Video and audio multiplex transmission system

A video and audio multiplex transmission system, wherein said system comprises:

• a transmission unit connectable to receive an audio input and a video input, comprising:
• an audio A/D converter connected to convert the audio input to a digital sound signal,
• an audio coding unit for coding the digital sound signal, for outputting coded sound data having a format that enables selection of a transmission amount and for outputting audio content data,
• a video A/D converter connected to convert the input to a digital picture signal,
• a video coding unit for coding the digital picture signal and for outputting coded picture data,
• a coding control unit for determining and outputting control data including an allocation signal indicative of a transmission ratio of the coded sound signal and the coded video data in accordance with the transmission amount of at least one of the coded sound data and the coded picture data, and
• a multiplexing unit for multiplexing the coded sound data and the coded picture data based on the allocation signal to output a multiplexed signal so as to obtain a certain transmission frame length, and
• a reception unit comprising:
• a demultiplexing unit for receiving and outputting coded sound data, coded picture data and control data including an allocation signal,
• an audio decoding unit for decoding the coded sound data to obtain a digital sound signal,
• a video decoding unit for decoding the coded picture data to obtain a digital picture signal,
• a decoding control unit for performing control of said audio decoding unit and said video decoding unit based on the allocation signal,
• an audio D/A converter connected to convert the digital sound signal to an audio output, and
• a video D/A converter for converting said picture signal to a video output, and
• wherein said audio coding unit comprises an SB-ADPCM coding unit which divides the digital sound signal into a low frequency bit portion and a high frequency bit portion for coding and selects an amount of allocation of the high frequency bit portion based on the allocation signal, and
• wherein said audio decoding unit performs SB-ADPCM decoding of said coded sound based on the allocation signal.

A video and audio multiplex transmission system having a transmission unit to receive an audio input and a video input and to transmit a multiplexed signal, comprising:

• an audio A/D converter connected to convert the audio input to a digital sound signal,
• an audio coding unit for coding the digital sound signal to output coded sound data,
• a video A/D converter connected to convert the video input to a digital picture signal,
• a video coding unit for coding the digital picture signal to output coded video data,
• a delay amount of calculation unit for calculating the variable time necessary to code the digital picture signal and output the coded video data in said video coding unit and for subtracting a fixed time necessary to code the digital sound signal and to decode the coded sound data from said variable time and output delay time data to be used for adaptively synchronizing a video reproduced signal and an audio reproduced signal in a reception unit connected to said transmission unit, and
• a multiplexing unit for multiplexing the coded video data, the coded sound data and the delay time data.

A video and audio multiplex transmission system wherein said system comprises:

• a transmission unit connectable to receive an audio input and a video input, comprising:
• an audio A/D converter connected to convert the audio input to a digital sound signal,
• an audio coding unit for coding the digital sound signal to output coded sound data,
• a video A/D converter connected to convert the video input to a digital picture signal,
• a video coding unit for coding the digital sound signal to output coded video data,
• a delay amount calculation unit for calculating the variable time necessary to code the digital picture signal and output the coded video data in said video coding unit and for subtracting a fixed time necessary to code the digital sound signal and to decode the coded sound data from said variable time and output delay time data to be used for adaptively synchronizing a video reproduced signal and an audio reproduced signal in a reception unit connected to said transmission unit, and
• a multiplexing unit for multiplexing the coded video data, the coded sound data and the delay time data, and
• a reception unit comprising:
• a demultiplexing unit connected to receive the multiplexed signal from the transmission line and to output audio data, coded picture data, and delay time data by subtraction of a fixed time necessary to code the digital sound signal and decode the coded sound data from a variable time necessary to code the digital picture signal and output the coded video data,
• a variable delay control unit for delaying the audio data in accordance with the delay time data and for outputting delayed audio data,
• an audio decoding unit for decoding the delayed audio data to output digital sound data,
• an audio D/A converter connected to convert the digital sound data to an audio output,
• a video coding unit for decoding the coded picture data, and
• a video D/A converter for converting said decoded digital picture to a video output.