AC3 support in AviSynth ?

[MaeWanto]

I'm looking for the best way to handle AC3 in AviSynth scripts ?
I've read in the forum that AC3source filter had some issues with downmixing and I wonder if DirectShowSource filter ( with an AC3 DS filter installed ) is really the best solution ( desynch ??? ) ...
Thanks for your help.

[esby]

well I'll try to give my personnal opinion about AC3 and avisynth, which might reflect other people opinion too:

AC3 is audio.

Avisynth is primary a video based server.

If you don't intend to process audio with audio filter, don't do it in avisynth, because you'll decompress the audio and recompress it later.

Now if you want to process audio, directshowSource() might be the best choice indeed, supposing you have a good decoder.

esby

[MaeWanto]

Hi esby,

Thanks a lot for your advice. I'll try to process audio separately to AviSynth then ...
BTW, does it exist the same kind of tool than AviSynth for audio ( a kind of "audio server" with processing filters ) ???
Best regards.

[esby]

I don't know any application like avs for audio processing...
but maybe some other people can answer that...

Now personnally, Besweet answers about all of my needing.

So if I were you, supposing you need to do audio processing with existing audio filter,
I'll convert the ac3 sound to a wav using besweet,
and then i'll use avisource() or wavesource() to load it and do the process.
Now you can still use directshowsource().
or rely more or less, (or completely) on besweet.

esby

[actionman133]

download ac3filter from soundforge.

it is a very detailed decoder allowing you to choose gain levels and downmix options. the only thing you need to look out for is to make sure it's the primay decoder and using directshow (set in the system options).

avisynth can be an audio frameserver. it can change audio frequencies, and select channels and the like. it can't apply effects like reverb though. so if you're after the effects, look elsewhere.

when the ac3filter is installed, you can load ac3 streams using directshowsource. there should be no synchronous issues, except if you've ripped it from a vob file, in which you'll need the delay from the vob file.

voila... or viola... however its spelt...

[esby]

voila.

viola has no meaning, or a bad one (conjugaison in future 3rd person of 'to rape')

esby

[buzzqw]

or a color (violet)

BHH

[actionman133]

lol... i was not expecting an english class, but okay... thanks...

actually, if you pronouce viola (vee-ole-a), isn't that basically a small violin?

have we diverted from the topic on hand? just thought i'd check.... lol

[buzzqw]

viola isn't a small violin. Is a bigger violin.

But stop with OT :D

BHH

[LigH]

To get back to the topic ... somehow ...

Would it be possible to add several options (as known e.g. from Azid or AC3Filter) to AC3Source, e.g. configuration presets which define downmix options, of channel amplification factors?

And another point: In contrast to other "...Source" functions, AC3Source uses internal "dubbing". Other audio source functions (WAV, MPA) import audio to a new audio-only clip. AC3Source is different, it needs an existing clip to add audio to. Would be nice if this behaviour could be equalised.