AAC to AC3/DTS? [For TV Media Box]

[Breakthrough]

I have this neat little Western Digital media box - the thing is amazing! Problem, though: I can't decode over 2-channel AAC! I have a bunch of stuff with 6-channel AAC, and was wondering how to convert it to AC3/DTS (my reciever supports both).

So far, I think I'll have to convert the AAC to raw PCM streams - the only thing is, every tool I have tried fails near the 1-hour mark (as in the output file stream is NEVER longer than an hour?!) and even if I try to encode it, EVERY SINGLE AC3 encoder I've tried STOPS AT THE 200MB MARK.

Can anyone try to recommend me a solution that might work? Thanks!

[shon3i]

Use BeHappy for transcoding, and you better go to AC3, because DTS is huge and will not provide better quality than higher AC3, only larger file size.

[Breakthrough]

Use BeHappy for transcoding, and you better go to AC3, because DTS is huge and will not provide better quality than higher AC3, only larger file size.

I've downloaded BeHappy, but I can't get it to be happy with the .AVS file I've made (all it is is a DirectShowSource import of the original .MKV file... I tried it pointing to the demuxed .AAC as well).

Any suggestions?

[qyot27]

You may have to use the commandline. For 5.1 AAC->5.1 AC3 conversions (the source being trailers from the Quicktime site about 99.9% of the time), I use faad and aften directly.
faad -o "output.wav" "input.aac"
aften -b [bitrate] "input.wav" "output.ac3"
For [bitrate] I generally use 576, and it seems to work fine for the DVDs I've authored with it, but I've read that 576kbps AC3 isn't compliant. So you might want to use 384kbps or 448kbps instead if the target is DVD authoring. For just playing over a receiver I don't know if those kinds of limits would still be imposed.

Doing it that way preserves the channel masking. I've not tested enough with AviSynth to trust that the channels are ordered correctly, or moreover, to simply save the audio, since what few times I did try I seem to remember the WAVE_FORMAT_EXTENSIBLE info not being written on output.

[Breakthrough]

Thanks man, that works perfectly. The media box I have outputs the stream directly to my reciever, and it handles 576kbps like a beast. It can't decode AAC though, which is why I had this problem in the beginning...

Thanks for your solution, it works PERFECTLY.

[Furiousflea]

maximum standard dolby digital 5.1 is 640k (448k for dvd).

Best use 640k for your purpose. No point using 576k, it's not exactly a standard bitrate, not that it matters. Also, you might as well max out the encoding since 640k isn't much more than 576k.