MP3 vs WMA

[JethroUK]

Hi

My Car stereo plays mp3 & wma files (neat :o) - i understand that wma files are half the size of mp3 - i converted a few cd tracks to wma and found them not to be half the size of mp3 but in fact a bit bigger? i converted both mp3 and wma to same rate (128k x 44k x 2)

Am i doing something wrong?

[FRZ]

Re: MP3 vs WMA

Hi

My Car stereo plays mp3 & wma files (neat :o) - i understand that wma files are half the size of mp3 - i converted a few cd tracks to wma and found them not to be half the size of mp3 but in fact a bit bigger? i converted both mp3 and wma to same rate (128k x 44k x 2)

Am i doing something wrong?

WMA files are not "half the size of MP3" unless you encode them @ half the bitrate, but then they will not sound nearly as good.
When you use VBR mode, the bitrate is an approximation that is generally, but not always, fairly accurate.

Your conception of audio compression needs some tuning. I recommend www.hydrogenaudio.org

[ChristinaS]

Re: MP3 vs WMA

WMA being half the size of MP3 comes from empirical results that show that wma at half the bitrate of an mp3 is about the same perceived audio quality as that mp3. This applies more at lower bitrates, like below 128kbps.

Because the bitrate is half for the wma, then the files size is also half that of the corresponding mp3 file to get similar perceptible audio quality.

So your 48kbps wma will sound about as good as the 96kbps mp3, but occupy half the space.

The best example is wma at 20kbps which is still acceptable whereas mp3 at 40kbps is quite poor.

Some internet radio stations often broadcast at 20kbps wma. It's low bandwidth and the audio quality is fair.

[xoas]

Re: MP3 vs WMA

As may be apparent, there is a difference of opinion regarding whether a wma file of a given fairly low bitrate is equivalent in quality to an mp3 of twice the bitrate of the wma file. Some people claim, on the basis of their experience that this is true. Others, myself included, disagree. My own listening tests (although not really scientific) convinced me that wma at low bitrates provides about the same quality as an mp3 file whose bitrate is half again as large (rather than twice as large) as the mp3 file. Thus, I find a wma file at 64 kbs is roughly the same quality as an mp3 file at 96 kbs (whereas for Christina the equivalent mp3 file size would be 128 kbs).
Regardless, wma provides superior quality to mp3 at low bitrates (and there has been a great deal of improvement in WMA's abilty to provide good quality at higher bitrates).
And I do not dispute what Christina says as being true for her. Where the true difference lies depends on a number of factors including your equipment, your listening environment, the types of music you listen to, and your own auditory acuity. For the purpose of your car stereo, cars are known to be a cruder listening environment and listening while driving is hardly likely to be as discerning as listening you might do when you are solely focussing on the music. So for car stereo, Christina's statement is more likely to be true for me than would be listening to music over my stereo system at home.

I mention this chiefly to provide you some perspective on this issue and, to the extent this makes a difference to you, to encourage you to try out different bit rqates in wma and/or mp3 to see what works for you best.

Best wishes,
Bill

[ChristinaS]

Re: MP3 vs WMA

You're right Bill, I think I've seen some other references to 1.5 being the factor involved rather than 2.

Some files compress well to low bitrates, others don't. For myself in general I find the factor of 2 to be about right. My hearing isn't all that sharp, nor do I have any great sound systems for sure.

[Spoons]

Re: MP3 vs WMA

in any event WMA VBR Q 10 or Q25 sounds great and takes up little space.