PDA

View Full Version : more help needed with mp3



duck-billed platypus
12-28-2001, 06:19 PM
Does anyone have any experience with the mp3 file format who can help me? I went to the links given to me in my last post, and I did a search on the internet. Although there is hardly any info one the technical aspects of mp3, I did manage to find a few things, but they all gave different information (albeit slightly) !

Basically, all im trying to do is read in each frame of an mp3. Does anyone have any experience and/or any code they can share with me? (I did also find some code, but its all uncommented and impossible to read)

maes
12-29-2001, 07:18 AM
Do you wan't to make an mp3 player. If that is the case I would do it using DirectX or Windows media player. Because most is done in assembler to decode the mp3 format(I think) and I doubt many companies will give you their code. here (http://www.planet-source-code.com/xq/ASP/txtCodeId.372/lngWId.3/qx/vb/scripts/ShowCode.htm) is the source code for the xing player. I haven't been able to let it work. It has almost no comment. But I think this is the closest you can get to an mp3 player.

And here (http://www.mp3-tech.org/programmer/sources/freeamp-2.0.7.tar.gz) is the code for the freeamp player.

Sorry I can't help you any furter :(

Shiro
12-29-2001, 08:03 AM
Take a look at bladeenc.mp3.no. Also Fraunhofer has many information on MPEG.

You want to make a MP3 decoder? Google gives a lot of results when searching "MP3 decoder source".

And what kind of technical information do you need?

MPEG is a lossy compression algorithm withs makes use of the model of human hearing. Depending on the frequencies in the signal the algorithm lays a mask upon the spectrum and then decides which frequencies can be left away. This is normally done by putting the signal into a filter bank. After filtering a "normal" datacompression algorithm, like Huffman encoding, is used to compress the data. I've been working with MPEG-2 for a while, at this moment it's still the standard used by the radio stations for compressing audio. But it won't take long before MPEG-4 will be the overall standard. There are already projects going on with MPEG-4 and Bluetooth.

Justin W
12-30-2001, 06:23 PM
There's some pretty well documented code in the lib here. (http://www.allegro.cc/link.taf?_url=http://sunsite.dk/allegro/files/almp3.zip&_UserReference=65CA67D0C4D009FE3C2FB086)