JP2009055358A - Repeater of video transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve transmission efficiency in transmitting video data through a plurality of kinds of transmission lines with different transmission rates. <P>SOLUTION: When relaying video data transmitted from an intercom master unit 1 to intercom secondary master units 2B and 2C, for example, the video data is transmitted by a standard pattern or a first thinning pattern for a transmission line (a transmission line connected to the intercom secondary master unit 2B) Ls with a relatively high transmission rate, and the video data is transmitted by a second thinning pattern for a transmission line (a transmission line connected to a radio adapter 5 (the radio intercom secondary master unit 2C)) Ls, consequently appropriate data amounts of video data corresponding to the respective transmission lines Ls can be relayed, so that the transmission efficiency can be improved more than a case where a data amount of the video data is fixed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides one or more video transmission apparatuses that transmit video data of moving images via a plurality of types of transmission paths having different transmission speeds, and a plurality of video data that are transmitted via the transmission paths. The present invention relates to a relay device that is used in a video transmission system having a video receiving device and relays video data transmitted from a video transmitting device provided in the middle of the transmission path to one or more video receiving devices.

As a conventional video transmission system, an interphone system including a door phone slave unit, an interphone master unit, an interphone sub-master unit, and the like is provided (for example, see Patent Document 1). In such an intercom system, the interphone master unit, which is a video transmission device, displays the video signal received from the door phone slave installed outside the home on its own display device (liquid crystal display, etc.) and at the same time via the transmission path. It has a function of transmitting a video signal to an interphone sub-master device or the like that is connected and installed in the house as a video receiver.
JP 2004-295408 A

  By the way, when a video transmission device is connected to a plurality of types of video reception devices via a plurality of types of transmission paths having different transmission speeds, conventionally, a low frame rate video matched to the transmission path with the slowest transmission speed. However, even a video receiver connected to a transmission path having a high transmission speed can reproduce only low-quality video, resulting in a problem that transmission efficiency is significantly reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a video transmission system capable of improving transmission efficiency when video data is transmitted through a plurality of types of transmission paths having different transmission speeds. It is to provide a relay device.

  According to a first aspect of the present invention, in order to achieve the above object, one or a plurality of video transmission apparatuses that transmit video data of moving images via a plurality of types of transmission paths having different transmission speeds, and the transmission paths 1 to a plurality of video receiving apparatuses used in a video transmission system having a plurality of video receiving apparatuses for receiving video data transmitted in the same manner and provided in the middle of the transmission path. A video compression unit that compresses video data received from the video transmission device, and sends the video data compressed by the video compression unit to one or more transmission lines connected to the video reception device Transmitting means, and control means for controlling the transmission procedure of the video data from the transmitting means to each transmission path. The video compression means includes a reference video frame and a reference video frame that can be independently expanded. A compensation video frame that compensates for a difference from the reference pattern, and the control means inserts a predetermined number of compensation video frames between a plurality of reference video frames arranged at regular time intervals and transmits the standard pattern, and the standard pattern A thinning pattern in which the reference video frame and the compensation video frame are thinned out at a constant interval and there is a remaining compensation video frame without being thinned out, and the compensation video frame is rearranged between the reference video frames at an equal interval and transmitted. One of these is selected according to the transmission speed of the transmission path, and the video data is sent from the transmission means to the transmission path.

  According to the first aspect of the present invention, a standard pattern in which a predetermined number of compensated video frames are inserted and transmitted between a plurality of reference video frames arranged at regular time intervals, the standard video frames at regular intervals from the standard pattern, and If there is a compensation video frame that has been thinned out without being thinned out, the compensation video frame is rearranged between reference video frames at equal intervals and one of the thinning patterns is transmitted on the transmission path. Since the video data is selected according to the transmission speed and sent from the transmission means to the transmission path, video data having a data amount corresponding to the transmission speed of each transmission path can be relayed. It is possible to improve the transmission efficiency when transmitting video data through different types of transmission paths.

  According to the present invention, there is an effect that it is possible to improve transmission efficiency when video data is transmitted through a plurality of types of transmission paths having different transmission speeds.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which the technical idea of the present invention is applied to a relay device used in an intercom system for a detached house will be described in detail with reference to the drawings. However, the video transmission system and the relay device to which the technical idea of the present invention can be applied are not limited to the interphone system and the relay device.

  First, the intercom system (video transmission system) in this embodiment will be described. As shown in FIG. 2, this intercom system includes a doorphone slave unit 100 installed at the exterior entrance of the dwelling unit H, an interphone master unit (video transmission device) 1 installed indoors in the dwelling unit H, and a transmission path (LAN cable). ) A router 3 connected to the intercom base unit 1 via Ls, an interphone sub-base unit 2A installed in the house and connected to the router 3 via the transmission path Ls, and a transmission path installed in the house The relay device 4 connected to the router 3 via Ls, the interphone sub-master 2B and the wireless adapter 5 installed in the house and connected to the relay device 4 via the transmission line Ls, and installed in the home A wireless interphone sub-master 2C communicating with the wireless adapter 5 and a home network including the router 3 connected to the router 3 via the transmission line Ls are connected to a wide area network (in Composed of the Internet connection device 6 for connection to Netto). However, since the present invention relates to transmission of video data, illustration and description of the configuration related to audio transmission are omitted in this embodiment.

  The router 3 is a conventionally well-known one that complies with the LAN standard (IEEE 802.3) called Ethernet (registered trademark), and both 10BASE-T with a maximum communication speed of 10 Mbps and 100BASE-TX with a maximum communication speed of 100 Mbps. It corresponds to. The router 3 is provided with a plurality of ports (not shown), and a LAN cable (transmission path Ls) is connected to each port. The Internet connection device 6 includes a DSL modem, a cable modem, and an ONU (Optical Network Unit), and has a function of connecting the interphone master unit 1 and the interphone sub-master units 2A, 2B, and 2C to the Internet via the router 3. Yes. However, since this type of router 3 and Internet connection device 6 are well known in the art, a detailed description thereof will be omitted.

  The doorphone slave unit 100 includes a call microphone and speaker, an imaging device such as a CCD camera that images a visitor, a call button operated by the visitor, and a call signal via a signal line Ld when the call button is operated. And transmitting a video image (analog video signal) captured by the imaging device to the interphone base unit 1 via the signal line Ld, and a interphone base unit. An analog audio signal is transmitted and received bidirectionally to and from 1 via the signal line Ld.

  Although not shown in the figure, the interphone master unit 1 that is a video transmission device takes in an analog video signal transmitted from the doorphone slave unit 100 via the signal line Ld, and converts the taken analog video signal into a digital video signal. And a compressed microphone and speaker, a display device for displaying video (for example, a liquid crystal display), a response button operated when responding to a ringing tone, There is also provided a call circuit for transmitting and receiving an audio signal through a call path formed with the door phone slave unit 100 when the response button is operated.

  Interphone sub-master units 2A and 2B, which are video receivers, have the same basic configuration as interphone master unit 1 except for the configuration for digital conversion and compression processing of video signals. By transmitting and receiving digital audio data and video data in packets, a call can be made to the doorphone slave unit 100 and a video (moving image) captured by the imaging device of the doorphone slave unit 100 can be displayed on the display device.

  Similarly, the wireless interphone sub-master 2C, which is also a video receiver, has the same basic configuration as that of the interphone master 1 except for the digital conversion and compression processing of the video signal. By transmitting and receiving the audio data and the video data by wireless signals, it is possible to make a call with the doorphone slave unit 100 and to display the video (moving image) captured by the imaging device of the doorphone slave unit 100 on the display device. Since the wireless adapter 5 is a conventionally known one corresponding to a wireless LAN standard (IEEE 802.11a / b / g, etc.), detailed description thereof is omitted.

  As shown in FIG. 1, the relay device 4 includes a network interface unit 40 that has a plurality of ports and transmits / receives a packet through each port, a control unit 41 having a microcomputer as a main component, and video data received by the packet. Are provided with a video compression processing unit 42 for performing compression processing to be described later. In the system configuration example shown in FIG. 2, a router 3, an interphone sub-master 2 </ b> B serving as a video reception device, and a wireless adapter 5 are connected to a plurality of ports of the network interface unit 40 via a transmission line Ls formed of a LAN cable. ing. Here, all devices constituting the home network (interphone system), that is, the interphone master unit 1, the interphone sub-master units 2A, 2B, 2C, the router 3, the relay device 4, and the wireless adapter 5 have unique addresses (private IP address) is assigned, and the devices can identify each other by the address and transmit / receive packets.

  Thus, when a visitor operates the call button of the door phone slave unit 100, a call signal is transmitted from the door phone slave unit 100 to the interphone master unit 1 via the signal line Ld, and the imaging device is activated in the door phone slave unit 100. Then, the video signal obtained by imaging the visitor is transmitted to the intercom base unit 1 through the signal line Ld. When the intercom base unit 1 receives the call signal, the intercom base unit 1 makes a ringing sound from the speaker and displays an image of the visitor on the display device by an analog video signal received from the doorphone slave unit 100. Then, if the resident of the dwelling unit H operates the response button of the interphone master unit 1, the intercom master unit 1 and the door phone sub unit 100 are formed by forming a communication path with the door phone sub unit 100 and starting the communication circuit. Calls can be made with In addition, when the interphone master unit 1 receives a call signal, it transmits (multicasts) a packet including a ringing tone command to all the video receivers (interphone sub-master units 2A, 2B, 2C), and also uses a door phone. Packets containing video data generated by digitally converting and compressing the analog video signal received from the device 100 are individually transmitted (unicast) to each interphone sub-master unit 2A, 2B, 2C. Interphone sub-master units 2A, 2B, and 2C, when receiving a call signal packet, ring a ringing tone from a speaker, and when receiving a video data packet, expand the video data and display a visitor's video on the display device. Let Then, if the resident of the dwelling unit H operates the response button of any of the interphone secondary master units 2A, 2B, 2C, the voice data is included between the interphone secondary master unit 2A, 2B, 2C and the interphone master unit 1. Packets are transmitted and received, and a call can be made between any of the interphone sub-master units 2A, 2B, 2C and the doorphone slave unit 100 via the interphone master unit 1.

  Of the interphone sub-master units 2A, 2B, and 2C that are video receivers, the interphone sub-master unit 2B supports 100BASE-TX with a maximum communication speed of 100 Mbps, but the radio interphone sub-master unit 2C is wireless. Since the communication speed with the adapter 5 is limited to the maximum speed (about 11 Mbps) or less in the IEEE 802.11b standard, it is connected to the two transmission lines Ls connected to the relay device 4, that is, the interphone sub-master 2B. The transmission speeds of the transmission line Ls and the transmission line Ls connected to the wireless intercom sub-master 2C (wireless adapter 5) are different from each other. Since the transmission speeds (communication speeds) of the transmission lines Ls for transmitting the video data from the interphone master unit 1 as the video transmission device to the interphone sub-master units 2B and 2C as the video reception devices are different from each other, the video data If the amount of data is fixed, the transmission path Ls with the slowest communication speed, for example, the transmission path Ls connected to the wireless intercom sub-master 2C (wireless adapter 5) becomes a bottleneck and the transmission efficiency decreases. It will be. Specifically, if the amount of video data is increased in accordance with the transmission path Ls having a relatively high communication speed, the video receiving apparatus (for example, the wireless interphone sub-master 2C) connected to the transmission path Ls having a low communication speed. However, if the amount of video data is reduced in accordance with the transmission path Ls having a relatively low communication speed, a video receiving apparatus (for example, connected to the transmission path Ls having a high communication speed) (for example, In the interphone sub-master 2B), it is necessary to reproduce the video with an image quality lower than the image quality that can be originally reproduced. As a result, the transmission efficiency of the image data is lowered.

  Therefore, in the present embodiment, as described below, the relay apparatus 4 increases and decreases the data amount of the video data according to the communication speed of the transmission path Ls, thereby improving the transmission efficiency.

  In the relay device 4, the control unit 41 decompresses the video data received from the interphone master unit 1 that is a video transmission device, reproduces the frame, and sequentially delivers the frame to the video compression processing unit 42. The video compression processing unit 42 compresses video data by a compression method compliant with the MPEG standard (for example, MPEG-4). Specifically, it is temporally adjacent to a first compression processing unit (not shown) that compresses video data using an intra-frame predictive coding method that predicts a target pixel using only neighboring pixels in the same frame. A second compression processing unit (not shown) that compresses video data by a unidirectional inter-frame predictive encoding method that predicts a difference between target pixels using pixels of a past frame among frames, The compression processing unit compresses the video data simultaneously and in parallel. Here, the frame compressed by the first compression processing unit is a frame (reference video frame) that can be expanded independently, and is usually called an I (Intra coded) frame, and is compressed by the second compression processing unit. A frame is a frame (compensated video frame) that can be decompressed only in pairs with an I frame, and is usually called a P (Predictive coded) frame. Note that the I and P frames generated by compression by the first and second compression processing units are sequentially stored in a memory (not shown).

  Here, the video data received from the interphone master unit 1 as the video transmitting device is a predetermined number (see FIG. 3) between a plurality of I frames FI1, FI2,... Arranged in a constant time interval T0 as shown in FIG. In the example shown, 5 frames) P frames FP11 to FP15, FP21 to FP25,... Are inserted, and are originally sent from the network interface unit 40 and relayed as they are. ), (C), the amount of video data to be relayed can be reduced by thinning out the I frames FI2, FI4,... And the P frame FP. That is, the pattern shown in FIG. 3A (hereinafter referred to as “standard pattern”) has the largest amount of data and high image quality, and the pattern shown in FIG. 3B (hereinafter referred to as “first thinning pattern”). 3) has the second largest amount of data and medium image quality, and the pattern shown in FIG. 3C (hereinafter referred to as “second thinning pattern”) has the smallest data amount and low image quality. It becomes. The first thinning pattern is inserted between every other I frame FI2, FI4,..., Which is thinned and thinned out, and the immediately preceding I frame FI1, FI3,. P frames FP11 to FP15, FP31 to FP35,... Are rearranged at equal intervals between the remaining I frames FI1, FI3, FI5,. Further, the second thinning pattern is obtained by thinning out every four I frames FI2 to FI5 and all P frames FP11,.

  Thus, when relaying the video data received from the interphone master unit 1 as the video transmission device to the interphone sub master units 2B and 2C as the video reception device, for example, a transmission path (interphone sub master unit having a relatively high transmission speed). 2B, the video data is transmitted with the standard pattern shown in FIG. 3 (a) or the first thinning pattern shown in FIG. 3 (b), and the transmission speed is relative. If the video data is transmitted with the second thinning pattern shown in FIG. 3C, the transmission line is slower than the transmission line Ls (transmission line connected to the wireless adapter 5 <sub-interphone sub-master 2C>). Therefore, it is possible to relay video data having an appropriate amount of data according to the transmission path Ls, and it is possible to improve transmission efficiency as compared with the case where the amount of video data is fixed. Note that the transmission speed (communication speed) for each transmission path Ls is notified in advance from each interphone sub-master 2B, 2C to the interphone master 1 or manually set, and each interphone sub-master 2B is set manually. , 2C and stored in the memory in association with each other.

It is a block diagram which shows embodiment of the relay apparatus which concerns on this invention. It is a system configuration | structure figure of the intercom system which is a video transmission system using the same as the above. It is operation | movement explanatory drawing same as the above.

Explanation of symbols

4 relay device 40 network interface unit 41 control unit 42 video compression processing unit

Claims (1)

One or more video transmission devices that transmit video data of moving images via a plurality of types of transmission paths having different transmission speeds, and a plurality of video reception devices that receive video data transmitted via the transmission paths, A relay device that relays video data transmitted from a video transmission device provided in the middle of the transmission path to one or more video reception devices,
Video compression means for compressing the video data received from the video transmission apparatus, transmission means for sending the video data compressed by the video compression means to one or more transmission paths connected to the video reception apparatus, Control means for controlling the video data sending procedure to the transmission line,
The video compression means generates a reference video frame that can be independently decompressed and a compensation video frame that compensates for a difference from the reference video frame,
The control means inserts and transmits a predetermined number of compensated video frames between a plurality of reference video frames arranged at regular time intervals, and thins the standard video frames and the compensated video frames from the standard pattern at regular intervals. If there is a compensation video frame remaining without being thinned, either one of the thinning patterns for rearranging and transmitting the compensation video frame between the reference video frames at equal intervals depends on the transmission speed of the transmission path. A relay device for a video transmission system, wherein the video data is selected and transmitted from the transmission means to the transmission path.

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