximum value of the transmission buffer capacity assumed on the transmission side. In S2003, it is determined whether or not to disconnect the connection. If yes, the process ends. If not, the process proceeds to S2001.

  When the communication state monitoring unit 1903 detects that data cannot be transmitted due to communication interruption, the receiver 104 on the transmission side makes a transition to S2101 and determines whether the increase in the transmission buffer area is the upper limit value. If it is the upper limit value, the process proceeds to S2105. When the increase amount of the transmission buffer is not the upper limit value in S2101, the process proceeds to S2102 and the transmission process is immediately stopped, and the process proceeds to S2103.

  In S2103, the capacity of the transmission buffer is increased, and the process proceeds to S2104. In S2104, data corresponding to the increased capacity of the transmission buffer is additionally buffered, and the process proceeds to S2105.

  Here, during the suspension and buffering of transmission, the time until the decoder of the video display device 101 finishes processing all the distribution data accumulated in the reception buffer of the video display device 101, the influence of the failure of the video display, etc. Does not come out. This transmission buffer control is performed until the communication environment is improved. In S2105, it is determined whether or not to disconnect the connection. If yes, the process ends. If not, the process proceeds to S2101.

  After that, when the communication environment is improved again, the amount of data stored in the reception buffer of the video display device 101 has decreased compared to the normal time (the amount of storage cannot be received because new distribution data cannot be received). (Increased and accumulated data is processed and consumed by the decoder).

  In order to compensate for the accumulated amount of the decrease, the receiver 104 transmits a large amount of data accumulated in the transmission buffer whose capacity has been increased by the transmission buffer control in S2103 and S2104 at as high a bit rate as possible. At this time, the amount of data to be transmitted is determined so that the transmission buffer does not underflow and is as much as possible.

  After transmitting the buffered data, the broadcast data received as usual is transmitted to the video apparatus 101 sequentially (with minimum buffering). In the video display apparatus 101, the reception buffer capacity has been increased by the processing of S2002, so that a large amount of data transmitted can be received and stored in the buffer, and communication interruption due to subsequent deterioration of the communication environment occurs. However, the effect on the video display can be reduced by the same method.

  In addition, when a channel selection operation is performed, in the same manner as in the first, second, third, or fourth embodiments, or a combination thereof, by discarding the data in the reception buffer and minimizing the capacity, An increase in delay time due to buffering time in the reception buffer can be suppressed.

  According to the present embodiment, it is possible to reduce the occurrence of video failure in the video display device 101 even in a communication environment in which temporary and short-time communication interruptions frequently occur. If the transmission buffer control and the reception buffer control according to this embodiment are not used, if communication is interrupted, the data that could not be transmitted during that time remains in the transmission buffer, but the content of the transmission buffer is overwritten with new data after a certain time. Old data will disappear. For this reason, the video is interrupted due to loss of data during the communication interruption period.

  The reception buffer control information generation method in the present embodiment is not limited to the above. In the above embodiment, as an example of an opportunity to increase the buffer capacity, detection of scene switching (for example, S704 in FIG. 7), detection of video failure (for example, S901 in FIG. 9), and length of video still time (for example, FIG. 11). S1101, 1102), etc. are shown, but the present invention is not limited to this, and the buffer capacity may be increased by detecting other video and / or audio features. Further, the scene change detection unit 209, the video failure detection unit 801, and the video still state determination unit 1001 described in the above embodiments are characterized as a generic term including means for detecting other video and / or audio features. It is also called a detection unit.

101 Video display device 102 Remote control 103 LAN
104 receiver 201 user interface unit 202 channel selection control unit 203 network interface unit 204 setting storage unit 205 separation unit 206 PCR acquisition unit 207 STC counter 208 video / audio decoding unit 209 scene switching detection unit 210 video output unit 211 audio output unit 212 Control unit 213 VCXO
214 system bus 301 reception buffer 302 reception buffer control unit 303 packet analysis unit 304 packet generation unit 305 network control unit 306 system bus 401 network interface unit 402 channel selection control unit 403 tuner unit 404 separation unit 405 control unit 406 system bus 801 video failure Detection unit 1001 Video still state determination unit 1201 Buffer control cycle determination unit 1401 Tuner block 1402 Tuner A
1403 Tuner B
1404 Separation part A
1405 Separation part B
1406 Back channel setting unit 1501 Packet analysis unit 1502 Transmission buffer A
1503 Transmission buffer B
1504 Transmission buffer switching unit 1505 Packet generation unit 1506 Network control unit 1507 System bus 1701 Reception buffer control information generation unit 1801 Communication state monitoring unit 1901 Transmission buffer 1902 Transmission buffer control unit 1903 Communication state monitoring unit 1904 Setting storage unit 2201 System control LSI
2202 Network control LSI
2203 Remote control light receiving unit 2204 Oscillator 2205 Memory 2206 Panel 2207 Speaker 2208 System bus 2301 System control LSI
2302 Network control LSI
2303 Tuner unit 2304 Oscillator 2305 Memory 2306 System bus

Claims (7)

A video display device that receives and plays back a video signal via a network,
A network interface unit for receiving a video signal via a network;
A reception buffer for temporarily storing video signals received by the network interface unit;
A reception buffer controller for controlling the capacity of the reception buffer;
A decoding unit for decoding the video signal in the reception buffer;
A feature detection unit that detects features from the video decoded by the decoding unit;
The video buffer according to claim 1, wherein the reception buffer control unit controls the reception buffer based on a video feature detected by the feature detection unit. The video display device according to claim 1,
The feature detection unit is a video display device that detects a change of a scene of the video decoded by the decoding unit as a feature. The video display device according to claim 1,
The feature detection unit is a video display device that detects a failure of the video decoded by the decoding unit as a feature. The video display device according to claim 1,
The feature detection unit is a video display device that detects a stillness of the video decoded by the decoding unit as a feature. A receiving device that transmits a received video signal to another device via a network,
A receiver for receiving a plurality of video signals;
A selection unit for selecting a video signal from a plurality of video signals received by the reception unit;
A separator for separating the video signal received by the receiver;
A network interface unit for transmitting the video signal separated by the separation unit via a network;
A plurality of transmission buffers for temporarily storing video signals to be transmitted by the network interface unit;
A transmission buffer switching unit that switches a transmission buffer that accumulates a video signal transmitted by the network interface unit from one transmission buffer of the plurality of transmission buffers to another transmission buffer of the plurality of transmission buffers; Have
The receiving device that switches the transmission buffer according to the selection of the video signal in the selection unit. A transmission / reception system having a reception device that transmits a received video signal via a network and a video display device that receives a video signal transmitted from the reception device via the network,
The receiving device is:
A receiver for receiving a plurality of video signals;
A separator that separates the video signal received by the receiver based on a request from the video display device;
A transmission-side network interface unit that transmits the video signal separated by the separation unit via a network;
A transmission buffer for temporarily storing a video signal to be transmitted via the transmission-side network interface unit;
A transmission buffer control unit for controlling the capacity of the transmission buffer;
The video display device
A receiving-side network interface unit that receives a video signal transmitted from the receiving device via a network;
A reception buffer for temporarily storing the video signal received by the reception-side network interface unit;
A reception buffer control unit for controlling the capacity of the reception buffer;
The transmission / reception system in which the transmission buffer control unit increases the capacity of the transmission buffer and the reception buffer control unit increases the capacity of the reception buffer when the network is disconnected. A video display method for receiving and playing back a video signal via a network,
A receiving step of receiving a video signal via a network;
A temporary storage step of temporarily storing the video signal received in the reception step;
A temporary storage capacity control step for controlling the capacity of the video signal stored in the temporary storage step;
A decoding step of decoding the video signal stored in the temporary storage step;
A feature detection step of detecting features from the video decoded in the decoding step,
In the temporary storage capacity control step, a video display method for controlling the capacity of the video signal stored in the temporary storage step based on the feature of the video detected in the feature detection step.

Images