MP3 Player Plug-Ins
I’m looking for an MP3 player or a plug-in that does time stretching without pitch shifting and/or pitch shifting without time stretching. I know that hard disk recording sequencers (Cubase, Logic, Digital Performer etc.) can do this and that there are even these kinds of plug-ins for the WinAmp MP3 Player. On my G3 PowerBook with Virtual PC I naturally can use WinAmp with one of these plug-ins, but this solution is slow and changing platforms isn’t comfortable. So if you’ve ever heard about real time stretching and/or pitch shifting with Mac MP3 software I would be happy to get a hint. I’m a teacher of music and would like to work with MP3 files in music lessons and rehearsals at school.
As far as I know, there are no Mac MP3 plug-ins as of yet to accomplish this task, though new ones are always being written. I have an old freeware program called Sound Hack that can independently change the pitch and duration of an AIFF file through phase vocoding. I describe this process within another program (Metasynth) in this month’s issue, but the basic points apply. I hope this helps for now. —David Ozab, Contributing Editor/Music
I read in MacFormat magazine’s review of iBook, from a year ago:
The batteries are lithium-ion-based, which means you can charge them whenever you like without the risks associated with some other types of battery, where charging before the battery was run down could limit the battery’s duration.
However my reseller said that it was still best to plug it into the mains only when it was empty, which is really quite a drag sometimes—if you’re travelling, you need to be able to plug it in when you get to a power point, not when it’s empty!
Can someone give an authoritative comment on this?
Your question makes reference to the infamous “memory effect” exhibited by Nickel Cadmium and, albeit to a lesser degree, Nickel Metal Hydride (NiCad and NiMH) batteries. Essentially if these types of batteries are used and charged regularly without being totally depleted, they will get confused and think they are empty when they are not (admittedly this is a bit of an oversimplification, but it will suffice as an explanation for the time being)…
Cordless phones are a great example. People use them for ten or fifteen minutes, and then throw them back into the charger. Doing this regularly conditions the battery to “think” that it is empty when it is at, say, 75% of its charge. Sometimes you can fix this by draining the battery completely, and then recharging it (called a deep discharge) but unless there is some built in provision for doing so, often you must throw the battery out and buy a new one.
Lead acid batteries (used in cars, uninterruptable power supplies, etc.) do not suffer from this problem at all. However, unlike NiCad and NiMH batteries, which thrive on deep discharges, if you drain a lead acid battery fully, you may ruin it and might not hold a charge ever again. I just wanted to mention that because some folks don’t realize how lead acid batteries differ.
Lithium ion batteries are the latest attempt to overcome the memory effect without resorting to the big, heavy lead acid batteries which are too cumbersome for laptops and other portable devices. Li-ions seem to combine the advantages of both technologies. They hold more charge than a NiCad or NiMH, yet they do not suffer from the memory effect. In this sense they are like lead acid batteries. However they are no heavier or bulkier than NiCad or NiMH, and they do not mind being deep discharged.
As laptops evolved and became more and more ridiculous (bigger screens, faster CPUs, lots of power hungry accessories, etc.) NiCad/NiMH were not providing enough juice to get usage durations whereas Li-ion provides a very nice block of time for even the most power hungry laptops.
In my experience the Li-ion batteries do not suffer from the memory effect at all. I plug and unplug mine with no regard for its relative charge—and I do not think you should concern yourself with this matter either. Your reseller is probably just offering you advice he was trained to give based on earlier battery technologies. I certainly wouldn’t encourage the practice of recklessly plugging and unplugging your PowerBook…keep it plugged in when you can, and use the battery when necessary. If you charge the batteries, do so for uninterrupted blocks of time if possible. But don’t concern yourself too much with these details…particularly if you are on the run.
Lithium Ion batteries are really fabulous—they are the best batteries we’ve seen yet, and everybody is jumping on the bandwagon: cordless phones, and all sorts of other battery powered gadgets are all switching over because the advantages are clear. Li-ion is still pricier than NiCad or NiMH—but that should change as they become more widely used. —Evan Trent
Does anyone have experience of trying to work with files in Real Audio format?
There’s a radio program here in Sweden about old customs and traditions, which you can download every week to listen to at home. That’s very nice…but they’ve gone for Real Audio format, and the friend who wants to archive them isn’t a computer user at all, and needs them on audio cassette.
The files are a bit quiet and I would have liked to normalize them in my sound editor, SoundMaker, but I can’t see any way of converting the .ra format to anything else—neither by exporting from the RealAudio player or producer, nor by importing into QuickTime Player, SoundMaker, or SoundApp.
Even just playing the files and recording them in the background direct in the cassette recorder doesn’t seem to work, I think, because the Real Audio player is constantly trying to connect to the Internet—which I don’t want since I have a modem/phone connection. And when the dialog box is on the screen the playback gets interrupted.
So it boils down to two questions, I guess. Can I convert from .ra format to something more flexible? Can I run the Real Player without it trying to connect to the Internet all the time?
This is an interesting question. I have come across a handful of plug-ins for sound editing suites which will export to the Real Audio format, but I have not found any that will import the .ra filetype.
One program to try is RealProducer Basic. This is a free program from Real that lets you create and edit .ra files. I have never used it and I have no idea if it will allow you to export to another format, but it’s worth a shot. They have a commercial version, RealProducer Plus, that provides considerably more in terms of functionality. But before plopping down cash I would ask them about the program to see if it can export to AIFF, for example.
It is possible that as Apple and Real.com become more closely intertwined that a RealAudio codec for QuickTime will show up, and then in theory any QuickTime capable audio or video editing suite should be able to do what you want. But I wouldn’t hold your breath on that one.
With respect to your question regarding recording .ra files as they are playing, keep in mind that there are two types of RealPlayer streaming files. Some files contain the audio data, just like an AIFF or System 7 Sound (double-clickable sound) file. These files tend to be on the larger side. However more often than not RealPlayer downloads a tiny little file which is, essentially, a bookmark to the RealAudio media server that hosts the audio or video stream. When you open or double-click that file RealPlayer will attempt to connect to the Net and retrieve the data, just as if you double-clicked on a URL bookmark file in the Finder.
The easiest way to determine which type of file you are dealing with is to get info on it in the Finder and determine its size. If it is very small, it is merely a bookmark; if it is larger, it is the actual audio/video data. In the case that it is a bookmark you will have to record the music out to a cassette recorder while connected to the Internet and listening to the audio in realtime.
The best way to do this is to connect your tape recorder to your Mac’s headphone or AV outputs (depending on the particular model Mac you have) and then set the audio output appropriately in your Sound (or Monitors and Sound) control panel.
If you need to amplify the output beyond RealPlayer’s maximum volume level, you may need to get an outboard amplifier from a local electronics/audio store for a few bucks. Here in the States I can get them at Radio Shack for about $10—$15. They go in between the computer and the cassette recorder and have a little volume knob so you can amplify the signal. The quality is usually quite poor, but it’s a cheap fix.
There may be some options on the PC, and if you are willing to run Virtual PC and ask the Real.com folks about PC options, then perhaps that will prove to be a worthwhile solution. —Evan Trent