[mythtv-users] Playback On Intel

Jean-Yves Avenard jyavenard at gmail.com
Wed May 14 23:19:29 UTC 2014


On 12 May 2014 01:10, David Edwards <david at more.fool.me.uk> wrote:

> Unfortunately, I'm having all sorts of issues with playback quality.
> I've tried the High Quality, OpenGL High Quality and VAAPI Normal
> playback profiles, but they all have different problems.
>
> Decoding - Using High Quality and OpenGL High Quality I get problems
> in dark areas of the picture. A pale cloud of decoding artefacts
> slowly builds in shadow areas over a few seconds, then abruptly drops
> back to black. This repeats every 10 seconds or so. This does not
> happen when using VAAPI to decode.

I had this a while back with some nvidia drivers, and it's a known
issue with the OpenGL deinterlacer.

You should try the OpenGL Normal which uses the KERNEL 2X HW
deinterlacer. I actually had the best results with that deinterlacer,
and it takes far less CPU usage....

Another deinterlacer you could try is Yadif 2X HW; it's *very* GPU
intensive and didn't work with most video cards I tried, but that was
several years ago, may be worth trying again

>
> Judder - On SD MPEG-2 broadcasts there is a noticeable judder every
> second or so, particularly on horizontal pans. On HD H.264 broadcasts
> the judder is there, but less noticeable. I am in the UK, so these are
> 25fps interfaced. On ripped DVDs (deinterlaced with Handbrake where
> applicable) at 25fps and Blurays at 23.976 fps playback is generally
> smooth, but there is an occasional jump. This happens on all playback
> profiles. The refresh rate on the TV appears to be correctly switching
> based on the content.

sounds like sync-to-vblank isn't enabled...

> 3. Motion Adaptive deinterlacing was added to the Intel graphics stack
> in 2013Q2 (see https://01.org/linuxgraphics/downloads/2013/2013q2-intel-graphics-stack-release),
> but does not appear as an option in the playback profile settings
> 4. Refresh rate switching doesn't select non-integer rates even though
> they can be selected manually using "xrandr" from the command line.

yes, it's only in very recent version of XRANDR API that those are
supported, and myth only supports Xrandr 1.2 API (and the NV-CONTROL
extension which lets do the same thing)

problem not that long ago, many graphic drivers only support xrandr
1.2, API drivers for a start...

Ill look into Motion Adaptative, just got a new haswell laptop got me
something to test, and I too have been looking at a cheap, low-power
frontend solution. Those tiny intel fits the bill

In the mean time, try using plain ffmpeg, openGL and kernel 2X HW...

won't be as good as nvidia vdpau (nothing is), but it's close


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