[gst-devel] FAAC bitrate

[Mike Dyer]

Hi all,

I'm trying to capture and encode some live audio/video to an mpeg-ts.
The audio is compressed using faac. However I've noticed that whatever
bitrate I request from faac, its always 128kbps.

I can replicate using an audio-only pipeline:

gst-launch alsasrc device=hw:0 !
audio/x-raw-int,channels=2,rate=44100,width=16 ! audioconvert ! faac
outputformat=1 profile=2 bitrate=8000 ! ffmux_mpegts ! filesink
location=faac.ts

gst-launch -v gives:

Setting pipeline to PAUSED ...
/GstPipeline:pipeline0/GstAlsaSrc:alsasrc0: actual-buffer-time = 200000
/GstPipeline:pipeline0/GstAlsaSrc:alsasrc0: actual-latency-time = 10000
/GstPipeline:pipeline0/GstAlsaSrc:alsasrc0.GstPad:src: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstAudioSrcClock
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:sink: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPipeline:pipeline0/GstAudioConvert:audioconvert0.GstPad:src: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPipeline:pipeline0/GstAudioConvert:audioconvert0.GstPad:sink: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPipeline:pipeline0/GstFaac:faac0.GstPad:src: caps = audio/mpeg,
mpegversion=(int)4, channels=(int)2, rate=(int)44100,
codec_data=(buffer)1210
/GstPipeline:pipeline0/GstFaac:faac0.GstPad:sink: caps =
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true,
width=(int)16, depth=(int)16, rate=(int)44100, channels=(int)2
/GstPipeline:pipeline0/ffmux_mpegts:ffmux_mpegts0.GstPad:audio_0: caps =
audio/mpeg, mpegversion=(int)4, channels=(int)2, rate=(int)44100,
codec_data=(buffer)1210
/GstPipeline:pipeline0/GstFileSink:filesink0.GstPad:sink: caps =
video/mpegts, systemstream=(boolean)true

How do I make faac listen to the bitrate setting?  

-- 
Mike Dyer
R&D Engineer
ProVision Communications