On Sat, Sep 30, 2000 at 03:09:31PM +0200, Robert Hegemann wrote:
> Mark Taylor schrieb am Sam, 30 Sep 2000:
> > It passes all my test cases, so no unexpected changes to the
> > algorithms :-). I had some comments yesterday, but I see
> > a lot of them have already been fixed today.
>
> strange, a simple make test resulted previously in perfect agreement,
> but not anymore now:
>
> Encoding testcase.wav to testcase.new.mp3
> Encoding as 44.1 kHz 128 kbps j-stereo MPEG-1 LayerIII (11.0x) qval=2
> LAME version 3.88 (alpha 1) (http://www.mp3dev.org)
> Using polyphase lowpass filter, transition band: 15115 Hz - 15648 Hz
> Frame | CPU time/estim | REAL time/estim | play/CPU | ETA
> 23/22 (100%)| 0:00/ 0:00| 0:00/ 0:00| 0.6991x| 0:00
> cmp -l testcase.new.mp3 testcase.mp3 | wc
> 23 69 345
>
> But the reason for this seems to be, that the old testcase
> is for LAME version 3.87 alpha. So the difference is only
> this text in the ancillary data section of the MP3s.
>
> A note to everyone who increases the version number, think
> about the testcases too.
>
To compare JPEGs I use jpegcmp. JPEG files with the same image contents
can differ in nearly all bytes. You need no tags or things like that.
Two different implementations of the huffman encoder are really enough,
also a HQ/Low Speed Switch of the same implementation is enough.
$ ls -la
-rw-r--r-- 1 pfk users 87488 Sep 30 17:49 origin-optimize.jpg
-rw-r--r-- 1 pfk users 89582 Sep 30 17:50 origin-progressive-optimize.jpg
-rw-r--r-- 1 pfk users 89582 Sep 30 17:50 origin-progressive.jpg
-rw-r--r-- 1 pfk users 102270 Sep 30 17:49 origin.jpg
May be the same is true for MP3 files.
--
Frank Klemm
--
MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
