[FFmpeg-trac] #6260(undetermined:new): NVENC H.264 encoding causes aliasing / stair-stepping colors, worse on interlaced than progressive
FFmpeg
trac at avcodec.org
Mon May 22 18:06:20 EEST 2017
#6260: NVENC H.264 encoding causes aliasing / stair-stepping colors, worse on
interlaced than progressive
-------------------------------------+-------------------------------------
Reporter: alexpigment | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: unspecified | undetermined
Keywords: NVENC | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Comment (by dpavlekovic):
Hi, I'm experiencing the same problem, I originally thought it's the nvenc
issue so thanks for reporting. Today I found that this is related to
padding of input surface width/height to be divisible by 32 in
libavcodec/nvenc.c:nvenc_alloc_surface:
{{{
allocSurf.width = (avctx->width + 31) & ~31;
allocSurf.height = (avctx->height + 31) & ~31;
}}}
If I remove this adjustment then the output looks OK (1920x1080 source,
would be padded to 1920x1088). I've no experience though with NVEnc APIs,
so not sure if this is a right thing to do for all cases.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/6260#comment:2>
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