QAAC / MP4

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QAAC / MP4

Postby musicmancm » Fri Aug 12, 2011 2:49 am

Hello all,

I guess I'm going to beat a dead horse again here - I apologize in advance.

I'm currently transcoding all of my MP3's into OGG at 64kbps. Works great and the sound quality is pretty good actually. I have the AT&T Atrix running Android 2.3.4. I'm happy with this - but I know HE-AAC is probably the best solution if I could somehow wrap raw AAC into an MP4 container and spit it out to STDOUT. HE-AAC seems to be superior to any other codec at low bitrates (to my ears anyway). I've been playing around with QAAC and can get it to work outside of Subsonic. That being said...

My wife has an iPhone 4. It can't do OGG and she has a limited data plan (yea I'm cheap). MP3 at low bitrates just doesn't cut it for me or the wife as far as sound quality. So I'm back to trying to find a way to encode HE-AAC (for both my wife's iPhone and my Android). Would help save some bandwidth and maybe I could take my cheapness to the next level and reduce my data plan a bit. :)

Finally, my question. :) Is there any solution that popped up recently that will allow me to transcode MP3 to HE-AAC, wrap it in an MP4 (or M4A) container and output that to STDOUT?

Any help is greatly appreciated!

And by the way, this goes without me saying, but Subsonic is a great product. You hit the bullseye Sindre. Thanks for the good stuff! I'm planning on donating some more money as well. (I'm not buttering you up for anything though) :D
musicmancm
 
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Re: QAAC / MP4

Postby musicmancm » Sun Sep 04, 2011 10:39 pm

Figured this out kinda.

I wrote a quick Perl script (compiled it, not the most effiecient way, but I know/like Perl) that takes all of the arguments - filename, bitrate, artist, album, title and does the processing. The script runs FFMPEG to convert to a WAV file, writes the WAV file out to a temp file. Then, it runs QAAC (suppose you could use any AAC encoder), which picks up the temp WAV file, coverts it to AAC/M4A and creates a second temp M4A file. Lastly, it reads the M4A file and prints it out to STDOUT in binary mode. Works pretty well actually - the only problem is the time waiting for FFMPEG and QAAC to do their thing before I can print the newly created file out to STDOUT. I'm going to try and figure out a way to have FFMPEG spit everything to STDOUT, then in a second step, read that in and on the fly generate the MP4 wrapper with the AAC data. Just need to figure out the format of an MP4 wrapper - doesn't sound too fun. Another small thing - QAAC only does up to 80kbps AAC, which is fine for me, but I just have to account for that in the script. If the passed in bitrate is anything other than what QAAC accepts, set it to some predetermined value.

Anyways, just wanted to post a reply to say there is an answer here. If anybody has questions, feel free to post and I'll try and reply.
musicmancm
 
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Re: QAAC / MP4

Postby marsmayhem » Thu Sep 08, 2011 12:15 am

Or you could try OPlayer Lite - will do OGG (and a bunch of others). Put it on her iphone, point it at your shares. It runs FFMPEG on the phone and transcodes on the fly.

http://itunes.apple.com/us/app/oplayer-lite/id385907472?mt=8
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Re: QAAC / MP4

Postby kingmos » Sun Nov 20, 2011 12:19 am

ffmpeg_new -i %s -f flv -vn -acodec libaacplus -ar 44100 -ab 64k -ac 2 -map_metadata 0:0 -

works in the webinterface, I don't use Android.

You need to compile ffmpeg with libaacplus for that.
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