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Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 04 Jul 2007 01:47
by anmingleung
I have an incoming H.264 stream that my device is unable to decode quick enough resulting in 100% CPU utilization and about 20% of the frames dropped. I am wondering what options I have to improve performance with VLC?

Is it possible to use a more efficient codec to interpret the H.264 stream and drop the quality to improve performance? (quality is not as important as performance; unfortunately, it is not an option to change the encoding of the stream).

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 04 Jul 2007 10:23
by DJ
Preferences, Video, Input / Codecs, Other codecs, FFmpeg change "Skip the loop filter for h.264 decoding" from "None" to "All" then press Save and restart the player.

If the machine is to slow this setting will appear to do NOTHING!

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 14 Jul 2007 16:30
by pachu007
Hey all,

I've used VLC for a long time and I never joined the forums because I never had any problems with it until now.
I'm trying to watch some MKV's with H.264 video and MP4 audio with SSA subtitles. Video res is 1024x720.
The issue is that VLC chokes when playing these, it plays fine for a while but when there are "action" scenes then it starts producing artifacts or drops the frames. I've played with the caching on the File Access Module (went up to 15000 ms, which allowed me to start watching some of the video, I couldn't with the default setting of 300 ms)

I've also played around with the other settings on the FFmpeg Codec (Error resilience, Workaround bugs, Low resolution decoding and skip the loop procesing for H.264 decoding) but ultimately they all drop quality in favor of keeping framerate which I don't want to do.

I have a pretty fast computer and I´m using VLC 0.8.6c
Pentium D @ 3.00GHz
1GB RAM
NVIDIA GeForce 7600 GT

Is there any other setting I can play with to avoid having VLC drop the framerate on this files?
Is this a known bug or it may be just my bad luck?

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 16 Jul 2007 10:56
by DJ
Your processor should be capable of 720p. What's the frame rate of the video? What's the CPU usage?

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 17 Jul 2007 02:42
by pachu007
That is what I would think... :D

CPU usage is between 15% and seldom spikes at 40%, usually between 25% and 35%.
Can you tell me how to get the framerate of the video?

Thanks a lot DJ!

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 18 Jul 2007 08:17
by DJ
Press ctrl i while playing the h.264 video and go to the advanced options tab.

Does Messages show repeating errors?

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 23 Jul 2007 05:18
by pachu007
Sorry for the delay in this...

I sometimes shows repeating errors in messages... I get these two kinds

Code: Select all

main warning: late picture skipped (617000)

Code: Select all

ffmpeg error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
In any case I've linked this issue, it seems to be related with Windows Live Mail desktop. Apparently when it polls the server for messages is when this happens. For some reason MS thinks bugging my CPU for this chore is acceptable...

I'm looking forward in getting the new version for correcting the issue mentioned in this post:

viewtopic.php?f=14&t=39019&p=120967&hil ... es#p120967

Thanks for your help DJ

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 31 Jul 2007 10:11
by krilla
Can anyone outline what exactly "Skip the loop filter for H.264 decoding" does?

I have just enabled this on my MacOSX version of VLC and I can now play my 1080p x264 video, but feel it may of dropped quality somewhat.

Any pointers?

Thanks,

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 01 Aug 2007 01:24
by VLC_help
http://ecadlab.hanyang.ac.kr/v3/image_t ... earch1.htm
De-blocking Filter

http://www.indigovision.com/whitepapers_h264video.php
3.6 Deblocking

hopefully it teaches someone something about loop filter.

Re: Incoming H.264 Stream Decodes Too Slowly - Dropped Frames

Posted: 01 Aug 2007 10:06
by krilla
Thanks very much for that, those two links are very useful.