Abstract: A scrambling and descrambling method that includes reading of original PID and TSC bits in the PID and TSC fields of a packet header of an MPEG2 stream which is at least partially scrambled. A temporary PID may be written in a PID field in place of the original PID, and may be a function of the original PID value and TSC bits according to a correspondence table of an original PID and TSC bits with the temporary PIDs. The value zero may be written in the TSC field in place of the original value, and scrambling of the stream with modified fields may occur. Applications include the satellite transmission of partially scrambled MPEG2 digital signals.

Abstract: The present invention relates to the domain of control methods of a plurality of formatting equipment (FE1, FE2) of streams (TS) used as backup. The items of equipment receive the streams (TS) and send, to a modulator (MOD1), formatted streams (TS_SFN1, TS_SFN2) comprising a succession of blocks of packets called “megaframe” and megaframe initialization packets (MIP) used by the modulator (MOD1) to identify in time a megaframe (MFn) relatively to a time base (TB).

Abstract: The method comprises the following steps: reading of an original PID and TSC bits in the PID and TSC fields of a packet header of an MPEG2 stream at least partially scrambled, writing of a temporary PID in a PID field in place of the original PID, function of the original PID value and TSC bits according to a correspondence table of an original PID and TSC bits with the temporary PIDs, writing of the value zero in the TSC field in place of the original value, scrambling of the stream with modified fields. Applications for the satellite transmission of partially scrambled MPEG2 digital signals.

Abstract: The present invention relates to the domain of control methods of a plurality of formatting equipment (FE1, FE2) of streams (TS) used as backup. The items of equipment receive the streams (TS) and send, to a modulator (MOD1), formatted streams (TS_SFN1, TS_SFN2) comprising a succession of blocks of packets called “megaframe” and megaframe initialisation packets (MIP) used by the modulator (MOD1) to identify in time a megaframe (MFn) relatively to a time base (TB).

Abstract: The present invention relates to a method for processing a stream (10) of multiplexed packets transporting multimedia data according to an MPEG-2 type format, this stream (10) being transmitted at a high bitrate to an intermediary network (12) having low bitrate transmission channels (141, 142, . . . 14n), wherein the high bitrate stream (10) is treated upstream of the intermediary network (12) carrying out the following steps: a step of demultiplexing the high bitrate stream (10) in order to insert packets (1, 2, . . . 44) of data in the low bitrate stream (161, 162, . . . 16n) transmitted by the intermediary channels (141, 142, . . . 14n), a step of alternating, in a synchronized way for set of low bitrate streams (161, 162, . . . 16n), the insertion of packets (1, 2, . . . 44) of data with the insertion of synchronization packets (M1, M2, M3, M4) in these low bitrate streams (161, 162, . . . 16n), so that these low bitrate streams (161, 162, . . .

Abstract: 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.

Abstract: The invention relates to a method and a device for multiplexing. The device is able to receive data packets from at least one coding device, some of the data packets comprising a time label, said device comprising a time reference and being able to transmit commands to the said coding device. According to the invention, the device is characterized in that it comprises: means for calculating an instant of action for the coding device at which it desires that the coding device perform the said command as a function of the instant at which it transmits the said command to the 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, means for transmitting said instant of action and the said command to the coding device.