System for digital time shifting and method thereof
View Patent ↗A multiplexed packetized data stream carrying real-time multimedia programs is received at a first hardware demultiplexer. Based on a user input, a video and timing portion of a program associated with the multiplexed packetized data stream can be stored for subsequent display. One type of subsequent display is time shifted display, where the stored portion of the program is played back while new portions of the program are being stored. During time shifted play back, a second hardware demultiplexer can be used, so that one demultiplexer stores new data and maintains a current clock value while the other decodes and displays the stored data.
1. A method comprising:
receiving a multiplexed packetized data stream that carries real-time multimedia programs;
during a first time:
parsing packet identifiers of the packetized data stream to identify video data and timing data associated with a first multimedia program, the timing data identified based on timing information transmitted in packets of the multiplexed packetized data stream;
storing, in response to parsing during the first time, a first portion of the first multimedia program, the first portion comprising first video data associated with a first packet identifier and first timing data associated with a second packet identifier ; and
setting a system time indicator to a stored system time value, wherein the stored system time value is based on a portion of the timing data of the first portion of the packetized data stream;
during a second time:
incrementing the system time indicator;
retrieving the first video data of the first portion of the packetized data stream for video decoding; and
parsing packet identifiers of the packetized data stream to identify video data and timing data associated with the first multimedia program;
storing, in response to parsing during the second time, a second portion of the packetized data stream, the second portion comprising second video data associated with the first multimedia program and second timing data of the first multimedia program.
2. The method of claim 1 , wherein storing includes providing the first video data to a first ring buffer associated with the first packet identifier.
3. The method of claim 2 , wherein storing further includes providing the first video data from the first ring buffer to a hard disk.
4. The method of claim 3 , wherein parsing includes parsing a transport stream header of a packet at an integrated circuit device while the packet associated with the transport stream header is being received at the integrated circuit device.
5. The method of claim 4 , wherein storing further includes
controlling access of the first ring buffer at the integrated circuit.
6. The method of claim 5 , wherein storing includes providing the first timing
data to a second ring buffer associated with the second packet identifier.
7. The method of claim 6 , wherein storing further includes providing the first
timing data from the second ring buffer to the hard disk.
8. A system comprising:
a first input to receive a multiplexed packetized data stream that carries real-time multimedia programs;
a first transport stream demultiplexer having an input coupled to the first input to select packets of data having a predefined packet identifier and an output to provide the select packets of data;
a storage device having a data port coupled to the output of the first transport stream demultiplexer to receive the select packets, wherein the storage device is to store the select packets;
a first clock recovery module having an input coupled to the first input, and an output, wherein the first clock recovery module is to generate a clock at the output based upon received timing information transmitted in packets of the multiplexed packetized data stream, the first clock recovery module to set a system time indicator based on the received timing information and to increment the system time indicator to generate the clock; and
a decoder having a first input coupled to the output of the first clock recovery module to receive the clock, a second input coupled the data port of the storage device to receive the select packets, and an output to provide decoded real-time data.
9. The system of claim 8 , wherein the first transport stream demultiplexer is at an integrated circuit and comprises a first parser to parse a header of transport stream while the transport packet is being received.
10. The system of claim 9 , wherein the first transport stream further comprises a second parser to parse a header of packetized elementary stream (PES) stream.
11. The system of claim 10 , wherein the second parser is further to parse the header of packetized elementary stream (PES) stream within a transport stream packet payload.
12. The system of claim 8 wherein the first clock recovery module is at the integrated circuit.
13. The system of claim 8 wherein the first transport stream demultiplexer is at an integrated circuit and comprises a parser to parse a header of packetized elementary stream (PES) packet within a payload of a transport stream packet being received.