Transport stream multiplexers and methods for providing packets on a transport stream
View Patent ↗Examples described include transport stream multiplexers that may not need to search for an appropriate source to use to generate a transport stream packet. Instead, the source to use may be indicated by a position (e.g. an entry) in a memory table, e.g. a metadata array. Methods for placing transport stream packets on a transport stream and initializing the metadata array are also described.
1. A method for providing packets on a transport stream, the method comprising:
reading a metadata array at a position indicated by an index pointer, wherein a source indicator and release time stamp are stored at the position in the metadata array;
generating a transport stream packet from the source indicated by the source indicator stored at the position indicated by the index pointer;
assigning a release time stamp to the transport stream packet based on the release time stamp stored at the position indicated by the index pointer; and
providing, using a transport stream multiplexer, the transport stream packet on the transport stream at a time corresponding to the release time stamp.
2. The method of claim 1 , further comprising:
calculating a next metadata array location for the source indicated by the source indicator stored at the position indicated by the index pointer;
store a corresponding source indicator at the next metadata array location if the next metadata array location is within the metadata array; and
store the corresponding source indicator in a ready list if the next metadata array location is not currently within the metadata array.
3. The method of claim 2 , wherein said calculating a next metadata array location is based on a leak rate of the source indicated by the source indicator.
4. The method of claim 2 , wherein said calculating a next metadata array location is based on a system clock frequency used by a transport stream multiplexer.
5. The method of claim 1 , further comprising updating the metadata array at the position indicated by the index pointer by storing an updated release time stamp.
6. The method of claim 5 , wherein the updated release time stamp is based on a size of the metadata array.
7. The method of claim 5 , further comprising updating the metadata array at the position indicated by the index pointer by storing an updated source indicator.
8. The method of claim 7 , wherein the updated source indicator corresponds to a source of stuffing packets.
9. A transport stream multiplexer comprising:
a processor;
memory storing instructions for transport stream multiplexing;
a metadata array having consecutive locations corresponding to consecutive packets of a transport stream, wherein each of the consecutive locations includes a stored release time stamp and source indicator; and
wherein the processor is configured, in accordance with the instructions for transport stream multiplexing, to read a location of the metadata array, generate a transport stream packet from a source specified by the source indicator at the read location of the metadata array, and provide the transport stream packet on the transport stream at a time corresponding with the release time stamp at the read location of the metadata array.
10. The transport stream multiplexer of claim 9 , wherein the transport stream multiplexer is in communication with a plurality of sources, and wherein the source specified by the source indicator at the read location is a selected one of the plurality of sources.
11. The transport stream multiplexer of claim 9 , further comprising a ready list, wherein the ready list is configured to store release time stamps and source indicators for packets which do not have a corresponding location in the current metadata array.
12. The transport stream multiplexer of claim 11 , wherein the processor is further operable, in accordance with the instructions for transport stream multiplexing, to provide packets on the transport stream corresponding to each consecutive location in the metadata array and update the metadata array using data stored in the ready list.
13. The transport stream multiplexer of claim 9 , wherein the metadata array comprises a first-in first-out (FIFO) memory.
14. The transport stream multiplexer of claim 9 , wherein the transport stream multiplexer is further configured to receive a clock signal, and wherein the a time corresponding with the release time stamp at the read location of the metadata array is based, at least in part, on the clock signal.