On Sun, Sep 24, 2000 at 10:57:39AM +0200, Gabriel Bouvigne wrote:
>
> I've got another question about window sizes: are the short ones really
> essential in VBR? Would it be possible to only use long ones, and then
> allocating a lot more bits in the case of transcients? After all, Xing uses
> only long ones, and does a not so bad job for transcients for an encoder
> using only long ones. (note: I'm not saying that Xing is a reference in term
> of quality)
>
Tested with a synthesized signal:
--noshort -b128: awful
--noshort -b320: bad
--noshort -b550 --freeformat: Decoder SIGSEG
-b320: good, but distinguishable from the origin
without any effort (20/20)
-b550 --freeformat: okay
Note:
All-purpose lossless compressing utilities gave a better compression ratio:
input uses input uses round to
HQ quantization nearest integer quantization
gzip 190 kbps 74 kbps
bzip 154 kbps 68 kbps
Very short attacks seems to be a nightmare for MP3.
Signal is:
* white noise
* attack time: 0.5 ms
* release time: 25 ms
* pause time to fill the bit pool: 474.5 ms
* both channels are uncorrelated
* all attacks are different and also sounding a little bit different
Note: The percussion attacks in "Money for nothing" are a little bit similar
to these attacks:
* white noise from 1...18 kHz (+/- 3 dB)
* attack time: ca. 0.5 ms
* release time: ca. 20...30 ms
* but: no silence between the attacks
How to capture Win95 Screen Shots? What utility would be the best?
--
Frank Klemm
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