Problems with AAC and qtdemux

Neil Jones neiljay at
Mon Mar 19 08:31:09 PDT 2012

Im trying to play MP4 files with my AAC Decoder but im having problems.

the file im playing is 'cooper.mp4' from these samples

this is a 48Khz LC-AAC with SBR (ie HE-AAC), looking a this with
qtdemux and fakesink gives:

 gst-launch -vvv filesrc location=cooper.mp4 ! qtdemux ! fakesink | more

caps = audio/mpeg, mpegversion=(int)4, framed=(boolean)true,
stream-format=(string)raw, codec_data=(buffer)139056e5a0,
rate=(int)44100, channels=(int)2

So as qtdemux gives us raw data (not adts or adif framed) I need to
setup my decoder on the info provided by qtdemux, unfortunatley it
gives me the wrong sample rate 44.1 instead of 48 and I need to know
that the profile has SBR as this effects my decoder setup.

How do other AAC decoders deal with this? Do they just parse the raw
data, I cant easily do this as my plugin is for a hardware decoder.

Any help appreciated,



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