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Subject:Joint-stereo vs Stereo mp3 encoding... Posted by: Xpred Date:3/6/2005 8:59:31 PM What is better usually? I've been hearing lots of myths about JS is better cause it's lossless, but don't know for sure...
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: mpd Date:3/7/2005 5:39:24 AM Joint stereo encoding is lossy. With encoding parameters, you really need to experiment, and the results will depend on your audio file.
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: rraud Date:3/7/2005 10:21:48 AM All mp3 s are lossy. A mono file will have less file compression (=cleaner sound) than a stereo file, all things being equal except "convert to mono"
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: SonyNateM Date:3/8/2005 9:36:33 AM Yes, all MP3 files are lossy. There is no such thing as a "lossless" MP3 compression. Most of the MP3 files you come across in day to day life are encoded in joint-stereo. For many files this will allow for a better preservation of quality than true stereo encoding. In the descriptions below "bandwidth" refers to the bits available to encode the audio (128kbps, 192kbps, etc) Mono: 1 channel of audio (full bandwidth used for each channel) Dual Mono: 2 channels of audio containing redundant data (half of bandwidth used for each channel) Stereo: 2 independently encoded channels of audio (half of bandwidth used for each channel) Joint Stereo: This uses Mid-Side encoding of the audio to help preserve quality and the stereo field. Most bits are used to encode audio that is redundant between both channels (audio on the center channel). The other bits are then used to encode the audio that is only on the left or right channels. Since in most situations the center channel will contain most of the audio you hear, this generally creates a higher quality sound file while preserving the stereo field. (Most of bandwidth used for center channel, left over amount divided between left and right channels).
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: mpd Date:3/8/2005 1:47:46 PM Joint stereo in MPEG audio is a little more complicated that just mid/side encoding. When you enable joint-stereo, the encoder chooses between normal stereo and joint stereo on a frame-by-frame basis. It also uses two type of joint stereo. One is mid/side encoding, and typically more bits are allocated to the middle channel than the sides. The other is called intensity stereo, which is basically a mono signal with some direction info. Intensity stereo is a psychoacoustic effect, and is only used on the upper portion of the band, and is only typically used at lower bitrates.
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: SonyNateM Date:3/8/2005 3:18:17 PM Thanks for the addition, mpd. Yeah... I should probably update the MP3 whitepaper in the Knowledge Base.
Subject:RE: Joint-stereo vs Stereo mp3 encoding... Reply by: farss Date:3/10/2005 4:21:23 AM That's be appreciated, I do a lot of mp3 encoding of talking books which have only a small portion of stereo music, the rest being mono narration. I'd kind of worked out that Joint Stereo would give the best results. I'm curious to know how many devices now support VBR mp3, I'm under the impression that this is still not that widespread. Not really a big issue as compatibility is our biggest concern, for that reason alone we encode at 128K. Bob.