Abstract: Techniques are disclosed for controlling data transmission in multi-stream digital systems. The techniques disclosed allow an input stream to a conditional access system to be throttled when a FIFO begins to fill up. Each data stream may have its own FIFO, which sends data to a MUX and exports its status to a backpressure rate control module. Multiple seconds worth of data may be stored in a BPRC buffer ahead of the backpressure rate control module prior to being transmitted to a MUX FIFO buffer. The backpressure rate control module may use the cached data to fill available spaces within a MUX FIFO buffer. The determination to forward a data packet may be based on the individual MUX FIFO buffer levels, the sum of all the MUX FIFO buffer levels, and/or one or more configurable threshold values. In some embodiments, individual thresholds may be assigned to each FIFO buffer.

Abstract: Methods and systems may provide for a sink module that receives packets from a source module, wherein each of the packets has a source timestamp corresponding to a source module packet arrival time. A reference timestamp may be associated with the source timestamp of the most recent packet having a program clock reference. A sink counter may be synchronized to a broadcaster transmit counter based on a current source timestamp and the reference timestamp. The sink counter and the source counter may be driven by asynchronous clocks, wherein the current source timestamp may be inferred based on a current value of the source counter. The packets may include video data and/or audio data. The sink counter may be synchronized by adjusting the frequency of a source clock and/or adjusting the sink counter.

Abstract: Techniques are described for determining whether a stream is in a stable state and permitting adjustment of the PTS value when the stream is in a stable state. The stream can be in a stable state when PTS values received over a period of time do not change unexpectedly. For example, when the stream is in a stable state, the PTS value for audio or video can be adjusted based on system buffer levels, i.e., over flow or under flow. The amount of adjustment of the PTS value can be based on whether the buffer level appears to be moving into greater overflow or underflow. In some cases, when the stream is not in a stable state, the audio is permitted to be played back at a sample rate and video is permitted to be played back at a frame rate instead of being controlled by PTS.

Abstract: Techniques are disclosed for controlling data transmission in multi-stream digital systems. The techniques disclosed allow an input stream to a conditional access system to be throttled when a FIFO begins to fill up. Each data stream may have its own FIFO, which sends data to a MUX and exports its status to a backpressure rate control module. Multiple seconds worth of data may be stored in a BPRC buffer ahead of the backpressure rate control module prior to being transmitted to a MUX FIFO buffer. The backpressure rate control module may use the cached data to fill available spaces within a MUX FIFO buffer. The determination to forward a data packet may be based on the individual MUX FIFO buffer levels, the sum of all the MUX FIFO buffer levels, and/or one or more configurable threshold values. In some embodiments, individual thresholds may be assigned to each FIFO buffer.

Abstract: Methods and systems may provide for a sink module that receives packets from a source module, wherein each of the packets has a source timestamp corresponding to a source module packet arrival time. A reference timestamp may be associated with the source timestamp of the most recent packet having a program clock reference. A sink counter may be synchronized to a broadcaster transmit counter based on a current source timestamp and the reference timestamp. The sink counter and the source counter may be driven by asynchronous clocks, wherein the current source timestamp may be inferred based on a current value of the source counter. The packets may include video data and/or audio data. The sink counter may be synchronized by adjusting the frequency of a source clock and/or adjusting the sink counter.

Abstract: Techniques are described for determining whether a stream is in a stable state and permitting adjustment of the PTS value when the stream is in a stable state. The stream can be in a stable state when PTS values received over a period of time do not change unexpectedly. For example, when the stream is in a stable state, the PTS value for audio or video can be adjusted based on system buffer levels, i.e., over flow or under flow. The amount of adjustment of the PTS value can be based on whether the buffer level appears to be moving into greater overflow or underflow. In some cases, when the stream is not in a stable state, the audio is permitted to be played back at a sample rate and video is permitted to be played back at a frame rate instead of being controlled by PTS.