[FFmpeg-devel] AAC decoding

Luc Roels luc.roels
Mon Jan 25 08:38:04 CET 2010


I am trying to decode AAC audio coming from AXIS IP cameras. I found out 
that Axis is actually sending RAW AAC audio Low Complexity frames ( 
Sampling frequency 16000Hz, 1 channel mono ). Using this info leads to 
the following decoder setupdata:

or in hex
0x14 0x08

When I initialize the extradata in the codec context like this

static uint8_t extradata[] = { 0x14,8};
psAudioCodecContext->extradata = extradata;
psAudioCodecContext->extradata_size = 2;

and use a prebuilt GPL enabled old r13242 windows SDK ( faad )

then this audio decoding works fine!

However, if I build the SDK myself using the code from SVN ( jan 6 2010 
) it doesn't work at all and even crashes in the avcodec_decode_audio2() 

Has anyone successfully used the new LGPL AAC decoder under Windows? Are 
there any differences or extra initializations required as compared to 
the old faad decoder?



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