muxing and demuxing multichannel audio files

[unkown]

How can I mux single channel audio files (AC3 or DTS) into multichannel files without recompressing? And what about the inverse proccess, that is, spliting multichannel files (again AC3 or DTS) into single channel files? Thanks a lot.

[Tuning]

Are you asking for multistream(different no of audios on a single video file)video file and how to create and de-mux them?

Hope this is what you are asking for,it is simple with using VirtualDub Mod.VitualDubMod Procedures here. (http://doom9.org/virtualdub_procedures.htm)

-Tuning

[unkown]

Hi Tuning!

I mean the following:for example,if I have a AC3 5.1 audio file,I'd like to split his channels into single channel audio files (left rear,front right,etc) without quality lost,and also the inverse, joining several sigle channel files into a multichannel AC3 file (and the same thing but using DTS audio files).

Thank you.

[Ramirez]

So basically you want an AC3 Stream files splitter\joiner tool, I don't think such a tool even exist ([AFAIK]) I think the only way for you to split an AC3 audio file is by Transcoding it into 6 separate WAV files and then encoding it back into AC3.

This is NOT a lossless procedure though.

[Tuning]

And this can be done using BeSweet.(Transcoding ac3->WAV/AIF and WAV->ac3)Look here:Here (http://www.doom9.org/ac3machine.htm)

-Tuning

[unkown]

Hi there!

if I demux into wav files there is not quality lost but if I want to mux these files again I must convert to AC3,and then I lost quality, am I right? Thanks.

[Tuning]

Yes some loss will occur as ac3 is a lossy compression format.
Are you trying to reduce the size of ac3 to fit to a particular media?
Or what are you trying to do?

Tuning

[unkown]

Hi Tuning

No,it's just that I'm trying to experiment with extracting and replacing channels from a multichannel audio file.Perhaps the only method is the one you are talking about and loosing a bit of quality.Well thank you anyway.Bye.

[tiki4]

Usually audio codecs use information that is similar in different channels to compress more efficiently. E.g. MP3 uses a method called joint-stereo to find information that exists in left and right channel. So your stereo file isn't just two mono channels but left and right channel are in close relationship (please have a look at the LAME devel site to find out how this really works). AFAIK the same is true for multi channel encoders. Your AC3 5.1 doesn't consist of 6 mono streams inside a container but similar information is different channels is used to compress more efficiently. Thus you can't just split a 5.1 to 6 mono files, but you have to decompress and the decoder can revert the process.

Regards,

tiki4

[unkown]

Thanks you tiki.I ignored that.I thought multichannel files simply were muxed like,for example,vob files.
Bye!