View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000342 | JVT JM H.264/AVC reference software | encoder | public | 2014-06-06 11:04 | 2014-06-06 11:04 |
| Reporter | Pankaj | Assigned To | |||
| Priority | high | Severity | minor | Reproducibility | always |
| Status | new | Resolution | open | ||
| Product Version | JM 18.6 | ||||
| Summary | 0000342: CAVLC_LEVEL_LIMIT fixed for all profiles while it should be dependent on the PROFILE | ||||
| Description | In the current JM18.6 version CAVLC_LEVEL_LIMIT is fixed in defines.h files: This value should be limited only for some profiles mentioned in the standard and not limited for other profile. NOTE 1 – When entropy_coding_mode_flag is equal to 0 and qP is less than 10 and profile_idc is equal to 66, 77, or 88, the range of values that can be represented for the elements cij of c is not sufficient to represent the full range of values of the elements dcYij of dcY that could be necessary to form a close approximation of the content of any possible source picture by use of the Intra_16x16 macroblock type. NOTE 2 – Since the range limit imposed on the elements dcYij of dcY is imposed after the right shift in Equation 8-322, a larger range of values must be supported in the decoder prior to the right shift. NOTE 1 – When entropy_coding_mode_flag is equal to 0 and qP is less than 4 and profile_idc is equal to 66, 77, or 88, the range of values that can be represented for the elements cij of c in clause 8.5.11.1 may not be sufficient to represent the full range of values of the elements dcCij of dcC that could be necessary to form a close approximation of the content of any possible source picture. NOTE 2 – Since the range limit imposed on the elements dcCij of dcC is imposed after the right shift in Equation 8-326 or 8-329, a larger range of values must be supported in the decoder prior to the right shift. NOTE – The value of level_prefix is constrained to not exceed 15 in bitstreams conforming to the Baseline, Constrained Baseline, Main, and Extended profiles, as specified in clauses A.2.1, A.2.1.1, A.2.2, and A.2.3, respectively. In bitstreams conforming to other profiles, it has been reported that the value of level_prefix cannot exceed 11 + bitDepth with bitDepth being the variable BitDepthY for transform coefficient blocks related to the luma component and being the variable BitDepthCfor transform coefficient blocks related to a chroma component. | ||||
| Steps To Reproduce | PSNR values are getting very low while encoding 12bit images with low QP (QP=-21). With modifying this limit to 32768 the PSNR values are fine. | ||||
| Tags | No tags attached. | ||||
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2014-06-06 11:04 | Pankaj | New Issue |
