May 19, 2004

The Great Audio Codec Test 2004

After having a few busy weeks, I find a day available to finally do this. Define in my own time, and with my own ears an audio codec test.

I was particularly taken by the promises from iTunes and Dubbers enthusiasm for converting his digital music collection from mp3 to the new AAC/mp4 technology, and since I'd also heard a bit about the open source OGG, I decided I needed to do this.

For testing I played the media through windows media player 9, winamp and foobar (for AAC/MP4) to get player perspectives. I have also written this so my Mum can understand what the hell it's all about.

Each test has a place winner, from first to fifth.

The first test I did was for - 128kbps, 44.1 stereo (CBR)
#1 The best sounding was MP3 although it wasn't the smallest file size.
#2 MP2 had a lot of high frequency 'bubbling' (Sounds like its underwater)
#3 OGG lost some treble.
#4 Windows Media Player was slow to play its own WMA files! Lots of lag and sounded metallic.
#5 AAC/MP4 was the worst sounding at this setting. just horrible.

The second test was 192kbps, 44.1 stereo, (CBR). Things should be really close to perfect here but,
#1 MP3 was as close to clean as could be, with a tiny bit of high frequency 'bubbling', but was hardly noticeable.
#2 AAC/MP4 certainly made up for its suckful performance at 128kbps.
#3 WMA still had a metallic sound to it, but had the smallest file size.
#4 MP2 still had some high frequency clipping, but not bad on the whole.
#5 OGG regained its top end, but still some bubbling on vocals.

Anything higher on any of these codecs should have been unnoticeable. So I went downward to streaming quality.

The final test was at 64kbps, 44.1 stereo, (CBR). I was looking for the cleanest, and most bandwidth friendly codec.
#1 OGG wins!. Double Take!! OGG is VERY clean and has a crisp top end. It also has the smallest file size, because it actually played at 57kbps. Unbelievable!
#2 WMA comes in a close second. Small chunk sizes, and you can hear the top end losing fidelity, but sounds ok on pc speakers.
#3 AAC lost a lot of top end. It sounds much better than mp3, considering they are the same file size.
#4 MP3 lands fourth, with only bass and midrange only. Pitiful output.
#5 MP2 is dead last in the streaming test. Sounds like an AM radio station. Muddy as hell.

#1 Big winner was still MP3 with general cross-compatibility, and consistent file sizes with most other competitors.
#2 Second runner up goes to OGG for its brilliant performance for streaming.
#3 Third place is MP2, for being a general all rounder considering its old age.
#4 Fourth place goes to WMA for best effort without superior result.
#5 finally, AAC lands last place - because of its general incompatibility, slow conversion times and average result.

FILE SHARING = MP3 (winner)
STREAMING = OGG (winner)

note - Real Media was not included because the codec could not be obtained, and it generally sucks anyway. Maybe Dubber should hold off?

1 comment:

Dubber said...

I have decided to hold off on AAC - though my own findings on comparisons at 128kbps differ from yours (the depth and clarity of AAC at that rate on my system was far superior to the less nuanced mp3). Eventually it came down to cross-platform compatibility.

I'd argue that AAC/mp4 would stand up on audio fidelity, but I'm not just archiving my CD collection - I'm also allowing for the fact that I'll be making radio programmes using both Sound Forge and Cool Edit Pro, so I need to use a format that can both work on those platforms, and sound good on the wireless... and let's be honest - once it goes through an FM processor and the broadcast chain, arguments over mp3 and AAC become purely academic. It's going to sound like crap no matter what you do.

I have a bias against WMA. I don't like it. So - I'm mp3-ing the lot. I'm buying a 160gig hard drive next week, and my CD collection will be travelling to the UK with me in a handy, pocket-sized form.