Lost sound in AviSynth

[stephen22]

AviSynth doesn't seem to be able to find the sound in some DV files.

I generate avi files with Laptop svga > Startech PAL converter > Datavideo DAC (digital/analogue converter) captured with Windows Live Photo Gallery.

Files function perfectly in VirtualDub which informs me that the compression codec is Cedocida DV 0.2.3, and sound is normal. BUT...

x="C:\users\me\videos\g&h.avi"
a=avisource(x)
return a

produces an avi file with no sound. (So does directshowsource).

x="C:\users\me\videos\g&h.avi"
a=avisource(x)
b=wavsource(x)
audiodub(a,b)

produces error report "audiodub needs video and audio track"

Workaround is to use "Audio from other file" in Virtualdub, using the same avi file, but I am baffled as to why some files behave like this in Avisynth. Other files generated by my DAC work perfectly well, and I can't see any difference in the Audio information provided by VD between files that work in AviSynth and files that don't.

Anyone got any ideas?

[Gavino]

AviSource cannot read audio from 'Type 1' DV files - you need to use 'Type 2' files.

I am surprised that DirectShowSource does not work, however.

[stephen22]

Thanks for reply.

My DAC does produce type 1 DV - I remember years ago having to convert it to type 2 (?for an earlier version of VD).

But Avisynth has no difficulty with audio for previous files produced by the same device.

[poisondeathray]

An alternative method, if you don't want to use vdub, or convert to Type2 DV using various converters - is to use ffms2 . You need the .dll and the .avsi from the package
http://code.google.com/p/ffmpegsource/

e.g
FFMpegSource2("video.avi", atrack=-1)
AssumeFPS(30000,1001)


(I'm assuming this is NTSC DV - sometimes FFMS2 reads the timestamps slightly off, that's what the AssumeFPS is for; or you can use FPSNUM, FPSDEN in ffms2)

[sneaker_ger]

ffms2's fpsnum and fpsden are usually not equivalent to AssumeFPS(). (Or are they for avi sources?)

[poisondeathray]

ffms2's fpsnum and fpsden are usually not equivalent to AssumeFPS(). (Or are they for avi sources?)

That's true, but AVI doesn't support VFR timecodes, so the end result will be the same

[sneaker_ger]

I just tested it: they are not equivalent, even for avi.

[poisondeathray]

I just tested it: they are not equivalent, even for avi.

I tested a bunch of type 1 DV-AVI files and they were the same

Out of curiosity, what was the difference ?

If there is a difference, I think AssumeFPS() would be more correct

[stephen22]

An alternative method is to use ffms2

I already have this magnificent dll. I tried it and it will load the rogue files with sound. But when I play the avs file VD works at first, then gives an "Access violation" report the 2nd or 3rd time I press the Play button.

In fact I have discovered that only files captured with Windows Live Photo Gallery have this problem (sound not found by aviSynth). Files captured with VirtualDub have normal sound. (All my captured video is from the same source - Datavideo DAC 100). Unfortunately VD is not up to the task, especially with long files - it drops lots of frames.

Does anyone have experience of capturing from Photogallery? I can't find any means of influencing sound capture with this program.

[sneaker_ger]

I tested a bunch of type 1 DV-AVI files and they were the same

Out of curiosity, what was the difference ?

If there is a difference, I think AssumeFPS() would be more correct

I assume it does the same as it does to VFR files: drop or duplicate frames to achieve the target fps (and tell set the fps values of AviSynth accordingly) . Maybe it does not make a difference for very small disparities where no frame drops/duplications are required during the length of a file, so that it is equivalent to assumefps() for such a corner case.

[poisondeathray]

I assume it does the same as it does to VFR files: drop or duplicate frames to achieve the target fps (and tell set the fps values of AviSynth accordingly) . Maybe it does not make a difference for very small disparities where no frame drops/duplications are required during the length of a file, so that it is equivalent to assumefps() for such a corner case.

I think you're right, that's what the documentation says as well

The files I tested probably weren't long enough, and the fps deviation was only off by a tiny bit, about 0.001fps .




I already have this magnificent dll. I tried it and it will load the rogue files with sound. But when I play the avs file VD works at first, then gives an "Access violation" report the 2nd or 3rd time I press the Play button.


If it's not the audio causing the problem, you can try

vid=AVISource()
aud=FFAudioSource()
AudioDub(vid,aud)

[stephen22]

vid=AVISource()
aud=FFAudioSource()
AudioDub(vid,aud)

Nice idea
Doesn't work
Thanks anyway