[Ffmpeg-devel] [PATCH] vbr audio encode
Sat Aug 13 16:01:34 CEST 2005
On Sat, Aug 13, 2005 at 12:40:13AM -0400, Justin Ruggles wrote:
> The patch for vbr audio is pretty much ready. From what I can tell, the
> only codecs that support vbr are all external to ffmpeg (vorbis, lame,
> faac). After this, I might revisit simplifying the work I was doing on
> adding vbr to ffmpeg's ac3 encoder, but that's for another day.
> I did implement both normalized & codec-specific quality scales. The
> normalized scale follows a similar pattern as video quality, using 0.01
> to 255. The options I chose were '-aq' for normalized, and '-aqc' for
> The guideline I've used is to scale the normalized value to codec value
> by holding to 0.01->best, 255->worst, and 128->default. This can result
> in a non-linear scale, but keeps uniformity of intent across codecs when
> using the normalized scale. A linear scale actually works for lame, but
> that won't always be the case.
> For now I have only implemented functionality for mp3 encoding, but I
> wanted to submit the patch for responses before I add faac and vorbis.
> Index: ffmpeg.c
> RCS file: /cvsroot/ffmpeg/ffmpeg/ffmpeg.c,v
> retrieving revision 1.341
> diff -u -r1.341 ffmpeg.c
> --- ffmpeg.c 10 Aug 2005 23:41:20 -0000 1.341
> +++ ffmpeg.c 13 Aug 2005 04:03:43 -0000
> @@ -216,6 +216,8 @@
> static int intra_only = 0;
> static int audio_sample_rate = 44100;
> static int audio_bit_rate = 64000;
> +static float audio_qscale = 0;
I'm against using floats for this. It's both inconsistent with video,
and I'm in general against extra float params.
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