Hello Caster,
Monday, May 15, 2000, 12:23:34 AM, you wrote:
C> For encoding I used lame 3.82 from http://www.chat.ru/~dkutsanov/. For
C> decoding, Exact Audio Copy with Radium fhg codec 1.2.
be aware that this 1.2 plugin has very poor performance on VBR. (last
half second is missing etc), to be sure just decode back to PCM or wav
and then do a freq analysis.
C> First I encoded the file with lame -V 1 -b 128 -h -m j
C> After decoding and opening in CoolEdit there are clearle visible volume ups
C> and downs in waveform view. Freqency analysis that the frequency curve is
C> not almost almost straight like in original file but there are also ups and
C> downs above 16 khz. When listening, there are very significant chirps (as
C> vdbj decribes them in his mail from 13.5.).
C> The most interesting thing is that vdbj's sweep produced with Sound Forge
C> (described on http://www.r3mix.net/) was clean! And it has the same
C> frequencies as mine sweep, even higher.
I don't know about this A440 setting, but when you do a complete
40Hz-22kHz sweep in CEP (instead of the 4.5kHz-22kHz SF sweep I used),
I got some visual minor distortion in the +17kHz range, but nothing
audible so not important.
(some part out of another mail:
I used: generate tones:(B/M/Mf): initial (0/0/10) final (22050/0/0), dB LR
-1.4, 10 seconds long
(I wanted (again mistake: (0/0/0)->(22050/0/0)), but same outcome)
So not much different conclusion:
256: perfect
vbr: audible perfect, gfx some distortion
xing: major cut-off at 16kHz)
Seems to me there are 1001 ways to do this kind of sweeps, and the
only way I used them was to easily show flaws in FhG vbr and Xing.
When I listen to what lame does in vbr mode, the only flaw I can
detect is that with some cymbal sounds not enough bits are assigned
(imho). My idea is just: for the moment 192kbit/s sounds poorer to me
on this area than 128 because @128 the lowpass filter gets out
potential sources of artifacts while @192 the full range is not
encoded too well I think.
C> Testing with some music source the analysis was also different above 16 khz
C> (as vdbj reports in his mail).
You cannot expect a perfect exact graph from original source and
encoded wav. I know 256 comes close, but this doesn't mean that a VBR
mode having more visual abberation from the original has poorer sound
quality.
--
Best regards,
vdbj mailto:[EMAIL PROTECTED]
--
MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
