Xvid-encoded videos skipping

[CoreyJKelly]

This may not be a VLC-specific problem, but I've only been able to debug it using the console in VLC, so I'm hoping somebody here can offer some insight. I don't recall updating anything before this started happening, but all videos encoded with Xvid seems to skip on my computer. These are videos that don't skip on other machines but seems to skip in both VLC and WMP on my computer. The videos always skip at precisely the same places, and the audio becomes jumbled for a few seconds. At first, the fact that the skips are at the same place every time led me to believe that I was dealing with a few corrupted files, but it seems to be happening with every video I play, including some which I know for sure are not corrupt.
I get the following in the console when the video skips:

Code: Select all

avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (13610 bytes) avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (15684 bytes) avcodec warning: cannot decode one frame (2376 bytes) avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (10695 bytes) avcodec warning: cannot decode one frame (2296 bytes) avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (14007 bytes) a52 debug: emulated sync word (no sync on following frame) avcodec warning: cannot decode one frame (1294 bytes) avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (13082 bytes) avcodec warning: cannot decode one frame (1941 bytes) avcodec warning: cannot decode one frame (7 bytes) avcodec warning: cannot decode one frame (14314 bytes) avcodec warning: cannot decode one frame (1859 bytes) main warning: late picture skipped (452189 > 0) main warning: computed PTS is out of range (437757), clearing out main warning: output PTS is out of range (451757), clearing out main debug: audio output is starving (251847), playing silence avcodec warning: cannot decode one frame (7 bytes) a52 debug: emulated sync word (no sync on following frame) main warning: buffer is 113625 in advance, triggering downsampling main warning: audio drift is too big (-138980), clearing out main warning: timing screwed, stopping resampling main warning: mixer start isn't output start (-70208) main debug: audio output is starving (186681), playing silence main debug: control type=1

I'm running VLC 1.1.1 on Windows XP SP3, with Xvid 1.3.2 installed. My video card is an NVIDIA GeForce GTX 275, with up-to-date drivers. I've tried all different output modules (audio and video) as well as disabling hardware acceleration in the Windows display settings.

EDIT: I was slightly mistaken, and should have known this from the log above. It seems the problem is with the audio codec. I've testing out a few videos now, but it seems that MPEG audio works fine, but A52 (AC3) audio causes the video to skip, with the error posted above.

[VLC_help]

Is there a short sample file you could share to us?

[CoreyJKelly]

Sure:
http://dl.dropbox.com/u/12510849/sample.avi

That skips near the 0:17 mark.

[BilBg]

Sure:
http://dl.dropbox.com/u/12510849/sample.avi

That skips near the 0:17 mark.

The file is broken.

It has several zeroed sectors at this offset:




You can see also that because of these broken/empty sectors the image is also distorted after ~0:13

I tried in 6-7 Players and Converters -
everyone of Players can't Play sound after 0:17
and Converters generate silence after 0:17

VLC 1.1.11
Media Player Classic (from K-Lite_Codec_Pack_710_Mega.exe)
Windows Media Player (uses ffdshow from K-Lite_Codec_Pack)
IrfanView (uses ffdshow from K-Lite_Codec_Pack)
Winamp (uses ffdshow from K-Lite_Codec_Pack) (stops the play at all after 0:17)
F3 View in Total Commander (instead of silence begins to repeat the several last words)
MPlayer (instead of silence begins to repeat the several last words)

GSpot

VirtualDub
Freemake Video Converter
Freemake Audio Converter


I also used HxD Hex Editor and deleted all the zeros (file become 13 KB smaller) but the resulting file acts the same.

 

[CoreyJKelly]

Thanks!

It's possible that the problem was actually made worse by my cropping a sample of the file in avidemux.

The reason I was confident that it wasn't the files is that they're mostly from torrents from private sites, where comment claimed that the audio/video were perfect. On my computer, these files are essentially unwatchable. If it were an issue with the files being written to my harddrive poorly, they wouldn't pass the hashcheck. The only other thing I can think of is that the files were potentially damaged when transferring from my torrent machine to my main PC. I'm going to check a few things to make sure this isn't the case, and I'll report back.

EDIT: I tried downloading one of the problem files directly to my PC, without using my torrenting machine, and it seems to play fine. Looks like this isn't a player/codec issue after all. I must have a hard drive or transfer problem somewhere in the chain. Thanks for the help, anyway!

[BilBg]

 
In fact your sample.avi file have several other long parts/places filled with zeros.
(I searched for 512 consecutive zeros = 256 zero bytes)

I checked a few of my .avi files and they have parts filled with zeros only at the beginning and sometimes at the end.

I must have a hard drive or transfer problem somewhere in the chain.

You can use Total Commander or HxD - Freeware Hex Editor and Disk Editor
http://mh-nexus.de/en/hxd/

to generate MD5 checksums before and after the transfer.