Xing Technology Audio Catalyst 2

An inexpensive program from MPEG software veterans Xing makes MP3 ripping and encoding quick and easy. But does it produce worthwhile results? Simon Trask has a ripping time with Audio Catalyst...

Historically, the software to rip, encode and play back audio in MP3 format has largely been made available as freeware or inexpensive shareware, more as a result of grassroots enthusiasm than any calculated commercial strategy. There again, the shareware approach has proved a very effective way of building a large user base, which in turn makes small companies attractive to bigger ones with plenty of money to spend — as Nullsoft, developer of the Winamp MP3 player, found when it was acquired by AOL in a multi‑million dollar deal this June, and MediaScience may yet find if the rumours as at writing about Yahoo! acquiring their Sonique MP3 player pan out. While MP3 player software has been the undoubted star of the MP3 scene, the software to encode audio in MP3 format has been thinner on the ground. Last year, MP3 technology licensing issues concerning royalties on encoding technology saw many freeware encoders disappear when the Fraunhofer Institute began pursuing its MP3 patent rights and associated royalty demands.

As a company which has specialised in developing MPEG encoding and decoding software since the early nineties, Xing Technology was well placed to involve itself commercially in the MP3 software scene. Last year it launched its XingMP3 product range, including an MP3 ripping and encoding program for Windows called Audio Catalyst. Sensibly, the company priced the software at the upper end of the shareware market, striking a balance between affordability and viability while also appealing to the large base of shareware users. It also made a demo version of the program available online, and sold the software in downloadable form from an online retail outlet. Xing has positioned itself well to catch the commercial upswing of the MP3 market, a fact borne out by its acquisition in April this year by the media streaming giant RealNetworks. Fortunately for MacOS users, Xing also released a Mac version of Audio Catalyst in February this year, and with the recent release of version 2.0 for Mac hot on the heels of the Windows v2.0 release, Mac users seemingly won't be the poor relatives either. Audio Catalyst, in both its Windows and Mac incarnations, is modestly priced at $29.95 from Beyond.com, the official online retail outlet.

Good Timing

The main Audio Catalyst screen.

Audio Catalyst, then, is a combined ripper and encoder. For those not familiar with the terminology, 'ripping' is the term traditionally used in MP3 circles to describe the process of converting a CD track's digital data into a computer‑readable stereo 16‑bit 44.1kHz audio file (WAV format on PCs, AIFF on Macs) which can then be encoded into MP3 format. Part of Audio Catalyst's appeal is that it can rip a track from CD and then automatically encode the ripped file into an MP3 file — effectively combining the ripping and encoding stages into one process. The program can also skip the ripping stage and just encode AIFF or WAV files into MP3s — so you don't have to burn your own recordings to CD before you can encode them.

MP3 encoding is scalable, meaning that you can choose the bit rate you want to encode at, offsetting sonic quality against file size. The de facto bit rate for MP3 files on the Internet is 128kbps (leading MP3 site MP3.com even specifies this rate for MP3 tracks hosted on its web site). This is because 128kbps is considered to provide the best‑case combination of reduced file size and acceptable audio quality, combining as it does an 11:1 compression ratio with what is variously called 'CD‑quality' or 'near‑CD‑quality' stereo audio.

With 128kbps stereo encoding, Audio Catalyst compresses a four‑minute track down to a 3.6Mb MP3 from a 40.5Mb CD‑quality stereo WAV or AIFF file. Xing claim that Audio Catalyst offers the fastest MP3 encoding times available, and it certainly doesn't hang about. With the program running on a 233MHz G3 Power Mac, a four‑minute track took just under half that time to encode at 128kbps. If you're ripping tracks from CD as well as encoding them then the overall process takes longer, of course; using Audio Catalyst's Rip Faster option, which copies the data at drive rate (24x in this case), the same four‑minute track took just over half a minute to rip.

If you select the Enable Temporary Buffer option in Audio Catalyst's encoding preferences window, the program rips to disk first then encodes from the ripped file, while with the buffer off it encodes as it rips. With version 1.0 the latter optiocould result in a burst of static at the beginning of an encoded track, a problem acknowledged by Xing in the ReadMe file. In practice I didn't find the buffer‑less option useable because of this. The static burst problem hasn't gone away with 2.0, and Xing are still acknowledging it in the ReadMe. In addition, I was getting some worse problems, where seemingly just the first few beats of a track would be encoded repeatedly. Xing have introduced a new feature called Rip Offset which lets you set start and end offsets in frames (75 frames = 1 second) up to 150 frames, but I didn't find this to be reliably helpful.

In the (electronic) documentation, Xing mention that if buffering isn't used problems can occur when the CD‑ROM is delivering data faster than the program can handle it, and for this reason recommends only using VBR encoding (see below) with buffering enabled. There again, selecting More Compatible (1x speed, the altenative to Rip Faster) didn't help matters. So all in all I found myself, again, sticking with the temporary buffer facility. With v1.0, I wasn't able to switch to another program during the ripping process, but thankfully with the new release this is possible — though you still can't stop the ripping process once it's underway, so be sure before you decide to rip that 30‑minute track! Encoding, as before, leaves you free to do something else on the computer while Audio Catalyst works away in the background — it even beeps to let you know that it's finished the encoding process — and you can stop it at any time. Of course, background encoding does take longer, as Audio Catalyst is sharing the computer's processing power, but it still clocks in at significantly less than the track duration. In fact, perhaps surprisingly, MP3 encoding isn't particularly CPU‑intensive; at one point, just for the hell of it, I had 128kbps stereo ripping/encoding, two MP3 tracks, a MIDI file and an AIFF stereo audio file all happily running at once, across five different programs, and the encoding time was still less than the track running time. Other Audio Catalyst options allow you to rip to a stereo 16‑bit 44.1khz AIFF file only, or load a PCM AIFF or WAV file from disk and encode it. And once you've encoded a file in MP3 format, you can select Launch Player from Audio Catalyst's Player menu to bring up an MP3 player you've previously chosen via the Set Player option (a new feature also lets you set the file type and creator for your MP3 files, so that when you double‑click on your files they open in your chosen player).

On Display

Audio Catalyst supports encoding in a variety of different bit rates, stereo and mono modes, and both constant and variable bit rates.

Although Xing have prettied up Audio Catalyst a bit in the new release, with a few coloured buttons in the main window, the program still won't win any awards for visual flair. The design is functional, crisp and easy to navigate, and the extra parameters for the new features in 2.0 have been well integrated into the basic user interface. The reorganised interface gives you the main encoding window, four preferences windows, and an ID3/track‑information window. The windows aren't resizeable, but apart from sometimes wishingcould make the track listing section of the main window bigger I didn't find this to be a problem. And there's plenty of room on screen for an MP3 player as well, even at 832 x 624 resolution. To add AIFF/WAV files or CD tracks to Audio Catalyst's track list, you can press the Add From File and Add From CD buttons, or drag file icons directly into the list from their folders on the desktop. CD tracks and AIFF/WAV files can be combined in the program's track list. Add From File uses the open/save dialogue, while Add From CD has its own CD Tracks window which lists the tracks on the inserted CD numerically and shows their durations; Play and Stop buttons in the window allow you to quickly audition tracks before selecting them, while Add All and Add Selected buttons let you quickly select the whole CD or one or more tracks (Command‑click to add extra tracks).

Encoding

Audio Catalyst's CD Tracks window.

Audio Catalyst's File menu duplicates the Add From CD and Add From File options, and also provides access to another couple of sourcing and encoding methods: Encode Direct Sound In and Realtime Encoding. You can use these to encode analogue sound input in real time from the Sound Monitoring Source that you select in the Monitors & Sound control panel. The former option first digitises the audio input to an AIFF file, then encodes the file in MP3 format. Realtime Encoding, as its name suggests, encodes thincoming analogue signal directly to MP3 as it receives it. Unlike the ripping and encoding method, both these options let you listen to a track as you're capturing it. Realtime Encoding lets you set input gain level prior to recording, but what's missing from both the real‑time options is a threshold triggering capability. There are now options in the Preferences to delete leading and trailing silences automatically, but these didn't work with either Encode Direct Sound In or Realtime Encoding; with the former, prior to encoding the AIFF file Audio Catalyst said it was deleting trailing silence, but on playback the resulting MP3 file still contained the silence.

Xing say that any PowerPC‑based Mac with System 7.5 or greater can run Audio Catalyst. However, when it comes to the Realtime Encoding option, the less technically defined requirement of "a really fast computer" is all that you get. Perhaps not surprisingly, the impromptu multi‑tasking test I described above did result in some dropped frames in the encoded file (producing an effect akin to a record needle skipping grooves), but Realtime Encoding running by itself presented no problems on the G3/233.

Audio Catalyst supports both CBR (Constant Bit Rate) and VBR (Variable Bit Rate) methods of encoding audio into MP3 format. With CBR, you select a fixed bit rate and the program encodes at that rate throughout the track regardless of the actual audio content at any point. Audio Catalyst gives you a choice of 14 bit rates, or CBR Quality settings, ranging from 32‑320 kbps (kilobits per second). The main advantage of CBR is that file sizes are a known quantity; in addition, playback of CBR files is more widely supported, and timing information more reliably presented in players.

With VBR encoding you can choose from five quality settings: Low, Low/Normal, Normal, Normal/High, and High. The main advantage of VBR is that it provides a more consistent audio quality thoughout a track, because more bits are allocated to passages which present greater encoding difficulties (such as sections containing relatively wide stereo separation). At the same time, easy passages (most notably silence!) are allocated fewer bits. Still, the size of a VBR‑encoded track can't be predicted, which is one potential drawback; others are, as mentioned above, that VBR playback isn't supported so widely, and that not all players will read VBR track timing information correctly (though VBR support is improving). Of course, if you're encoding your favourite CD tracks from your collection purely for your own use, these drawbacks won't apply. Other options, available for both CBR and VBR, are Stereo, Joint Stereo, Dual Stereo, and Mono recording (mono is automatically encoded at half the selected bit rate with CBR — for instance, with 128kbps selected, it is encoded at 64kbps). Joint Stereo, the default method, is the most versatile option and delivers the best results for music. Additionally, you can choose MPEG‑1 or MPEG‑2 Layer III encoding, or let the program automatically choose the more appropriate method (the latter option is the default and recommended one). Another new option lets you choose the start and end points for encoding; these are presented relative to the start of the CD, not the individual track, which could be more confusing but also means you can encode more than one track at a time. Finally, a new Normalisation feature has been included to facilitate level matching of tracks from different CDs.

Labelling And Cataloguing

One of the biggest areas of improvement with version 2.0 has to do with labelling tracks. Audio Catalyst now supports writing to and reading from the Mac's CD Remote Programs file. This is a file which sits in the System's Preferences folder and holds artist and track data. Originally it was designed by Apple to store data entered manually into the AppleCD Audio Player program by users, but it can be accessed by other programs. When a CD with entered details is inserted subsequently, the details can be retrieved automatically from the CD Remote Programs file.

This capability really comes into its own with the CDDB, or Compact Disc DataBase, an online database of CD artist, title and track data information built up by Internet users from around the world. Originally a public project, it is now owned by a private company. Version 1.0 of Audio Catalyst was able to log on to the CDDB and retrieve information for a CD if it was available in the database (and a surprisingly large range of CDs are included), but couldn't store it locally. This was all very well for anyone having a constant net connection, but tiresome otherwise. Version 2.0 not only stores retrieved data locally in the CD Remote Programs file, but crucially, it can also check the local file before looking up the CDDB, and you can tell it not to check the CDDB if it doesn't find the CD details locally (so it won't try to log on to the net when you don't want it to).

...I came away pleasantly surprised, even impressed, with the quality of the MP3‑encoded tracks that Audio Catalyst was able to deliver...

When you select CD tracks for ripping and encoding, the program doesn't automatically check for their information locally — you have to click on the rightmost icon in the main window to initiate the search. For successful matches, Audio Catalyst displays track titles in the list. Double‑clicking on a track calls up the ID3/Track Information window, which displays full information for the track and lets you input or alter this information along with the filename. ID3 is an open and fairly widely adopted protocol (see www.id3.org) for track‑identification information which is included with encoded MP3 files and read and displayed by MP3 players. Currently over 70 ID tags are defined, though typically only a small number of those will be supported by programs. What's more, not all players will support the same version of the spec; for this reason, Audio Catalyst gives you a choice of ID3 v1, 1.1, 2 and 2.3 (or you can turn off ID3 tagging altogether).

Final Encoding

While Audio Catalyst (still) won't win any awards for visual flair, I was impressed by its speed and reliability/robustness in operation, and by its combination of ease of use and flexible encoding functionality. Having tried out the program with a variety of artists, tracks and musical styles and a range of encoding choices, playing back its MP3 files using both MacAmp and MRAP, and A/B'ing with CD originals, I came away pleasantly surprised, even impressed, with the quality of the MP3‑encoded tracks that Audio Catalyst was able to deliver — perhaps most importantly at the widely‑used 128kbps bit rate. MP3 won't shame your recordings — but equally, of course, it won't make them sound better! In fact, it's worth bearing in mind that an MP3 track that sounds duff may simply have been recorded or mixed badly. Having said that, MP3 isn't the be‑all and end‑all of perceptual audio coding technologies — already MPEG AAC (Advanced Audio Coding) as pioneered by a2b music/AT&T and adopted also by Liquid Audio, offers superior quality at equivalent MP3 bit rates, or alternatively equivalent quality at lower bit rates (which means smaller file sizes). But the momentum behind MP3, both commercially and as an open format, shouldn't be underestimated. Now is a good time to explore MP3 encoding, and this is the program with which to do it.