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LAME Ain't a Mp3 Encoder
~~~~~~~~~~~~~~~~~~~~~~~~
Don't be fooled by the name, LAME is a mp3 encoder, and a damn good one at that
too! ;)
Since v3 it started using GPSYCHO, a GPL'd psycho-acoustic model (if you don't
know what that is, read up on the mp3 format) that produces a very nice final
result.
This is my (very successful ;) ) attempt at porting it to the Amiga, since I
felt that the other ports out there were too poor and unstable, and not updated
frequently enough (LAME is still a project in progress, and there are often
updates available). This port has been extensively tested and proved very
stable, and will be updated frequently alongside the original project.
- CISC
News
~~~~
LAME now uses asyncio.library (yes, even the PPC binary (Developers: I might
release a SDK package on Aminet later)) which improves speed some (esp on PPC
and slow media)...
LAME now also uses mpega.library to decode mpeg audio (for re-encoding)
instead of linking with MPGLIB .. this saves 40-50k (+is more optimized)! ;)
I've started including proper Amiga version-strings in the binaries .. try
"Version LAME.xxx FULL" to see for yourself... ;)
I've started doing some assembler optimizations on the 68k versions of LAME.
There are no known problems with this .. extensive testing show that the
output is equal, however, if any problems should occur (most likely precision)
that could be caused by this, please report to lame@honeypot.net
..so far I've only replaced a few functions, but already a speed-increase of
10-20% should be expected! ;))
Hints & Tips
~~~~~~~~~~~~
Experiencing startup or random crashes when running LAME?
- Get http://ftp.uni-paderborn.de/aminet/aminet/hard/misc/CSPPC233Fix.lha it
fixes a strange bug which corrupts the PPC LR register sometimes (seems to
occur more often under heavy CPU load) .. use NOREQ and QUIET options to
avoid the pesky debug info/requesters... ;)
- Try increasing stacksize (LAME needs atleast 100000 (This only applies to PPC
version, as the 68k versions have automatic stackextend)).
- Unplug your accelerator board and plug it in again, as it is known that there
sometimes occur a bad connection for whatever reason that will make your
programs behave badly (esp. PPC).
- Remove nasty patches.
When I Version LAME, I get really strange dates?!
- You have a non-Y2K compliant Version command, please get an updated version
from http://www.amiga.de/diary/developers/Version_v40.3.lha
I'm encoding directly from CD using AsimCDFS, and all my RAM disappears.
- Turn off "Stream CDDA Audio" in AsimCDFS_Prefs. (Thanks to Denis Zwornarz)
I'm unable to encode from CDDA files or the resulting MP3 sounds like trash.
- Most CD-ROMs return CDDA in the Intel byte order (little endian), you have to
use the -r -x options to select raw input and force byteswapping on the data.
LAME is too slow, I want something faster!
- I've optimized the exe's as good as I can, but if you want to encode even
faster (but with poorer quality), use the "-f" option.
(on a 060/50 the speed is 0.1675x vs. 0.3936x here. (v3.53)) ;)
- Get a PPC card (my 604e/233 encodes at 1.1827x (no options enabled) and
2.2705x (-f option) with a 44.1kHz stereo AIFF). ;))
- Use big-endian files (AIFF), byte-swapping can drag down performance.
Why does the PPC and 68k version produce slightly different MP3-files?
- The main reason is different precision, 68k FPU uses 80-bit, while PPC uses
64-bit, however there should be no noticeable difference on the sound.
Where's the WarpOS version of LAME?
- Use Frank Wille's ppclibemu, with that the ELF works gr8 under WarpOS.
Links
~~~~~
The Amiga Alternative Audio Page (Homepage of LAME, BladeEnc, SoX and RAPlay)
-> http://csc.smsu.edu/~strauser/audio.html
LAME
-> http://www.sulaco.org/mp3/
MP3'Tech
-> http://www.mp3tech.org/