[FFmpeg-devel] AAC decoding

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


Hi,

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:

0001010000001000
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() 
function.

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?

regards,

Luc





More information about the ffmpeg-devel mailing list