1. Apparatus for a receive circuit that receives a receive sequence having noise, said apparatus comprising:
a noise estimator adapted to receive the receive sequence and to determine an estimated value of the noise present in the receive sequence, said estimated value determined by subtracting a remodulated training sequence from the received sequence;
a noise autocorrelation estimator adapted to receive said estimated value, calculate a first autocorrelation function based upon said estimated value, and determine an absolute value of said first autocorrelation function as an autocorrelation estimate; and
a filter characteristic selector adapted to receive said autocorrelation estimate from said autocorrelation estimator, to compare said autocorrelation estimate to a threshold autocorrelation value, and to select a filter characteristic for a filter in response to the comparison, wherein said filter characteristic selector is adapted to select a unitary-filter characteristic in which whitening noise is not added upon a determination that said autocorrelation estimate is below said threshold autocorrelation value and adapted to select one non-unitary filter characteristic in which whitening noise is added upon a determination that said autocorrelation estimate is above said threshold autocorrelation value.
2. The apparatus of claim 1 wherein said noise estimator is further configured to determine a channel impulse response of a channel upon which the receive sequence is communicated, and wherein estimation of the noise component utilizes the channel impulse response.
3. The apparatus of claim 1 wherein said filter is adapted to receive a representation of the receive sequence and an indication of the filter characteristic selected by said filter characteristic selector, said filter configured to filter the receive sequence in conformity with the filter characteristic selected by said filter characteristic selector.
4. The apparatus of claim 3 wherein said filter comprises a linear prediction error filter.
5. The apparatus of claim 4 wherein the linear prediction error filter comprises a multi-tap filter.
6. The apparatus of claim 4 wherein the linear prediction error filter forming said filter is defined by filter coefficients and wherein the filter characteristic selected by said filter characteristic selector is determinative of the filter coefficients.
7. The apparatus of claim 4 wherein said filter comprises an INWF, adaptive Input Noise Whitening Filter.
8. A method for operating upon a receive sequence received at a receiving station, the received sequence having noise, said method comprising the operations of:
estimating an estimated value of noise present in the receive sequence by subtracting a remodulated training sequence from the received signal;
receiving the estimated value of the noise present in the receive sequence;
calculating a first autocorrelation function based upon the estimated value;
determining an absolute value of the first autocorrelation function as the autocorrelation estimate;
comparing the autocorrelation estimate to a threshold autocorrelation value; and,
selecting a filter characteristic for a filter in response to the comparison, a unitary-filter characteristic in which whitening noise is not added being selected upon a determination that the autocorrelation estimate is below the threshold value and a non-unitary filter characteristic in which whitening noise is added being selected upon a determination that the auto correlation estimate is above the threshold value.
9. Apparatus for a receive circuit that receives a receive sequence x(n) having noise, said apparatus comprising:
a noise sample estimator configured to receive a timing offset, to receive a channel impulse response \u201cCIR\u201d of a channel upon which the receive sequence is communicated, and to receive a known training sequence \u201cTS\u201d, from which CIR and TS a remodulated training sequence is generated, the remodulated training sequence being subtracted from the receive sequence to determine an estimated value of the noise present in the receive sequence;
a noise autocorrelation estimator adapted to: receive the estimated value of the noise present in the receive sequence, calculate a first autocorrelation function based upon the estimated value, and determine an absolute value of the first autocorrelation function as the autocorrelation estimate;
a filter-characteristic selector adapted to: receive from the estimator the autocorrelation estimate, to compare the autocorrelation estimate to a threshold autocorrelation value, and to select a filter characteristic in response to the comparison, wherein the filter-characteristic selector is adapted to select a unitary-filter characteristic from which whitening noise is not added upon a determination that the autocorrelation estimate is below the threshold value and adapted to select one non-unitary filter characteristic from which whitening noise is added upon a determination that the autocorrelation estimate is above the threshold value; and
a linear prediction error filter adapted to receive a representation of the receive sequence and an indication of the filter characteristic selected by said filter-characteristic selector, said filter configured to filter the receive sequence in conformity with the filter characteristic selected by said filter characteristic selector.
10. A method for operating upon a receive sequence received at a receiving station, the received sequence having noise, said method comprising the operations of:
estimating an estimated value of noise present in the receive sequence utilizing a known training sequence comprising the steps of:
receiving a timing offset,
receiving a channel impulse response \u201cCIR\u201d of a channel upon which the receive sequence is communicated,
receiving a known training sequence \u201cTS\u201d,
generating a remodulated training sequence from the CIR and TS, and
subtracting the remodulated training sequence from the receive sequence to determine an estimated value of the noise present in the receive sequence;
receiving the estimated value of the noise present in the receive sequence;
calculating a first autocorrelation function based upon the estimated value;
determining an absolute value of the first autocorrelation function as the autocorrelation estimate;
comparing the autocorrelation estimate to a threshold autocorrelation value; and,
selecting a filter characteristic in response to the comparison, a unitary-filter characteristic being selected from which whitening noise is not added upon a determination that the autocorrelation estimate is below the threshold value and a non-unitary filter characteristic from which whitening noise is added being selected upon a determination that the auto correlation estimate is above the threshold value; and
receiving a representation of the receive sequence and an indication of the selected filter characteristic and filtering the receive sequence in conformity with the selected filter characteristic by way of a linear prediction error filter.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of processing video data, the method comprising:
receiving in a video bitstream an access unit having a first random access point (RAP) picture;
receiving in the video bitstream, after the access unit in the bitstream, a subsequent access unit having a second RAP picture; and
in a case that one or more random access skipped leading (RASL) pictures for the subsequent access unit are not present in the received video bitstream, shifting a picture buffer removal time for a picture buffer earlier based on a picture buffer removal delay offset.
2. The method of claim 1, wherein the picture buffer comprises a coded picture buffer (CPB) and the picture buffer removal delay offset comprises a CPB removal delay offset.
3. The method of claim 2, wherein the CPB removal delay offset is signaled for the RAP picture of the subsequent access unit.
4. The method of claim 1, wherein the picture buffer comprises a decoded picture buffer (DPB) and the picture buffer removal delay offset comprises a DPB removal delay offset.
5. The method of claim 1, further comprising receiving the picture buffer removal delay offset for the access unit.
6. The method of claim 1, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
7. The method of claim 1, wherein the RAP picture includes one of a clean random access (CRA) picture and a broken link access (BLA) picture.
8. A method of processing video data, the method comprising:
receiving an access unit after an earlier initialization of a hypothetical reference decoder (HRD), the access unit having a random access point (RAP) picture, wherein associated access units containing random access skipped leading (RASL) pictures are not received; and
re-initializing the HRD, including re-initializing a picture buffer removal time and a picture buffer removal delay offset, in response to receiving the access unit and not receiving the associated access units containing RASL pictures.
9. The method of claim 8, wherein the picture buffer removal time comprises a coded picture buffer (CPB) removal time and the picture buffer removal delay offset comprises a CPB removal delay offset.
10. The method of claim 9, wherein the CPB removal delay offset is signaled for the RAP picture of a subsequent access unit.
11. The method of claim 8, wherein the picture buffer removal time comprises a decoded picture buffer (DPB) removal time and the picture buffer removal delay offset comprises a DPB removal delay offset.
12. The method of claim 8, wherein the RAP picture is a clean random access (CRA) picture.
13. The method of claim 8, wherein the RAP picture is a broken link access (BLA) picture that may have associated RASL pictures or random access skipped decodable (RADL) pictures.
14. The method of claim 8, wherein the RAP picture is one of a broken link access (BLA) picture that does not have associated RASL pictures, but may have RADL pictures, and a BLA picture that does not have associated leading pictures.
15. The method of claim 8, further comprising processing the received access unit as the first access unit in a bitstream.
16. The method of claim 8, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
17. A device for processing video data comprising:
a processor configured to:
receive in a video bitstream an access unit having a first random access point (RAP) picture;
receive in the video bitstream, after the access unit in the bitstream, a subsequent access unit having a second RAP picture; and
in a case that one or more random access skipped leading (RASL) pictures for the subsequent access unit are not present in the received video bitstream, shift a picture buffer removal time for a picture buffer earlier based on a picture buffer removal delay offset.
18. The device of claim 17, wherein the picture buffer comprises a coded picture buffer (CPB) and the picture buffer removal delay offset comprises a CPB removal delay offset.
19. The device of claim 18, wherein the CPB removal delay offset is signaled for the RAP picture of the subsequent access unit.
20. The device of claim 17, wherein the picture buffer comprises a decoded picture buffer (DPB) and the picture buffer removal delay offset comprises a DPB removal delay offset.
21. The device of claim 17, wherein the processor is further configured to receive the picture buffer removal delay offset for the access unit.
22. The device of claim 17, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
23. The device of claim 17, wherein the RAP picture includes one of a clean random access (CRA) picture and a broken link access (BLA) picture.
24. A device for processing video data comprising:
a processor configured to:
receiving an access unit after an earlier initialization of a hypothetical reference decoder (HRD), the access unit having a random access point (RAP) picture, wherein associated access units containing random access skipped leading (RASL) pictures are not received; and
re-initializing the HRD, including re-initializing a picture buffer removal time and a picture buffer removal delay offset, in response to receiving the access unit and not receiving the associated access units containing RASL pictures.
25. The device of claim 24, wherein the picture buffer removal time comprises a coded picture buffer (CPB) removal time and the picture buffer removal delay offset comprises a CPB removal delay offset.
26. The device of claim 25, wherein the CPB removal delay offset is signaled for the RAP picture of a subsequent access unit.
27. The device of claim 24, wherein the picture buffer removal time comprises a decoded picture buffer (DPB) removal time and the picture buffer removal delay offset comprises a DPB removal delay offset.
28. The device of claim 24, wherein the RAP picture is a clean random access (CRA) picture.
29. The device of claim 24, wherein the RAP picture is a broken link access (BLA) picture that may have associated RASL pictures or random access skipped decodable (RADL) pictures.
30. The device of claim 24, wherein the RAP picture is one of a broken link access (BLA) picture that does not have associated RASL pictures, but may have RADL pictures, and a BLA picture that does not have associated leading pictures.
31. The device of claim 24, wherein the processor is further configured to designate the received access unit as the first access unit in a bitstream.
32. The device of claim 24, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
33. A device for processing video data comprising:
means for receiving in a video bitstream an access unit having a first random access point (RAP) picture;
means for receiving in the video bitstream, after the access unit in the bitstream, a subsequent access unit having a second RAP picture; and
means for shifting a picture buffer removal time for a picture buffer earlier based on a picture buffer removal delay offset in a case that one or more random access skipped leading (RASL) pictures for the subsequent access unit are not present in the received video bitstream.
34. The device of claim 33, wherein the picture buffer comprises a coded picture buffer (CPB) and the picture buffer removal delay offset comprises a CPB removal delay offset.
35. The device of claim 33, wherein the picture buffer comprises a decoded picture buffer (DPB) and the picture buffer removal delay offset comprises a DPB removal delay offset.
36. The device of claim 33, further comprising means for receiving the picture buffer removal delay offset for the access unit.
37. The device of claim 33, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
38. The device of claim 33, wherein the RAP picture includes one of a clean random access (CRA) picture and a broken link access (BLA) picture.
39. A device for processing video data comprising:
means for receiving an access unit after an earlier initialization of the hypothetical reference decoder (HRD), the access unit having a random access point (RAP) picture, wherein associated access units containing random access skipped leading (RASL) pictures are not received; and
means for re-initializing the HRD, including re-initializing a picture buffer removal time and a picture buffer removal delay offset, in response to receiving the access unit and not receiving the associated access units containing RASL pictures.
40. The device of claim 39, wherein the picture buffer removal time comprises a coded picture buffer (CPB) removal time and the picture buffer removal delay offset comprises a CPB removal delay offset.
41. The device of claim 39, wherein the picture buffer removal time comprises a decoded picture buffer (DPB) removal time and the picture buffer removal delay offset comprises a DPB removal delay offset.
42. The device of claim 39, wherein the RAP picture is a clean random access (CRA) picture.
43. The device of claim 39, wherein the RAP picture is a broken link access (BLA) picture that may have associated RASL pictures or random access skipped decodable (RADL) pictures.
44. The device of claim 39, wherein the RAP picture is one of a broken link access (BLA) picture that does not have associated RASL pictures, but may have RADL pictures, and a BLA picture that does not have associated leading pictures.
45. The device of claim 39, further comprising means for processing the received access unit as the first access unit in a bitstream.
46. The device of claim 39, further comprising receiving the picture buffer removal delay offset in a buffering period SEI message.
47. A non-transitory computer readable storage medium storing instructions that upon execution by one or more processors cause the one or more processors to:
receive in a bitstream an access unit having a first random access point (RAP) picture;
receive in the video bitstream, after the access unit in the bitstream, a subsequent access unit having a second RAP picture; and
shift a picture buffer removal time for a picture buffer earlier based on a picture buffer removal delay offset in a case that one or more random access skipped leading (RASL) pictures for the subsequent access unit are not present in the received video bitstream.
48. A non-transitory computer readable storage medium storing instructions that upon execution by one or more processors cause the one or more processors to:
receive an access unit having a random access point (RAP) picture, wherein associated access units containing random access skipped leading (RASL) pictures are not received; and
re-initialize the HRD, including re-initializing a picture buffer removal time and a picture buffer removal delay offset, in response to receiving the access unit and not receiving the associated access units containing RASL pictures.
49. A method of processing video data comprising:
signaling a CPB removal delay offset for each CRA or BLA access unit;
shifting the CBP removal time of each of the access units following the CRA or BLA access unit in decoding order is earlier by the CPB removal delay offset for each CRA or BLA access unit for which the associated RASL pictures are not present; and
regardless of whether the HRD initializes at the CRA or BLA access unit.