AVISynth Question

[Alexstarfire]

Not sure where this kinda of question should be posted since it's not directly about audio. I'd have asked this on the Doom9 Forums since they have a section for AVISynth, but I just registered their today and you have to wait 5 days to make threads.

Anyway, I use AVISynth and VDub to do as much of my converting as possible. I have a TON of files that need to be converted and as a result I've made a very basic program in Java to make AVS files for me. With my variety of files naturally comes a variety of video/audio codecs used. Haven't had any trouble with video codecs and VDub so far, but audio has been somewhat of an issue. I'm able to get it all working, but many times I end up having to do things manually when it comes to setting up the audio in the AVS files. So, my question is this. Is there any way in AVISynth to have it detect what kind of audio is used in a video file? I'd rather not have to find out this information manually if I don't have to.

[poisondeathray]

It depends what source filter you are using, and the type of file. For example AVISource won't open MKV containers

You can specify audio in the script if you want. Some source filters do not specify audio and you could combine using audiodub().

FFMS2 will open most types of files, and if you use the defined function ffmpegsource2, specifying atrack=-1 will use 1st audio track

You have to be more specific (i.e .post information on the specific files, and your script used) if you want more specific help

BTW, there are avs batch scripters available

[Alexstarfire]

I'm sure there are AVS batch scripters out there. I've never checked because I just felt like making one myself. Helps me with my Java programming.

I thought I asked a pretty straight-forward question already and don't see how posting any of what you request is going to make any difference because it's something I don't know. All I'm wondering is if there is a way in AVISynth to determine how many audio channels are in an audio source so that I can then specify how to downmix it? I use DirectShowSource currently to open all of my files, MKV, MP4, OGM, AVI, and whatever else I have. Almost all of the audio sources I've come across have been AC3 so if what I'm asking can't be done across any audio source then would it be possible with just an AC3 source? To be even a bit more specific, it's coming from an MKV file, though I'm sure I have a few other files types that'll have 6-channel AC3.

[Gavino]

All I'm wondering is if there is a way in AVISynth to determine how many audio channels are in an audio source so that I can then specify how to downmix it?

AudioChannels(clip) returns the number of audio channels.
http://avisynth.org/mediawiki/Clip_properties

[Alexstarfire]

Now that is exactly what I was looking for. Very useful. Now I won't have to manually specific how the AVS file should handle the audio track.

Thanks for the help.

[AlanHK]

All I'm wondering is if there is a way in AVISynth to determine how many audio channels are in an audio source so that I can then specify how to downmix it? I use DirectShowSource currently to open all of my files

If you use DirectShowSource and have ffdshow installed, go to "ffdshow audio decoder configuration" and select "Mixer". If you set that to, say, "2/0/0 stereo" then all audio using DirectShowSource will be downmixed to Stereo, or whatever you select.

[Alexstarfire]

I had tried that before and it didn't seem to ever work right. Worth trying again I suppose since I've cleaned up my codecs since then and have a new version of ffdshow.