View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000119 | JVT JM H.264/AVC reference software | encoder | public | 2008-07-27 08:12 | 2008-08-05 21:24 |
| Reporter | behdad analui | Assigned To | Alexis Michael Tourapis | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | resolved | Resolution | fixed | ||
| Product Version | JM-14.1 | ||||
| Fixed in Version | JM 14.2 | ||||
| Summary | 0000119: Wrong codeword and codelength are generated for levels greater than 2063, when encoding level in CAVLC | ||||
| Description | While encoding a level, for both "suffixLength"=0 and "suffixLength">0, the generated codeword is not valid in some cases. Function "writeSyntaxElement_Level_VLC1" and "writeSyntaxElement_Level_VLCN" which are implemented in file "vlc.c", for levels greater than 2063, produce wrong codewords. The problem is that the original source code (JM14.1) does not subtract the "offset" value from the "levabsm16", when setting the "iCodeword" in "writeSyntaxElement_Level_VLC1" function. So it does not take full advantage from the suffix bits, therefore overflow occurs and destroy the codeword. In addition, while loop condition of both functions are wrong according to the H.264 Standard 2005, and 4096 should be changed to 2048. In this way both functions works properly for all kind of levels. We can provide more information and mathematical relations according to the standard to prove that our modification is correct upon your request. | ||||
| Additional Information | A *.rar file has been uploaded, which contains 3 files. "Bug_Report_Examples.xls" contains some examples that wrong codeword is produced using original code, and correct codewords are produced using our proposed code. using examples of this file, you can reproduce the problem. "Original Code.txt" contains the original code functions that should be modified. "ourCode.txt" contains the modified functions that works properly. it seems that the problem only occurs when inputs are larger than 8 bits.( 10 bits for example) | ||||
| Tags | No tags attached. | ||||
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2008-07-27 08:12 | behdad analui | New Issue | |
| 2008-07-27 08:12 | behdad analui | File Added: Bug_report.rar | |
| 2008-08-05 21:24 | Alexis Michael Tourapis | Note Added: 0000214 | |
| 2008-08-05 21:24 | Alexis Michael Tourapis | Status | new => resolved |
| 2008-08-05 21:24 | Alexis Michael Tourapis | Fixed in Version | => JM 14.1-dev |
| 2008-08-05 21:24 | Alexis Michael Tourapis | Resolution | open => fixed |
| 2008-08-05 21:24 | Alexis Michael Tourapis | Assigned To | => Alexis Michael Tourapis |
