>
> Am Sam, 09 Okt 1999 schrieben Sie:
> > >
> > > I made a short test with lame-3.32.
> > >
> > > With the new Takehiro routines the encoder speed has improved.
> > > However, I noticed some high frequency artefacts that were not present
> > > in the last three or four releases. I tested both with -b 160 -m s and
> > > with 128kbps settings. The ringing artefacts are minute but noticeable. I
> > > also used xmms with a highpass engaged and with stereo enhancement effect
> > > plugin activated to ease my listening tests.
> > >
> > > I�m not sure where this comes from.
> > > Do Takehiro's and Leonid's latest enhancements comply?
> > >
And:
>
> I also get artefacts with lame 3.32 that weren't in lame 3.31.
> With my -X5 VBR code I can get up to the cutting edge of lames
> PSY model. And the new code produces on the Glockenspiel
> SQAM files VERY audible scratchy artefacts, the old code not.
> And the difference in file size for gspi35_1 is 188624 bytes (lame 3.32)
> compared to 188716 bytes (lame 3.31). For harp40_1 the new code
> produces even larger files, 199774 bytes (lame 3.32) compared to
> 199712 bytes (lame 3.31).
>
> To the ATH problematic. After some earlier listening tests with the SQAM files
> I would suggest to change line 216 in quantice.c as follows:
> ath = ath/3.5 - 114;
> This was considered above.
>
> Robert
>
I have double checked the code, and as far as I can tell, Takehiro's
improvements only make the lossless compression more efficient, and
thus make more bits available in about 10% of the granules. So my
guess is that these changes are revealing other flaws that we need to
track down.
But if you really want to test this, I've added the old code and
will put lame3.33 on the web page tonight. To go back lame3.31
output, there are just two changes:
1.
In takehiro.c, there are now three #define's:
/* Define one and only one of: QUANTISO, QUANTISO2, QUANTTAKE */
/* takehiro routines. more efficient, sometimes up to 96 bits per granule */
#define QUANTTAKE
/* ISO routines */
//#define QUANTISO
/* takehiro tables, ISO bit count. mp3 files will differ, but decoded .wav */
/* file will indentical to that produced by QUANTISO */
/* Used for testing takehiro code */
/* When defined, l3bitstream.c will print a message whenver bits are wasted */
//#define QUANTISO2
2.
in quantize.c(), uncomment the "//break" in this loop:
/* from Takehiro TOMINAGA <[EMAIL PROTECTED]> 10/99
* loop over *all* posible values of scalefac_compress to find the
* one which uses the smallest number of bits. ISO would stop
* at first valid index */
cod_info->part2_length=10000;
for ( k = 0; k < 16; k++ )
{
if ( (max_slen1 < slen1[k]) && (max_slen2 < slen2[k]) &&
(cod_info->part2_length > tab[k])) {
cod_info->part2_length=tab[k];
cod_info->scalefac_compress=k;
ep=0; /* we found a suitable scalefac_compress */
//break;
}
}
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