Device and method for multiplexing associated with a coding device
View Patent ↗A multiplexing device is coupled to various coding devices. The multiplexing device does not attempt to mutually synchronize the various coding devices but, instead, circumvents such synchronization while making it possible to work with the various coding devices and to obtain synchronous actions at the input of the multiplexer. In particular, the multiplexing device transmits control commands and an instant of action to each of the coding devices.
1. Multiplexing device able to receive data packets from at least one coding device, some of the data packets comprising a time label, said multiplexing device comprising a time reference and being able to transmit control commands to said coding device, wherein said multiplexing device comprises:
means for calculating an instant of action for the coding device at which said multiplexing device desires that the coding device perform said commands as a function of the instant at which said multiplexing device transmits said control commands to said coding device, of the time label of the data packets, of its time reference and of the maximum transfer time between the coding device and the multiplexing device, and
means for transmitting said instant of action and said control commands to the coding device.
2. Device according to claim 1 wherein it is connected to the coding device by way of a transport network on the one hand allowing the transmission of the data packets and by way of a communication network on the other hand allowing the transmission of the control commands and of the associated instants of action, the two networks having variable transit times bounded in time, the maximum transfer time between the coding device and the multiplexing device being the sum of the maximum transit times through the two networks.
3. Device according claim 1 wherein the means of calculation calculate said instant of action according to the following formula:
PCRc _Action= PCRm _Action+Delta_Action+Delta PCRc
where PCRm_Action represents the instant at which the multiplexer decides on said action,
where Delta_Action represents the time within which the multiplexer desires to receive the effects of said action,
with Delta_Action>Temax+Tsmax,
where DeltaPCRc=PCRc−PCRm,
with PCRm representing the last time reference of the multiplexing device at the instant of reception of the last time label, PRCc, of a data packet.
4. Device according to claim 3 wherein it calculates the difference between the time label of the data packets and its time reference with each reception of a data packet comprising a time label.
5. Device according to claim 1 wherein it is connected to at least two coding devices by way of distinct transport networks allowing the transmission of the data packets and by way of a common communication network allowing the transmission of the control_commands and the associated instants of action, said device being adapted to calculate an instant of action for each coding device, in such a way that it receives synchronously the effects of said command of the various coding devices.
6. Device according to claim 5 wherein it is adapted to transmit bit rate adaptation commands to said coding devices so as to effect dynamic bit rate allocation.
7. Device according to claim 6 wherein it is adapted to receive complexity cues synchronized with the time labels of the various coding devices through said transport networks.
8. Device according to claim 6 wherein it is adapted to receive complexity cues from the various coding devices through said communication networks, the complexity cues then being marked by said time label transmitted in a data packet.
9. Device according to claim 6 wherein it transmits bit rate modification commands to said coding devices as a function of its bit rate of output and of coding complexities.
10. Device according to claim 5 wherein the means of calculation calculate said instant of action for each coding device according to the following formula:
PCRci _Action= PCRm _Action+Delta_Action+Delta PCRci
where PCRm_Action represents the instant at which the multiplexer decides on said action,
where Delta_Action represents the time within which the multiplexer desires to receive the effects of said action,
with Delta_Action>Max(Tscimax)+Max(TcRimax),
where DeltaPCRci=PCRci−PCRmi,
with PCRmi representing the time reference of the multiplexing device (M) upon the reception of the time label, PRCc of each coding device.
11. Method of multiplexing in a multiplexing device, able to receive data packets from at least one coding device, some of the data packets comprising a time label, said multiplexing_device comprising a time reference, said method comprising a step of transmitting control_commands to said coding device, wherein it comprises the steps of:
calculating an instant of action at which said multiplexing device desires that the coding device perform said control_commands as a function of the instant at which said multiplexing device desires to receive the effects of said control commands, of the time label of the data packets, of its time reference and of the maximum transfer time between the coding device and the multiplexing device, and
means of transmitting said instant and said control_commands to the coding device.