VirtualDub distorting audio + video while capturing [Archive]

ChibiBoi

22nd April 2007, 18:42

whenever i capture, after a while, virtualdub inserts like hundreds of frames:

http://i3.photobucket.com/albums/y68/ChibiBoi/frameinserts.jpg

and it causes the audio and video to mess up. i've got a sample link here:
http://www.sendspace.com/file/ed6fmy

i've re-encoded it to xvid from the original .avi file which i captured with huffyuv. can someone please tell me how to fix this?? it's really getting on my nerves

GrofLuigi

23rd April 2007, 02:32

Something is wrong with your audio. 46696.81 is too far away from 48k, the rate which is set (bottom of the window).

Reasons can be different - compression of audio (codec can't keep up?), something wrong with the audio device, settings of VirtualDub... Unfortunately (or not) I haven't experienced this case, so I doubt I could be of much help. Maybe someone else can step in?

GL

olnima

23rd April 2007, 09:57

I think GrofLuigi is totally right. Your Audio is way too slow so VirtualDub inserts Videoframes to get video as slow as audio.
Do You use an audiocodec while capturing? I would recommend to capture pcm (uncompressed audio). Did You try another samplerate like for example 44.1 kHz? Did You ever try to capture without audio? Do You have the chance to use another audiodevice (Soundcard from a friend for example)?

Good luck
Olnima

ChibiBoi

24th April 2007, 05:18

Boulder

24th April 2007, 06:28

Have you tried with the latest VirtualDub 1.6 version, which is the stable one..v1.7 is still experimental.

GrofLuigi

24th April 2007, 15:28

i've tried without audio and i wound up with the same problem. i usually compress my audio with lame mp3 at 160kbps while capping. this problem kinda comes and goes.. i don't know why

Have you tried uncompressed? What are your VirtualDub Capture>Timing settings? Please provide a screenshot if you can.

like today, when i first started my PC it did this... then after a while it went away... and then it came back again..

Maybe you have virus or antivirus :) on your computer. Both can cause interruptions.

GL

ChibiBoi

25th April 2007, 03:42

i have tried with the 1.6 version and it's the same thing. i have also tried uncompressed, and it doesn't seem to fix it either.

this is my timing dialog:
http://i3.photobucket.com/albums/y68/ChibiBoi/timingdialog.jpg

and i have also tried antivirus and defragmenting my PC. sometimes it works, but after i cap like 1 or 2 episodes, it messes up again... and it usually messes up at certain times, like 1 minute in the video, 12 minutes in the video, and 20 minutes in the video are the usual times when my thing starts inserting these frames

Boulder

25th April 2007, 04:07

You might also want to try a different capture codec such as MJPEG. ffdshow includes a free, high quality MJPEG codec.

http://sourceforge.net/projects/ffdshow-tryout/

ChibiBoi

25th April 2007, 04:31

alright, i've added my timing dialog screenshot. these aren't the settings i used while i made the sample video. i had "sync audio to video" selected instead.

i changed it to "sync video to audio" so it stops the audio distortion. but the frame inserts still happen. and when there's a bunch of frames inserted, it makes everything desync...

olnima

25th April 2007, 09:46

I suggest to NOT encode audio during capturing. Lame is so fast, You don't waste too much time if You do that afterwards (f. ex. with lame.acm in VirtualDub)

For finding the problem:
Play around with settings and capture ONLY Video until no frames are dropped or inserted and everything is o.k. for You. Then add Audio (uncompressed!!!) and see what happen. If the frame-drops/insertations return, play around with the samplerate and have a look at VirtualDub-window if the wanted samplerate can be reached (GrofLuigis 1 post in this thread) If not (like in the appended pic of your 1st post), maybe your soundcard has a defect.

Olnima

P.S.: Have always a look at your CPU-Power in windows-taskmanager !!!

P.P.S.: Your framerate is setted (in the appended pic of your 1st post) to 29,97 fps is that o.k. for your region?

Boulder

25th April 2007, 10:02

It might be useful to use automatic audio latency detection. And as others have said, use uncompressed audio to avoid problems.

For better support, posting at the official VirtualDub forum is also a good idea as the author will answer questions there.

GrofLuigi

25th April 2007, 16:06

Dropped/inserted frames during capture can't be avoided completely. Sometimes there is a desync in the source or in the transmission or a glitch on the tape (it would help if you tell us what capture card you have and where you capture from).

As for your settings, generally they're OK. I would leave "sync audio to video" too, but that depends on what hardware you have. Also, it's better to have "Null frame burst limit" to default (10) or even more. It's kind of a protection feature.

On my rig I have "correct video timing for fewer drops/inserts" checked too, but I'm not sure whether that would help in your case. I think it wouldn't hurt. Try either way.

GL

ChibiBoi

26th April 2007, 15:35

alright, thanks for your help everyone. i don't usually have the audio latency to fixed, i just did that as a test. anyway, everything's fine now. i tried encoding with ffdshow's mjpeg codec with the audio uncompressed and it works fine now

ChibiBoi

27th April 2007, 15:39

actually, now i'm having another problem. when i encode with mjpeg, it sort of washes out some of the color. like the dark parts of the video wouldn't be as dark and the video itself would be less saturated than the source... is there a way to make mjpeg not do that? because i've tried with fddshow's huffyuv and it doesn't do that

GrofLuigi

27th April 2007, 16:47

ChibiBoi

27th April 2007, 19:44

Which mjpeg codec? Picvideo had some option to mess with that...

GL

it's the mjpeg codec that comes with cccp's ffdshow

GrofLuigi

28th April 2007, 23:07

it's the mjpeg codec that comes with cccp's ffdshow

I haven't used that build, but you could try forcing input colorspace to yuy2 and/or disable image processing.

If this (mjpeg encoding) happens during capture, try "extend luma black/white point in VirtualDub (try both, either ways, enable histogram to see what you're doing).

Also check if yuv > rgb conversion is going on somewhere and with what ranges.

GL

ChibiBoi

28th April 2007, 23:47

that didn't work. and i know there IS a yuv to rgb conversion going on since when i go to my mjpeg encoded file and set the compressions it says that encoding it uncompressed would make it rgb/ycbcr

GrofLuigi

29th April 2007, 06:49

that didn't work. and i know there IS a yuv to rgb conversion going on since when i go to my mjpeg encoded file and set the compressions it says that encoding it uncompressed would make it rgb/ycbcr

I don't understand. Who says and when? (which program)

Is the mjpeg encoding taking place during capture or after?

Have you checked PLAYBACK settings? (ffdshow > video decoder configuration)

GL

ChibiBoi

29th April 2007, 17:54

1. virtualdub says

2. it's taking place during capture

3. i just checked the settings and i don't think there's anything there that might be causing it

here's a sample picture:
http://i3.photobucket.com/albums/y68/ChibiBoi/mjpegloss.jpg

the image on the left is what i get while capturing with mjpeg codec. the one on the right is the original tv broadcast. when i capture with mjpeg, it makes the colors less contrasted (whites and blacks are more gray and such...) and the coloring becomes less saturated... (like if you compare the blond person's skin)

Boulder

3rd May 2007, 10:57

How did you take those screenshots?

ChibiBoi

4th May 2007, 02:13

i used the "print screen" button on my keyboard and pasted the images onto photoshop, cropped out the extras that weren't part of the video, and saved it with 8/10 quality

Boulder

4th May 2007, 19:57

I downloaded those clips of yours in that other thread and using AviSynth, the colors were almost if not completely identical. In some frames there was a weird chroma shift..maybe you didn't capture in interlaced mode?