JP6468663B2 - 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 the video content to a viewing terminal via a network. In particular, the video content encoding method is determined from a destination of a wireless viewing terminal. The present invention relates to a video content distribution apparatus that is optimized according to an estimated network environment.

  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. In particular, since moving image content has a large amount of data and is encoded by an encoding method with high compression efficiency, it still requires a large amount of wireless resources for reproduction, and the load on the network is also large.

  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.

  Patent Document 2 discloses a technique for encoding live video into a time series of still images and distributing them as pseudo videos in order to distribute live video via a communication network that does not support real-time video distribution. Has been.

JP 2003-309834 A JP 2003-299060 A

  In Patent Document 1, since the number of still images (number of frames) to be extracted and synthesized from a moving image is determined based on the actual value of the communication speed, extra traffic other than video content is separately added to measure the communication speed. Must be generated.

  In Patent Document 2, even when the video content viewing terminal is a wireless mobile terminal and can be connected to various networks at the movement destination, the network environment of the connection destination cannot be estimated. Therefore, when a viewing terminal connected to a network that supports video distribution moves and the destination network does not support video distribution, this is detected and the encoding method is changed from video encoding. It could not cope with adaptive control such as switching to video capture.

  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 optimizing the video content encoding method according to the network environment estimated from the current position of the wireless mobile terminal. is there.

In order to achieve the above object, the present invention encodes video content by encoding video content in a video content distribution device that distributes video content of a video output from a content player to a wireless mobile terminal via a wireless network. Moving image encoding means for converting to data, and moving image capturing means having a processing load lighter than that of the moving image encoding means by periodically capturing video content, encoding and converting it into time-series encoded data of still images A conversion method selection means for selecting one of the video encoding means and the video capture means, an interface for delivering the converted video content via a network, a current position of the wireless mobile terminal, and each wireless base in the wireless network wireless area that the station covers Based of, in the wireless area, the area information includes at least one of usage and equipment capability of the radio resources when the wireless mobile terminal is time and accommodated housed in wireless area and, moving the radio Comprising a reproduction capability reflecting means for estimating whether or not a wireless network that accommodates a terminal has a moving image transmission capability necessary for distribution of video content converted into the encoded data of the moving image, When the reproduction capability reflecting means estimates that the wireless network accommodating the wireless mobile terminal does not have the moving picture transmission capability necessary for the distribution of the video content converted into the encoded data of the moving picture, the moving picture capturing means is selected. It is characterized by that.

  (1) If it turns out that the network environment estimated based on the current location of the wireless mobile terminal cannot provide sufficient wireless resources for video distribution, the video content encoding method can be switched from video encoding to video capture. Thus, it becomes possible to select an encoding method that is optimal for the network environment at the current position of the wireless mobile terminal without generating additional test traffic.

  (2) If the wireless mobile terminal moves while viewing video content and the wireless base station of the accommodation destination switches, and the capability and wireless environment of the wireless base station of the switching destination are inferior, the video content encoding method is Although video distribution continues from video encoding to video capture, viewers can continue to view video content while moving.

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 wireless mobile terminal during remote operation. It is a time chart which showed the operation | movement of the reproduction | regeneration capability reflection part. It is the functional block diagram which showed the other structure of the content delivery apparatus.

  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 device 1 are connected by an interface and cable compliant with HDMI (registered trademark).

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

  Here, it is assumed that the initial registration and the initial setting have already been completed, and the device ID unique to the content distribution apparatus 1 and the reproduction application ID unique to the reproduction application installed in each wireless mobile terminal 2 are registered 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 wireless mobile terminal 2.

  When the playback application installed in the wireless mobile 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 on the display of the wireless mobile terminal 2 (in this case, the content distribution device 1) is selected, an inquiry about the global IP address and port number of the content distribution device 1 is made. A request is transmitted from the wireless mobile terminal 2 to the admin server 6. At time t4, the admin server 6 notifies the wireless mobile terminal 2 of the requested global IP address and port number of the content distribution apparatus 1.

  At time t5, a transmission request is notified from the wireless mobile 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 apparatus 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 wireless mobile 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 wireless mobile 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 wireless mobile 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 between the playback application of the wireless mobile terminal 2 and the content distribution apparatus 1 by hole punching.

  At time t13, a streaming start request is notified from the playback application of the wireless mobile 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 wireless mobile 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 (registered trademark) switching unit 103 sends the output destination of the video content output from the content player 3 in the HDMI (registered trademark) format to either the TV monitor 4 for home viewing or the video content conversion unit 102. Switch by the so-called "winning win" that gives priority to the one connected from.

  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 wireless mobile terminal 2 via the network. Part 102a and a moving picture capture part 102b for converting a still picture periodically acquired by moving picture 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 encrypted encoded data or time series of JPEG images to the wireless mobile terminal 2 via a wireless network. The remote control signal processing unit 105 converts the remote control signal received from the wireless mobile 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 a reproduction capability reflection unit 104b. The encoding method employed by the video content conversion unit 102 is determined based on the content of the remote operation or the connection destination that accommodates the wireless mobile terminal 2. Select according to the wireless network environment, especially the video transmission capability. That is, in response to the remote operation mode request transmitted from the wireless mobile terminal 2, the remote operation reflection unit 104a switches the encoding method from moving image encoding to moving image capture. The reproduction capability reflecting unit 104b switches the encoding method from video encoding to video capture when the video transmission capability (such as the availability of radio resources and facility capability) of the wireless network that accommodates the wireless mobile terminal 2 is insufficient. .

In the reproduction capability reflecting unit 104b, the position information acquiring unit 104c acquires information on the current position of the wireless mobile terminal 2. The area information acquisition unit 104d acquires the availability of wireless resources and the facility capacity as area information for each area (wireless coverage) of the wireless network. The reproduction capability estimation unit 104e estimates the moving image transmission capability of the wireless network that accommodates the wireless mobile terminal 2 by comparing the current position information of the wireless mobile terminal 2 with the area information.

  Next, 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 wireless mobile terminal 2 shown in FIG.

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

  In the wireless mobile 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 wireless mobile terminal 2 starts streaming playback of video content with a transmission delay of about 10 at the maximum.

  Thereafter, during streaming playback of video content, when the viewing user taps the screen of the wireless mobile terminal 2 as shown in FIG. 5A at time t13, the remote operation mode is activated and the content distribution apparatus 1 is activated. A request to start the remote operation mode is transmitted. Here, a streaming stop request message is transmitted from the wireless mobile 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. On the display of the wireless mobile terminal 2, the captured image is updated and displayed at a cycle of 0.5 second 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 transmission until the video content output from the content player 3 is played back by the wireless mobile terminal 2 is performed. The delay is greatly shortened, for example, approximately 3 seconds. Therefore, after the time t13, the wireless mobile terminal 2 can view the video content output from the content player 3 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 wireless mobile terminal 2, as shown in FIG. 5B, 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.

  After that, at time t22, when the screen of the wireless mobile terminal 2 is tapped again or a predetermined button is tapped to request the end of the remote operation mode, the operation mode of the wireless mobile terminal 2 is changed to remote. The operation mode is switched to the moving image 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 wireless mobile 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.

  Next, the functions of the video content conversion unit 102 and the reproduction capability reflection unit 104b will be described with reference to the time chart of FIG.

  In the reproduction capability reflecting unit 104b, the position information acquiring unit 104c periodically acquires the current position measured by the wireless mobile terminal 2 using its own GPS function or the like via the network. If the current position can be estimated based on the position of the base station that accommodates the wireless mobile terminal 2, the current position is periodically acquired from a node (server) on the network having these position estimation functions. Anyway.

  The area information acquisition unit 104d acquires, as area information, the availability of wireless resources, facility capacity, and the like for each area (wireless coverage) of the wireless network. The area information is collected and managed by a node (server) on the network, and the area information acquisition unit 104d periodically acquires area information from the node.

  Here, there is room in the bandwidth of the wireless network accommodating the wireless mobile terminal 2, and the video content output from the content player 3 is encoded by the moving image encoding unit 102a and is being viewed on the wireless mobile terminal 2. The explanation starts from the state.

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

  After that, when the wireless mobile terminal 2 moves to another area and is accommodated in another wireless base station, the playback capability estimation unit 104e checks the current position of the wireless mobile terminal 2 after movement against the area information. The Then, a request for switching to video capture, which is difficult to secure wireless resources necessary for video distribution because the destination wireless network is congested or the facility capacity is low, is sent to the video content conversion unit 102. Be notified.

  In response to the switching request, in the conversion unit 102, the moving image encoding unit 102a stops the moving image encoding, and the moving image capture unit 102b converts the still image obtained by periodically capturing the moving image content into a JPEG image by JPEG encoding. Convert to series. As a result, the video content output from the conversion unit 102 switches 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 wireless mobile terminal 2. Is periodically updated and displayed.

After that, when the video transmission capability is recovered at time t22 and this is recognized by the reproduction capability reflection unit 104b, a request to switch the encoding method from video capture to video encoding is output to the video content conversion unit 102. . In the conversion unit 102, in response to the switching request, the moving image capturing unit 102b stops moving image capturing, and the moving image encoding unit 102a restarts moving image 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 the present embodiment, if the wireless network in which the wireless mobile terminal 2 is accommodated lacks wireless resources, or if the wireless resources necessary for moving image distribution cannot be secured due to low facility capacity, video content is encoded. The system is switched from video encoding to video capture. Therefore, while suppressing further consumption of wireless resources, the content of the video content can be continuously viewed although the quality is lower than usual.

In the above embodiment, whether or not the content distribution device 1 acquires the current position information of the wireless mobile terminal 2 and the area information about the wireless network and the moving image transmission capability of the wireless network accommodating the wireless mobile terminal 2 is sufficiently high. It was described as a judgment. However, the present invention is not limited to this, and a node on the network collects and collates the current location information and area information of each wireless mobile terminal 2 so that each wireless mobile terminal 2 can be accommodated. The video transmission capability may be estimated, and the estimation result may be notified to each content distribution apparatus 1.

In this way, the function of acquiring current position information from the wireless mobile terminal 2, the function of acquiring and storing area information of the wireless network, and the wireless mobile terminal 2 by comparing the current position of the wireless mobile terminal 2 with the area information The function of estimating the moving picture transmission capability of the wireless network that accommodates the mobile terminal 2 can be concentrated in one or a small number of nodes on the network.

Therefore, as shown in FIG. 7, the content distribution apparatus 1 is provided with only a playback capability information acquisition unit 104f that periodically acquires the video transmission capability from the node, instead of the above functions, and reflects the playback capability. The unit 104a may select an encoding method in response to the acquired moving picture transmission capability information, so that the processing load can be reduced and the required memory capacity can be reduced.

  DESCRIPTION OF SYMBOLS 1 ... Content delivery apparatus, 2 ... Wireless mobile 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 unit, 102b ... video capture unit, 103 ... HDMI (registered trademark) switching unit, 104 ... conversion method selection unit, 104a ... remote operation reflection unit, 104b ... reproduction capability reflection unit, 104c ... position information acquisition unit, 104d ... area Information acquisition unit, 104e ... reproduction capability estimation unit, 104f ... reproduction capability information acquisition unit, 105 ... remote control signal processing unit, 106 ... encryption unit

Claims (9)

In a video content distribution apparatus that distributes video content of a video output from a content player to a wireless mobile terminal via a wireless network,
Video encoding means for encoding video content and converting it into encoded video data;
A video capturing unit that captures video content periodically, encodes and converts the encoded content into time-series encoded data of a still image, thereby reducing the processing load from the video encoding unit ,
Conversion method selection means for selecting any one of the video encoding means and the video capture means;
An interface for distributing the converted video content via a network;
Of each radio area in which each radio base station at the current position and the radio network of the wireless mobile terminal covers, in the wireless area, the radio resources when the wireless mobile terminal is time and accommodated housed in the wireless area Whether or not the wireless network accommodating the wireless mobile terminal has moving image transmission capability necessary for distribution of the video content converted into the encoded data of the moving image based on area information including at least one of usage status and facility capacity A reproduction ability reflecting means for estimating
When the conversion method selecting unit estimates that the reproduction capability reflecting unit does not have the moving image transmission capability necessary for distributing the video content converted into the encoded data of the moving image, in which the wireless mobile terminal is accommodated. And selecting the moving image capturing means. The reproduction capability reflecting means is
Position information acquisition means for acquiring the current position of the wireless mobile terminal;
Area information acquisition means for acquiring the area information;
The reproduction capability estimation means for collating current location information of the radio mobile terminal with the area information and estimating video transmission capability of a radio network accommodating the radio mobile terminal. Video content distribution device. When the wireless mobile terminal viewing the video content moves to another wireless area in the wireless network, the playback capability reflecting means reflects the current location information after the movement and the usage status and facilities of the wireless resource in the moved wireless area. 3. The video content distribution apparatus according to claim 2, wherein collation with area information including at least one of the capabilities is performed to estimate a moving image transmission capability of a wireless network accommodating the wireless mobile terminal after movement.   The video content distribution apparatus according to claim 1, wherein the reproduction capability reflecting means includes area information acquisition means for acquiring the area information from a server on a network.   In addition, the remote operation reflecting means includes the conversion method selecting means for selecting the moving image capturing means or the moving image encoding means in response to the remote operation mode request received from the wireless mobile terminal. The video content distribution apparatus according to claim 1, wherein the video content distribution apparatus is a video content distribution apparatus.   In response to the remote operation mode request being a start request, the remote operation reflection means causes the conversion method selection means to select the moving image capture means, and if the remote operation mode request is an end request, the remote operation reflection means responds to the moving image 6. The video content distribution apparatus according to claim 5, wherein an encoding unit is selected.   7. The video content distribution apparatus according to claim 5, further comprising remote control signal processing means for transferring a remote control signal received from a wireless mobile terminal to the content player during the remote operation mode.   The video content distribution apparatus according to claim 1, wherein the moving image capturing unit periodically captures video content and converts the video content into a time series of JPEG images.   9. The video content distribution apparatus according to claim 8, wherein the moving image capturing unit converts a still image periodically acquired from the video content into a time series of JPEG images.