PCR jitter reduction in a VSB and/or EVSB multiplexer system
Program clock references in first and second MPEG data streams are re-stamped in accordance with delays introduced into the first and second MPEG data streams. Accordingly, the program clock references in the first MPEG data stream are re-stamped according to a variable delay in the first MPEG data stream, and the program clock references in the second MPEG data stream are re-stamped according to a variable delay in the second MPEG data stream. The re-stamped program clock references in the second MPEG data stream are corrected according to a fixed delay in the second MPEG data stream. The first and second MPEG data streams are multiplexed, and the multiplexed first and second MPEG data streams are transmitted and received.
1. A method of receiving a signal having re-stamped program clock references in an MPEG data stream, wherein the re-stamped program clock references in the MPEG data stream comprise corresponding original program clock references re-stamped according to an amount of a delay caused by a buffer, the method comprising:
recovering the MPEG data stream from the signal;
reading the re-stamped program clock references in the MPEG data stream; and,
processing the MPEG data stream in accordance with the re-stamped program clock references,
wherein the original program clock references are designated original_PCR n , wherein the re-stamped program clock references are designated restamped_PCR n , wherein n comprises an integer, wherein a delayed_PCR n comprises the sum of the original_PCR n and the delay, wherein, for n=1, the restamped_PCR n comprises the original_PCR n , and wherein, for n>1, the restamped_PCR n comprises restamped_PCR n−1 +(delayed_PCR n −delayed_PCR n−1 ).
2. A method of receiving a signal having re-stamped program clock references in an MPEG data stream, wherein the re-stamped program clock references in the MPEG data stream comprise corresponding original program clock references re-stamped according to an amount of a delay caused by a buffer, the method comprising:
recovering the MPEG data stream from the signal;
reading the re-stamped program clock references in the MPEG data stream; and,
processing the MPEG data stream in accordance with the re-stamped program clock references,
wherein the recovered MPEG data stream comprises first and second MPEG data streams, wherein the recovering of the MPEG data stream from the signal comprises recovering the first and second MPEG data streams from the signal, wherein the reading of the re-stamped program clock references in the MPEG data stream comprises reading re-stamped program clock references in the first and second MPEG data streams, and wherein the processing of the MPEG data stream in accordance with the re-stamped program clock references comprises processing of the first and second MPEG data streams in accordance with the re-stamped program clock references,
wherein the original program clock references are designated original_PCR n , wherein the re-stamped program clock references are designated restamped_PCR n , wherein n comprises an integer, wherein a delayed_PCR n comprises the sum of the original_PCR n and the delay, wherein, for n=1, the restamped_PCR n comprises the original_PCR n , and wherein, for n>1, the restamped_PCR n comprises restamped_PCR n−1 +(delayed_PCR n −delayed_PCR n−1 ).
3. The method of claim 2 wherein the recovering of the MPEG data stream from the signal comprises:
tuning to the signal;
de-modulating the tuned signal; and,
de-multiplexing the de-modulated signal to recover the first and second MPEG data streams.
4. A method of receiving first and second MPEG data streams, wherein the first MPEG data stream includes first re-stamped program clock references, wherein the first re-stamped program clock references in the first MPEG data stream comprise corresponding first original program clock references re-stamped in accordance with a first variable delay, wherein the second MPEG data stream includes corrected program clock references, wherein the corrected program clock references in second MPEG data stream comprise corresponding second re-stamped program clock references corrected in accordance with a fixed delay, wherein the second re-stamped program clock references comprise corresponding second original program clock references re-stamped in accordance with a second variable delay, the method comprising:
recovering the first and second MPEG data streams from the signal;
reading the first re-stamped program clock references in the first MPEG data stream;
processing the first MPEG data stream in accordance with the first re-stamped program clock references;
reading the corrected program clock references in the second MPEG data stream; and,
processing the second MPEG data stream in accordance with the corrected program clock references.
5. The method of claim 4 wherein the first original program clock references are designated first_original_PCR n , wherein the first re-stamped program clock references are designated first_restamped_PCR n , wherein n comprises an integer, wherein a first_delayed_PCR n comprises the sum of the first_original_PCR n and the first variable delay, wherein, for n=1, the first_restamped_PCR n comprises the first_original_PCR n , wherein, for n>1, the first_restamped_PCR n comprises first_restamped_PCR n+1 +(first_delayed_PCR n −first_delayed_PCR n−1 ).
6. The method of claim 5 wherein the second original program clock references are designated second_original_PCR n , wherein the second re-stamped program clock references are designated second_restamped_PCR n , wherein a second_delayed_PCR n comprises the sum of the second_original_PCR n and the second variable delay, wherein, for n=1, the second_restamped_PCR n comprises the second_original_PCR n , wherein, for n>1, the second_restamped_PCR n comprises second_restamped_PCR n−1 +(second_delayed_PCR n −second_delayed_PCR n−1 ), wherein the corrected program clock references are designated new_PCR n , wherein, for n=1, the new_PCR n comprises the second_restamped_PCR n , and wherein, for n>1, the new_PCR n comprises new_PCR n−1 +(second_restamped_PCR n+1 −second_restamped_PCR n ).
7. The method of claim 6 wherein the recovering of the first and second MPEG data streams from the signal comprises:
tuning to the signal;
de-modulating the tuned signal; and,
de-multiplexing the de-modulated signal to recover the first and second MPEG data streams.
8. The method of claim 7 wherein the first MPEG data stream comprises a VSB MPEG data stream, and wherein the second MPEG data stream comprises an EVSB MPEG data stream.
9. The method of claim 8 wherein the reading of the corrected program clock references in the second MPEG data stream comprises:
decoding the second MPEG data stream as the EVSB MPEG data stream; and,
reading the corrected program clock references in the decoded second MPEG data stream.
10. The method of claim 4 wherein the first re-stamped program clock references in the first MPEG data stream comprise corresponding first original program clock references re-stamped according to a first measured variable delay.
11. The method of claim 4 wherein the first re-stamped program clock references in the first MPEG data stream comprise corresponding first original program clock references re-stamped according to a first measured variable buffering caused delay.