richpeet wrote:
>
> I have not only been staying way from mp3pro but vbr as well. Not
> from having knowledge rather the lack of it. I have kept control of
> things with a constant bit rate. Should I change to variable bits?
> It seems I loose control of what happens in compression when using it.
It does get a little less predictable just what you will get from a
given setting. But there's considerable unpredictability even in fixed,
depending on just which encoder you are using.
It will give you considerable smaller files for the same sound quality.
But, even now, some things don't support it. Most of my frogcall mp3's
on my website are encoded with it. They are, of course, put out as dead
ends for listening only and that's the way I made them, changing
settings downward as long as the calls sounded ok. I've, so far, in 6
months, had one person who had problems playing them, he was using a
very old mp3 player. I get over 250 visitors/day to my frogpages, and
average more than 13 frogcall mp3's/day downloaded.
I've only had mp3 pro for about a month. It's supposed to do even better
than VBR. I've experimented a little, but need to play with it some more
before knowing just how good it will be. It's a fairly rare one for now.
I have it in Audion 3 for the mac. I used to use Soundjam, which was
bought by apple and gutted of a lot of useful stuff to become iTunes. So
I'm in another round of looking at choices. Audion also has the PMLame
encoder for mp3. I've also got the Fraunhofer encoder in Spark XL I can
use. There seem to be endless choices.
VBR is just varying the bit rate for different parts by a intelligent
choice system, to more effectively use the available storage. For most
encoders you set either a average or minimum bit rate to limit how far
it goes. This sort of thing is done by ATRAC, so, if applied well it can
be very effective.
With all mp3, you are making a file for listening, and the best way to
judge is listen with good headphones. Then try the various settings to
determine the smallest file size that does not mess up the sound too
much for what you are trying to do. This may vary depending on the
source, like with different frog species, for instance. There's nothing
really magic about a particular setting.
The other term you want to get comfortable with is Joint Stereo if you
encode stereo. This one pools the allotted bitrate for both stereo
channels and assigns bits according to which channel has the greater need.
I personally think using both Joint Stereo and VBR is ok now and should
probably be standard. All current players seem to do fine with them and
they do decrease file sizes. MP3Pro I consider experimental, for my
local use only.
Walt
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