[FFmpeg-trac] #6260(undetermined:new): NVENC H.264 encoding causes aliasing / stair-stepping colors, worse on interlaced than progressive

[FFmpeg]

#6260: NVENC H.264 encoding causes aliasing / stair-stepping colors, worse on
interlaced than progressive
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             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.

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Ticket URL: <https://trac.ffmpeg.org/ticket/6260#comment:2>
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