Audio bit rate settings

Kapitano kapitano72 at
Thu Feb 7 06:25:52 EST 2013

On 2/7/2013 13:05 PM, Heff wrote:
> However, each download I do has very low bitrate audio. Even on the flashhd quality level, downloads have 96kbps audio, which sounds terrible!
> It appears that ffmpeg/rtmp or something converts the downloaded flv to mp4, which I'm guessing effects the audio quality too. Is there a way to adjust the default audio conversion setting so that the final video file contains something like 320kbps audio?

IIRC, GiP uses ffmpeg to *extract* the audio, not convert it to a 
different format. The same for the video.

The BBC uses FLV as a container for the MP4 file (for no good reason 
that I can see), and GiP just takes the MP4 out. For radio files, 
they're AAC inside FLV...which is inside an M4A container, which is the 
name for MP4 with only audio. Still with me? :-).

(I download radio using the --raw switch, which takes the FLV out of the 
M4A, then I use a program called FLV-Extract to get the AAC out of the 
FLV. Complicated, but it works.)

BTW, if I'm talking rubbish and anyone can correct me, please do.

96kbps shouldn't sound terrible, especially if the audio of the video is 
in AAC format. It isn't wonderful quality, but it's perfectly good for 
speech and okay for music. So maybe the problem is your audio playback 
equipment? You might have a bad soundcard, or it might be playing back 
too loud and distorting?

320kbps is much higher than a tv show needs - anything higher than 192 
and I don't think you'd notice the difference. You *might* want 320 for 
classical music - Radio 3.


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