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Topic: Removing LATM/LOAS headers (Read 6244 times) previous topic - next topic
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Removing LATM/LOAS headers

Hi everyone,

I have some files that were previously encoded with AAC-HE and use LOAS transport. Now I need to get the raw data from those "containers". As far as I understand there's an header per frame which depends on the transport format used (LOAS, LATM, ADTS ...). Is this correct?
So I need to know the size of that header. Where can I get such information?

Removing LATM/LOAS headers

Reply #1 –
Remove ADTS headers:
ffmpeg -i ADTSinput.aac -absf aac_adtstoasc -acodec copy output.mp4

Remove LATM:
http://forum.doom9.org/showthread.php?p=1453484#post1453484
Quote
VLC can play these files as long as they are muxed in a ts or mp4 container, but I found out that if you remuxed a ts file with VLC it would strip the LATM bit packing from the stream.

First I would use eac3to with the -demux parameter to demux the ts file and get the raw audio stream as a file.
So then I use a command like this to remux the .aac file back into a transportstream and VLC will do it's thing.

Code: [Select]
vlc.exe -I dummy aud_latm.aac --sout #std{access=file,mux=ts,dst="aud_nolatm.ts"} vlc://quit


Also works using: mux=mp4,dst="aud_nolatm.mp4"