Experimental update to make m4a audio from aac

[Nick Ludlam]

After a lot of trial and error, it looks like you can indeed use ffmpeg (git HEAD) to reliably create m4a audio container for the flash aac audio. The caveat is that you must first extract to raw aac, and then in a second step, convert to m4a with the 'aac_adtstoasc' bitstream filter, as noted by Shevek. Combining both steps into one will mangle the resulting output.

If you import these audio files into iTunes on a Mac, then you get some initial weirdness with the current seek point in the file, but if you jump to the beginning manually for the first time, it seems happy after that, with correct audio filesizes. More importantly for me, it seems happy to play back on my phone.

To this end, I've committed my changes and pushed them to https://github.com/nickludlam/get_iplayer . If anyone has a chance to test, it would be helpful. Please make sure you have a very recent build of ffmpeg from the git repo, NOT 0.6.1.


Nick