Methods and apparatus for transcoding progressive I-slice refreshed MPEG data streams to enable trick play mode features on a television appliance

• US 20010026677A1
• Filed: 05/02/2001
• Published: 10/04/2001
• Est. Priority Date: 11/20/1998
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Du Breuil, Tom, Luthra, Ajay, Chen, Kun-Pei, Narasimhan, Mandayam, Mehr, Joseph
• Granted Patent: US 7,046,910 B2
• Time in Patent Office: Days
• US Class Current: 386/68
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream

Abstract

Progressive I-slice refreshed MPEG data streams are transcoded to I-frame based MPEG data streams to enable trick play modes on a television appliance, such as pause, scan forward, scan backward, jump, or still frame displays for use, e.g., in film indexing (chapters). A progressive I-slice refreshed MPEG data stream 10 having I-slices distributed over multiple P-frames is received by a television appliance 300. The P-frames are decoded at decoder 22 to recover the I-slices which make up a complete I-frame. The recovered I-slices are assembled (e.g., by processor 230) into a complete I-frame. The complete I-frame is encoded at an encoder 250. A selected P-frame in the MPEG data stream is replaced with the encoded I-frame (e.g., via multiplexer 255) to provide an encoded I-frame based data stream 200. The I-frame based data stream is stored (e.g., in memory 240) for trick play mode use.

Claims

1. A method for transcoding progressive I-slice refreshed MPEG data streams to enable trick play mode features on a television appliance, comprising the steps of:

receiving at the appliance a progressive I-slice refreshed MPEG data stream having I-slices distributed over multiple P-frames;

decoding the P-frames to recover the I-slices which make up a complete I-frame;

assembling the recovered I-slices into a complete I-frame;

encoding the complete I-frame;

replacing a selected P-frame in the MPEG data stream with the encoded I-frame to provide an I-frame based MPEG data stream; and

storing the I-frame based MPEG data stream for trick play mode use.

2. A method in accordance with

claim 1

, comprising:

storing each recovered I-slice in memory as each P-frame is decoded until all I-slices required to assemble a complete I-frame are recovered from the decoded P-frames.

3. A method in accordance with

claim 1

, comprising:

storing the received progressive I-slice refreshed MPEG data stream.

4. A method in accordance with

claim 1

, wherein the I-frame based data stream is stored on one of a personal versatile recorder (PVR), a digital video recorder, a set-top terminal, a digital television, or a personal computer.

5. A method in accordance with

claim 1

, wherein:

a number N of P-frames are decoded to recover the I-slices which make up the complete I-frame; and

the encoded I-frame is inserted into the MPEG data stream in place of Nth P-frame.

6. A method in accordance with

claim 5

, wherein:

one or more additional P frames are decoded to recover additional I-slices;

the additional I-slices allow assembly of additional complete I-frames; and

said additional complete I-frames are insertable after encoding into the MPEG data stream at a programmable rate.

7. A method in accordance with

claim 1

, comprising:

inserting additional I-frames into the I-frame based data stream at a programmable interval.

8. A method in accordance with

claim 1

, wherein the encoded I-frame replaces the selected Pframe at least once per refresh cycle.

9. A method in accordance with

claim 1

, wherein the trick play mode features comprise at least one of pause, scan forward, scan backward, jump, and still frame display.

10. A method in accordance with

claim 1

, comprising:

determining whether the data stream is an I-frame based MPEG data stream or a progressive I-slice refreshed MPEG data stream, such that, in the event that the data stream is an I-frame based MPEG data stream, the data stream is stored for trick play mode use without further processing.

11. A method in accordance with

claim 1

, comprising:

determining whether the data stream is an I-frame based MPEG data stream or a progressive I-slice refreshed MPEG data stream; and

in the event that the data stream is an I-frame based MPEG data stream, inserting additional I-frames into the data stream prior to storing the data stream for trick play mode use.

12. A method in accordance with

claim 1

, wherein the television appliance is one of a personal versatile recorder (PVR), a digital video recording device, a set-top terminal, a digital television, or a personal computer.

13. A method in accordance with

claim 1

, wherein:

the P-frames are re-encoded using motion estimation techniques in order to remove the I-slices.

14. A television appliance capable of transcoding progressive I-slice refreshed MPEG data streams to enable trick play mode features, comprising:

a receiver for receiving a progressive I-slice refreshed MPEG data stream having I-slices distributed over multiple P-frames;

a decoder for decoding the P-frames to recover the I-slices which make up a complete I-frame;

a processor associated with the decoder for assembling the recovered I-slices into a complete I-frame;

an encoder for encoding the complete I-frame; and

a multiplexer for replacing a selected P-frame in the MPEG data stream with the encoded I-frame to provide an encoded I-frame based MPEG stream;

wherein;

said I-frame based data MPEG stream is stored on a storage device for trick play mode use.

15. An appliance in accordance with

claim 14

, comprising:

memory for storing each recovered I-slice as each P-frame is decoded until all I-slices required to assemble a complete I-frame are recovered from the decoded P-frames.

16. An appliance in accordance with

claim 14

, comprising:

memory for storing the received progressive I-slice refreshed MPEG data stream.

17. An appliance in accordance with

claim 14

, comprising said storage device.

18. An appliance in accordance with

claim 14

, wherein said storage device is external to said television appliance.

19. An appliance in accordance with

claim 14

, wherein:

a number N of P-frames are decoded to recover the complete I-frame; and

the encoded I-frame replaces the Nth P-frame.

20. An appliance in accordance with

claim 19

, wherein:

one or more additional P frames are decoded to recover additional I-slices;

the additional I-slices allow assembly of additional complete I-frames; and

said additional complete I-frames are insertable after encoding into the MPEG data stream at a programmable rate.

21. An appliance in accordance with

claim 14

, wherein:

additional I-frames are inserted into the I-frame based data stream at a programmable interval.

22. An appliance in accordance with

claim 14

, wherein the encoded I-frame replaces the selected P-frame at least once per refresh cycle.

23. An appliance in accordance with

claim 14

, wherein the trick play mode features comprise at least one of pause, scan forward, scan backward, jump, and still frame display.

24. An appliance in accordance with

claim 14

, wherein the receiver determines whether the data stream is an I-frame based MPEG data stream or a progressive I-slice refreshed MPEG data stream, such that, in the event that the data stream is an I-frame based MPEG data stream, the data stream is stored in the storage device for trick play mode use without further processing.

25. An appliance in accordance with

claim 14

, wherein:

the receiver determines whether the data stream is an I-frame based MPEG data stream or a progressive I-slice refreshed MPEG data stream; and

in the event that the data stream is an I-frame based MPEG data stream, the processor inserts additional I-frames into the data stream prior to storage of the data stream for trick play mode use.

26. An appliance in accordance with

claim 14

, wherein the appliance is one of a personal versatile recorder (PVR), a digital video recording device, a set-top terminal, a digital television, or a personal computer.

27. An appliance in accordance with

claim 14

, wherein:

the encoder re-encodes the P-frames using motion estimation techniques in order to remove the I-slices.