Method and system for generating transport stream packets
View Patent ↗In accordance with a specific aspect of the present invention, a compressed video stream, such as an MPEG-2 video stream, is received by a transport demultiplexor, synchronized, parsed into separate packet types, and written to buffer locations external the demultiplexor. Adaptation field is handled by a separate parser. In addition, primary elementary stream data can be handled by separate primary elementary stream parsers based upon the packet identifier of the primary elementary stream. Video packets can be parsed based upon stream identifier values. Specific packets of data are stored in one or more system memory or video memory buffers by an output controller based upon allocation table information. Private data associated with specific elementary streams or packet adaptation fields are repacketized, and written to an output buffer location. In specific implementations, the hardware associated with the system is used to acquire the data stream without any knowledge of the specific protocol of the stream. In another embodiment, the hardware is used to implement a splicing of streams of data. A method and system for generating a transport stream for testing such a system is disclosed using a data record specifying a packetized elementary stream payload portion, a transport packet portion, and an adaptation field portion. A text data record is used to generate specific transport stream data to test demultiplexer systems.
1. A device comprising:
a framer comprising a first input configured to receive a data stream, a counter, and an output, the framer configured to:
identify a first location of the data stream based on a predefined data value;
monitor a plurality of subsequent locations of the data stream, each of the plurality being an integer multiple of a predetermined distance from the first data stream location;
adjust a value stored at the counter in response to determining a data value associated with a first of the plurality of subsequent locations is equal to the predefined data value; and
asserting a synchronization indicator in response to the counter reaching a specified value.
2. The device of claim 1 , further comprising a transport packet parser comprising an input coupled to the output of the framer, the transport packet parser configured to parse packets of the data stream in response to assertion of the synchronization indicator.
3. The device of claim 1 , wherein the framer further comprises a second input configured to receive a clock signal not based on the data stream, the framer configured to synchronize the data stream to the clock signal.
4. The device of claim 1 , wherein the framer further comprises:
a second input configured to receive a data clock for qualifying data associated with the data stream;
a storage medium configured to store a first representation of at least a portion of the data stream based upon a rising edge of the data clock and to store a second representation of at least a portion of the data stream based upon a falling edge of the data clock.
5. The device of claim 4 , wherein the framer is configured to store the first representation of the transport stream in response to a first mode of operation where the data is known to be qualified with a rising edge of the data clock and is configured to store the second representation of transport stream in response to a second mode of operation where the data is known to be qualified with a falling edge of the data clock.
6. The device of claim 1 , wherein:
the first input is configured to receive bits of data associated with a data word sequentially, beginning with a first bit;
the framer is configured to, when in a first mode of operation, receive the bits of data in a memory location with the first bit of data being a right most bit of the data word; and when in a second mode of operation, receive the bits of data in a memory location with the first bit of data being a left most bit of the data word.
7. The device of claim 1 , wherein the predefined data value is a hexadecimal value 47h.
8. The device of claim 1 , wherein the predetermined distance is 188 data words from the first data stream location.
9. The device of claim 1 , wherein the predetermined distance is an amount of time corresponding to 188 data words of the data stream.
10. The device of claim 1 , wherein the framer is configured to reset the counter to an initial value in response to determine a data value of a second of the plurality of subsequent location is not equal to the predefined data value.
11. The device of claim 10 , wherein the framer is configured to provide an interrupt in response to resetting the counter.
12. The device of claim 11 , wherein the framer is configured to provide the interrupt to indicate a lock on the predefined data has been lost.