Saving AAC files!!

[gojensen]

So, we have a few AAC files with incorrect headers. Is there any manipulation or player/writer tool around that is able to see "past" the wrong headers and let us access the audio?

The files are a result from a beta version of an Envivio Broadcaster that couldn't handle files larger than 2 gb when archiving. During streaming it recorded the video to an MP4-ES file and the audio to an AAC-ES file. Upon broadcast end it was supposed to add these files to an mp4 container and hint it etc. But it failed because of the file sizes. The MP4-ES video looks okay and MPEG4IP tools understand it and can add it as a track, but it won't understand the AAC audio. (Because it looks like Envivio added some proprietary header information to the files...)

So, anyone know of any tool that is able to "manipulate" AAC files with erronous headers?

[Kurtnoise]

Originally posted by gojensen
So, anyone know of any tool that is able to "manipulate" AAC files with erronous headers?

Maybe with BeSplit (http://besplit.doom9.org/)... :) You can fix the bad headers with this tool.

[hans-jürgen]

Originally posted by gojensen
The MP4-ES video looks okay and MPEG4IP tools understand it and can add it as a track, but it won't understand the AAC audio. (Because it looks like Envivio added some proprietary header information to the files...) It may be simpler than that, perhaps this is just an ADIF header at the beginning of an *.aac file. As far as I know, mp4creator cannot read and multiplex these files, only the ones with ADTS headers, but you could try to play them with any FAAD2-based plugin, e.g. in Winamp or foobar2000. On the other hand an incomplete ADIF AAC file might not be playable at all, because that's one of the reasons for inserting ADTS headers at the beginning of each frame (= Audio Data Transport Stream).

[bond]

So, anyone know of any tool that is able to "manipulate" AAC files with erronous headers? did you also try other muxers, like 3ivx or mp4box (get a list from my faq)?
still mp4creator should be the most powerful one when it comes to audio

Originally posted by gojensen
MPEG4IP tools understand it and can add it as a track, but it won't understand the AAC audio. (Because it looks like Envivio added some proprietary header information to the files...)can you upload a small example plz?

[gojensen]

I could upload, the files are 150-250MB in size though, and I can't edit them since nothing will read it. (Haven't tried the suggestions here yet, been busy). I did however, do a hex view of the first part of a "normal" AAC file and our "crashed" AAC files. (BTW; my guess is that the files are complete, the encoder just barfed when it tried to mux them into the mp4 container).

The "good" AAC files :D00000000h: FF F1 4C 80 0E A7 FF 08 4B 13 FF FF FF FF FF FF ; ÿñL€.§ÿ.K.ÿÿÿÿÿÿThe "BAD and the Evil" AAC files :devil:
00000000h: 6D 61 67 6E 65 74 00 00 4D 50 34 41 00 00 AC 44 ; magnet..MP4A..¬D
00000010h: 00 00 00 17 04 80 80 13 40 15 00 06 00 00 03 00 ; .....€€.@.......
00000020h: 00 00 01 80 00 05 80 80 02 12 10 00 00 01 1D 00 ; ...€..€€........
00000030h: 00 00 00 00 00 00 00 02 08 03 01 21 20 02 A8 55 ; ...........! .¨UI'm guessing those are the headers, as I had 5 different "good" files with the same headers, and all the "bad" AAC files began in the same way aswell... as you see it's much longer.