I’ve now got the automatic podcast running on the sheevaplug. Because I can’t so easily re-encode mp3s, I’ve had to come up with a different way to make the podcast. The file is much larger, but the sound quality should be better.
It might be a few days before it runs from the sheevaplug every day.
CompRec, though extremely poor quality (no psychoacoustic modelling! Old-school twinkly-burbly MP3s here we come!) is a fast MP3 encoder you can build on the SheevaPlug. It’s perfect for my limited needs.
(thanks to wb6ymh for finding this.)
The prime reason I bought the Sheevaplug is to run the automatic podcast. Every day, the script has to decode a bunch of mp3s to WAV format.On a normal computer, this takes a few seconds per file. On the Sheevaplug – with no floating-point instructions, things get painful:
$ time lame --mp3input 03-in_the_aeroplane_over_the_sea.mp3 03-in_the_aeroplane_over_the_sea.wav
ID3v2 found. Be aware that the ID3 tag is currently lost when transcoding.
LAME 3.98 32bits (http://www.mp3dev.org/)
Using polyphase lowpass filter, transition band: 16538 Hz - 17071 Hz
Encoding as 44.1 kHz j-stereo MPEG-1 Layer III (11x) 128 kbps qval=3
FrameÂ Â Â Â Â Â Â Â Â |Â CPU time/estim | REAL time/estim | play/CPU |Â Â Â ETA
7750/7750Â (100%)|Â Â Â 8:45/Â Â Â 8:45|Â Â Â 8:46/Â Â Â 8:46|Â Â 0.3851x|Â Â Â 0:00
kbpsÂ Â Â Â Â Â Â LRÂ Â Â MSÂ %Â Â Â Â longÂ %
128.0Â Â Â Â Â Â Â 2.1Â 97.9Â Â Â Â Â Â 100.0
Writing LAME Tag...done
realÂ Â Â 8m46.408s
userÂ Â Â 8m45.940s
sysÂ Â Â 0m0.090s
That’s right – nearly 9 minutes to decode a song! My very first Pentium 75 could probably do better than that.
I’d heard that MAD was really fast on integer-only CPUs, so I tried it:
$ time madplay -o 03-in_the_aeroplane_over_the_sea.wav 03-in_the_aeroplane_over_the_sea.mp3
MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
Title: In the Aeroplane Over the Sea
Artist: Neutral Milk Hotel
Album: In the Aeroplane Over the Sea
7748 frames decoded (0:03:22.3), +1.2 dB peak amplitude, 1423 clipped samples
realÂ Â Â 0m7.134s
userÂ Â Â 0m6.500s
sysÂ Â Â 0m0.580s
Seven seconds sure beats nearly nine minutes. Now, if only I could find an integer MP3 encoder …
Well, not really that awe-inspiring. But it does show that the Sheevaplug boots and runs out of the box. Given that it has only 512MB of RAM and the same amount of Flash storage, it’s a fairly small system.
I really want to have this replace my Firefly Media Server installation on the laptop. First, I need to work out how to get it to boot from an external HD.
I ordered one of Marvell’s SheevaPlug Development Kit; wonder when it will arrive? It will make the best mini-server I could ever wish for.