aac 5.1 conversion to anything(pulling hair out)

[dog-god]

i have mkv anime epsiode that has 5.1 aac audio
i been reading and experminting for the last 3 days but i cannot for the life of me find a way to convert this to 5.1 ac3 preferrable or mp3 downmix at worst

ive used mplayer - accdop - dbpoweramp - besweet - virtualdubmod - graphedit etc
if anybody has done this successfully ive appreciate some help
ive read the post concerning this on this forum but the sampling rate ,speed ,lenght vary using different methods
also there sems to be an issue with how the channels are mapped differently from ac3 5.1

if any want to play with the aac file(extracted from the mkv with MKVextractGUI_154) size 38mb mail and ill send link for download

[dog-god]

http://rapidshare.de/files/3564535/Track2.rar.html

grab file here

[Junpei]

I have the same problem, a surround sound AAC file that I just don't know how to convert to AC3.

[celtic_druid]

Try foobar2k, should be able to convert to AC3, taking into account the different channel order.
mplayer would have been able to decode to PCM though? For actual audio encoding you would need to use mencoder. mencoder -ovc copy -oac lavc or whatever.

[Snowcrystal]

I have a bunch of aac files (extracted from mkv) which I want to convert to wav. I have downloaded a couple of programs to convert to wav. But the problem is the lenght of the wav isn't the same as the video.
And I've tried other solutions mentioned above, but it doesn't work either.
I need help!

[celtic_druid]

Well if the video is VFR then it is not supposed to be the same length as the audio.

[Snowcrystal]

What's VFR??

I've tried to convert the wav to mp3 and join the avi and mp3 with virtualdubmod, but the video is out of sync.

[celtic_druid]

VFR = Variable Frame Rate.

[Junpei]

In my case, I gave up on being able to get it to AC3, too much effort, disk space, and time. Went to stereo MP3 but then it was all out of sync, so I've given up on viewing that particular file for now.

[celtic_druid]

Well you don't need to convert it to view it.

[Schmendrick]

Hi dog-god!

I have found a solution for your 5.1-aac to 5.1-ac3 conversion.
For 5.1-aac into 6channel-WAV-file conversion I have found the
following tool:

http://www.hydrogenaudio.org/forums/index.php?act=Attach&type=post&id=1081

This aac_zip.zip contains an aac-encoder/decoder-demo-programme from the
following discussion:

http://www.hydrogenaudio.org/forums/index.php?showtopic=28759&hl=

For a conversion of this 6-channel-WAV-file which I could not use as input
file for Besweet I have found the following conversion programme to
produce 6 mono WAV files:

http://home.arcor.de/needfulthings/tools/Tranzcode_v0.30+guiv1.4.rar.rar

From the following web-page:

http://needfulthings.c-f-h.com/tools/item.php?id=18

These 6 mono-WAV-files you then have to encode with an AC3-Encoder
like Belight. In the case of your example
AAC-file as it is 22500 Hz sound you first have to upsample
it in an audioeditor like Goldwave to 48000 Hz to obtain files which can produce a compatible 5.1-AC3-file. With Belight you first have to load the MONO-WAV-files using "File" and then "Create Mux File" and click on
"Load automatically this .mux file as input file", give a file name at "Save as..", selct "AC3" as "Select the Output format" and click "OK". Finally select AC3 and 5.1 and Bitrate (usually at least 384) and start processing.

Good luck

CU

Schmendrick

[Danno100]

I have used the commercial Xillisoft software to convert Nero MP4 files which contain AAC audio to AVI's contained MP3 audio. Works well, and also allows other conversion options. Has batch conversions which is handy. Well worth the price in my opinion.

[Junpei]

Well you don't need to convert it to view it.

Usually, buy my aging computer was too slow to play the file as it was. ^_^ And then I also can't get surround audio from it either. Well I just wish people would create Divx hardware compatible files but that's not going to happen, and it's not fair for me to complain anyway.

[celtic_druid]

To surround sound out either use analogue out or use something like ffdshow to convert to AC3 on the fly.

So no one tried foobar 2000?

[Morkeleb]

Hi.

I tried with MKVtoolnix/MKVextract(GUI) and Foobar 2000, but
it would not recognize the format. Maybe it cannot handle 5.1 aac correctly.

I found another way that is quite simple:
Get mplayer/mencoder (http://www.mplayerhq.hu) and use a command like this (or similar):

mencoder input-file.mkv -oac mp3lame -lameopts cbr:br=192 -ovc copy -o "output-file.avi"

This would take the aac, convert it from multichannel to stereo if required and encode it using lame.
If you only want the audio and no video, i'm sure there are other options to accomplish this, but i'm too lazy to look it up in the documentation and I don't need it anyway.
I first encoded without the lameopts which gave me a variable bitrate mp3, and for some reason a/v syncronisation was not ok then. Its ok with constant bitrate however, and recommended anyway for avi.
If the video is not treated correctly, just use the original from the mkv using VirtualDubMod and use the new mp3 stream from the newly converted.

Another way I tried was to demux with VirtualDubMod, convert to multichannel .wav using Nero SoundTrax (part of the nero burning rom bundle 7), then used CoolEdit 2000 to save it to mp3 because I would have to pay extra for mp3 (lame!) encoding in nero. I had to manually tell the format of the audio to CoolEdit because (my guess) the file header was screwed up. Any other program I tried would not do anything with the demuxed aac (either with VirtualDubMod or with MKVextract).
The endresult was usable, however syncronisation was off by a little bit.

Cheers, Morke

PS.: I know this response comes really late to this thread, but I thought if others have the same problem and google for it, they might stumple over my solution here.

[newyear1967]

Another way to convert AAC to AC3

1. Convert (Decode) AAC to wav using Nero AAC Codec (NeroAacDec.exe) command line version.
Alternatively NeroAAC UI can be used if you don't want to use command line.
2. Convert wav to ac3 using Eac3to.
Alternatively EAC3to conversion utility if you like GUI.