JP4303166B2 - Data receiving apparatus, data receiving method, and data transmission system - Google Patents

Description

  The present invention relates to a transmission system, a receiving apparatus, and a receiving method suitable for application to a case where a video signal source and a video display apparatus are connected using, for example, DVI (Digital Visual Interface), and in particular, video data and audio data. The present invention relates to a technology for time division multiplexing transmission.

  In recent years, when a video signal source such as a television tuner, a video playback device, or a personal computer device is connected to a video display device such as a monitor receiver, the DVI standard allows video data to be transmitted to the display device as digital data. What is called is standardized.

  The details of the DVI standard will be described later in an embodiment described later. Briefly, the video data is converted into data obtained by digitizing each of the primary color signals R, G, and B in units of pixels. The image is transmitted to the display device, and a high-quality image can be transmitted and displayed. Further, since the video data is in pixel units, the display device can directly drive the display driver with the received video data, and display can be performed with a relatively simple processing configuration.

  By the way, the data transmitted by the cable stipulated by the DVI standard is basically only video data, and when considering simultaneous transmission of audio data, it is different from the cable stipulated by the DVI standard. It is necessary to connect the tuner and the audio output device with an audio cable. However, when connecting with a plurality of cables in this way, there is a problem that the connection configuration becomes complicated.

  That is, when considering a system configuration for transmitting only video data, for example, as shown in FIG. 10, the video signal source 1 and the display device 3 are connected by a cable 2 of the DVI standard, and this cable 2 is used. If video data encoded according to the DVI standard is transmitted, the video data can be transmitted from the video signal source 1 to the display device 3. On the other hand, for example, as shown in FIG. 11, when video data and audio data are transmitted from the video / audio signal source 4 to the speaker-equipped display device 6, the video data is transmitted by the cable 2 of the DVI standard. In addition, it is necessary to connect so that audio data is transmitted by an audio signal cable 5 different from the cable 2. By connecting as shown in FIG. 11, the video output from the video / audio signal source 4 can be displayed on the display device 6, and audio is output from the speakers 6 </ b> L and 6 </ b> R attached to the display device 6. Can be made.

  However, as shown in FIG. 11, if the video data and the audio data are connected using different cables, there is a problem that the connection configuration becomes complicated accordingly. If possible, it is preferable that the number of cables connecting the devices is small.

  Note that the technology for multiplexing video data and audio data so that they can be transmitted using a single cable uses, for example, a bus line standardized as the IEEE (The Institute of Electrical and Electronics Engineers) 1394 system. Although it is possible by applying a data transmission technique, in order to perform data transmission through such an IEEE 1394 bus line or the like, very complicated data processing is required, and encoding for transmission on the transmission side is required. As a configuration of processing and a configuration of decoding processing of data received via the bus line on the receiving side, a very large circuit configuration is necessary, and there is a problem that costs are high. In addition, in the IEEE 1394 system and the like, video data and audio data are compressed and multiplexed due to problems such as transmission rate, and video data digitized in units of pixels as in the DVI standard described above is transmitted. There is a problem that the image quality is inferior to that of the image.

  In addition, when digitalized audio data is transmitted, an error correction process different from the case of transmitting video data is required. However, if special processing is performed for error correction, transmission is performed. There is a problem that the audio data processing configuration on both the reception side and the reception side becomes complicated.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to make it possible to satisfactorily receive audio data multiplexed with video data with a simple configuration.

The present invention receives video data transmitted using the first, second and third channels, and represents a synchronization signal in the blanking period of the first channel of the three channels. When receiving data in which data is arranged and control information is arranged in the blanking period of video data of the second and / or third channel, digital audio data having a parity code for each packet is received for a plurality of packets. Combining and cutting out bit data from each packet by a predetermined bit to form a data unit, for each data unit, converting into one of the specific data having a predetermined number of types, encoding, and encoding and the data, video data placed in place of the control information to the second and / or blanking period of the video data in the third channel, where Of the transmission line is received via, arranged in the blanking period of the video data of the second and / or third channel is received, separated encoded data is converted into one of the specific data Then, the data encoded by converting into one of the separated specific data is decoded from the predetermined encoding, and error detection data is output when data other than the specific data is detected The decoded data is assembled into the original structure, and an error flag is set based on the error detection data for each predetermined bit of the assembled packet.

  By doing so, it is possible to receive audio data multiplexed with video data by applying an existing video data transmission format such as the DVI standard.

  According to the present invention, when video data multiplexed with audio data is received using a blanking period of video data, error correction of the audio data can be performed with a simple process.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  In this example, the present invention is applied to a system for transmitting video data output from a video / audio signal source such as a video tape recording / playback device, video disk playback device, tuner, etc., to a display device such as a monitor receiver or a television receiver. It is a thing. Here, a display device having an audio output function is used to transmit video data and audio data from a video / audio signal source using a single cable. As this transmission cable, a cable for transmitting data according to a standard called DVI (Digital Visual Interface) is used.

  FIG. 1 is a diagram showing the overall configuration of the transmission system of this example. A video / audio signal source 10 is connected to a display device 20 with a speaker using a DVI cable 2, and video data and audio data are transmitted by the cable 2. The connector part of the video / audio signal source 10 and the display device 20 to which the DVI cable 2 is connected is composed of, for example, a 24 pin connector, and the cable 2 has 24 pins of the connectors of both devices 10 and 20. Are connected individually.

  FIG. 2 shows a processing configuration in the video / audio signal source 10 for executing a function as a transmission device for sending video data and audio data to a DVI cable. The video data input unit 11 is supplied with video data encoded according to the DVI standard from a video processing unit (not shown) of the device 10. The video data obtained by the video data input unit 11 is supplied to the video / audio synthesis unit 12, and the synthesis unit 12 performs a synthesis process of multiplexing the audio data with the video data, and the synthesized data is converted into DVI format data. The data is supplied to the output unit 18 and sent from the output unit 18 to the DVI cable connected to the device 10.

  Here, a configuration in which video data is transmitted in the DVI format will be described with reference to FIG. 4. As transmitted video data, B data (blue data) shown in FIG. 4A and G data (FIG. 4B) ( Green data) and R data (red data) shown in FIG. 4C are transmitted as individual channel data. The data of each channel is data of 8 bits per pixel, and data of 24 bits in total per pixel for 3 channels. However, when actually transmitting pixel data by DVI, 8-bit data is converted into 10-bit data and transmitted. The pixel data of each channel is transmitted in synchronization with the pixel clock shown in FIG. 4C. FIG. 4E shows the details of the bit data of each channel, and 10-bit pixel data [0, 1, 2,... 9] of each channel is transmitted in synchronization with the pixel clock.

  In the DVI format, the pixel data of each channel is not transmitted during the horizontal blanking period and the vertical blanking period. In the B data transmission channel shown in FIG. 4A, data defined as the horizontal synchronization signal HSYNC is transmitted during the horizontal blanking period, and data defined as the vertical synchronization signal VSYNC is transmitted during the vertical blanking period. In the G data transmission channel shown in FIG. 4B, two control data (CTL0 data and CTL1 data) are arranged for each blanking. In the R data transmission channel shown in FIG. 4C, two control data (CTL2 data and CTL3 data) are arranged in each blanking. In the following description, the control data CTL0, CTL1, CTL2, and CTL3 are referred to as control data C0, C1, C2, and C3, respectively.

  Each control data C0, C1, C2, C3 is arranged in a blanking period of each channel by converting 2-bit data into 10-bit data. That is, for example, in the G data channel shown in FIG. 4B, 2-bit data of 1 bit of control data C0 and 1 bit of control data C1 is obtained, and this 2-bit data is converted into 10-bit data of a specific pattern. Thus, the converted 10-bit data is arranged in the blanking period. Specifically, there are four combinations of [00], [01], [10], and [11] as shown in FIG. 5 as combinations of 2-bit control data C0 and C1, respectively. For each combination, a 10-bit CTL code is assigned as shown in FIG. Therefore, in the G data channel, data other than these four types of 10-bit data is not transmitted during the blanking period. The control data C2 and C3 transmitted through the R data channel are similarly processed.

  Here, in this example, audio data (audio data) is transmitted by the control data C0 and C1 arranged in the horizontal blanking period of the G data transmission channel shown in FIG. 4B. Returning to the description of FIG. 2, a configuration for transmitting the audio data will be described.

  The audio data obtained from the audio processing unit (not shown) of the device 10 to the audio data input unit 13 is supplied to the video / audio synthesis unit 12 after data conversion processing. The audio data obtained in the audio data input unit 13 in the case of this example is audio data packetized as an IEC (International Electrotechnical Commission) 60958 system.

  As shown in FIG. 6A, the packet data of the IEC60958 system is configured such that one packet (one subframe) is composed of 32 bits, a preamble is arranged in the first 4 bits, and one sample of audio in the subsequent 24-bit section. Data (audio sample word) is arranged. In some cases, data of a bit number (for example, 16 bits) of less than 24 bits is arranged in one sample. A subcode is arranged in the last 4 bits.

  As a subcode in one packet, as shown in FIG. 6A, a validity bit V, a user data bit U, a channel status bit C, and a parity bit P are arranged. The 1-bit parity bit P is a code for performing a parity check of the audio data, and can determine whether or not there is an error in the audio data in the packet by a parity check by an operation using the parity code. is there. However, only the data of the parity bit P can be used to determine whether or not there is an error, and error correction cannot be performed.

  Note that, as shown in FIG. 6B, a 4-bit section following the 4-bit preamble may be an auxiliary data section, and a section in which an audio sample word is arranged may be 20 bits.

  When the audio data is 2 channel data of left channel data and right channel data, one frame is composed of a total of 2 packets of 1 packet of left channel audio data and 1 packet of right channel audio data, Two packets of 64-bit data are transmitted in one unit.

  Returning to the description of FIG. 2, the audio data of the packet structure obtained in the audio data input unit 13 is obtained by the 2-sample packet conversion unit 14 in units of audio data of 2 packets and 64 bits (1 frame). The data arrangement is such that 32 pieces of 2-bit data arranged one bit at a time are obtained, and the 32 pieces of 2-bit data are supplied to the symbol cutout unit 15.

  The symbol cutout unit 15 cuts out and outputs the supplied 32 pieces of 2-bit data one by one (that is, every two bits). The 2-bit data cut out by the symbol cutout unit 15 is supplied to the 2-bit / 10-bit conversion unit 16. The conversion process to the 10-bit data in the conversion unit 16 is the same as the process of converting the 2-bit data of C0 and C1 shown in FIG. That is, it is converted into one of the four types of CTL codes shown in FIG.

  The converted 10-bit data is supplied to the video / audio synthesizing unit 12, and the synthesizing unit 12 arranges it in the horizontal blanking period of the G data channel, and multiplexes the audio data with the video data. By synthesizing in this way, audio data is transmitted as control data C0 and C1 transmitted in the horizontal blanking period of the G data channel. Note that details of actual data processing will be described in the operation description to be described later. In the case of this example, audio data of a maximum of 8 subframes (4 frames) can be transmitted in one horizontal blanking period. .

  In the horizontal blanking period of the R data channel, control data supplied from the control data input unit 17 to the video / audio synthesis unit 12 is converted into 10-bit control data C2 and C3, and then arranged. The video / sound synthesizer 12 is also supplied with data necessary for the DVI format such as a horizontal synchronization signal, a vertical synchronization signal, and a pixel clock.

  FIG. 3 shows a processing configuration for executing a function as a receiving device for receiving video data and audio data transmitted via the DVI cable in the display device 20. Data transmitted via the DVI cable connected to the device 10 is obtained in the DVI format data input unit 21. The data obtained at the input unit 21 is supplied to the video / audio separation unit 22, and each data (audio data, control data) arranged in the blanking period is separated from the video data. The video data from which the data has been separated by the video / audio separation unit 22 is supplied to a video processing unit (not shown) in the display device 20 via the video data output unit 23 to be processed for display. Executed. Further, the control data (control data C2 and C3 multiplexed in the blanking period of the R data channel) separated by the video / audio separation unit 22 is sent to the controller of the display device 20 via the control data output unit 24. (Not shown).

  The audio data (data transmitted as control data C0 and C1) separated from the horizontal blanking period of the G data channel by the video / audio separation unit 22 is supplied to the 10-bit / 2-bit conversion unit 25. The 10-bit / 2-bit conversion unit 25 performs a decoding process for converting the 10-bit CTL code shown in FIG. 5 into 2-bit data C0 and C1. However, when data other than the four types of 10 bits shown in FIG. 5 is detected, it is determined that a transmission error has occurred, error detection data is output, and the corresponding 2-bit data is 0 data. Or erasure data that has not been determined.

  The 2-bit unit data converted by the 10-bit / 2-bit conversion unit 25 is supplied to the packet assembly unit 26. The packet assembly unit 26 collects 32 pieces of supplied 2-bit data and performs a process of assembling two packets (2 subframes: 1 frame). The error detection data output from the 10-bit / 2-bit conversion unit 25 is supplied to the packet assembly unit 26, and each bit of the packet assembled by the packet assembly unit 26 is based on the error detection data. An error flag is set. The data at the bit position where this error flag is set is erasure data.

  The packet data assembled by the packet assembly unit 26 is supplied to the error correction unit 27 and the parity extraction unit 28. The parity extraction unit 28 extracts parity bits in the supplied packet data, and supplies the extracted parity bits to the error correction unit 27. In the error correction unit 27, when there is lost data in the supplied packet data, the lost data is determined by a parity check operation using a parity bit, and error correction processing for restoring the lost data is performed. However, since the parity bit is 1 bit per packet in the case of this example, it is possible to restore up to 1 bit per packet, and when there is 2 bits or more of lost data in one packet, the operation by parity check In error correction is not possible.

  Then, the packet data in units of two subframes corrected by the error correction unit 27 is supplied to the audio processing unit (not shown) of the display device 20 via the audio data output unit 29, and is shown in FIG. A process of outputting from the speakers 20L and 20R shown is executed.

Next, details of a state in which audio data (audio data) is transmitted in the system of this example will be described. FIG. 7 is a diagram showing a state in which audio data packets conforming to the IEC 60958 standard are arranged in the horizontal blanking period on the transmission side (video / audio signal source 10 in this example). As shown in FIG. 7A, an audio data packet according to this standard includes one subframe, which is one packet, of 32 bits, and a left channel (Lch) packet and a right channel (Rch) packet alternately. Arranged and supplied. In the example of FIG. 7A, odd-numbered packets A ₁ , A ₃ , A ₅ ... Are left channel subframes, and even-numbered packets A ₂ , A ₄ , A _6. is there.

Here, as shown in FIG. 7B, the two-sample packet conversion unit 14 converts the data of _two packets (here, packets A ₁ and A ₂ ) into a data array in which data of the same bit positions of each packet are arranged. The symbol cutout unit 15 sequentially extracts 2-bit data between the same bit positions. Then, as shown on the right side of FIG. 7B, each 2-bit data is converted into the 10-bit CTL code shown in FIG.

Here, as shown in FIG. 7B, 0-bit to 31-bit data of the packet A ₁ and the packet A ₂ is 10-bit data [A ₁ , A ₂ 0], [A ₁ , A for each bit position. ₂ 1], [A ₁ , A ₂ 2]... [A ₁ , A ₂ 31].

The 10-bit data obtained in this way is synchronized with the pixel clock shown in FIG. 7C, and in a horizontal blanking period indicated by the horizontal synchronizing signal in FIG. 7D, a specific channel (here, G data channel) of video data. Placed in. FIG. 7E is a diagram showing a state of a horizontal blanking period of a channel in which the audio data is arranged as control data C0 and C1. Here, the 10-bit data [A ₁ , A ₂ 0], [A ₁ , A ₂ 1], [A ₁ , A ₂ 2]... [A ₁ , A ₂ 31] are synchronized with the pixel clock. Are output in order. After the last data [A ₁ , A ₂ 31] of the packets A ₁ and A ₂ are transmitted, the 10-bit data [A ₃ , A ₄₀ ] to [[ ₂ ] of the next two packets A ₃ and A ₄ are sent. A ₃ , A ₄ 31] are sequentially output in synchronization with the pixel clock.

  In this way, the audio data of each packet is sequentially transmitted during the horizontal blanking period. In this example, audio data of 6 packets (6 subframes or 3 frames) is arranged in one horizontal blanking period, and audio data of 8 packets (8 subframes or 4 frames) is arranged in one horizontal blanking period. FIG. 7E shows an example in which 6 packets are arranged. In the remaining horizontal blanking period in which audio data for 6 packets is transmitted, 0 data (that is, 10-bit data in which C0 and C1 are both 0) is continuously arranged.

  8 shows an example in which 6 subframes (3 frames) are arranged within one horizontal blanking period indicated by the horizontal synchronization signal shown in FIG. 8A (FIG. 8B) and an example in which 8 subframes (4 frames) are arranged. (FIG. 8C) is shown. As can be seen from a comparison between FIG. 8B and FIG. 8C, the length of the last 0 data section differs between the case where 6 subframes are arranged in one horizontal blanking period and the case where 8 subframes are arranged. In an actual transmission state, a horizontal blanking period in which 6 subframes are arranged and a horizontal blanking period in which 8 subframes are arranged are periodically set in a predetermined order.

  For example, if the horizontal frequency of the video data is 15.75 kHz and the sampling frequency of the audio data is 48 kHz, one horizontal scanning period of the video data is about 63.5 μsec, and one sampling period of the audio data is about 20 .8 microseconds, every time a process of sending audio data of 3 frames (3 samples per channel: 6 subframes in total) on one horizontal line is performed several tens of times, 4 frames (4 per channel) By combining the two processes so that the process of sending the audio data (sample: total of 8 subframes) is performed once, transmission can be performed without causing an audio delay with respect to the video.

Next, a state in which error correction is performed on the side where the audio data transmitted in the horizontal blanking period is received will be described with reference to FIG. FIG. 9 shows an example when _two subframes A ₁ and A ₂ are transmitted. That is, as shown at the left end of FIG. 9, each of the 32-bit subframes A ₁ and A ₂ includes 10-bit data [A ₁ , A ₂ 0], [A ₁ , a ₂ 1], [a _1, a 2 _2] is converted into ‥‥ [a _1, a ₂ 31], the converted 10-bit data is found in order by using the DVI cable to the horizontal blanking period Is transmitted.

When transmission is performed in this way, as shown in FIG. 9, for example, a transmission error occurs in 10-bit data [A ₁ , A ₂ 1], and the 10-bit data cannot be decoded into the original 2-bit data. To do. The other 10-bit data is correctly received and can be correctly decoded into 2-bit data. At this time, in the packet assembling unit 26, the bit in which the transmission error of the subframes A ₁ and A ₂ has occurred becomes lost data (bit data indicated by x in the figure), and the error flag at the corresponding bit position is set to 1. Data (the error flag at the bit position without error is 0 data).

Then, when there is lost data in this way, the lost data is restored by arithmetic processing in the error correction unit 27. That is, for each of the subframes A ₁ and A ₂ , lost data is determined by calculation using a parity bit. As a method for setting the parity bit, various methods conventionally used for encoding digital data can be applied. For example, when all 32 bits in one subframe are added by adding a parity bit, the value of the parity bit is set so as to be an even value, thereby adding 31 bits other than lost data, It can be determined whether the lost data is 1 data or 0 data. Accordingly, the subframe that has been error-corrected by the error correction unit 27 is obtained in the audio data output unit 29.

  As described above, since the audio data can be multiplexed and transmitted with the video data, the audio data can be easily and satisfactorily transmitted using the configuration for transmitting the video data. That is, it is possible to transmit audio data using the same signal cable using an existing digital video data transmission system standardized as the DVI standard. Particularly in the case of this example, since audio data is transmitted during the horizontal blanking period of the video data, it is not necessary to change the conventional DVI standard at all for the transmission processing configuration of the video data. The processing block of video data prepared for the DVI standard can be used as it is on the receiving side.

  In the case of this example, packet data of the IEC 60958 system, which is a standard of transmission data widely used for transmission of digital audio data, is transmitted as it is as audio data. When there is a transmission error, error correction can be performed using a parity bit prepared in advance in a packet of this method, and good transmission with few errors can be performed.

  In other words, when an IEC60958 audio packet is transmitted as it is, the operation using the parity bit in the packet only determines whether or not there is an error in the data in the packet. No parity bit was used. Here, in the case of this example, the packet data is decomposed in bit units, and then converted into a 10-bit CTL code every 2 bits, so that an error occurs in the data in the packet. The bit position where the error occurred is known. Therefore, error correction can be performed using parity bits, and error correction can be easily performed without preparing a special error correction code.

  In the above-described embodiment, two channels of digital audio data are transmitted. However, the present invention is also applicable to the case of transmitting one channel of digital audio data or the case of transmitting three or more channels of digital audio data. Is possible. For example, when transmitting multi-channel data of three or more channels, the CTL2 and CTL3 portions of the horizontal blanking period of the R data channel shown in FIG. 4 may be used for audio data transmission.

  In the above-described embodiment, a packet in which digital audio data having a constant sampling rate is arranged is transmitted. However, digital audio compressed and encoded by a predetermined method (for example, ATRAC method or MP3 method). Data may be arranged and transmitted in a packet.

  In the above-described embodiment, the horizontal blanking period is used as the audio data transmission period. However, the vertical blanking period may be used for audio data transmission.

  Further, in the embodiments described so far, audio data is multiplexed and transmitted using the transmission path of the DVI standard, but other standards for video data transmission may be applied. . In this case, the transmission path may be a wireless transmission path in addition to the transmission path connected by a wired cable.

It is a block diagram which shows the system configuration example by one embodiment of this invention. It is a block diagram which shows the structural example of the transmission system by one embodiment of this invention. It is a block diagram which shows the structural example of the receiving system by one embodiment of this invention. It is a timing diagram which shows the transmission timing of a DVI system. It is explanatory drawing which showed the example of a response | compatibility with CTL0 data (C0 data) of DVI system, CTL1 data (C1 data), and a CTL code. It is explanatory drawing which shows the structural example (example of 1 sub-frame structure of IEC60958 format) of the packetized audio data. It is explanatory drawing which shows the transmission processing example of the audio packet by one embodiment of this invention. It is explanatory drawing which shows the example of arrangement | positioning of the sub-frame by one embodiment of this invention. It is explanatory drawing which shows the example of an error correction process by one embodiment of this invention. It is a block diagram which shows the example of a connection by the conventional DVI specification. It is a block diagram which shows the example of a connection by the conventional DVI standard (example which prepared the cable for audio separately).

Explanation of symbols

  2 ... DVI standard cable, 10 ... Video / audio signal source, 11 ... Video data input unit, 12 ... Video / audio synthesis unit, 13 ... Audio data input unit, 14 ... 2 sample packet conversion unit, 15 ... Symbol cutout unit 16 ... 2 bit / 10 bit conversion unit, 17 ... control data input unit, 18 ... DVI format data output unit, 20 ... display device with speaker, 20L, 20R ... speaker, 21 ... DVI format data input unit, 22 ... video Audio separation unit, 23 ... Video data output unit, 24 ... Control data output unit, 25 ... 10 bit / 2 bit conversion unit, 26 ... Packet assembly unit, 27 ... Error correction unit, 28 ... Parity extraction unit, 29 ... Audio Data output section

Claims (8)

The video data transmitted using the first, second and third channels is received, and data representing the synchronization signal is arranged in the blanking period of the first channel of the three channels. And a data receiving device for receiving the control information arranged in the blanking period of the video data of the second and / or third channel,
Combining digital audio data with a parity code for each packet for multiple packets, cutting out bit data from each packet by a predetermined bit to form a data unit, and the number of types specified in advance for each data unit Converting and encoding to one of the data, the encoded data, the video data arranged in place of the control information in the blanking period of the video data of the second and / or third channel , Receiving means for receiving via a predetermined transmission path;
The encoded data converted into one of the specific data arranged in the blanking period of the received second and / or third channel video data through a predetermined transmission path is separated. Separating means;
When the data separated by the separating means and converted into one of the specific data is decoded from a predetermined encoding, and when data other than the specific data is detected, Decoding means for outputting error detection data;
A data receiving apparatus comprising: data assembling means for assembling the data decoded by the decoding means into an original structure and setting an error flag on the basis of error detection data for each predetermined bit of the assembled packet. The data receiving device according to claim 1, wherein
The data received via the transmission path includes the parity code of the audio data to be transmitted, and the data at the position where the error flag is set by the data assembling means is the original by the calculation using the parity code. Data receiver that restores the data and corrects errors. The video data transmitted using the first, second and third channels is received, and data representing the synchronization signal is arranged in the blanking period of the first channel of the three channels. A data receiving method for receiving the control information arranged in the blanking period of the video data of the second and / or third channel,
Combining digital audio data with a parity code for each packet for multiple packets, cutting out bit data from each packet by a predetermined bit to form a data unit, and the number of types specified in advance for each data unit Converting and encoding to one of the data, the encoded data, the video data arranged in place of the control information in the blanking period of the video data of the second and / or third channel , Received via a predetermined transmission path,
Separating the encoded data converted into one of the specific data arranged in the blanking period of the received video data of the second and / or third channel ;
Decoding the separated and encoded data converted into one of the specific data from a predetermined encoding;
When data other than the above specific data is detected, error detection data is output,
A data receiving method for assembling the decoded data into an original structure and setting an error flag for each predetermined bit of the assembled packet based on error detection data. The data receiving method according to claim 3, wherein
The data received via the transmission path includes the parity code of the audio data to be transmitted. For the data at the position where the error flag is set, the original data is restored by calculation using the parity code. A data receiving method for performing error correction. A data transmission system for transmitting video data and digital audio data from a data transmission device to a data reception device using the first, second and third channels ,
Of the above three channels, data representing a synchronization signal is arranged in the blanking period of the video data of the first channel, and control information is arranged in the blanking period of the video data of the second and / or third channels. In the data transmission system that transmits
As the data transmission device,
Data dividing means for combining digital audio data having a parity code for each packet for a plurality of packets , cutting out bit data by a predetermined bit from each packet, and configuring a data unit;
Encoding means for converting and encoding into one of the specific data having a predetermined number of types for each data unit divided by the data dividing means;
The data encoded by the encoding means is arranged in place of the control information in the blanking period of the video data of the second and / or third channel and synthesized, and the synthesized data is predetermined. Data sending means for sending to the transmission line,
As the data receiving device,
Receiving means for receiving the video data of the three channels via a predetermined transmission path;
Separating means for separating data encoded by converting into one of the specific data, arranged in a blanking period of the received video data of the second and / or third channel ;
Decoding means for decoding data encoded by converting into one of the specific data from the encoding, and outputting error detection data when data other than the specific data is detected; ,
A data transmission system comprising data assembling means for assembling the data decoded by the decoding means into an original structure and setting an error flag on the basis of error detection data for each predetermined bit of the assembled packet. The data transmission system according to claim 5, wherein
The packet structured digital audio data divided by the data dividing means of the data transmitting device includes a parity code of the audio data, and the parity code is also transmitted to the data receiving device via the transmission path. system. The data transmission system according to claim 6, wherein
A data transmission system that corrects an error by restoring the original data by calculation using the parity code for the data at the position where the error flag is set by the data assembling means of the data receiving apparatus. The data transmission system according to claim 5, wherein
A data transmission system in which the data unit is 1 bit per packet.

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