PRX the Lion-Hearted
If you’re a proud new owner of a Mac Lion machine, you’ve likely spent the last month overindulging in swipes, multi-touch gestures, and multiple desktops — neglecting anything non-Lion, like friends, family, your appearance.
Soon, however, you’ll attempt to actually produce something, and find the stalwart PRX Audio Encoder couldn’t enter the Lion’s lair — i.e., it won’t run on Mac 7.0+. Never fear, once again, PRX has come to our rescue: they’ve released their new, free PRX Converter for Lion (Beta).
MP2 (aka, MPEG-1 Audio Layer II) is the soundfile format required for sharing your programs with stations via PRX and NPR’s ContentDepot (complete specs below). The PRX Encoder creates flawless MP2 files. PRX wrote that app in 2003 for the old PowerPC Mac processor. Modern Intel processor Macs use Rosetta to run PowerPC apps. That is, alas, until Lion, which abides no such ancient technology, leaving some of us producers without a reliable, affordable MP2 encoder.
Before you run out into the street screaming audio Armageddon, know this: If you run a pre-Lion Mac OS, you’re fine. If you’re on Windows, you’re fine. The existing PRX Member Tools are all you need.
Some of us, though, can’t help but hop on every new piece of pricey Apple propaganda. It’s for we poor early-adopting souls that the bit-twisters at PRX labored long and heroically to release their Lion-taming beta, the PRX MP2 Converter.
Install App on Your Inner Lion
To get it going, you do the familiar download dance, from
- Go to the PRX “Converter for Lion (Beta)” page.
- Click the “Download the Converter Tool for Lion” link to get their file:
PRX_mp2converter_1-3beta.dmg.zip(a compressed archive).
- After it’s downloaded, go to your
/Downloadsfolder. You should see a PRX
.dmg(disk image) file there. (The
.zipshould auto-unzip, then auto-delete itself into your
- Double-click the file:
PRX_mp2encoder_1-3beta.dmg. That puts a new disk icon on your desktop named “mp2converter“.
- Click open “mp2converter“. Inside is the file:
mp2converter.appto your /Applications folder.
- Eject the “mp2converter” disk image, and trash the
- Launch your new
mp2converter.appto start sharing your sonic brilliance with the world. For uploading advice consult the ContentDepot “Producer Guide” and PRX’s “Help and Resources” .
New Hotness v. Old & Busted
The new Converter works much like PRX’s old Encoder. You can drag-&-drop a file onto your new app’s icon, or use the menu command File>Encode…. The app makes an MP2 copy of your uncompressed
.wav file. The encoded MP2 ends up in the same folder as your original
.wav (same filename too, but with an
.mp2 extension at the end).
The Converter was made for Lion (10.7) but runs fine on all Mac’s felines: tested on Tiger (10.4), Leopard (10.5) and Snow Leopard (10.6). There’s are a couple key differences from the old Encoder:
- The new PRX Converter is hold-onto-your-hat lightning fast. We clock it five times faster than the old PRX Encoder. On 10.4 with the new Converter, a half-hour file took less than a minute to encode, but more than four minutes using the Encoder. On 10.7 a half-hour file encodes in just a few seconds. However…
- The new Converter is still in beta testing phase, use at your own risk. As PRX tells us: “it just isn’t as polished or battle tested” as the stable, secure Encoder.
- The new Converter does not do batch encodes (via File>Encode…). It’s one file at a time. But Batchers Beware: there have been file corruptions in batch-encoded files. And those corrupted files have gone undetected by ContentDepot, then into station systems, where they’ve wreaked havoc. Unless you like late-night calls from upset engineers, encoding files one at a time is best.
- The Converter and Encoder apps have the same app-icon. If you have both, you can tell them apart by their names (in your apps folder or Dock): The new is called “mp2converter.app“; the old is: “PRX Audio Encoder.app“.
Soundfile Specs: PRX and ContentDepot
File Format: MP2 (MPEG1, Layer II)
Mode: mono or stereo
Bit Rate: 128 kbps for mono or 256 kbps for stereo
Sampling Rate: 44.1 KHz
Word Length: 16 bit
Frame Padding: must be turned off
ID3 (Audio) Tags: must be turned off
Audition Before Upload?
Notice that last line above: ID3 Tags. That’s the info associated with an audio file, such as Artist, Album, Name — the metadata an audio player might display. Also notice those ID3 Tags “must be turned off.” Trouble is, just playing a soundfile in a program like iTunes can turn those tags on — meaning the file no longer meets the specs.
So how do you, being the conscientious producer you are, confirm your MP2 file is complete and uncorrupted, before unleashing it upon the public and public radio stations. PRX can now handle ID3 tags, but ContentDepot cannot. If you upload an auditioned audio-file, with ID3 now on, ContentDepot file will reject it — with a pop-up error warning, reprimanding you for your errant ways.
Thus, many of us have taken to making copies of our MP2s, then listening to those copies to confirm the files. Just make sure to upload the originals, not the copies.
More MP2 Makers
ContentDepot’s “Producer FAQ” lists several other MP2 encoding options, for Win and Mac. Also, Hindenburg Journalist Pro ($375) can export in MP2, and “1-click publish to PRX”; Hindenburg Journalist ($95) cannot.
If you, dear reader, have additional MP2 insight, please comment below. We’ll revisit and revise this article as needed. Much thanks to PRX’s Andrew Kuklewicz & Genevieve Sponsler and Scott Bridgewater of PRSS ContentDepot for their help.