Methods and Systems for Transport Stream Time Base Correction
Provided are methods and systems for correcting decoder artifacts.
1 . A method for correcting decoder artifacts comprising:
receiving a stream previously stamped with an incoming Presentation Time Stamp (PTS)/Decode Time Stamp (DTS);
re-stamping the incoming PTS/DTS with a predetermined value;
applying a time base corrector; and
providing the stream to a set-top box for display.
2 . The method of claim 1 , wherein the re-stamped PTS and the re-stamped DTS are a predetermined value apart and a predetermined modulo.
3 . The method of claim 2 , wherein the predetermined value apart is a proper multiple of 3003.
4 . The method of claim 2 , wherein the predetermined value apart is a function of a Group of Pictures (GOP) structure.
5 . The method of claim 2 , wherein the predetermined modulo is 3003.
6 . The method of claim 1 , wherein applying the time base corrector comprises:
determining a difference between the incoming PTS/DTS and the re-stamped PTS/DTS; and
re-syncing the re-stamped PTS/DTS to the incoming PTS/DTS, respectively, when the difference exceeds a predetermined frame-time.
7 . The method of claim 6 , wherein the step of re-syncing is performed on a B frame.
8 . The method of claim 6 , wherein the predetermined frame-time difference for re-syncing is one frame.
9 . The method of claim 1 , wherein the time base corrector compensates for drift between the incoming PTS/DTS and the re-stamped PTS/DTS.
10 . The method of claim 1 , wherein the time base corrector shifts the incoming PTS/DTS by a multiple of a frame-time to cause a decoder to drop or repeat a frame.
11 . The method of claim 1 , wherein the time base corrector manipulates field repetition bits to repeat individual fields.
12 . The method of claim 11 , wherein manipulating field repetition bits to repeat individual fields comprises adding a field in consecutive B frames wherein the field compensates for PTS/DTS drift.
13 . The method of claim 1 , wherein providing the stream to a set-top box for display comprises modulating to a QAM and adding to an RF network.
14 . A system for correcting decoder artifacts comprising:
an encoder, configured for encoding a signal;
a video pump, coupled to the encoder, configured for receiving the encoded signal, wherein the video pump is further configured for
receiving a stream previously stamped with an incoming Presentation Time Stamp (PTS)/Decode Time Stamp (DTS),
re-stamping the incoming PTS/DTS with a predetermined value, and
applying a time base corrector, resulting in a processed encoded signal; and
a multiplexer, coupled to the video pump, configured to receive the processed encoded signal from the video pump.
15 . The system of claim 14 , further comprising a decoder configured to receive the processed encoded signal and decode the processed encoded signal.
16 . The system of claim 14 , further comprising a modulator, coupled to the multiplexer, configured for modulating the processed encoded signal to a modulated signal and for providing the modulated signal to an upconverter.
17 . The system of claim 16 , wherein the upconverter is configured for shifting a frequency content of the modulated signal to an available portion of RF spectrum.
18 . The system of claim 14 , wherein the re-stamped PTS and the re-stamped DTS are a predetermined value apart and a predetermined modulo.
19 . The system of claim 14 , wherein applying the time base corrector comprises:
determining a difference between the incoming PTS/DTS and the re-stamped PTS/DTS; and
re-syncing the re-stamped PTS/DTS to the incoming PTS/DTS, respectively, when the difference exceeds a predetermined frame-time.
20 . The system of claim 19 , wherein the predetermined frame-time difference for re-syncing is one frame.
21 . The system of claim 14 , wherein the time base corrector compensates for drift between the incoming PTS/DTS and the re-stamped PTS/DTS.
22 . The system of claim 14 , wherein the time base corrector shifts the incoming PTS/DTS by a multiple of a frame-time to cause a decoder to drop or repeat a frame.
23 . The system of claim 14 , wherein the time base corrector manipulates field repetition bits to repeat individual fields.
24 . The system of claim 23 , wherein manipulating field repetition bits to repeat individual fields comprises adding a field in consecutive B frames wherein the field compensates for PTS/DTS drift.
25 . A computer readable medium comprising computer executable instructions embodied thereon for correcting decoder artifacts comprising:
receiving a stream previously stamped with an incoming Presentation Time Stamp (PTS)/Decode Time Stamp (DTS);
re-stamping the incoming PTS/DTS with a predetermined value;
applying a time base corrector; and
providing the stream to a set-top box for display.