Specialized MP3 Compression Hardware?

Syn Ack asks: "Does there exist any specialized hardware for the sole purpose of compressing audio into MP3 format? Without going into too much detail, I'm putting together a platform that has to rip and compress as many songs as possible in the shortest amount of time (ie compressing several thousand CDs). I was considering a large ~20 machine *BSD or Linux cluster of high end x86 or Alpha hardware solely for compressing digital audio into MP3 format. Before I go ahead and look at other solutions, I wanted to check the distributed minds of the Slashdot readers to see if they know of any specialized hardware for this purpose. Price isn't really a concern. Something like the dedicated encryption boxes/cards used on Web servers is the type of thing I'm thinking of. Anyone have any ideas?"

Comments

hardware, or targeted compile options?

[Tumbleweed]

I dunno if there's any hardware out there for that purpose, but if you can find an open source encoder and compile it with Intel's SSE or AMD's 3DNOW! (depending on machine type) you'd likely get a substantial boost.

Also, if price really is no object, for efficiency's sake, rip them all to wav first, then encode later.

If quality is a concern, use something like EAC (Exact Audio Copy - for Windows. There's a Linux/unix equivalent available, but I can't remember the name right now) when ripping. You'll get copies as accurate as possible before you start encoding.

Make sure you use the right encoder, and make DAMN sure you use the right settings!

LAME is considered the best encoder by most people, especially at higher bitrates. (I wouldn't bother with anything less than 128, but for my own collection, I do 256.)

Looks like DSP chips are in

[pjrc]

It looks like anything you find is likely to be DSP chips running the encoder. For example, here's a little announcement that at first looks like a custom encoder chip, but actually turns out to be a Texas Instruments TMS320C1500 DSP chip. Even the dedicated decoder chips (MAS3507D and STA013) are just DSPs packaged up with built-in firmware. I recall seeing a board with a few DSP chips on it a couple years ago, that could do real-time (back when no PC could). Obviously that's obsolete... maybe that's why I couldn't find the page again.

It looks like PCs are hard to beat. Here's a claim of a Fraunhofer encoder at 10X real time on a 500 MHz Pentium3. Maybe it's vapor, but if it's real it's certainly a lot faster than LAME 3.87 (beta) when I tried it on a 800 MHz machine (Lame ran at approx 2X using "-V 3"). I recall hearing claims of LAME doing real time on a 266 MHz PC... maybe it does with different settings.

Constraints

[maggard]

You're going to have several constraints ripping 1000's of CD's to MP3s.

1. Physically loading the CD's into the readers. The cycle for retrieve CD, open CD, remove disk, insert disk into drive, retrieve CD, replace in box, refile box is slow & complex. I don't know of any system that automates this for jewel-box CD's; all autoloaders *I* know require the CD's be first loaded into special magazines which of course makes them pointless.
2. Reading the CD into the system. Even with fast drives we're talking several minutes of time to read in each CD. Bus bandwidth would also come into play - I'm betting that SCSI would be the way to go here.
3. Converting the CD audio to MP3s. Here you finally have a straight-forward read-compute-write process.

All three processes would be best tuned to each other. Given that the only means I'm aware of actually getting the CD's into readers is manually then one can assume a hard limit of loading & reading any CD is going to be about 5 minutes under best-case hardware conditions (fast SCSI reader etc.)

Since a single load-person could likely service two readers alternately this would make a work station. This work station would then produce 2 CD-datasets every 5 minutes. Assuming about six hours of loading per day one would achieve around 144 CD's of data loaded per station per day.

Assuming two CPU's per station (1 CD-ROM/1 CPU) one would have 20 minutes to process each CD over 24 hours in order to keep pace. As I believe this rate is achieviable with a current fast system then you have a well tuned solution.

Workstations consisting of 1 load person with two fast PC's = ~140 CD's per day processed

No need for custom hardware, no need for clustering, all off-the-shelf stuff.