[FFmpeg-trac] #7523(undetermined:new): VAAPI: Fail to Decode an H264 LP Multi-Slice Encoded Video
FFmpeg
trac at avcodec.org
Tue Oct 30 06:05:02 EET 2018
#7523: VAAPI: Fail to Decode an H264 LP Multi-Slice Encoded Video
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Reporter: uartie | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: git-master | undetermined
Keywords: vaapi | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Comment (by uartie):
This bug is not really about i965 backend driver. It was only mentioned
because it was unclear whether i965 should actually support it or if it
was because of a HW limitation. In case of HW limitation, the conclusion
would be that iHD is reporting it wrong. But, HW limitation or not, it
seemed odd that i965 has logic to support VAConfigAttribEncMaxSlices > 1
for LP but not support for VAConfigAttribEncSliceStructure.
Nonetheless, on i965, VAConfigAttribEncSliceStructure returns NOT
SUPPORTED, and ffmpeg doesn't get choked up about
VAConfigAttribEncMaxSlices > 1... and thus, refuses to proceed with
encoding. This seems like reasonable behavior for ffmpeg in that case,
right?
Finally (the original reason for this bug), since iHD
VAConfigAttribEncSliceStructure returns {{{EQUAL_ROWS | MAX_SLICE_SIZE}}},
ffmpeg proceeds to encode it with this setting since iHD said it's
supported. Unfortunately, iHD seems to have trouble encoding with this
setting.
So, I'm not sure what you would expect needs patched in ffmpeg.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/7523#comment:5>
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