JP6034113B2 - Video content distribution device - Google Patents

Description

  The present invention relates to a video content distribution apparatus that encodes video content output from a content player and distributes it to a viewing terminal via a network, and in particular, a video that can quickly provide highly urgent information to a viewer with a short delay time. The present invention relates to a content distribution apparatus.

  Digital content is encoded and compressed in advance in order to reduce the amount of data, and is decoded at the viewing terminal during reproduction. Video encoding generally has a heavy processing load, especially in content distribution via a network, because it uses an advanced encoding method with a heavy processing load to increase the compression rate. Transmission delay can occur.

  Furthermore, if the transmission rate of encoded data decreases due to a narrow network bandwidth allocated to content distribution or congestion in the network, the viewing terminal starts decoding and reproducing encoded data immediately after reception. Decoding cannot be started, and decoding must be started after waiting for a predetermined amount of encoded data to be accumulated in the buffer.

  As described above, in content distribution via a network, a transmission delay Td may occur due to various factors. Therefore, as illustrated in FIG. 8, the video content output from the content player at time t1 is reproduced on the viewing terminal from time t11 with a delay time Td, and thereafter, the video content output from the content player is It is played back with a delay of Td seconds on the viewing terminal. That is, the video played back on the viewing terminal is always a video output Td seconds before from the content player. Although the delay time Td depends on the function and performance of the viewing terminal, it is generally several seconds to 10 seconds, and FIG. 8 shows an example in which the delay time Td is 10 seconds.

  In relation to such a technical problem, Patent Document 1 discloses a communication speed between a video server and a communication terminal so that a mobile terminal with a small communication path and a low video playback capability can smoothly implement video distribution. A technique is disclosed in which the number of still images that can be transmitted per unit time is calculated based on the measurement result, and the moving image is transmitted as a time series of still images.

  In Patent Document 2, the viewing operation history of the past user is stored, and for a few seconds from the time when the operation such as fast forward or rewind is performed, the transcoding process of the reproduction data currently used for reproduction is performed. A technique is disclosed in which pre-read data is acquired in parallel with the data, transcoding is performed, and converted pre-read data is created and stored.

  In Patent Document 3, the problem is to reduce the waiting time until video is played when starting the distribution of video content, and the video layer is decoded with only a basic layer that guarantees a minimum image quality and only the basic layer. It is composed of an enhancement layer that can obtain an image quality higher than the result. From the start of video content distribution until the base layer distribution data amount reaches the first target amount, the base layer distribution bit rate is There is disclosed a technique for increasing the encoding bit rate and reducing the distribution bit rate of the higher enhancement layer accordingly.

JP 2003-309834 A JP 2008-206039 A JP 2010-28516 A

  In Patent Document 1, when video content includes highly urgent information, adaptive control that prioritizes transmission delay over video quality cannot be performed.

  In Patent Document 2, not only a large memory capacity for storing prefetched data is required, but also, for example, a breaking news is displayed during playback of a TV program. It is not possible to deal with an event in which prefetching is impossible, such as switching to a still image and immediately providing emergency information to a viewing user.

  In Patent Document 3, although the waiting time until video playback is started at the start of video content distribution can be shortened, the delay in video distribution cannot be resolved with the broadcasting of highly urgent information.

  Therefore, as illustrated in FIG. 8, a breaking news is displayed in a telop at the top of the screen while watching a TV program at time t13, or a normal program is interrupted and switched to an emergency program. Even if the information is broadcast, the viewer can recognize the distribution video after time t23 after Td seconds (10 seconds in this case), so it is possible to respond quickly to highly urgent information. Can not.

  An object of the present invention is to solve the above-described problems of the prior art and to provide a video content distribution apparatus capable of reflecting highly urgent information on a viewing video with a short delay time.

  In order to achieve the above object, the present invention encodes video content into encoded video data in a video content distribution device that distributes video content of a video output from a content player to a viewing terminal via a network. Video encoding means for conversion, video capture means for periodically capturing video content and converting it to a time series of still images, conversion method selection means for selecting conversion by either the video encoding means or the video capture means, And an interface for distributing the converted video content via the network. The conversion method selection means is provided with emergency information reflecting means for switching from the conversion by the moving image encoding to the conversion by the moving image capture in response to the notification sound signal of the emergency information included in the video content.

  According to the present invention, when highly urgent information is detected from video content, the method for converting the video content for network distribution is switched from video encoding to video capture, and a time series of still images is distributed. Therefore, video encoding with a large processing load is not required, and transmission delay is shortened. In addition, since the playback content is switched from a moving image to a still image in time series on the viewing terminal side, playback can be started immediately without waiting for a certain amount of data to be buffered, so that the delay time here is also shortened. . As a result, it is possible to reflect highly urgent information on the viewing video with a short delay time.

1 is a block diagram of a content distribution system including a content distribution apparatus of the present invention. It is the sequence flow which showed the procedure until the delivery of a video content is started based on the request | requirement from a content player. It is the functional block diagram which showed the structure of the principal part of a content delivery apparatus. It is a time chart which showed operation of a remote operation reflection part. It is a screen transition diagram of the viewing terminal during remote operation. It is a time chart which showed operation of an emergency information reflection part. It is the screen transition figure which showed the example of delivery of emergency information. It is a figure for demonstrating the delay in the delivery of a video content.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a content distribution system including a content distribution apparatus of the present invention.

  Each user's home has a content player 3 such as a digital terrestrial tuner, a DVD recorder, or a digital video camera that reproduces and outputs digital content of video and audio (hereinafter collectively referred to as video content), and these video contents are stored in the home. A content distribution device 1 for controlling transmission / reception of video content and a remote control signal described later between the TV monitor 4 for viewing on the Internet, the content player 3 and the Internet, and a wireless LAN connection to the content distribution device 1, A Wi-Fi router 5 that provides route control and a NAT function is provided. The content player 3 and TV monitor 4 and the content distribution apparatus 1 are connected by an HDMI-compliant interface and cable.

  An authentication Admin server 6 is arranged on the Internet, and a user who views video content can view 3G, WiMAX (registered trademark) or Wi-Fi (registered trademark) from his / her viewing terminal 2 such as a smartphone or personal computer. The UDP communication session is established with the content distribution apparatus 1 by accessing the Admin server 6 via a public network such as), and the video content is distributed from the content player 3.

  Here, it is assumed that initial registration and initial setting have already been completed, and a device ID unique to the content distribution apparatus 1 and a reproduction application ID unique to the reproduction application installed in each viewing terminal 2 are stored in advance in the Admin server 6. The description starts assuming that the wireless LAN connection has been established between the content distribution apparatus 1 and the Wi-Fi router 5.

  FIG. 2 is a sequence flow showing a procedure until distribution of video content is started based on a request from the viewing terminal 2.

  When the playback application installed in the viewing terminal 2 is activated at time t1, a device list acquisition request is transmitted from the playback application to the https server function unit of the admin server 6 together with the playback application ID. At time t2, a list of device IDs of the content distribution apparatus 1 that is associated with the reproduction application ID in advance is returned.

  At time t3, when one of the device IDs (listed here as content distribution device 1) displayed on the display of the viewing terminal 2 is selected, an inquiry request regarding the global IP address and port number of the content distribution device 1 is selected. Is transmitted from the viewing terminal 2 to the admin server 6. At time t4, the requested global IP address and port number of the content distribution apparatus 1 are notified from the admin server 6 to the viewing terminal 2.

  At time t5, a transmission request is notified from the viewing terminal 2 to the https server function unit and UDP server function unit of the admin server 6 using the global IP address and port number of the content distribution device 1 as parameters. At time t6, a transmission request is notified from the admin server 6 to the content distribution apparatus 1. At time t7, an inquiry request for the global IP address and port number of the viewing terminal 2 is notified from the content distribution apparatus 1 to the UDP server function unit of the admin server 6. At time t8, the admin server 6 notifies the content distribution apparatus 1 of the global IP address and port number of the viewing terminal 2.

  At time t9, a transmission request response is notified from the content distribution apparatus 1 to the UDP server function unit of the admin server 6. At time t10, a transmission request response is notified from the admin server 6 to the content distribution apparatus 1 together with the global IP address, port number, and secret key. At time t11, a transmission request response is notified from the admin server 6 to the playback application of the viewing terminal 2 together with the global IP address, port number, and secret key of the content distribution apparatus 1. At time t12, a UDP connection is established by hole punching between the playback application of the viewing terminal 2 and the content distribution apparatus 1.

  At time t13, a streaming start request is notified from the playback application of the viewing terminal 2 to the content distribution apparatus 1. In response to the streaming start request, the content distribution device 1 encrypts the encoded data of the video content output from the content player 3 with the secret key, and sets the global IP address and port number of the content distribution device 1. Deliver as a destination. In the viewing terminal 2, the received data is released with the secret key, and further decoded and reproduced. Note that video content that does not require encryption is distributed without being encrypted.

  FIG. 3 is a functional block diagram showing the configuration of the main part of the content distribution apparatus 1 according to the present invention. Here, the configuration unnecessary for the description of the present invention is omitted. Here, the expression “video content” is used as a general term for “video including audio”, “only video (image)”, and “only audio”.

  The HDMI switching unit 103 gives priority to the destination of the video content output in the HDMI format from the content player 3 to the TV monitor 4 for home viewing or the video content conversion unit 102 later. Switching by so-called "after winning".

  The video content conversion unit 102 converts video encoded data into video encoded data by H.264 (H.264 / MPEG-4 AVC) encoding when distributing video video content to the viewing terminal 2 via the network. 102a, and a moving image capture unit 102b that converts a still image periodically acquired by moving image capture into a time series of JPEG images by JPEG encoding.

  The encryption unit 106 encrypts the encoded data in the H.264 format or the time series of JPEG images with the secret key. The wireless LAN interface 101 establishes a wireless LAN connection with the Wi-Fi router 5 and distributes the encoded encoded data or the time series of JPEG images to the viewing terminal 2 via the network. The remote control signal processing unit 105 converts the remote control signal received from the viewing terminal 2 into a CEC command and transfers it to the content player 3.

  The conversion method selection unit 104 includes a remote operation reflection unit 104a and an emergency information reflection unit 104b, and selects a conversion (encoding) method adopted by the video content conversion unit 102 in response to remote operation and emergency information. In response to the remote operation mode request transmitted from the viewing terminal 2, the remote operation reflection unit 104a selects conversion by the moving image capture unit 102b. The emergency information reflection unit 104b includes a classifier 104c and a notification sound detection unit 104d, and captures a video in response to a specific notification sound output together with the video when a news bulletin or an emergency earthquake warning is reproduced as video content. The conversion by the unit 102b is selected.

  Next, the functions of the video content conversion unit 102, the remote operation reflection unit 104a, and the remote control signal processing unit 105 will be described with reference to the time chart of FIG. 4 and the screen transition diagram of the viewing terminal 2 shown in FIG. Here, the description starts from a state in which the delay time Td is 10 seconds and the video content of the moving image output from the content player 3 is being viewed on the viewing terminal 2.

  The video content (moving image) output from the content player 3 at time t1 is sent to the conversion unit 102 by the HDMI switching unit 103 of the content distribution apparatus 1, and converted into encoded data by H.264 encoding in the moving image encoding unit 102a. Then, the data is encrypted by the encryption unit 106. The encrypted encoded data is distributed from the wireless LAN interface 101 to the viewing terminal 2 via the Wi-Fi router 5 and the Internet.

  In the viewing terminal 2, the received encoded data is decoded and buffered, and decoding is started when a predetermined amount of buffering is completed at time t11. As a result, streaming playback of video content is started at the viewing terminal 2 with a delay of about 10 seconds.

  After that, during streaming playback of video content, when the viewing user 2 taps the screen of the viewing terminal 2 by the viewing user as shown in FIG. 5A at time t13, the remote operation mode is activated and the content distribution apparatus 1 is remotely controlled. An operation mode start request is transmitted. Here, a streaming stop request message is transmitted from the viewing terminal 2 to the content distribution apparatus 1, and a streaming start request message specifying a still image mode is transmitted.

  In the conversion unit 102 of the content distribution apparatus 1, the moving image encoding unit 102a stops the moving image encoding in response to the streaming stop request message, and the moving image capture unit 102b responds to the streaming start request message specifying the still image mode. Thus, a still image obtained by periodically capturing moving image content is converted into a time series of JPEG images by JPEG encoding. As a result, the video content output from the conversion unit 102 is switched from the moving image encoded by the H.264 encoding to the time series of the JPEG encoded JPEG image, and the captured image is displayed on the display of the viewing terminal 2. Update display is made at a period of 0.5 seconds to 1 second.

  At this time, the processing load of the moving image capture unit 102b is sufficiently light compared to the processing load of the moving image encoding unit 102a, so that the transmission delay until the video content output from the content player 3 is reproduced on the viewing terminal 2 Is significantly shortened, for example, approximately 3 seconds. Therefore, the viewing terminal 2 can view the video content output from the content player 3 after time t13 with a sense close to real time, although it is not a moving image but a time series of still images.

  On the other hand, when the remote operation mode is activated on the display of the viewing terminal 2, as shown in FIG. 5 (b), a remote control menu is superimposed on the upper part of the screen of the captured image. When the playback operation button is tapped here, as shown in (c) of the figure, at the bottom of the screen are buttons for "fast reverse", "pause", "play", "stop", and "fast forward" When one of the buttons is tapped, a remote control signal corresponding to the button is transmitted to the content player 3 via the content distribution device 1. In the content player 3, the received remote control signal is transferred to the content player 3 by the remote control signal processing unit 105.

  Similarly, when the cursor button “↑” of the remote control menu is tapped, a plurality of arrow buttons indicating the moving direction of the cursor are superimposed on the bottom of the screen as shown in FIG. When the button is tapped, a remote control signal corresponding to the button is transmitted to the content player 3.

  Similarly, when the channel button “ch” of the remote control menu is tapped, as shown in FIG. 5 (e), the channel button is superimposed on the entire screen, and when any channel button is tapped, A remote control signal corresponding to the button is transmitted to the content player 3.

  Similarly, when the function button “btn” of the remote control menu is tapped, as shown in FIG. 5 (f), various function buttons are superimposed on the lower part of the screen, and any one of the buttons is tapped. Then, a remote control signal corresponding to the button is transmitted to the content player 3.

  Thereafter, when the end of the remote operation mode is requested at time t22 when the screen of the viewing terminal 2 is tapped again or a predetermined button is tapped, the operation mode of the viewing terminal 2 is changed to the remote operation mode. Is switched to the video reproduction mode, and the remote operation mode end request is transmitted to the content distribution apparatus 1. Here, a streaming stop request message is transmitted from the viewing terminal 2 to the content distribution apparatus 1, and a streaming start request message specifying a moving image is further transmitted.

  In the conversion unit 102 of the content distribution apparatus 1, the video capture unit 102b stops video capture in response to the streaming stop request message, and the video encoding unit 102a responds to the streaming start request message specifying the video playback mode. Resume video encoding. As a result, the video content output from the conversion unit 102 is switched from a time series of JPEG-encoded still images to an H.264-encoded video.

  As described above, according to the content distribution apparatus 1 of the present embodiment, when the remote operation mode request transmitted from the viewing terminal 2 is detected, the encoding method for encoding the video content for network distribution is the moving image. Since switching from encoding to JPEG encoding is performed and a time series of JPEG images is distributed, video encoding with a large processing load is not required, and the delay time is shortened.

  Furthermore, since the content reproduced on the viewing terminal 2 is switched from a moving image to a still image in time series, buffering of encoded data, which is indispensable for streaming reproduction of a moving image, is unnecessary, and reproduction can be started immediately. Therefore, it is possible to reflect the contents of the remote operation on the viewing video with a short delay time.

  Next, the functions of the video content conversion unit 102 and the emergency information reflection unit 104b will be described with reference to the time chart of FIG. 6 and the screen transition diagram of the viewing terminal 2 shown in FIG. Here, the description starts from a state in which the video content output from the content player 3 is being viewed on the viewing terminal 2.

  The video content (moving image) output from the content player 3 at time t1 is sent to the conversion unit 102 by the HDMI switching unit 103 of the content distribution apparatus 1, and converted into encoded data by H.264 encoding in the moving image encoding unit 102a. Then, the data is encrypted by the encryption unit 106. The encrypted encoded data is distributed from the wireless LAN interface 101 to the viewing terminal 2 via the Wi-Fi router 5 and the Internet.

  In the viewing terminal 2, the received encoded data is decoded and buffered, and decoding is started when a predetermined amount of buffering is completed at time t11. As a result, the viewing terminal 2 starts streaming playback of the video content with a delay of about 10 seconds, as shown in FIG.

  Thereafter, during streaming playback of video content, at time t13, as shown in FIG. 7 (b), a news bulletin flows, and in synchronization therewith, a notification sound 20 specific to the news bulletin is emitted, the notification sound 20 is detected by the classifier 104c and the notification sound detection unit 104d of the emergency information reflection unit 104b and notified to the video content conversion unit 102. In the classifier 104c, a signal pattern unique to the notification sound is learned in advance, and the notification sound detection unit 104d detects the notification sound 20 based on the classification result by the classifier 104c.

  In the conversion unit 102, the video encoding unit 102a stops the video encoding in response to the notification, and the video capturing unit 102b converts the still image obtained by periodically capturing the video content into a JPEG image by JPEG encoding. Convert to time series. As a result, the video content output from the conversion unit 102 is switched from the moving image encoded by the H.264 encoding to the time series of the JPEG encoded JPEG image, and the captured image is displayed on the display of the viewing terminal 2. It will be updated and displayed periodically.

  At this time, the processing load of the moving image capture unit 102b is sufficiently light compared to the processing load of the moving image encoding unit 102a, so that the transmission delay until the video content output from the content player 3 is reproduced on the viewing terminal 2 Is greatly shortened. Therefore, the viewing terminal 2 can view the video content output from the content player 3 after time t13 with a sense close to real time, although it is not a moving image but a time series of still images. Thereafter, when the screen of the viewing terminal 2 is tapped at time t22, an emergency information termination request is transmitted to the content distribution apparatus 1.

  In the conversion unit 102 of the content distribution apparatus 1, the video capture unit 102b stops video capture in response to the end request, and the video encoding unit 102a resumes video encoding. As a result, the video content output from the conversion unit 102 is switched from a time series of JPEG-encoded still images to an H.264-encoded video.

  According to this embodiment, when a news bulletin flows in a program that is being viewed with a delay of about 10 seconds, video content is encoded for network distribution in response to the notification sound 20 generated in synchronization with the news bulletin. The encoding method is switched from moving image encoding to still image capture, and a time series of still images is distributed, so that moving image encoding with a large processing load is not required and the delay time is shortened. Therefore, the terminal user can view the breaking news in substantially real time.

  In the above embodiment, the encoding method has been described as being switched from video encoding to still image capture in response to the alert sound of the news breaking news. However, the present invention is not limited to this, and the earthquake early warning is not limited thereto. Alternatively, a signal pattern of a notification sound that is generated in synchronization with other disaster information may be learned in advance, and the encoding method may be switched using the notification sound as a trigger.

  DESCRIPTION OF SYMBOLS 1 ... Content delivery apparatus, 2 ... Viewing terminal, 3 ... Content player, 4 ... TV monitor, 5 ... Wi-Fi router, 6 ... Admin server, 101 ... Wireless LAN interface, 102 ... Video content conversion part, 102a ... Movie encoding , 102b ... Movie capture unit, 103 ... HDMI switching unit, 104 ... Conversion method selection unit, 104a ... Remote operation reflection unit, 104b ... Emergency information reflection unit, 104c ... Classifier, 104d ... Notification sound detection unit, 105 ... Remote control Signal processing unit 106: Encryption unit

Claims (5)

In a video content distribution apparatus that distributes video content of a video output from a content player to a viewing terminal via a network,
Video encoding means for encoding video content and converting it into encoded video data;
Movie capture means for periodically capturing video content and converting it into a time series of still images;
Conversion method selection means for selecting conversion by either the video encoding means or the video capture means;
An interface for distributing the converted video content via a network;
Said conversion method selecting means is responsive to a notification sound signal of the emergency information included in the video content, characterized in that the conversion by said video encoding means includes a toggle its emergency information reflecting means conversion by the video capture unit Video content distribution device. The emergency information includes news bulletins and earthquake bulletins,
The emergency information reflecting means is
A classifier for identifying a notification sound signal unique to each of the bulletins;
The video content distribution apparatus according to claim 1, further comprising notification sound detection means for detecting a notification sound signal by applying an audio signal of the video content to the classifier. Said conversion method selecting means, the claims in response to the remote operation mode request received from the viewing terminal, characterized in that the conversion by the video encoding means further comprising a remote operation reflection means for switching the conversion by the video capture unit 3. The video content distribution apparatus according to 1 or 2.   4. The video according to claim 3, wherein the remote operation reflecting unit selects the moving image capturing unit in response to a remote operation mode start request, and selects the moving image encoding unit in response to an end request. Content distribution device.   5. The video content distribution apparatus according to claim 3, further comprising remote control signal processing means for transferring a remote control signal received from a viewing terminal to the content player during the remote operation mode.