Jerky playback within VirtualDub

[djdust]

Hi all

Got a really odd problem but not sure how to fix it. I've got some AVI files that I want to edit/trim within VirtualDub, a piece of software I've used many times before. The problem is, VirtualDub seems to have become really jerky and choppy and won't play any file at all without start-stop-start-stopping all the way through and it's making it nigh-on impossible to get anything done. I was using an older version of the software but just downloaded and tried the latest version yet it's exactly the same.

Any idea how to fix it?

cheers

[poisondeathray]

do the files play normally in a media player like mpchc or kmplayer ?

what type of avi files ? use mediainfo

[djdust]

Yep, they play fine outside of VirtualDub.

Mediainfo dump:

Format : AVI
Format/Info : Audio Video Interleave
File size : 96.0 MiB
Duration : 4mn 18s
Overall bit rate : 3 116 Kbps
Writing library : VirtualDub build 32842/release

Video

ID : 0
Format : MPEG-4 Visual
Format profile : Advanced Simple@L5
Format settings, BVOP : 2
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default (MPEG)
Codec ID : XVID
Codec ID/Hint : XviD
Duration : 4mn 18s
Bit rate : 2 928 Kbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate : 30.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy

[poisondeathray]

not sure, it's not a very "taxing" video, so it's unlikely to be a "cpu horsepower" issue

is there audio in the avi ? if so what kind ?

are the performance and display options set as default ?

[djdust]

The audio format is Microsoft ADPCM 4 bit 177kps.

Do you mean the Performance option under Options with "AVI Output Buffering" and Wave input buffering"..? I set them both to 6mb and tried again and, the video actually lasted a little a longer before then starting to stutter again...

[poisondeathray]

do you have an adpcm acm decoder?

with the file loaded, when you use file=>file information in vdub, what does it say ? if it can't decode the audio, it can cause stuttering

[djdust]

Yep, it seems it can see the codec fine....

[Ai Haibara]

I believe the official stance is that "VirtualDub is not a player," and that there's always a chance normal playback of a video loaded in VirtualDub might not display the way you want it to (so always test normal playback with a different player). Can't remember exactly where I read that, though, as it's been quite some time.

Checking the VD documentation on its homepage, I did find this, though:

Why does the sound stutter during playback?

This will occur if your CPU isn't fast enough to handle real-time preview. When checking the results of filtering, it's better to be able to see all frames in slow-motion rather than to see a sync'ed, 1 FPS slideslow. You can enable the "drop frames when behind" option in the menu, but it's not very effective in most cases and can simply lead to a 1 FPS, stuttering slideshow. If you must see the results in real-time, using frame rate decimation is usually far more effective.

Short answer: VirtualDub is not a player.

[djdust]

Ahar!

Have got the "Drop Frames When Behind" option ticked and it's all fine now!

Cheers...

[djdust]

Ah, scratch that last statement. It made it work ok for a bit but now, once again, it's stuttering and it's even worse than before....

[DarrellS]

What Ai Haibara said. Virtualdub is not meant to be a media player.

[djdust]

Im not trying to use VirtualDub as a media player.....

[DarrellS]

I'm not sure why you are having problems with an XviD AVI. I have trouble trying to move around in an MP4 file but not with AVI. A 2.66Ghz P4 might not have enough processor power to play them correctly in Virtualdub.

You might check in the Virtualdub forum to see if there is possibly a bug in the new version. I'm using version 1.10.0 with no issues.

http://forums.virtualdub.org/