WO2011087025A1

WO2011087025A1 - Radio transmitter apparatus, radio receiver apparatus, radio transmitting method and radio receiving method

Info

Publication number: WO2011087025A1
Application number: PCT/JP2011/050374
Authority: WO
Inventors: 国俊金; 泳佳呉; 超徐
Original assignee: 株式会社ユビナビ
Priority date: 2010-01-12
Filing date: 2011-01-12
Publication date: 2011-07-21
Also published as: JPWO2011087025A1

Abstract

Provided are a radio transmitter apparatus, a radio receiver apparatus and methods therefor whereby video and audio data can be wirelessly transmitted between AV devices, thereby making the AV contents available therebetween. A transmitter apparatus (200) generates, from an HDMI audiovisual multiplexed signal supplied from a transmitting side device (100), and outputs a compressed audiovisual multiplexed signal to a receiver apparatus (400), which then generates, from the compressed audiovisual multiplexed signal, and outputs the HDMI audiovisual multiplexed signal to a receiving side device (500). The transmitter apparatus (200) comprises: a means (220) for separating the HDMI audiovisual multiplexed signal supplied from the transmitting side device (100) into video and audio signals; a video codec chip (230) for compressing the separated video signal with a delay time of 2 msec or less to generate a compressed video signal; a network control chip (240) for performing a zero-copy processing in which the separated audio signal and the separated compressed video signal are written, by use of a DMA function (291), into a memory area (281) of an OS (280) and then transferred to a network stuck (292), thereby multiplexing these signals to generate the compressed audiovisual multiplexed signal; and a transmitting chip (260) for transmitting this signal to the receiver apparatus (400).

Description

Wireless transmission device, wireless reception device, wireless transmission method, and wireless reception method

The present invention relates to a wireless transmission device, a wireless reception device, a wireless transmission method, and a wireless reception method, and in particular, a wireless transmission device, a wireless reception device, and the like that mutually use AV content by wirelessly transmitting video / audio data between AV devices. The present invention relates to a wireless transmission method and a wireless reception method.

In recent years, the types of AV equipment used in the home, such as televisions, personal computers, television tuners, DVD players, and video game machines, have increased, and digital AV equipment and personal computers are connected to each other for communication, moving images, There is an increasing trend to realize a home network environment in which various AV contents such as images and music are mutually used.
Such a home network related to AV content is realized, for example, by using a system described in Patent Document 1 (see Patent Document 1).

In the AV system of Patent Document 1, a transmission device and a reception device are connected by a wireless transmission path.
When the user performs a video signal transmission operation, an uncompressed video signal of the video content selected by the user is output from the playback unit of the transmission device. The format (resolution, etc.) of the uncompressed video signal is converted into a format that can be displayed by the receiving device by the signal converter. The video signal output from the reproduction unit is supplied to the wireless transmission / reception unit as it is or after being subjected to data compression processing by the data compression unit.

At this time, if BR1 ≦ BR2 (BR1: bit rate of the uncompressed video signal output from the playback unit, BR2: transmission bit rate of the wireless transmission path), the uncompressed video signal output from the playback unit is transmitted. The video signal is supplied to the wireless transmission / reception unit as it is.

On the other hand, when BR1 ≦ BR2, data compression processing is performed on the uncompressed video signal output from the playback unit by the data compression unit, and the output compressed video signal is a wireless transmission / reception unit as a video signal to be transmitted. To be supplied.
In the wireless transmission / reception unit, the video signal or the compressed video signal supplied from the switch unit is transmitted to the reception device via a wireless transmission path by predetermined communication. In this case, since the bit rate of the video signal to be transmitted is suppressed within the transmission bit rate of the wireless transmission path, the transmission device transmits the video signal having a desired bit rate within the transmission bit rate of the wireless transmission path. , Can be transmitted to the receiving device satisfactorily.

JP 2009-213110 A (paragraphs 0258, 0291-0296)

However, in the AV system described in Patent Document 1, transmission data is transmitted uncompressed or compressed in accordance with the transmission bit rate of the wireless transmission path, but basically transmission of uncompressed data is assumed. It has become. Therefore, in such a mechanism that is basically based on the transmission of uncompressed data, for example, transmission of video with information overlaid on the playback screen of a Blu-ray disc, or transmission of graphics and video images as in a video game machine. In the case of transmitting a combined video, there is a problem that it is not possible to cope with transmission of a video signal that originally has a large transmission bit rate.

Furthermore, when the compressed video signal is transmitted wirelessly, there is a problem that a delay due to the compression process occurs. When the video system to be transmitted is compressed and transmitted in the AV system described in Patent Document 1, Due to the delay due to the compression processing, the quality of the reproduced video / audio on the receiving device side is extremely lowered. In particular, the delay due to the compression processing becomes larger due to an increase in the resolution and frame rate of the video signal to be transmitted and the control processing of the transmission bit rate, and a problem in transmitting a signal including a high-definition image is serious.

The present invention has been made in view of the above circumstances, and its object is to provide a wireless transmission device, a wireless reception device, and a wireless reception device for mutually using AV content by wirelessly transmitting video / audio data between AV devices. In a wireless transmission method and a wireless reception method, a wireless transmission device, a wireless reception device, a wireless transmission method, and a wireless reception method that transmit video / audio data including high-definition images with low delay are provided.

According to the wireless transmission device according to claim 1, the problem is that a compressed video / audio multiplexed signal is generated from an HDMI video / audio multiplexed signal of a transmitting-side video / audio device, and the HDMI video / audio multiplexed signal is generated from the compressed video / multiplexed audio signal. A wireless transmission device that outputs a signal to a wireless reception device that outputs the signal to a reception-side video / audio device for reproduction via a wireless transmission path, the HDMI video supplied from the transmission-side video / audio device Multiplex signal separation means for separating an audio multiplexed signal into a video signal and an audio signal, a video codec chip for generating a compressed video signal by compressing the separated video signal with a processing delay time of 2 ms or less, and separation The audio signal and the compressed video signal thus written are written in the system memory area of the operating system by a DMA (Direct Memory Access) function. A network control chip that performs zero copy processing to transfer to a network stack, asynchronously multiplexes the compressed video signal and the separated audio signal to generate the compressed video audio multiplexed signal, and the compressed video audio multiplexed signal, And a transmission chip for transmitting to the wireless reception device via the wireless transmission path.

According to the wireless transmission method of claim 7, the problem is that a compressed video / audio multiplexed signal is generated from an HDMI video / audio multiplexed signal of a transmitting-side video / audio device, and the HDMI video / audio multiplexed signal is generated from the compressed video / audio multiplexed signal. A wireless transmission method for generating a signal and outputting to a wireless reception device for output to a reception-side video / audio device via a wireless transmission path, wherein the HDMI video supplied from the transmission-side video / audio device Multiple signal separation procedure for separating an audio multiplexed signal into a video signal and an audio signal, and a procedure in which a video codec chip compresses the separated video signal with a processing delay time of 2 milliseconds or less to generate a compressed video signal And the network control chip uses the DMA (Direct Memory Access) function to convert the separated audio signal and compressed video signal into the operating system A step of performing zero copy processing to be transferred to the network stack after writing to the stem memory area, asynchronously multiplexing the compressed video signal and the audio signal, and generating the compressed video and audio multiplexed signal; And a procedure for transmitting the compressed video / audio multiplexed signal to the wireless reception device via the wireless transmission path.

Thus, by providing the video codec chip and the network control chip, the processing delay time due to the compression processing of the video signal is reduced by the video codec chip, and the processing delay time due to the transmission processing of the compressed video / audio multiplexed signal is controlled by the network. Since it can be reduced by the chip, even if the video / audio data supplied from the transmitting audio device contains high-definition images with a large transmission bit rate, the quality of the reproduced video / audio is not affected. Due to this low delay, it is possible to play back on the receiving video / audio equipment.
In addition, since the wireless transmission apparatus and method of the present invention are achieved by three chips, that is, a video codec chip, a network control chip, and a transmission chip, the functions of these three chips are mounted on a single substrate. Also, it can be configured at low cost.

Further, it may be configured so as to be detachably attached to the data transmission port of the transmission-side video / audio device or built in the transmission-side video / audio device.
With this configuration, when the wireless transmission device is built in the transmitting-side audio / video device, there is no need to attach or detach the wireless transmission device, and the wireless transmission device can be used conveniently, while wireless transmission is possible. Even a transmission-side video / audio device that does not have a built-in device can be used for any video / audio device because a wireless transmission device can be externally mounted.

Further, the transmission chip determines whether or not a bit rate required for the compressed video / audio multiplexed signal to be transmitted is larger than a transmission bit rate of the wireless transmission path at regular intervals during transmission of the compressed video / audio multiplexed signal. If it is larger, the video codec chip may be provided with means for issuing a command to increase the compression rate of the compressed video signal.
With this configuration, an optimal transmission state corresponding to the actual state of the transmission path is realized, and a high-quality signal can be transmitted to the wireless reception device.

The network control chip includes an application program, an operating system, a DMA controller, and a network stack. The system call from the application program causes the DMA controller to store the buffer information descriptor in the memory area of the operating system. Write the compressed video signal to the corresponding memory page, read the written compressed video signal in the order of identification information in the buffer information descriptor, and multiplex the read compressed video signal and the audio signal asynchronously To generate the compressed video / audio multiplexed signal, transfer the compressed video / audio multiplexed signal to the network stack, and supply the compressed video / audio multiplexed signal transferred to the network stack to the transmission chip. Means may be provided with a that.
With this configuration, in the compressed video / audio multiplexed signal transmission processing, the memory copy by the host processor of the network control chip is eliminated, and the data for transmission is written into the memory area of the operating system by the DMA function. It becomes possible to reduce the processing delay time in the transmission processing of the video / audio multiplexed signal.

According to the wireless receiver according to claim 5, the problem is that the compressed video / audio multiplexed signal generated from the HDMI video / audio multiplexed signal of the transmission-side video / audio device is received from the wireless transmitter via the wireless transmission path. A wireless reception device that generates the HDMI video / audio multiplexed signal from the compressed video / audio multiplexed signal and outputs the generated signal to the receiving video / audio device for reproduction, the compressed video / audio multiplexed signal being transmitted to the wireless transmission line; The receiver chip that receives from the wireless transmission device via the wireless transmission device and the compressed video / audio multiplexed signal is subjected to zero copy processing by writing to the system memory area of the operating system from the network stack by a DMA (Direct Memory Access) function, and the compression A network control chip that separates a video / audio multiplexed signal into a compressed video signal and an audio signal, and the compressed compression A video codec chip that generates a video signal by expanding a video signal with a processing delay time of 2 milliseconds or less, and the separated audio signal and the expanded video signal are multiplexed in synchronization, and the HDMI video It is solved by comprising signal multiplexing means for generating an audio multiplexed signal and transmitting it to the transmitting-side video / audio device.

According to the wireless reception method of claim 8, the problem is that a compressed video / audio multiplexed signal generated from an HDMI video / audio multiplexed signal of a transmission-side video / audio device is received from a wireless transmission device via a wireless transmission path. , A wireless reception method for generating the HDMI video / audio multiplexed signal from the compressed video / audio multiplexed signal and outputting the generated video / audio multiplexed signal to a receiving-side video / audio device for reproduction, wherein the receiving chip receives the compressed video / audio multiplexed signal, The procedure of receiving from the wireless transmission device via the wireless transmission path, and the network control chip writes the compressed video / audio multiplexed signal from the network stack to the system memory area of the operating system by the DMA (Direct Memory Access) function. Performing a zero copy process to separate the compressed video / audio multiplexed signal into a compressed video signal and an audio signal; The video codec chip synchronizes the procedure of generating the video signal by decompressing the separated compressed video signal with a processing delay time of 2 milliseconds or less, and the separated audio signal and the decompressed video signal. And a signal multiplexing procedure for generating the HDMI video / audio multiplexed signal and transmitting it to the transmitting-side video / audio device.

Thus, by providing the video codec chip and the network control chip, the processing delay time due to the decompression process of the compressed video signal is reduced by the video codec chip, and the processing delay time due to the reception process of the compressed video / audio multiplexed signal is reduced by the network. Since it can be reduced by the control chip, even if the video / audio data supplied from the audio device on the transmission side contains high-definition images with a large transmission bit rate, the quality of the reproduced video / audio is not affected. With such a low delay, it is possible to play back on the receiving video / audio device.
In addition, since the wireless reception apparatus and method of the present invention are achieved by three chips, that is, a video codec chip, a network control chip, and a transmission chip, the functions of these three chips are mounted on a single substrate. Also, it can be configured at low cost.

Further, it may be configured such that it is detachably attached to the data transmission port of the receiving video / audio device or is built in the receiving video / audio device.
With this configuration, when the wireless reception device is built in the receiving video / audio device, there is no need to attach or detach the wireless reception device, and the wireless reception device can be conveniently used. Even a receiving-side video / audio device that does not have a built-in device can be externally mounted with a wireless reception device, and thus can be used for any video / audio device.

According to the wireless transmission device and the method thereof of the present invention, by including the video codec chip and the network control chip, the processing delay time due to the compression processing of the video signal is reduced by the video codec chip, and the compressed video / audio multiplexed signal Since the processing delay time due to transmission processing can be reduced by the network control chip, even if the video / audio data supplied from the audio device on the transmission side contains a high-definition image with a large transmission bit rate, -It can be played back on the receiving video / audio device with a low delay that does not affect the audio quality.
In addition, since the wireless transmission apparatus and method of the present invention are achieved by three chips, that is, a video codec chip, a network control chip, and a transmission chip, the functions of these three chips are mounted on a single substrate. Also, it can be configured at low cost.

According to the wireless receiver and method of the present invention, the video codec chip and the network control chip are provided, so that the processing delay time due to the decompression process of the compressed video signal is reduced by the video codec chip, and the compressed video and audio are Since the processing delay time due to the reception processing of the multiplexed signal can be reduced by the network control chip, even when the video / audio data supplied from the transmitting-side audio device includes a high-definition image having a large transmission bit rate. Thus, it is possible to play back on the receiving video / audio device with a low delay that does not affect the quality of the playback video / audio.
In addition, since the wireless reception apparatus and method of the present invention are achieved by three chips, that is, a video codec chip, a network control chip, and a transmission chip, the functions of these three chips are mounted on a single substrate. Also, it can be configured at low cost.

1 is an overall conceptual diagram of a transmission system S including a transmission device and a reception device according to an embodiment of the present invention. 1 is a configuration diagram of a transmission system S including a transmission device and a reception device according to an embodiment of the present invention. It is a hardware block diagram of the transmitter which concerns on embodiment of this invention. It is a block diagram which shows the main function structures of the network control part of the transmitter which concerns on embodiment of this invention. It is a figure which shows the data structure of IOCTL. It is a figure which shows the header attached | subjected to the WHDMI communication protocol packet transmitted to a receiver from a transmitter in embodiment of this invention. It is a hardware block diagram of the receiver which concerns on embodiment of this invention. It is a control sequence diagram of processing for transmitting a video / audio signal from a transmission device to a reception device via a wireless transmission path. It is a detailed flowchart of the process which a transmitter transmits a video / audio signal. It is a detailed flowchart of the process which a transmitter transmits a video / audio signal. It is a detailed flowchart of the process which a transmitter transmits a video / audio signal. 7 is a flowchart of processing for adjusting a compression rate of transmission data according to a transmission bit rate of a wireless transmission path during transmission of a video / audio signal from the transmission apparatus via the wireless transmission path.

S Transmission system 100

Transmission side device

101, 501 Cable 111 Personal computer (PC)
112 TV game machine 113 Set-top box 114 DVD player 200 Transmitting device 210 HDMI sink connector 211 EDID ROM
220

HDMI receiver

230, 430

Video codec

240, 440 Network controller 241 Interface 242 I / O controller Signal router 243 Audio input 244 CPU core 245 A / V multiplexer 246

Memory controller

250, 450 Memory 260 Transmitter 270 Application (application) program)
280 OS (Operating System)
281

System memory area

282a, 282b, 282c Memory area 283 Network transfer dedicated circular link list 283a Buffer information descriptor 284 Memory page 291 DMA (Direct Memory Access) controller 292 Network stack 300 Wireless transmission path 301 Access point 400 Receiver 410 HDMI transmitter Connector 420 HDMI transmitter 460 Receiver 500 Receiver device 511 High-definition television

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that members, arrangements, and the like described below do not limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

The transmission system S including the transmission device 200 and the reception device 400 according to the present embodiment is constructed in a space having a plurality of rooms separated by walls, such as a residence, an office, and the like. Connected to the transmission-side device 100 and the reception-side device 500 from the transmission-side device 100 such as the video game machine 112 and the DVD player 114 to the reception-side device 500 that is a display such as a high definition television (High Definition Television) 511 In this system, high definition video / audio data is wirelessly transmitted via the transmission device 200 and the reception device 400.

FIG. 1 is an overall conceptual diagram of the transmission system S, and FIG. 2 is a configuration diagram of the transmission system S. The transmission system S of the present embodiment includes a transmission-side device 100 such as a known personal computer (hereinafter referred to as “PC”) 111, a video game machine 112, a TV set-top box 113, a DVD player 114, and the like. The main components are a transmitting device 200 incorporated in the receiver, a receiving device 500 that is a display such as a known high-definition television 511, a receiving device 400 built in the receiving device 500, and a known access point 301. In this embodiment, the transmission device 200 and the reception device 400 are built in the transmission-side device 100 and the reception-side device 500, respectively, but the data transfer port such as the USB port of the transmission-side device 100 and the reception-side device 500 is used. It may be connected to and detachably attached externally. In this case, it is preferable that the transmission device 200 and the reception device 400 are housed in a case.
The access point 301 is a radio wave relay that connects terminals with a wireless LAN, and relays transmission between the transmission device 200 and the reception device 400 using the wireless LAN. Also, as a mechanism provided by WPS (Wi-Fi Protected Setup), a role as a registrar that registers clients (child devices) such as the transmission side device 100, the reception side device 500 or the transmission device 200, the reception device 400, etc. in the wireless LAN Fulfill.
The transmission-side device 100 and the transmission device 200, and the reception-side device 500 and the reception device 400 are connected via

cables

101 and 501, respectively.

Based on FIG. 2 and FIG. 3, the hardware configuration of the transmission apparatus 200 will be described.
The transmission apparatus 200 includes an HDMI sink connector 210, an extended display identification data (EDID) ROM (Read Only Memory) 211, an HDMI receiver 220, a video codec 230, a network control unit 240, a memory 250, and a transmission unit 260 as main components. .
The HDMI sink connector 210 is a connector provided on the transmission side device 100 connection side of the transmission device 200, and is connected to the cable 101 connected to the transmission side device 100, so that the raw video / audio from the transmission side device 100 is connected. Multiple signals are input.
The EDID ROM 211 stores EDID (Extended Display Identification Data) that is information relating to performance such as reproduction capability of the transmission apparatus 200. The performance of the transmission device 200 stored in the EDID includes a manufacturer name (Vendor ID), a model (Product ID), a supported resolution, and the like.

The HDMI receiver 220 performs decryption of HDCP (High-bandwidth Digital Content Protection) encrypted data, conversion of RGB data to YUV 4: 2: 2 data, separation of video / audio multiplexed signals, etc. A video signal and an audio signal having a format handled in the above are generated, and the video signal is supplied to the video codec 230 and the audio signal is supplied to the network control unit 240.
The video codec 230 encodes the video signal supplied from the HDMI receiver 220 to generate an H.264 video signal. The H.264 compressed video signal is obtained and supplied to the network control unit 240. The video codec 230 is configured as a single video codec chip.

The network control unit 240 multiplexes the audio data supplied from the HDMI receiver 220 and the video signal supplied from the video codec 230, and supplies the video / audio multiplexed signal to the transmission unit 260. The network control unit 240 is configured as a single network control chip.
As shown in FIG. 3, the network control unit 240 includes an interface 241 to which a video signal from the video codec 230 is supplied, an I / O controller signal router 242, an audio input 243 to which audio data from the HDMI receiver 220 is supplied. The CPU core 244 includes an A / V multiplexer 245 that multiplexes video signals and audio signals, and a memory controller 246 that controls the memory 250.

FIG. 4 is a block diagram illustrating a main functional configuration of the network control unit 240. In the configuration shown in FIG. 4, the video codec 230 is hardware, and the other configuration is software.
The application (application program) 270 is a set of network applications that operate on the transmission apparatus 200, and includes, for example, a data transmission application that wirelessly transmits the video / audio multiplexed signal described in FIG. 4 to the reception apparatus 400. It is.
The application 270 issues an IOCTL, which is a system call (input / output control command) having the data structure shown in FIG. 5, and the processing shown in FIGS. 4A to 4C and FIG. 9. The process of the flowchart of FIG. 10 is executed.
The data structure of IOCTL is shown in FIG.
At the top is the ID of the video codec 230 represented by the Channel ID, followed by the socket file descriptor for the network I / O represented by the IO file descriptor, the frame / second represented by the frame rate, and the src port UDP port (encoder) of the sender represented by: UDP port (decoder) of the receiver represented by dest port, IP address (encoder) of the sender represented by src IPV4 address, IP address of the receiver (decoder) represented by dest IPV4 address ) Is arranged. Here, the receiver (decoder) is connected to a sender (encoder).

The OS (Operating System) 280 is a space where data processed by the application 270 is copied and various processes are performed, and stores a network transfer dedicated circular link list 283 and a video signal associated with the link list 283. A system memory area 281 in which a memory page 284 is stored.
As shown in FIG. 4, the network transfer dedicated circular link list 283 holds a plurality of buffer information descriptors (BD; Buffer Descriptor) 283a. The buffer information descriptor 283a holds management information such as a physical address (Baddr) and length information (Blen) for a specific buffer (memory area) in the system memory area 281. As shown in FIG. 4, the buffer information descriptor 283a indicates each buffer information descriptor 283a, and physical addresses (Baddr_i) BD1 to BDi for specifying the memory page 284 to which the buffer information descriptor 283a corresponds, It holds ADDR describing the physical address of the buffer information descriptor 283a to be processed, a flag FG (0/1) for identifying whether the buffer information descriptor 283a is unused or used.
In this embodiment, the system memory area 281 includes a memory area 282a for writing the compressed video packet and its information to the network transfer dedicated circular link list 283. The system memory area 281 includes another set of a circular list dedicated to network transfer and a memory page (not shown), and this set is stored in the memory area 282b. This memory area 282 and a set of circular lists and memory pages dedicated to network transfer (not shown) are used to store voice packets and their information and send them to the network stack 292.

The OS 280 performs reading of a signal to be transmitted, writing to the system memory area 281, and transfer to the network stack 292.
A DMA (Direct Memory Access) controller 291 is a dedicated LSI that controls DMA transfer that performs data transfer without using a CPU. The DMA (Direct Memory Access) controller 291 receives IOCTL that is a control command from the application 270 and is supplied from the video codec 230. The compressed video data is written to the memory page 284 of the memory area 282a of the system memory area 281 of the OS 280. Further, the DMA controller 291 writes the audio data in a memory page (not shown) in the memory area 282 b of the system memory area 281 of the OS 280.

The network stack 292 is a well-known protocol stack group. The user space layer at the top, that is, the application layer defines users of the network stack, and the physical device at the bottom connects to the network. A kernel space exists between these two layers. A socket buffer that flows inside this network stack 292 moves packet data between the source and sink.
The network stack 292 divides the video / audio multiplexed signal supplied from the system memory area 281 side into network transmission units, that is, packet unit lengths. A WHDMI communication protocol header is added to each of the divided data, that is, payloads to generate a video / audio multiplexed signal packet, and the packet is transmitted to the receiver 400 via the transmitter 260 and the wireless transmission path 300.

FIG. 6 shows a data structure of a WHDMI communication protocol header (hereinafter referred to as “header”) attached to the video / audio multiplexed signal.
At the top, packet specific information represented by Protocol ID is arranged. This Protocol ID is for attaching a correct header to the packet. Next, packet type indicating audio, video, control, etc., represented by Protocol Type, additional information of the packet represented by Stream Information, bandwidth (bit rate) request (transmitting side) and response represented by Rx / Tx Bandwidth (Receiving side), status of frame from DMA buffer descriptor (buffer information descriptor 283a) represented by CNW BD flags, resolution code of video packet represented by Resolution Code, format of additional option represented by Option format, video and A time stamp DTS (decoding time stamp) and a PTS (presenting time stamp), which are time information for synchronized playback of audio, are sequentially arranged.
The transmission unit 260 is an interface on the wireless transmission path 300 side of the transmission device 200, and transmits the wireless transmission video / audio multiplexed (asynchronous) signal supplied from the network control unit 240 to the reception device 400.

Next, the configuration of the receiving apparatus 400 will be described with reference to FIGS.
The receiving apparatus 400 includes a receiving unit 460, a memory 450, a network control unit 440, a video codec 430, an HDMI transmitter 420, and an HDMI transmitter connector 410 as main components.
The reception unit 460 is an interface on the wireless transmission path 300 side of the reception device 400, receives a wireless transmission video / audio multiplexed (asynchronous) signal from the transmission device 200, and transmits it to the network control unit 440. The receiving unit 460 is composed of a single receiving chip.

The network control unit 440 is a control device that controls the operation of each unit of the reception device 400, and separates the video / audio multiplexed signal supplied from the reception unit 460, converts the compressed video signal to the video codec 430, and the audio signal. This is supplied to the HDMI transmitter 420. The network control unit 460 is composed of a single network control chip.
The video codec 430 decompresses (decodes) the compressed video signal supplied from the network control unit 440 to obtain a video signal, and supplies the video signal to the HDMI transmitter 420. The video codec 430 is composed of a single video codec chip.
The HDMI transmitter 420 converts the video signal supplied from the video codec 430 and the audio signal supplied from the network control unit 440 to HDCP encryption, conversion of YUV4: 2: 2 data to YUV4: 4: 4 data, and video signal. And an audio signal are multiplexed, and a video / audio multiplexed signal is generated and supplied to the HDMI transmitter connector 410.

The HDMI transmitter connector 410 is a connector provided on the receiving device 400 connection side of the receiving device 400, and is connected to the cable 501 connected to the receiving device 500, and the HDMI video / audio generated by the HDMI transmitter 420 is connected. The multiplexed signal is supplied to the receiving side device 500.

Next, the operation of the transmission system S will be described.
First, the transmission system S is installed and set.
In homes and offices, etc., a PC 111, a video game machine 112, a TV set top box 113, a TV set top box 113, a DVD player 114, etc. A receiving device 500 such as a fine television 511 and an access point 301 are installed in each room. When the transmission device 200 and the reception device 400 are not incorporated in the transmission-side device 100 and the reception-side device 500, the external transmission device 200 and the reception device 400 having a terminal such as a USB terminal are transmitted. The transmission device 200 and the reception device 400 may be connected to the transmission side device 100 and the reception side device 500 by being inserted into a port such as a USB port of the side device 100 and the reception side device 500. Further, instead of incorporating the transmission apparatus 200 into the PC 111 or the like, a program for performing the same processing as the transmission apparatus 200 may be installed as software.

Then, the connection setting of the transmission device 200 and the reception device 400 is performed by a known method using a mechanism provided by WPS (Wi-Fi Protected Setup). Specifically, when the user turns on the transmission device 200 or the reception device 400 while the access point 301 is operating, the access point 301 automatically detects it. Next, when the user presses a dedicated button mounted on the access point 301 and the detected transmission device 200 or reception device 400, the connection and security settings are completed. By performing this operation for all the transmission devices 200 and the reception devices 400, the transmission device 200 and the reception device 400 are set.

Next, video and audio generated by the transmission-side device 100 using the transmission system S are transmitted via the wireless transmission path 300 via the transmission device 200 and the reception device 400, and the reception-side device 500 such as the high-definition television 511. The process of reproducing will be described.
FIG. 8 shows a control sequence in a case where a wireless transmission video / audio multiplexed (asynchronous) signal is transmitted from the transmission-side device 100 and the transmission device 200 to the reception device 400 via the wireless transmission path 300.
(A) First, the power of the transmission device 200 and the reception device 400 is turned on by the user. (B) The receiving device 400 always outputs a beacon periodically to check whether the transmitting device 200 exists in the wireless network. (C) The transmission apparatus 200 that is already turned on and is in a standby state makes a request for establishment of a link and a link establishment by returning an acknowledge to the beacon. (D) The receiving apparatus 400 recognizes the transmitting apparatus 200 and returns a link establishment acknowledge.

(E) The transmission-side device 100 requests the transmission device 200 to transmit EDID data that is information regarding the performance of the transmission device 200. (F) Upon receiving the request, the transmission device 200 reads predetermined data from the EDID ROM 211 of the transmission device 200 and transmits the data to the transmission-side device 100. The transmission-side device 100 recognizes settings that can be supported by the transmission device 200 from the transmitted EDID data, and determines the data method of the transmission-side device 100 according to the settings.
(G) The transmission-side device 100 converts the raw video / audio multiplexed signal selected by the user into a signal that matches the resolution, scanning method, and other capabilities of the transmission device 200 based on the EDID data, and transmits this signal. To start.

(H) The transmission device 200 performs the processing of FIGS. 4, 9, and 10 on the raw HDMI video / audio multiplexed signal received from the transmission-side device 100, and the header and the radio transmission video / audio multiplexed (asynchronous). The signal is transmitted to the receiving apparatus 400 as a signal.
(I) When receiving the wireless transmission video / audio multiplexed (asynchronous) signal with the header attached, the receiving apparatus 400 returns a connection acknowledge to the transmitting apparatus 200 and transmits the bit rate information of the wireless transmission path. To do.
(J) Upon detecting the transfer bit rate of the wireless transmission path, the transmitting apparatus 200 changes the compression ratio / compression method of the wireless transmission video / audio multiplexed (asynchronous) signal to be transmitted according to the transfer speed by the processing of FIG. .
(K) When transmission stop of video data is instructed by a user's operation, the transmission-side device 100 stops transmission of the HDMI video / audio multiplexed signal according to a command from the network control unit 240 of the transmission device 200.

Next, the signal flow in FIGS. 3 and 7 will be described.
The raw video / audio multiplexed signal is input from the HDMI sink connector 210 to the transmission device 200. The HDMI video / audio multiplexed signal is decoded by the HDMI receiver 220 and separated into a video signal and an audio signal.
The separated video signal is converted into YUV 4: 2: 2 data of RGB data, then supplied to the video codec 230, encoded by the video codec 230, and H.264. The H.264 compressed video signal is supplied to the network control unit 240.
On the other hand, the separated audio signal is supplied to the network control unit 240 and multiplexed in a non-synchronized manner with the compressed video signal supplied to the network control unit 240 via the video codec 230, and video / audio multiplexing (asynchronous) is performed. ) Signal. This video / audio multiplexed (asynchronous) signal is supplied to the transmitter 260 and transmitted from the transmitter 260 to the receiver 460 of the receiver 400 via the wireless transmission path 300 as a wireless transmission video / audio multiplexed (asynchronous) signal. Is done.

The wireless transmission video / audio multiplexed (asynchronous) signal transmitted to the receiving unit 460 is supplied to the network control unit 440 and separated into a compressed video signal and an audio signal by the network control unit 440. H. isolated. The H.264 compressed video signal is supplied to the video codec 430, is decompressed to become an uncompressed video signal, and is supplied to the HDMI transmitter 420. The video signal is converted into YUV 4: 4: 4 data from YUV 4: 2: 2 data in the HDMI transmitter 420.
On the other hand, the separated audio signal is supplied to the HDMI transmitter 420, multiplexed in synchronization with the video signal based on the time stamp attached to the header of the packet, and the video / audio multiplexed signal in which the video and audio are synchronized. Become.
The video / audio multiplexed signal in which the video and audio are synchronized is supplied to the receiving-side device 500 as an HDMI video / audio multiplexed signal via the HDMI transmitter connector 410 and reproduced by the receiving-side device 500.

Here, the transmission processing of the header and the wireless transmission video / audio multiplexed (asynchronous) signal by the transmission device 200 of FIG. 8H will be described in detail with reference to the block diagram of FIG. 4 and the flowcharts of FIGS. To do. When the data transmission source system, that is, the network control unit 240 of the transmission apparatus 200 is a big endian system, the processing of FIGS. 9 and 10, and when the network control unit 240 is a little endian system, FIG. The process of FIG. 11 is executed.
When the network control unit 240 is a big endian system, the transmission of the HDMI video / audio multiplexed signal from the transmission-side device 100 in FIG. 8G starts, and the processing of the flowcharts in FIGS. 9 and 10 starts. To do. The processing of the flowcharts of FIGS. 9 and 10 is executed by an IOCTL instruction that is a system call issued from the application (application program) 270 of the transmission apparatus 200.
First, in step S1, the video codec 230, the DMA controller 291 of the network controller 240, the data structure of the network transfer dedicated circular link list 283 in the system memory area 281 and the network stack 292 are initialized, and the transmitting device 200 and the receiving device 400 are initialized. Establish a wireless network connection between. This step is shown as initialization via OS (b) in FIG.

Next, in step S2, a DMA request signal is issued to the DMA controller 291. Thereby, compression of the video signal in the video codec 230 and transfer by the DMA controller 291 are started. The DMA controller 291 writes one packet of the video signal from the video codec 230 to one memory page 284 of one memory area 282 a of the system memory area 281.
In this step, as shown in FIG. 4, the DMA controller 291 packetizes the video signal from the video codec 230 and writes it into a memory page 284 in one memory area 282a of the system memory area 281. Next, in step S3, the flag FG of the buffer information descriptor 283a of the network transfer dedicated circular link list 283 corresponding to the memory page 284 in which the video signal is written is set to 1.

Next, in step S4, it is determined whether or not the flags FG = 1 of all the buffer information descriptors 283a in the writing area.
If the flags FG of all the buffer information descriptors 283a in the area where writing is not performed are not 1 (step S4: No), that is, the buffer information where the flag FG = 0 is present in the memory area 282a where writing is performed. If the descriptor 283a exists, the process returns to step S2, and a DMA request signal is issued to the DMA controller 291 for one packet of the next video signal, and the DMA controller 291 sends one packet of the video signal from the video codec 230 to the system memory. Write to the next memory page 284 of one memory area 282a of area 281.

When the flags FG = 1 of all the buffer information descriptors 283a in the area where writing is performed (step S4: Yes), the buffer information descriptor 283a and the corresponding memory page 284 in the memory area 282a include Assuming that all video signals and buffer information have been written, the process proceeds from step A in FIG. 9 to step A in FIG. 10 to step S5, and the memory page in the memory area 282a for storing the buffer information descriptor 283a with flag FG = 1. The 284 packet data group is used as a data group in preparation for transfer, and the header shown in FIG. 6 is added to each data frame output from the video codec 230 by a known method.

Then, in step S6, the data in the memory area 282a is sent from the network transfer dedicated circular link list 283 data structure in the order of the physical addresses BD1 to BDi of the buffer information descriptor 283a.

In step S7, the video data sent in step S6 and the audio data sent separately from the other memory area 282b in the system memory area 281 to the network stack 292 are asynchronously time-division multiplexed in a known manner. To do.
The audio data that is time-division multiplexed with the video data in step S7 is processed in the same manner as in step S1 in FIG. 9 to S6 in FIG. The buffer information descriptor 283a and the memory page 284 shown in FIG. 4 are stored in the 282b.

Next, in step S8, it is determined whether transmission of data of all buffer information descriptors 283a in one memory area 282a is completed.
If transmission of data of all the buffer information descriptors 282a in one memory area 282a is not completed (step S8: No), the process returns to step S6, and the buffer information description is obtained from the network transfer dedicated circular link list 283 data structure. Data in the memory area 282a is sent in the order of the physical addresses BD1 to BDi of the child 283a.

When transmission of data of all buffer information descriptors 283a in one memory area 282a is completed (step S8: Yes), video and audio time-division multiplexed data is wirelessly transmitted from the network stack 292 in step S9. The data is transmitted to the receiving device 400 via the transmission line 300.
Next, in step S10, the new memory area 282c is distributed to the point ahead of the network transfer dedicated circular link list 283 data structure, the flag FG is set to 0, and the processing returns to the end of the network transfer dedicated circular link list 283 circular column.
In step S <b> 11, it is determined whether an instruction to stop transmission of image / audio data from the transmission-side device 100 to the reception-side device 500 is issued by the system user.

When the user of the system has not issued an instruction to stop the transmission of the image / sound data from the transmission-side device 100 to the reception-side device 500 (step S11: No), the system changes from B in FIG. 10 to B in FIG. In step S2, the DMA controller 291 writes one packet of the video signal from the video codec 230 to one memory page 284 in the new memory area 282c of the system memory area 281. That is, steps S2 to S11 are repeated until the user of the system issues a command to stop the transmission of the image / audio data from the transmitting device 100 to the receiving device 500.
When the user of the system issues a command to stop transmission of the image / sound data from the transmission-side device 100 to the reception-side device 500 (step S11: Yes), the processing of the flowcharts of FIGS. To do.

On the other hand, when the network control unit 240 is a little endian system, the processes of FIGS. 9 and 11 are executed.
In this case, when transmission of the HDMI video / audio multiplexed signal from the transmission-side device 100 in (g) of FIG. 8 is started, the processing of the flowcharts of FIGS. 9 and 11 is started. The processing of the flowcharts of FIGS. 9 and 11 is executed by an IOCTL instruction that is a system call issued from an application (application program) 270 of the transmission apparatus 200.
The processing in steps S1 to S4 is performed in the same manner as the processing in steps S1 to S4 when the network control unit 240 is a big endian system, and thus description thereof is omitted.
In step S4, when the flags FG = 1 of all the buffer information descriptors 283a in the area in which writing is performed (step S4: Yes), the buffer information descriptor 283a in the memory area 282a and the corresponding memory page Assuming that all video signals and buffer information are written in 284, the process proceeds from step A in FIG. 9 to step S21 through step A in FIG. 11, and a memory area 282a for storing the buffer information descriptor 283a with flag FG = 1. The packet data group of the memory page 284 is set as a data group in preparation for transfer, and the header of FIG. 6 is added for each data frame output from the video codec 230 by a known method.

Next, in step S22, one piece of data is read in order from the data group being prepared for transfer in units defined in the header.
The processing from step S22 to S25 is to convert the data arrangement method to big endian if the data packet to be transferred exceeds 1 byte when the network control unit 240 of the transmission apparatus 200 is a little endian system. It is. Therefore, when the network control unit 240 of the transmission apparatus 200 is a big endian system, the processing of steps S22 to S25 related to the data arrangement method is not performed as shown in FIG. 10, and the process directly proceeds to step S6.
Next, in step S23, it is determined whether this data is a single byte data structure consisting of 1 byte.
If this data is not a single byte data structure consisting of 1 byte (step S23: No), in step S24, this data arrangement method is converted to big endian, and in step S25, it is read into the data group being prepared for transfer. Determine if there is missing data.

When there is data that has not been read in the data group being prepared for transfer (step S25: Yes), the process returns to step S22, and one piece of data is sequentially added from the data group being prepared for transfer in the unit defined in the header. In step S23, it is determined whether this data is a single byte data structure consisting of 1 byte. That is, steps S22 to S25 are repeated until it is determined whether all data in the data group being prepared for transfer has a single-byte data structure.

If the data read in step S22 is a single byte data structure consisting of 1 byte (step S23: Yes), it is assumed that the data is 1 byte and the data arrangement method does not matter, and the transfer preparation is in progress in step S25. It is determined whether there is unread data in the data group.
If there is no unread data in the data group being prepared for transfer (step S25: No), it is determined that all the data in the data group being prepared for transfer are determined to be single byte data structures or not. In S26, data in the memory area 282a is sent from the network transfer dedicated circular link list 283 data structure in the order of the physical addresses BD1 to BDi of the buffer information descriptor 283a.

In step S27, the video data sent in step S26 and the audio data sent separately from the other memory area 282b in the system memory area 281 to the network stack 292 are asynchronously time-division multiplexed in a known manner. To do.
The audio data that is time-division multiplexed with the video data in step S27 is processed in the same manner as in steps S1 to S26 in FIG. 9 and different memory areas in the system memory area 281 by the control command of the application 270. The buffer information descriptor 283a and the memory page 284 shown in FIG. 4 are stored in the 282b.

Next, in step S28, it is determined whether transmission of data of all buffer information descriptors 283a in one memory area 282a is completed.
If transmission of data of all the buffer information descriptors 282a in one memory area 282a is not completed (step S28: No), the process returns to step S26, and buffer information description is obtained from the network transfer dedicated circular link list 283 data structure. Data in the memory area 282a is sent in the order of the physical addresses BD1 to BDi of the child 283a.

When transmission of data of all the buffer information descriptors 283a in one memory area 282a is completed (step S28: Yes), time division multiplexed data of video and audio is wirelessly transmitted from the network stack 292 in step S29. The data is transmitted to the receiving device 400 via the transmission line 300.
Next, in step S30, the new memory area 282c is distributed to the point ahead of the network transfer dedicated circular link list 283 data structure, the flag FG is set to 0, and the processing returns to the end of the network transfer dedicated circular link list 283 circular column.
In step S31, it is determined whether an instruction to stop transmission of image / audio data from the transmission-side device 100 to the reception-side device 500 is issued by the system user.

When the user of the system has not issued a command to stop the transmission of the image / sound data from the transmission-side device 100 to the reception-side device 500 (step S31: No), the system B is changed from B to FIG. In step S2, the DMA controller 291 writes one packet of the video signal from the video codec 230 to one memory page 284 in the new memory area 282c of the system memory area 281. That is, steps S2 to S31 are repeated until the user of the system issues a command to stop the transmission of the image / sound data from the transmitting device 100 to the receiving device 500.
When the user of the system issues a command to stop the transmission of the image / sound data from the transmission-side device 100 to the reception-side device 500 (step S31: Yes), the processing of the flowcharts of FIGS. To do.

Next, processing for changing the compression ratio / compression method according to the transfer speed in FIG. 8J will be described with reference to the flowchart of FIG. The processing of the flowchart of FIG. 12 is controlled by the transmission unit 260 of the transmission device 200, and every time a certain time elapses due to interrupt processing or the like during video / audio time division multiplexed signal transmission from the transmission device 200 to the reception device 400. Executed.
First, in step S41, the transfer capability of the wireless transmission path 300 to be transferred is detected. In this step, information on the transmission bit rate status output from the receiving apparatus 400 at regular time intervals is stored in “Rx / Tx Bandwidth” of the header of FIG. 6 of the transmitted packet. By confirming “Bandwidth”, the transmission bit rate status of the wireless transmission path 300 is confirmed. This is because in wireless transmission, the bandwidth, that is, the transmission bit rate is unstable and changes every moment depending on the conditions of the wireless transmission path 300.

Next, in step S42, the current bit rate, that is, the necessary transmission bit rate of the video / audio signal to be transmitted, is compared with the transfer capability of the transfer line acquired in step S41, that is, the transmission bit rate of the wireless transmission path 300. It is determined whether the bit rate is greater than the transfer capability.
If the current bit rate is larger than the transfer capability (step S42: Yes), the video codec 230 compresses the video signal in step S43, assuming that the required transmission bit rate of the current transmission signal is too larger than the transfer capability. Give orders to increase rates. By this command, the video codec 230 increases the compression rate of the video signal by a known method. As a result, the required transmission bit rate of the transmission signal from the transmission device 200 to the reception device 400 is lowered by one step.
Thereafter, the process returns to step S41 to detect the transfer capability of the wireless transmission path 300 to be transferred.
If the current bit rate is smaller than the transfer capability (step S42: No), the process ends, assuming that there is no problem in the relationship between the required transmission bit rate of the current transmission signal and the transfer capability.

Claims

A compressed video / audio multiplexed signal is generated from the HDMI video / audio multiplexed signal of the transmitting video / audio device, and the HDMI video / audio multiplexed signal is generated from the compressed video / audio multiplexed signal and output to the receiving video / audio device for playback. A wireless transmission device that outputs to a wireless reception device via a wireless transmission path,
Multiplex signal separating means for separating the HDMI video / audio multiplexed signal supplied from the transmission-side video / audio device into a video signal and an audio signal;
A video codec chip that compresses the separated video signal with a processing delay time of 2 milliseconds or less to generate a compressed video signal;
The separated audio signal and the compressed video signal are written in a system memory area of an operating system by a DMA (Direct Memory Access) function, and then transferred to a network stack to perform a zero copy process, and the compressed video signal and the separated video signal are separated. A network control chip for asynchronously multiplexing the generated audio signal to generate the compressed video / audio multiplexed signal;
A wireless transmission device comprising: a transmission chip that transmits the compressed video / audio multiplexed signal to the wireless reception device via the wireless transmission path.
The wireless transmission device according to claim 1, wherein the wireless transmission device is detachably attached to a data transmission port of the transmission-side video / audio device or built in the transmission-side video / audio device.
The transmission chip determines whether or not a bit rate required for the compressed video / audio multiplexed signal to be transmitted is larger than a transmission bit rate of the wireless transmission path at regular intervals during transmission of the compressed video / audio multiplexed signal. The wireless transmission apparatus according to claim 1, further comprising means for issuing a command to increase the compression rate of the compressed video signal to the video codec chip when the size is large.
The network control chip includes an application program, an operating system, a DMA controller, and a network stack, and the DMA controller corresponds to a buffer information descriptor in the memory area of the operating system by a system call from the application program. Write the compressed video signal to a memory page, read the written compressed video signal in the order of identification information in the buffer information descriptor, multiplex the read compressed video signal and the audio signal in an asynchronous manner, and Means for generating a compressed video / audio multiplexed signal, transferring the compressed video / audio multiplexed signal to the network stack, and supplying the compressed video / audio multiplexed signal transferred to the network stack to the transmission chip The radio transmitting apparatus according to claim 1, characterized in that it comprises.
A compressed video / audio multiplexed signal generated from the HDMI video / audio multiplexed signal of the transmitting video / audio device is received from a wireless transmission device via a wireless transmission path, and the HDMI video / audio multiplexed signal is generated from the compressed video / audio multiplexed signal. A wireless receiver that outputs to the receiving video / audio device for playback,
A reception chip for receiving the compressed video / audio multiplexed signal from the wireless transmission device via the wireless transmission path;
Performs zero-copy processing to write the compressed video / audio multiplexed signal from the network stack to the system memory area of the operating system using a DMA (Direct Memory Access) function, and separates the compressed video / audio multiplexed signal into a compressed video signal and an audio signal. A network control chip to
A video codec chip that generates the video signal by expanding the separated compressed video signal with a processing delay time of 2 milliseconds or less;
Signal multiplexing means for synchronizing and multiplexing the separated audio signal and the decompressed video signal, generating the HDMI video / audio multiplexed signal, and transmitting the generated signal to the transmitting-side video / audio device; A wireless receiver characterized by that.
6. The wireless receiver according to claim 5, wherein the wireless receiver is detachably attached to a data transmission port of the receiving video / audio device or built in the receiving video / audio device.
A compressed video / audio multiplexed signal is generated from the HDMI video / audio multiplexed signal of the transmitting video / audio device, and the HDMI video / audio multiplexed signal is generated from the compressed video / audio multiplexed signal and output to the receiving video / audio device for playback. A wireless transmission method for outputting to a wireless reception device via a wireless transmission path,
A multiplexed signal separation procedure for separating the HDMI video / audio multiplexed signal supplied from the transmission-side video / audio device into a video signal and an audio signal;
A procedure in which a video codec chip compresses the separated video signal with a processing delay time of 2 milliseconds or less to generate a compressed video signal;
The network control chip writes the separated audio signal and the compressed video signal in a system memory area of an operating system by a DMA (Direct Memory Access) function, and then performs zero copy processing to transfer to the network stack, and the compression A procedure for asynchronously multiplexing the video signal and the audio signal to generate the compressed video and audio multiplexed signal;
A wireless transmission method comprising: a transmission chip comprising: transmitting the compressed video / audio multiplexed signal to the wireless reception device via the wireless transmission path.
A compressed video / audio multiplexed signal generated from the HDMI video / audio multiplexed signal of the transmitting video / audio device is received from a wireless transmission device via a wireless transmission path, and the HDMI video / audio multiplexed signal is generated from the compressed video / audio multiplexed signal. A wireless reception method for outputting to a receiving video / audio device for reproduction,
A receiving chip receiving the compressed video / audio multiplexed signal from the wireless transmission device via the wireless transmission path;
A network control chip performs a zero copy process of writing the compressed video / audio multiplexed signal from a network stack to a system memory area of an operating system by a DMA (Direct Memory Access) function, and the compressed video / audio multiplexed signal is converted into a compressed video signal. And the procedure of separating into audio signals,
A procedure in which a video codec chip expands the separated compressed video signal with a processing delay time of 2 milliseconds or less to generate a video signal;
A signal multiplexing procedure for synchronizing and multiplexing the separated audio signal and the decompressed video signal, generating the HDMI video / audio multiplexed signal, and transmitting the generated signal to the transmitting-side video / audio device; A wireless reception method.