Builder ffmpegsos-solaris10-sparc Build #13888

Results:

Failed shell_2 shell_3 shell_4 shell_5

SourceStamp:

BuildSlave:

Reason:

The SingleBranchScheduler scheduler named 'schedule-ffmpegsos-solaris10-sparc' triggered this build

Steps and Logfiles:

1. git update ( 4 secs )
   1. stdio
2. shell 'gsed -i ...' ( 0 secs )
   1. stdio
3. shell_1 'gsed -i ...' ( 0 secs )
   1. stdio
4. shell_2 'gsed -i ...' failed ( 0 secs )
   1. stdio
5. shell_3 './configure --samples="../../../ffmpeg/fate-suite" ...' failed ( 9 secs )
   1. stdio
   2. config.log
6. shell_4 'gmake fate-rsync' failed ( 0 secs )
   1. stdio
7. shell_5 '../../../ffmpeg/fate.sh ../../../ffmpeg/fate_config_sos.sh' failed ( 0 secs )
   1. stdio
   2. configure.log
   3. compile.log
   4. test.log

Build Properties:

Forced Build Properties:

Responsible Users:

1. J. Brandt Buckley

   brandtohnoyoudont@runlevel1.com

Timing:

All Changes:

:

1. Change #278925

   Category	ffmpeg
   Changed by	J. Brandt Buckley <brandtohnoyoudont@runlevel1.com>
   Changed at	Sat 22 Aug 2026 19:48:39
   Repository	https://git.ffmpeg.org/ffmpeg.git
   Project	ffmpeg
   Branch	master
   Revision	ec8411e8548de7270f6e799cdc94f45b7a7a92d3

   Comments

   avcodec/vc1_block: don't drop the last macroblock when 1 bit remains
   The P- and B-picture per-MB guards added in 2a8785966c bail out of the loop
   to error concealment when get_bits_left() <= 1, but P- and B-picture MBs can
   legitimately cost exactly 1 bit in certain cases. This patch relaxes the guards
   to accommodate those cases.
   
   ## Explanation
   
   With the SKIPMB bitplane in Raw mode a skipped macroblock is a single SKIPMBBIT
   (SMPTE ST 421:2013, 7.1.3.7, p.109) and then "may only contain the HYBRIDPRED
   syntax element" (8.3.4.4, p.140), which is only read when predictors A and C
   are in-bounds and the predicted vector differs from A or C by more than 32
   quarter-pels (8.3.5.3.5, Figure 55, pp.149-150). That condition isn't met in a
   static region so such a MB costs just 1 bit. A direct+skipped B-picture MB
   likewise reads nothing beyond its raw flag (Table 30, p.86).
   
   In Simple/Main profile a picture is byte-aligned with no stop bit, so if a
   picture ends with a 1-bit skipped macroblock and its last coded bit lands on a
   byte boundary, the final MB is reached with exactly one bit left. The guard
   then conceals a valid macroblock, sets FF_DECODE_ERROR_CONCEALMENT_ACTIVE
   on an undamaged frame, and the damage propagates to every frame up to the next
   keyframe. (Advanced Profile BDUs end in a trailing '1' bit per Annex E.2/E.3
   p.437, so they always have at least two bit left and are therefore unaffected.)
   
   ## Reproducing
   
   Reproducible with an existing sample (prior to this patch):
   
       $ ffmpeg -i https://samples.ffmpeg.org/V-codecs/WMV9/wmv-samples/sample-wmv9-simple-SP@ML.wmv -map 0:v -f null - 2>&1 | grep -A1 concealing
       [wmv3 @ 0x122605430] concealing 75 DC, 75 AC, 75 MV errors in P frame
       [vist#0:0/wmv3 @ 0x122604080] [dec:wmv3 @ 0x122604df0] corrupt decoded frame
       [wmv3 @ 0x122605430] concealing 50 DC, 50 AC, 50 MV errors in P frame
       [vist#0:0/wmv3 @ 0x122604080] [dec:wmv3 @ 0x122604df0] corrupt decoded frame
       [wmv3 @ 0x122605430] concealing 100 DC, 100 AC, 100 MV errors in P frame
       [vist#0:0/wmv3 @ 0x122604080] [dec:wmv3 @ 0x122604df0] corrupt decoded frame
   
   ## References
   
   - SMPTE ST 421:2013 spec: https://pub.smpte.org/doc/st421/20131008-pub/
   
   Signed-off-by: J. Brandt Buckley <brandt@runlevel1.com>

   Changed files

   • libavcodec/vc1_block.c