The VideoLAN Forums

Hello,

I recently upgraded VLC and found that some H.264 MKV videos that played without problems in 0.8.6i now have choppy picture in 0.9.8a.

I can produce this problem (correct playback in 0.8.6i but incorrect in 0.9.8a) on two different computers:
- 1.5 GHz Pentium M laptop running Windows XP SP2 (32-bit) with integrated graphics (circa 2005)
- 2.0 GHz 8-core Xeon desktop running Windows XP x64 with NVidia Quadro NVS 285 graphics (circa 2007)

On both computers and both VLC versions, CPU usage remains far below 100%.

I copied the first 5MB of two such problem videos to separate sample files, which reproduce the problem (plays fine in 0.8.6i, but picture is choppy in 0.9.8a).
I uploaded the samples here:
ftp://streams.videolan.org/incoming/smo ... 0.9.8a.mkv
ftp://streams.videolan.org/incoming/smo ... sample.mkv
[Edited to add this second, more obviously-choppy sample]

The original files were encoded from DVD source using Handbrake 0.9.2.

When playing this sample in 0.9.8a, the Messages window doesn’t report any errors besides “cannot load some cues/chapters/tags etc. (broken seekhead or file)” which I presume is because the file is only the first 5MB of a larger MKV file.

I also tried to find the earliest version after 0.8.6i which gave choppy playback on the sample. I didn’t see Win32 binaries on the FTP site for 0.9.0 or 0.9.1, but 0.9.2 does have the choppiness. So if this issue is a “bug” then I guess it was introduced somewhere between 0.8.6i and 0.9.2

Has this issue been addressed somewhere already? If so, I’d appreciate a pointer to the discussion.

If not, I’d be happy to provide any more information or help to people who can fix this issue.

Thanks for your time,

Gabriel Rosenhouse
gabriel.i.r@gmail.com

EDIT: As requested by j-b below, I filed a bug report, here: http://trac.videolan.org/vlc/ticket/2562

Is your CPU peaking?

No, as I stated in the original post, on both computers CPU usage is mild when playing samples in either VLC version. (On the laptop, it's around 60%, on the desktop it's less than 3%).

Can you test the 1.0.0-dev test version?

I tried the Win32 build at http://people.videolan.org/~jb/build/vl ... -win32.exe (dated 23 Feb 2009) and had the same problem.

Is there a different build I should try?

No, fill a bug report.

Any other players other then vlc you can find will play this file correctly?
Looks like playback frame rate issue

Try and encode the same clip again with frame rate of 30 or 25 fps or with megui this clearly looks like an encoder issue.