Re: How to configure AudioConverter to write VBR?
Re: How to configure AudioConverter to write VBR?
- Subject: Re: How to configure AudioConverter to write VBR?
- From: William Stewart <email@hidden>
- Date: Wed, 11 Feb 2009 18:33:52 -0800
On Feb 10, 2009, at 9:15 AM, Jens Alfke wrote:
Thanks a ton for elucidating this, Bill! I've read it over a few
times, and here's my understanding; is this accurate?
• Setting CodecQuality affects only the speed of encoding and the
audio quality, not the file size.
Yep
• Setting the BitRateStrategy to CBR, ABR or Constrained VBR should
have small effects on the file size, while altering the audio
quality (and presumably the encoding time, too?)
I don't know that it would have a big affect on encoding time - more
on size
The bit rate will vary around the BitRate setting. The
SoundQualityForVBR is ignored.
yes
• Setting the BitRateStrategy to VBR will cause the bit-rate and
file size to vary greatly depending on the SoundQualityForVBR
setting. The BitRate setting is ignored.
yes
Now I'm thinking of what this means for my UI. It seems like there
are two disjoint modes — either the user can select a target bit-
rate and optionally enable two levels of constrained VBR; or the
user can enable Full Gonzo VBR and set an audio quality level, but
not a bitrate. Independently, they could could also adjust a "faster
vs. better sound" slider.
yes - this is how the QT dialog in export does this.
The converter publishes a dictionary of settings and we reflect these
settings / changes according to the state of the codec. The QT UI is
totally drawn off this converter dictionary
This seems like a lot of widgets for a consumer-type app … I wonder
if both the bitrate-centric and quality-centric modes are necessary.
The quality-centric one seems nice for nontechnical users, but if I
just have that, I know I'll get lots of people asking "where do I
set the bitrate?"
Yep :)
Funnily enough though, we're all happy just setting a quality setting
when deciding what to do with JPEG encoding :)
Bill
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