Method and coding and decoding devices for picture transmission through a variable rate network
First Claim
1. A method of coding and decoding a digital signal including picture information, comprising:
- coding and rate decreasing an incoming digital video signal including picture information into a first coded digital signal having a variable rate at most equal to a maximal information rate and less than the rate of said incoming digital signal,transmitting said first coded digital signal in a first variable-rate transmission path of a digital transmission network, said rate decrease being a function of an instantaneous information rate dispatched by said first path,producing additional picture information in response to said instantaneous information rate in said first path being lower than said maximal information rate, said additional picture information being substantially deduced from a difference in picture information between said incoming digital signal and said first coded signal,coding said additional picture information into a second coded digital signal,transmitting said second coded digital signal in a second variable-rate transmission path of said network,decoding and rate increasing said first coded digital signal in said first path as a function of said instantaneous rate of said first path, thereby deriving a first decoded signal,decoding said second coded signal in said second path into a second decoded signal, andadding said first and second decoded signals into a recovered digital video signal substantially analogous to said incoming digital video signal.
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Abstract
The coding and decoding devices embodying the invention are connected by two paths, a main path and an auxiliary path, of a variable rate digital transmission network. When the main path is capable of dispatching the totality of the information rate that the coding device is able to issue, only a main coder and a main decoder, respectively of the coding and decoding devices, are active. When the main path is not capable of dispatching the totality of the picture information, an auxiliary coder and an auxiliary decoder, respectively of the coding and decoding devices, are also active and the auxiliary path dispatches the part of the information rate that cannot be dispatched by the main path. A decoder and a subtracter are provided in the coding device so as to estimate the part of information not transmitted by the main path.
29 Citations
10 Claims
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1. A method of coding and decoding a digital signal including picture information, comprising:
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coding and rate decreasing an incoming digital video signal including picture information into a first coded digital signal having a variable rate at most equal to a maximal information rate and less than the rate of said incoming digital signal, transmitting said first coded digital signal in a first variable-rate transmission path of a digital transmission network, said rate decrease being a function of an instantaneous information rate dispatched by said first path, producing additional picture information in response to said instantaneous information rate in said first path being lower than said maximal information rate, said additional picture information being substantially deduced from a difference in picture information between said incoming digital signal and said first coded signal, coding said additional picture information into a second coded digital signal, transmitting said second coded digital signal in a second variable-rate transmission path of said network, decoding and rate increasing said first coded digital signal in said first path as a function of said instantaneous rate of said first path, thereby deriving a first decoded signal, decoding said second coded signal in said second path into a second decoded signal, and adding said first and second decoded signals into a recovered digital video signal substantially analogous to said incoming digital video signal. - View Dependent Claims (2)
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3. A coding device for an incoming digital video signal including picture information comprising:
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first coding means for coding said incoming digital video signal into a first coded digital signal having a variable rate at most equal to a maximal information rate and less than the rate of said incoming digital signal, thereby transmitting said first coded digital signal in a first variable-rate transmission path of a digital transmission network, said first coded signal undergoing with respect of said incoming signal a rate decrease that is a function of an instantaneous information rate dispatched by said first path, means for estimating picture information included in said incoming digital video signal and effectively carried by said first coded signal thereby producing an estimated digital video signal, means responsive to said instantaneous information rate in said first path being lower than said maximal information rate for subtracting said estimated digital video signal from said incoming digital video signal into a digital video signal representative of additional picture information, second means for coding said additional picture information video signal into a second coded digital signal thereby transmitting said second coded signal in a second variable-rate transmission path of said network. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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Specification