select Audio streams from AVI

[zerowalker]

Is it possible to use 2 Audio Streams within an AVI with Avisynth?

Cause it seems that it isn´t possible from what i can see. As you can´t select streams, so it always use the default stream, which makes it a bit complicated.

So the only way to use the other streams is to extract them and use them that way, with Audiodub/MixAudio or something.

[raffriff42]

> you can´t select streams, so it always use the default stream
This should select any audio stream from any media file:
FFmpegSource2(<path>, atrack=<stream number>)
You have to know, or guess, the stream number.

> Is it possible to use 2 Audio Streams
At the same time? Not sure.

[zerowalker]

I would prefer not to use ffmpegsource2, as it´s so slow compared to AVISource cause of the Indexing. I would like to get it to work with AVISource.

[creaothceann]

Demux the audio (could be automated with mkvmerge and mkvextract) and try one of the audio input plugins?

[zerowalker]

That´s what i would like to prevent, as it takes quite awhile on long videos.
A player can easily choose the streams, but Avisynth can´t (with AviSource), and i would like it to work, but as i can´t find any information on it, i guess there is a limitation.

[raffriff42]

Open in VirtualDub
Audio menu, Source, select stream
Frameserve from vdub to signpost AVI
AviSource(<signpost AVI>)

[zerowalker]

Originally Posted by raffriff42

>Thanks for taking the time to respond to my thread
Don't mention it. Oh, that's right, you didn't.

It´s not that i didn´t care, i just haven´t tried it yet
But i think i got how to do it, i need to use a frameserver, and use that as a "handholder".

Not the ideal approach, would prefer to just use Avisource, and have a setting to choose the Track. Without having to use some third party.

But it will probably work and does let me choose the selected track, so thanks for the tip, will keep it in mind!

[raffriff42]

Yeah, I know it's a hackish workaround, just throwing it out there as a possibility. Personally I would recommend using FFmpegSource2, and taking a break away from the computer for a few minutes while it indexes

[zerowalker]

Yeah but ffmpegsource2 has it´s own problems, it does it´s own decoding which isn´t always that good. It often isn´t on par with what AVISource has, even if you skip the indexing part and just looks at the decoding. But it´s often more stable than DirectShowSource.

[IanB]

Avisynth only supports one audio track per clip. That audio track can of course have multiple channels.

FFmpegSource has options to select the required video and audio track when multiple tracks are present.

DirectshowSource supports custom .GRF files to allow controlling the filter pin connections. Where a DS filter implements multiple streams as separate pins connect all the unwanted pins to null renderers and leave the pin hosting the required stream unconnected, Avisynth will connect to the first unconnected pin providing the appropriate basic format (audio or video). For DS filters that require optional settings to choose streams there is currently no Avisynth interface to support custom settings per filter.

Avisource selects the first video and first audio streams.

This is implemented in avisynth/src/sources/avi/AudioSource.cpp @ 121

	pAVIStream = pAVIFile->GetStream(streamtypeAUDIO, 0);

The forum threads are for support, PM's are for the exchange of confidential or personal information.

[Wilbert]

Originally Posted by IanB

Avisource selects the first video and first audio streams.

This is implemented in avisynth/src/sources/avi/AudioSource.cpp @ 121

	pAVIStream = pAVIFile->GetStream(streamtypeAUDIO, 0);

I was looking at this last week, but got side tracked with the documentation on avisynth.nl.

Isn't it possible to add an option atrack to AviSource which let you pick

	pAVIStream = pAVIFile->GetStream(streamtypeAUDIO, atrack);

and return an error if it doesn't exist. Or are more changes needed for that to work?

[zerowalker]

Thanks.

Hmm makes me wonder as Wilbert says, if it tells to select the first track, why shouldn´t it be possible to tell it to select the second track?
Unless there is some fundamental issue which prevents any customization of it.

[IanB]

I don't know.

The referenced code is where the audio track is selected from the VFW (Video for Windows) environment. You will need to check how the IAVIReadHandler::GetStream() interface works and how to specify "atrack" to do what you want, if it's at all possible. All I currently know is specifying 0 apparently gets the first track of the type specified.

The sources in avisynth/src/sources/avi/ are code given to BenRG by Avery Lee from VirtualDub's code base circa 2003.

[raffriff42]

Should work. Virtualdub code looks for first audio stream with stream number >= argument.
avisynth/src/sources/avi/AVIReadHandler.cpp @ 2181

IAVIReadStream *AVIReadHandler::GetStream(DWORD fccType, LONG lParam) {
. . .
while(pasn_next = pasn->NextFromHead()) {
  if (pasn->hdr.fccType == fccType && !lParam--)
	break;

  pasn = pasn_next;
  ++streamno;
}

(EDIT my source download is old, so line numbers may be off)

[zerowalker]

Interesting. Though out of my league sadly. If someone can get it to work or want to get deeper in it, please discuss it hear.
I however can´t be much help, as my programming skills are extremely lacking, i can barely understand the concept.

[StainlessS]

Being able to Query contents of source files does not seem too weird.

Does however sound like a lot of work. (Permit this to pass).

[raffriff42]

FWIW, it looks like the AVI file parser scans for all audio streams just as V-dub does (IOW it does not seem to be crippled)

avisynth/src/sources/avi/AVIReadHandler.cpp @1848
bool AVIReadHandler::_parseStreamHeader(
		List2<AVIStreamNode>& streamlist, DWORD dwLengthLeft, bool& bIndexDamaged)
. . .
avisynth/src/sources/avi/AVIReadHandler.cpp @ 1960
	streamlist.AddTail(pasn);

@ZeroWalker, all this is contingent on a developer taking an interest and having the time.