Archive

Posts Tagged ‘vorbis’

Vorbis is not Theora

April 21st, 2010 17 comments

Recently I have started to mess around with the Vorbis audio codec, commonly found within the Ogg media container. Unlike Theora, which I had also experimented with but won’t post the results for fear of a backlash, I must say I am rather impressed with Vorbis. I had no idea that the open source community had such a high quality audio codec available to them. Previously I always sort of passed off Vorbis’ reason for being regarded as ‘so great’ within the community as simply a lack of options. However after some comparative tests between Vorbis and MP3 I must say I am a changed man. I would now easily recommend Vorbis as a quality choice if it fits your situation of use.

What is Vorbis?

Like I had mentioned above, Vorbis is the name of a very high quality free and open source audio codec. It is analogous to MP3 in that you can use it to shrink the size of your music collection, but still retain very good sound. Vorbis is unique in that it only offers a VBR mode, which allows it to squeeze the best sound out of the fewest number of bits. This is done by lowering the bitrate during sections of silence or unimportant audio. Additionally, unlike other audio codecs, Vorbis audio is generally encoded at a supplied ‘quality’ level. Currently the bitrate for quality level 4 is 128kbit/s, however as the encoders mature they may be able to squeeze out the same quality at a lower bitrate. This will potentially allow a modern iteration of the encoder to achieve the same quality level but by using a lower bitrate, saving you storage space/bandwidth/etc.

So Vorbis is better than MP3?

Obviously when it comes to comparing the relative quality of competing audio codecs it must always be up to the listener to decide. That being said I firmly believe that Vorbis is far better than MP3 at low bitrates and is, at the very least, very comparable to MP3 as you increase the bitrate.

The Tests

I began by grabbing a FLAC copy of the Creative Commons album The Slip by Nine Inch Nails here. I chose FLAC because it provided me with the highest quality possible (lossless CD quality) from which to encode the samples with. Then, looking around at some Internet radio websites, I decided that I should test the following bitrates: 45kbit/s, 64kbit/s, 96kbit/s, and finally 128kbit/s (for good measure). I encoded them using only the default encoder settings and the following terminal commands:

For MP3 I used LAME and the following command. I chose average bitrate (ABR) which is really just VBR with a target, similar to Vorbis:

flac -cd {input file goes here}.flac | lame –abr {target bitrate} – {output file goes here}.mp3

For Vorbis I used OggEnc and the following command:

oggenc -b {target bitrate} {input file goes here}.flac -o {output file goes here}.ogg

Results

I think I would be a hypocrite if I didn’t tell you to just listen for yourself… The song in question is track #4, Discipline.

Note: if you are using Mozilla Firefox, Google Chrome, or anything else that supports HTML5/Vorbis, you should be able to play the Vorbis file right in your browser.

45kbit/s MP3(1.4MB) Vorbis(1.3MB)

64kbit/s MP3(2.0MB) Vorbis(1.9MB)

96kbit/s MP3(2.9MB) Vorbis(2.8MB)

128kbit/s MP3(3.8MB) Vorbis(3.6MB)




I am currently running a variety of distributions, primarily Ubuntu 14.04.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).
Check out my profile for more information.