1080p MVK file playback - stutters, dropped frames.

[CitizenCain]

Hi all - sorry if this has been asked before (and I figure it must have been, but the search function wasn't helpful).

I am having a problem with playback on *some* 1080p mkv files (encoded with an h.264 codec). Basically, during high motion scenes, the video gets very stuttery, and VLC will start dropping upwards of 10 fps. Even during slower motion scenes, there's some noticeable stutter in things like waves, of peoples' lip movement, etc. It seems to happen primarily with large mvks (>10GB), and I can't seem to fix it. The videos in question have bitrates of ~20-30 Mb/s, as expected for 1080p video, and I've ensured that VLC is able to achieve those data rates from the media in question. I've tried disabling loop filters on the FFMpeg codecs, tried increasing buffer length up to 5000 ms (which helps somewhat, but ultimately seems to lose it effectiveness after the first ~10 minutes of playback) and am now stumped.

Same problem with all VLC versions since 0.9.8a, (though I haven't tried it on earlier versions) on multiple hardware platforms, my primary computer being a quad core Intel machine with 8 GB RAM, a 1 GB DDR RAM video card and running Vista Ultimate x64. VLC's been given affinity on all cores, but even when it's frame dropping like crazy, never spikes above about 25% (or full capacity of one processor core). The performance is no better or worse than it is on an AMD dual core with 4 GB RAM, running Xp Pro SP3, so I'm obviously fairly certain it's a program or preferences limitation rather than a hardware/OS one.

I've heard VLC doesn't handle mvks all that well at present, but I just plain like VLC better than anything else out there, so if there's a way to tweak and/or hack it to make VLC play these 1080p mkvs without stutter, I'm all ears.

Any ideas?

[CitizenCain]

Something of an update - I've managed to make the 1080p mkvs work flawlessly in WMP 11, by installing CoreAVC for video decoding and FFDShow for audio. The major problem with this solution (aside from the 14 day trial period on CoreAVC) is that it forces me to use WMP, which sucks horribly, and also I loathe it.

I also think I'm getting slightly better results with VLC when I force it to use only one processor core - it only seems to drop about 4% of my frames instead of 6%. Still not watchable, IMO, but maybe that's a clue to the root cause of the problem, or something like that.

Thanks.

[VLC_help]

DivX 7 contains free H.264 decoder in case you want to drop CoreAVC.

[CitizenCain]

I don't suppose I can force VLC to use either CoreAVC or DivX 7 to decode H.264 (or just troublesome files), can I? Everything I've read seems to say VLC does not use external codecs and can't be forced to.

I appreciate the heads up, but like I said, I'm really hoping I can find a solution which enables me to keep using VLC, rather than WMP or some other inferior video player.

[VLC_help]

VLC cannot use external decoders. So if loop filter trick doesn't help, then the only option is to wait better libavcodec H.264 decoder.

[CitizenCain]

OK, thanks.

And I'm pretty sure the answer here is "no" too, but there's no way to get VLC to use hardware acceleration through my video card, is there?

[Leovinus]

I just registered here to say that I too have the same problem, the slight difference is that it doesn't matter what size or resolution the MKV file is in. The files I tried watching were both encoded in H.264.

Info given by VLC:
Stream 2
Type: Subtitle
Codec: SSA
Language: English

Stream 0
Type: Video
Codec: avc1
Language: English
Resolution: 1280x536
Display resolution: 1280x536
Frame rate: 23.976215

Stream 3
Type: Audio
Codec: a52
Language: English
Channels: 3F2R/LFE
Sample rate: 48000Hz
Bitrate: 448kb/s

I am running a dual core AMD Athlon 6000+ on a motherboard with 2 gigs of ram and an inbuilt graphics card called AMD HD3300; All drivers are up to date and the OS is XP SP3. Testing shows that turning subtitles off entirely removes the stuttering. Is there a way for me to contribute more information? Looking at this information myself I don't really see how it is enough to seriously help in the matter.

[VLC_help]

but there's no way to get VLC to use hardware acceleration through my video card, is there?

Windows version of VLC doesn't include hardware decoding support.

Leovinus: libssa has some performance issues that might be fixed in next release, but I ain't sure if they make to 1.0.1 or do we have to wait for 1.1.0

[TimeWaster]

Testing shows that turning subtitles off entirely removes the stuttering.

yep, you're right, after deactivating the checkboxes "Enable OSD" and "Show media title on video" in the "Subtitles & OSD" tab in the preferences, all hd videos in all sizes play fine on my machine.

looks like one of those features is very buggy in the windows port.

[Rasheeke]

I've got a quad core, is there any way to make VLC to use all 4 so it stops stuttering? It's seems to be fine for the fastpaced scenes but for slower scenes when the image is held on a persons face during dialogue, it chops out and freezes while the audio still continues.

Upgrading to vlc 1.* helped a bunch but it's still buggy.

I keep seeing very old comments on the google about making VLC use multiple decoding threads, how can I make VLC do that? That advice is from old forum threads dating 2-3 years ago though, so is that changed, maybe automatic now?

[VLC_help]

I've got a quad core, is there any way to make VLC to use all 4 so it stops stuttering?

VLC can use the cores, but stable libavcodec can't (so 4 cores cannot decode same video at same time).

I keep seeing very old comments on the google about making VLC use multiple decoding threads, how can I make VLC do that? That advice is from old forum threads dating 2-3 years ago though, so is that changed, maybe automatic now?

What thread has this info?

[patch]

And I'm pretty sure the answer here is "no" too, but there's no way to get VLC to use hardware acceleration through my video card, is there?

I've got a quad core, is there any way to make VLC to use all 4 so it stops stuttering?

I believe the answer to both is currently no but both may change with later version of vlc

In the mean time you could try
Splash, free version available discussed here
Or Media Player Classic Home Cinema Official page, Hardware acceleration, checklist for problems, SVN builds which supports external decoders including the multiprocessor ffdshow SVN builds. Main discussion is here