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

[John Pilkington]

On 06/11/2019 16:07, Mark Kendall wrote:
> On Wed, 6 Nov 2019 at 15:55, John Pilkington <johnpilk222 at gmail.com> wrote:
>>
>> On 05/11/2019 18:24, John Pilkington wrote:
>>> On 05/11/2019 17:35, Mark Kendall wrote:
>>
>>>>
>>>> Peter has also just offered to resync to latest FFmpeg - so hopefully
>>>> we'll pick up sundry fixes like this.
>>>
>>> That's great - but I should clarify.  When I said that ffmpeg works, I
>>> was referring to mythffmpeg, not current ffmpeg master.
>>>>
>>>> Regards
>>>> Mark
>>
>> Amazingly d88a61dd rpms built and are running under Fedora 30.
>> Unfortunately that hasn't fixed the static frame blockiness, and now I'm
>> getting a brief shimmering effect after any jump :-(
> 
> You should update again for the new nv-codec-headers - not that it
> will necessarily fix anything! - but nvdec won't be enabled by the
> configure script without them.

but the startup check and the OSD say nvdec is in use.   ?

> I'm not seeing any improvements with the FFmpeg update. There is at
> least one regression with resolution changes - it now crashes...
> 
> Other than that there seems to be a lot of 'green frame' flashes at
> startup and the various issues I have with some vp9 and hevc clips
> have not been resolved. So not the greatest update!
> 
> I'll keep digging.
> 
>> The OSD reports 1920x1080 at 25fps, H.264 nvdec, 2xGLSL linearblend.  The
>> Firestick frontend and leanfront both play - apparently as before - with
>> the new backend.
> 
> Any reason you are using GLSL (i.e. shaders) rather than the nvdec
> deinterlacer? Just curious.

It's what I get when I select 'Medium quality deinterlacers' and 'Prefer 
OpenGL deinterlacers.'   No other reason.  The hardware drivers 
mentioned don't include nvdec - only VDPAU and VAAPI.

And 'Current Video Playback Profile' offers 'Normal', 'NVDEC Normal', 
and others which seemed less likely to match my hardware.  My 
understanding is that 'Normal' would give the myth-specific ffmpeg, aka 
mythffmpeg, in the versions before or after yesterday's re-sync.

That setting appears to carry over to the next page.

I really don't know which options 'ought' to be best...


> 
> With respect to your previous report re mythffmpeg - what command line
> are you using? I'm pretty sure mythffmpeg won't be using any form of
> direct rendering, so probably not a meaningful comparison with the
> myth code at present (and will also be why it is using more CPU).
> 
> regards
> Mark