AAC format tells me nothing. At this time, mp3s are NOT AAC. AAC uses psyco acustic compression before the normal lossy compression which removes enough high pitch to conform to the bit rate. This provides a tiny bit more quality. M4as, wmas and a host of other formats are. I doubt they will go to WMA or some other AAC format.
6.2.2009 08:37 #1
Originally posted by Mez: AAC format tells me nothing. At this time, mp3s are NOT AAC. AAC uses psyco acustic compression before the normal lossy compression which removes enough high pitch to conform to the bit rate. This provides a tiny bit more quality. M4as, wmas and a host of other formats are. I doubt they will go to WMA or some other AAC format.AAC is a Lossy Compression format capable of delivering relatively high quality at relatively low bitrates for either MPEG2 or 4 compression so this is a good thing and a standard format instead of their proprietary impossible to manage format, that is without their iTunes player.
I wouldn't purchase from them but for those that do this is a good thing.
6.2.2009 12:48 #2
Itunes releases their tracks in AAC format, they chose it so they could put in the DRM, so their just going to disable the DRM and keep the format....
8.2.2009 11:49 #3
engage16, AAC is not a format but a compression concept. Yes mp3s can not be DRMed while AACs can be. Not because of the compression process but because the files are held in a package that can be DRMed.
EVERYTHING but lossless and mp3s are AAC. That is why I said that doesn't tell me much.
I do understand what AAC is.
AAC is only a bit better than CBR mp3s but it IS better. I realise they are trying to bundle the best quality in the 128 package. However, the extra compression that is used, psychoacoustic compression (PS), actually does not add much to the quality because of how it is used. PS throws away what you can't hear. Normal compression uses lossless compression techniques then adds a lossy compression. That lossy compression removes high pitch, hard to hear tones that that up lots of bits. PS is great for reducing the size of variable bit (VBRs) rate mp3s but is not as valuable for constant bit rates in AAC. The best place to seriously throw away bits is during silence. Adding higher frequencys during silence or relitive silence does not give you much. That is how AAC works it adds higher frequency music to make up the difference for psychoacoustic compression savings. AAC has varable quality where VBRs have variable bit rates both as a result of the variable compression.
I also don't like AAC because each format I know of is specific to a player. Only apple players play apple AAC. More play WMAs but Apple products don't play them. That is why I was wondering what the format was. Maybe they will make a mp3 compatible AAC. But that would be too good to be true.
AAC does not cleanly convert to non AAC formats. VBRs of about the same bit rates are as good as you can do.
9.2.2009 10:06 #4
How about just releasing MP3s? Would than not be FairPlay, if you were allowed to play the music that you bought fair and square? I know that an MP3 will Play4Sure, unlike the microsoft product.
As for bitrate, I know they make a lot of claims about audio quality, and AAC is more efficient than MP3, but not by enough. I know that they claim transparency at 128K, but I found it closer to 192K in testing...and that is the same place that Lame MP3 seems to get transparency. Maybe it is just that the music I listen to is too complex, or has too many frequencies outside of the areas that AAC is targeted at...or maybe the whole supposed quality thing is just a lie to get people to accept a format that is designed for DRM.
19.5.2010 02:10 #5
