MP3...in Surround Sound 247
A number of people sent in the latest news from the fine folks at Frauhofer that they are expecting to have surround sound working for MP3s by July. The details are pretty sketchy in the article, but supposedly it won't be much more space per MP3s, and existing players will work with it.
Ipod? (Score:3, Interesting)
DRM (Score:2, Interesting)
Silly? (Score:5, Interesting)
If they are just adding information to the main track, why put that information in the file to begin with? Just let the user have a "spatial" encoder plug-in that jacks into winamp or whatever. Doing it this way increases the file size for everybody... people with and without surround systems.
Surround information should not be "created." It should be ripped and converted from the original source.
Before long we'll have the mp3 mess that we currently have with all the video codecs.
Davak
MS ahead of the game?? (Score:4, Interesting)
Was MS first to have this technology for the mainstream consumer???
Re:Ipod? (Score:3, Interesting)
As far as ipod updates go it's fairly easy. ITunes will pull down updates when new ones are released and updated your ipod when it's connected. Not very difficult and apple is on top of their updates. Apple makes updates easy.
Re:Ipod? (Score:3, Interesting)
It would need a new connector, because you can only get stereo stereo from the iPod as far as I can tell. And how do you get surround sound from a pair of headphones with only with a left and right channel? Or am I missing something here?
Comment removed (Score:3, Interesting)
Re:Competition (Score:2, Interesting)
http://www.zalman.co.kr/english/product/ZM-RS6F
How discrete are the channels? (Score:2, Interesting)
Re:Nothing to see here. (Score:5, Interesting)
One of the places Ogg Vorbis has become surprisingly popular is in soundtracks for computer games. The no licensing fees must be one useful aspect, but there's also definite technological advantages such as better compression, more channels and - very important for sound effects and looped audio - arbitrary length samples.
I was really impressed to discover that Halo for the PC uses Ogg Vorbis for all its sound, and it's published by Microsoft! It's not alone, either - if you've bought a PC game at all recently there's a good chance the audio's compressed with Ogg Vorbis.
Is Ogg Vorbis successful? I'd say it was.
Re:Previous extensions, like mp3-pro, not successf (Score:1, Interesting)
we'll wait and see what happens later
Re:How hard will it be to convert? (Score:1, Interesting)
Binaural Explained (Score:5, Interesting)
It would need a new connector, because you can only get stereo stereo from the iPod as far as I can tell.
For a surround output to an audio system, you would need a new connector offering at least 4 channels (Front L/R, rear L/R), line level. They'd probably make it straight-up 5.1, though.
And how do you get surround sound from a pair of headphones with only with a left and right channel?Easily. Headphones have two channels (L/R), you have two ears (L/R). Your brain does some pretty heavy duty phase analysis to figure out where a sound is coming from. In fact, binaural recording is a technique where two microphones (L/R) are mounted on a form resembling the human head, but you need to wear headphones for the full effect.
A portable device could either use 4 channel headphones (expensive, requires 4 amplifiers to drive them, would increase battery consumption) or could use a DSP integrated circuit to decode the surround sound channels, perform the phase analysis done by the human brain, and send this synthetic binaural signal to regular headphones.
But it's still a lot of work for little payoff. Most of the use for surround sound in any form is movies. Music tends to be mixed to 2 channels from the perspective of a listener sitting in front of the stage, so I think its importance in a portable device primarily used for music is pretty limited.
Re:WOW. Awesome. (Score:3, Interesting)
All this said, it's really annoying to have the SACD and DVD-A dual "standards". I am format-agnostic, but a lot more cooler music has been coming out on SACD, like the 30th Anniversary Dark Side of the Moon, and a whole collection of Bob Dylan albums; all of these have been remastered for SACD Stereo or SACD Surround Sound, and the quality is fantastic.
Anyway, my recommendation for a universal player is the Pioneer DV-563A [pioneerelectronics.com]... it's pretty inexpensive, at about $160 in the stores, and can handle both SACD and DVD-A. Just make sure your receiver can take those inputs as well...
Multichan MP3 is already *in* the MPEG2 standard (Score:4, Interesting)
ISO13818 describes
* the Low Sampling Frequency extensions (which describe encoding mpeg audio at 16/22.05/24 kHz). This is already incorporated in most encoders.
* 3/2-stero+LFE (Section 0.2.3.2 describes the various configurations e.g. 3/2, 3/1, etc)
For a very brief moment when I had too much time, I worked on getting the multichannel stuff working in tooLame (the layer2 mpeg audio encoder) and the way it works is this:
1. The encoder works out the overall bitrate for all the channels (X bits)
2. The encoder assigns some bits (Y) to be used for the backwards compatible 2-channel stereo so that all compliant decoders will work. Y gt X. (The way the 5 channels are crosstalked and cancelled out to get 2 stereo channels is complex. Read the standard if you want more info).
3. There will then be Z bits (Z=X-Y) left over for the storage of the other channels. (Referred to as "Ancillary data").
4. The beginning of the mpeg audio frame has a flag set so that compliant decoders know about the extra info.
5. Old decoders won't grok the flag, and so they'll just read the stereo info, skip over all the extra info and then find the next bit of data they do understand.
The outcome of all this is that you may have a 512kbps mpeg audio stream which contains 256kbps of the stereo information and then 256kbits of "extra" info that is used to reconstruct the full 3/2 channels of sound.
There is a problems with this however. Compliant MPEG audio streams have a maximum bitrate as set out in the original MPEG1 standard (11172). For example, the maximum total bitrate of a 44.1kHz mp3 file is 1011 kbps. However, when you do really high bitrate multichannel stuff, you can exceed this limit: in this case, the MPEG2 standard suggests using another file to store the information (referred to as the "extension bitstream").
Hope this helped someone.
later
mike