TV judder, occasional dropped frames (1 Viewer)

[Caesium]

Hi

I've been suffering with this for many months now and no amount of tinkering seems to make it go away.

Essentially, I have an almost perfect TV viewing experience, except for occasional dropped frames and single-frame judder (most obvious in panning) which really jar the experience.

I attach logs and a screenshot of Shift-1 stats in the hope someone can tell me what might be going on here.

I'm using LAV and MPAR, TV source is Argus. It happens on both live TV and recorded - but not in the same place every time on recorded, suggesting its not signal (and also no discontinuities in TSReader log suggests the same).

I've tried a Microsoft DTV-DTD decoders as well, also not using MPAR as I know its not recommended for live TV, and changing the hardware decode method in LAV (DXVA, QuickSync) and nothing has any effect.

This system (in system specs, just updated) should be plenty powerful enough to do this and hopefully from the stats screenshot you can see all the refresh rates match up too - any ideas?

Thanks

 

[Owlsroost]

If you are viewing UK Freeview HD, try installing (old) LAV filters 0.58.2 (get old versions from here - https://code.google.com/p/lavfilters/downloads/list )

My experience is that the later versions don't deal as well with the dynamic field/frame encoding scheme that Freeview HD uses, so you get more stutters/dropped/repeated frames when it switches between 25p and 50i depending on picture content.

The LAV video settings I use are in the attached picture (I use an nVidia GT430, so the Hardware Decoder settings might need to be different for your setup)

 

[CypherMK]

Maybe try default sound device instead of mpar

 

[Caesium]

I spent the afternoon playing with different LAV versions without much success, 0.55 and 0.58 both did the same thing. Eventually on a whim I turned off subtitles and the dropped frames stopped.

With subtitles off, LAV versions 0.55, 0.58, and 0.62 are all fine - several minutes of athletics footage (great for spotting this, long panning scenes make it obvious) and not one dropped frame or repeat.

I need to watch more to be sure but I can't quite decide if 0.62 is actually juddering occasionally despite not dropping frames, this might be what you're referring to about the newer versions not handling i/p changes properly.

 

[Owlsroost]

I run with DVB subtitles enabled but the default country set to somewhere very unlikely - this means they can still be used if required, but it doesn't seem to have an impact on performance when not required. Might be worth a try if you occasionally need subtitles.

I've noticed that playing AVCHD files (from camcorders/cameras) on my GT430 is fine, but the same on a Celeron 1007U (HD Graphics 2500) drops frames unless I disable subtitles in LAV splitter, even though they are not being displayed. (AVCHD has a subtitle stream with date/time etc. information).

 

[Caesium]

Unfortunately I am hard of hearing so I do usually need the subtitles

Is the performance impact with DVBSubs an open bug that might someday be fixed or is it not really fixable?

(edit: quick search of mediaportal jira issues didn't find anything)

 

[mm1352000]

A suggestion. Maybe a dumb thought and maybe you've tried it already, I don't know...

Your Intel GPU is not all that powerful, so I'm wondering if the combined load of everything - h.264 decoding, deinterlacing and subtitles - tips it over the edge.

Your i3 CPU is relatively powerful and should be good enough to decode 1080i H.264 without assistance from the GPU. I know it probably isn't something you'd consider ideal, but have you tried turning off DXVA (hardware accelerated video decoding)? I suggest this because it might shift enough load off the GPU to enable smooth playback...

 

[Caesium]

Interesting idea actually, and it was so obvious I hadn't tried no hardware decoding. Sadly it doesn't help. I ran a few numbers, as measured by GPU-Z and Task Manager..

Software; 35% GPU load, 15% CPU usage
DXVA native; 36% GPU load, 10% CPU usage
QuickSync; 49% GPU load, 14% CPU usage

Quite strange that DXVA doesn't add hardly any load to the GPU but removes it from the CPU, but from this I take that the load is so trivial to the GPU its unnoticeable. QuickSync is a bit higher because it was doing adaptive deinterlacing; turning that off dropped the GPU load to about 35% as well (didn't help with the drops though).


So I don't think its pushing against the limits of the hardware, I wonder if just rendering the subtitle on top is upsetting something else. Is it possible that the EVR has to wait just long enough for the subtitle to be ready to render that it misses a frame sometimes?

 

[mm1352000]

Sadly it doesn't help.

Hmmm, sorry - that's me out of ideas.

Is the performance impact with DVBSubs an open bug that might someday be fixed or is it not really fixable?
(edit: quick search of mediaportal jira issues didn't find anything)

I'm no subtitles guru. About all that I can tell you is that our DVB subtitles filter comes from MPC HC, so you're unlikely to find any MP JIRAs for that.
You might try looking here:
https://trac.mpc-hc.org/report

...though a warning: I could be sending you on a wild goose chase.

 

[Caesium]

I'm no subtitles guru. About all that I can tell you is that our DVB subtitles filter comes from MPC HC, so you're unlikely to find any MP JIRAs for that.
You might try looking here:
https://trac.mpc-hc.org/report

...though a warning: I could be sending you on a wild goose chase.

I suppose it might be a worthwhile test to see if MPC-HC exhibits the same behaviour, smooth without subtitles, droppy with subtitles.. I'll try it and report back