View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000263 | JVT JM H.264/AVC reference software | encoder | public | 2011-05-20 18:07 | 2011-11-10 17:19 |
| Reporter | Diego F. de Souza | Assigned To | |||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | new | Resolution | open | ||
| OS | Linux | ||||
| Product Version | JM 17.2 | ||||
| Summary | 0000263: Losing the right references in B slices for block 16x16 | ||||
| Description | If the 'determine_prediction_list' function in the md_high.c (mode_decision.c) selects BI_PRED_L0 or BI_PRED_L1 as the best prediction, the right references for LIST_0 and LIST_1 are lost. Since these predictions (BI_PRED_L0 and BI_PRED_L1) use always the first reference of each list, the right references from the LIST_0 and LIST_1 predictions will be erased from the variable 'best'. The problem is because in the optimization loop, in the 'compute_mode_RD_cost' function in the md_high.c (mode_decision.c), all predictions (LIST_0, LIST_1, BI_PRED, BI_PRED_L0 and BI_PRED_L1) for 16x16 blocks are tested. The function which realizes these tests is in mode_decision.c file inside the 'compute_mode_RD_cost' function: terminate_16x16 = bslice_16x16_termination_control(p_Inp, p_Vid->b8x8info, &ctr16x16, mode, bslice); But this function will return the wrong references for the LIST_0, LIST_1 and BI_PRED predictions. | ||||
| Additional Information | I didn't test, but I believe the same mistake will happen on the JM 18.0. | ||||
| Tags | mode decision | ||||
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The code seems to need some reorganization and cleanup in term of mode decision to avoid contamination of information, as is happening in this case. Currently, it is somewhat of a lower priority unfortunately :(. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2011-05-20 18:07 | Diego F. de Souza | New Issue | |
| 2011-05-20 18:10 | Diego F. de Souza | Tag Attached: JM 17.2 | |
| 2011-05-20 18:10 | Diego F. de Souza | Tag Attached: mode decision | |
| 2011-06-13 00:49 | Alexis Michael Tourapis | Note Added: 0000488 | |
| 2011-11-10 17:19 | Karsten Suehring | Tag Detached: JM 17.2 |
