..:: ZOMBiE Destinee ::..

Friday, November 03, 2006
How to choose the correct lossy audio codec for you
[ZOMBiE CyGiG] ranted at 8:40 PM --- Post#116256042354423138

We have mp3, ogg, wma...lots and lots of audio codecs. If you dunno what an audio codec is, it is the format that you music is made up of and how the computer data are structured to represent the sound. Just like there are formats for exams, letters, dining...Different audio format definitely sound different. By sounding different it means how nice and how bad your music sound, not that guitar will sound like drums. Just like an obvious example is that we know mp3s from our computer generally sound better than normal telephone and common radios.

Mp3, ogg, wma and so on are call lossy format, while CD/DVD audio, FLAC, APE, PCM Wave are lossless audio. Lossy audio makes file size smaller by striping out certain frequencies that our ear mostl likely cant hear. Lossless audio do not lose quality when converting from one lossless format to another. Lossy audio are normally "ripped" or processed from audio CD to produce your familiar mp3 or wma.

When ripping from a CD, we are sometimes given the choice in perhaps Windows Media Player or iTunes to choose the bitrate. Bitrate refers to how much data is held per second, the more the bigger the file size and sound better and visa versa. Common bitrate includes 128 kbps, 192 kbps, 320 kbps and so on.

But how much bitrate and which format to choose from? Between the various audio format, the differences are actually quite minimal. Some say that ogg vorbis and musepack yield the best quality compared to other lossy audio format of the same file size, so you may be considering them, but take note not all digital audio player support these formats. Vorbis and musepack are open source format as well. The file size difference of the same bitrate between these formats are usually matter of few kilobytes, thus file size is also not a major concern.

The majour thingy is how much bitrate suits you? 128kbps? 256 kbps? What i did was not to rely too much on "technically which will sound better", but rather if my ear can tell. Normally we listen to a collection of music of different tracks, the best bitrate for you is when you cannot tell if the sounding is good or bad.

Some people can tell between 64kbps mp3 and 192kbps mp3, while others cannot. By being able to differentiate, it is more useful that you can differentiate the two different bitrate independently THAN comparatively. If given two similar sound source, one of 64kbps and another of 320kbps, and you play one source after another using a delicated earphone and good player, most people will be able to differentiate the different. Its simply because our ear can draw a distinct comparison when the play the two sound source one after another. This is comparative differentiation between a good and bad sound.

But if given two different sound source (ie different track), you may not tell the difference. As mentioned earlier, we listen to music in a way that each track normally differs from the previous one, thus our brain find it difficult to really draw comparison between which track sounds better than rest as every track is different. For example is easier to tell which apple is sweeter between two, than to tell which is sweeter between an apple and a pear, because generally the taste of apple and pear is different, which makes it difficult to tell which is the sweeter one. But if your tongue is sensitive, yes you may be able to tell. Similarly, this is independent differentiation between a good and bad sound.

So for a rough gauge, take eight different songs and encode two in 128kbps, two in 192 kbps, two in 256kbps and the remaining two in 320kbps. Remember to do this from an audio CD. Never encode a lossy to lossy format, eg 128kbps mp3 to 320kbps mp3. There will only be further loss in quality. Then play the six songs, and see if you can tell which song has a better quality than another and which few songs you cant tell at all. Try to get a decent earphone and player for this test.

If between 192 and 320 you cant tell the difference, a good choice of bitrate maybe 192 or 256. But if you really cannot tell the differences between the above eight songs, congratulations! You have an untrained ears and you need not waste money on upgrading your equipments. 128kbps should suffice you. Generally i will recommend 128kbps as the minimum you go. And if your mp3 player has enough space, just go as high as you can, like 256 or 320 kbps.

As a note, when ripping, you may be given an option to rip at a certain speed, nromally "Fast speed lower quality", "medium" and "slow speed best quality". I will strongly recommend ripping at slower speed, that few more minutes of ripping will not increase your file size but will do significant upgrade to your sound quality.

View/Post Comments (0)