difference between rm and mp3 formats

Question

rm files are comparitively much smaller in size. how do they compare quality-wise?

for a songs warehouse application, is it advisable to convert all mp3 to rm before archiving to save storage space?

Answer 1

Please, stay far far far far far away from Real Media files - they're very poorly supported by even such advanced encoding applications as mplayer.

I would stick with MP3s or at least re-encode them to a lower bitrate. You could alternatively re-encode them to .ogg, which is an open source format.

Answer 2

Unless audio quality is very much a secondary consideration, I would say you are best storing all audio in the highest quality, least compressed format you can; 16bit 44kHz WAV if at all possible. This ensures you can encode in any format you wish to in future without losing further information during transcoding.

Oh, and Real Media? Is this 1999? Run, don't walk, to any other format.

Answer 3

I echo Artem Rusakovskii's and Lunatik's replies. Do not use rm, instead use ogg.

Answer 4

I second Lunatiks answer, but suggest FLAC instead of WAV.

FLAC is a lossless compression method. Quote from http://flac.sourceforge.net/:

FLAC stands for Free Lossless Audio Codec, an audio format similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality. This is similar to how Zip works, except with FLAC you will get much better compression because it is designed specifically for audio, and you can play back compressed FLAC files in your favorite player (or your car or home stereo, see supported devices) just like you would an MP3 file.

The reason why you'd want to go with a lossless method (FLAC or WAV) for storage in a warehouse is as follows:

Lossy methods like MP3 or RM are perfectly OK quality wise. The problem shows up when you have to convert one lossless format to another lossless format. If you do for example WAV -> MP3 -> RM you will end up with a file that has artifacts from MP3 encoding and RM encoding.

The proper way to store the files would be to store lossless and convert it to the appropriate format for your customers.

         OGG
          ^
          |
RM  <--  FLAC  -->  MP3
          |
          v
         WAV

Answer 5

• For losseless data storage use FLAC.
• For loosy data storage use OGG.

Don't even get closer to RM... You would get problems.

Answer 6

Real Media is not bad at compression; but there are other codecs that better, and Real Media has patent and licensing issues, as well as being a poorly documented and supported protocol.

Xiph (the people behind Ogg Vorbis) have published a comparison between the leading codecs (rm, mp3, wma, aac, and ogg) - you can listen and compare each of the codecs.

If your data is already in mp3 (a lossy format) it would not be advisible to convert it, particularly to another lossy format. You won't gain anything much in storage, and you will automatically lose quality.