Compression and speed of lossless audio formats

Encouraged lately by some new & improved lossless audio formats, I got curious how all these would compare in a graphical form, as a function of their (realtime) speed.

Seven albums with different music types were used. Each album was ripped to a single big wav file, then compressed and decompressed with batchfiles like this (renamed to .txt for convenience). Then the file creation times and -sizes were entered in excel worksheets, where also the graphs were generated.

The speed results come from my 900 MHz Athlon PC, harddisk in ATA-66 mode, W2000 SP3. I noticed that the highest-speed formats not only depend on the CPU, but also on the harddisk read/write speed. For example with shorten, CPU usage only reaches about 70%. To have the harddisk's performance as constant as possible, I kept it defragged before running each batchfile, and erased the generated lossless- and wav files afterwards, so the files got placed in about the same place on the harddisk.

Graphs:
In the graphs, the Y-axis shows the compressed file size as a percentage of the uncompressed (wav) file size.
The X-axis shows the speed, for example 10 means a 5 minute track was processed in 30 seconds.
Use the links on top of the page to switch quickly between the graphs.

graph album comments
Titanic James Horner: Titanic - Music from the motion picture (1997) Orchestral music, only one song (Celine Dion).
Gema Gema Cuatro: Grandes boleros a capella (1994) A capella quartet.
Fleetwood Fleetwood Mac: Rumours (1977) Soft rock.
Aphex Aphex Twin: Richard D. James album (1996) Electronica.
Trance Trance 2001, The 4th edition, CD1 Trance compilation mix.
Platina De platina editie (2000) Compilation of ballads, pop & rock songs.
Steve Steve Vai: Passion & warfare (1990) Guitar rock.
All albums Average result of all 7 albums. Each album weighs equally (irrespective of playtime).
All (2004) All 7 albums, but with some old compressor versions.  
All (2003) All 7 albums, but with some even older compressor versions.  

Compressors tested:

homepage ext version
released
winamp
plugin
foobar plugin used compressor presets (default)
comments
Monkey's Audio .ape 4.01b2
feb 2006
3.99 2.1 fast (c1000), normal (c2000), high (c3000), extra high (c4000), insane.
Free Lossless
Audio Codec
.flac 1.1.2
feb 2005
1.1.2 inclu'd 1, 2, 3, 4, 5, 6, 7, 8.
Lossless Audio .la 0.4
apr 2003
0.4 0.4 (default), high.
OptimFROG .ofr 4.520b1
apr 2006
1.07 1.21b fast, normal, high, extra, best, highnew, extranew.
WavPack .wv 4.31
dec 2005
2.3 inclu'd fast, fx2, fx4, fx6, (default), x2, x4, high, hx2.
For clarity, the decompression graphs only show the letters f, d and h.
RK Audio .rka 1.07
oct 2000
1.0.5 no 1 (fast), 2 (normal), 3 (max).
Windows Media
Audio (lossless)
.wma 9.0
jan 2003
inclu'd 9.0 default.
dBpowerAMP Music Converter was used.
Shorten@shnutils
Shorten@etree
.shn 3.6.0
may 2004
2.0.2 0.3.14 default.
ICL6 binary by john33 was used (en/decodes 15/5% faster than Cygwin binary).
WinRAR .rar 3.51
oct 2005
no inclu'd normal.
ALAC 
(Apple Lossless)
.m4a -
apr 2004
no 1.0 default.
iTunes 4.5 was used.
The True Audio
compressor
.tta 3.3
may 2005
3.1 2.4.2 default.
MPEG-4 ALS
(Audio Lossless)
.als RM17
apr 2006
1.00 no 1(-a-o5), 2(-a-o10), 3(-o10), 4(-a-o30), 5(-a-b-o50), 6(-a-b-o50-g1), 7(-a-b-o50-t2)
Also used -r5 for Winamp seeking. These are preset suggestions only.
Lossless Predictive
Audio Compression
.pac 1.41
feb 2002
1.00 @case 2 (simple), 3 (medium), 4 (high), 5 (extra high).
Development frozen, replaced by MPEG-4 ALS

Some other links:

Lossless Encoding forum at Hydrogenaudio, and the original thread that made me start this page.

Lossless comparison wiki at Hydrogenaudio, it considers many properties, not just speed and compression.

Speek's encoder frontends for most of the above formats, and his Comparison of lossless audio compressors.

Updates:

4 June 2003: OptimFrog 4.506 with new 'highnew' mode (compression with other modes did not change since 4.504b).
21 June 2003: Updated hyperlinks.
17 January 2004: Added tta.
1 May 2004: Updated ape, ofr, shn, rar, tta, hyperlinks, removed winamp seeking comments, new Apple Lossless, removed BONK.
9 May 2004: Updated WavPack.
19 May 2004: Some more WavPack levels.
3 July 2006: Updated ape, flac, ofr, wv, rar, tta, hyperlinks.
7 July 2006: New MPEG-4 ALS, removed LPAC.
11 July 2006: Some more ALS levels.

Hans