[mythtv] 2019-render: nvdec decoding artefacts in the editor

John Pilkington johnpilk222 at gmail.com
Thu Nov 7 16:34:16 UTC 2019


On 07/11/2019 13:08, Mark Kendall wrote:
> John
> 
> I've just pushed a fix for direct rendering - solves the green flashes
> I was seeing and sundry issues with out of order frames.

Yes, that (9eba7cc) seems to have fixed it for me too. The same BBC HD 
recording now plays smooth and crisp, with or without playback data 
displayed, in Fedora 30 with nVidia 440.31

And when the editor's skip to a keyframe gives a blocky picture, going 
back one frame gives clarity - and a burst of sound...

> 
> Running through my test clips and samples this gives flawless playback
> of VP9 up to 5k/30fps (probably 60fps as well but I don't have any
> samples for that), HEVC 4k/60fps and H264 4k/60fps. It tries hard with
> 8k vp9 but runs out of memory:)
> 
> For reference, this is a GT1030 with 420.26 drivers.
> 
> I did have to adjust my audio read ahead settings to get some of these
> files playing well - but that is a different issue.
> 
> The only remaining problem I see is the corruption around seeks. This
> appears to only occur with interlaced H624.
> 
> The same corruption is seen when using nvdec-dec as the decoder (i.e.
> copyback) and when using mythffplay - both of which are using
> 'vanilla' ffmpeg code with no direct rendering. A quick check with mpv
> (which is using direct rendering I think, on top of ffmpeg) produces
> the same issues.
> 
> So in short, this is almost certainly an FFmpeg and/or cuda issue but
> I can't find any bug reports relating to it.
> 
> Regards
> Mark
> 
> On Wed, 6 Nov 2019 at 23:19, John Pilkington <johnpilk222 at gmail.com> wrote:
>>
>> Now running 0822d3c with nVidia 430.40, and using High quality nvdec
>> deinterlacing on a BBC DVB-T2 HD recording.  Static pictures are still
>> often blocky and the 'new' shimmer after a skip is still there, but the
>> most obvious new feature looks like bad frame ordering when an OSD is
>> present; particularly the display of playback data.  Linear playback is
>> good.
>>
>> I see rpmfusion-testing now has nVidia 440.31  I'll try that.
>>
>> John



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