James, 2008/6/4 James Cridland <[EMAIL PROTECTED]>:
> > > @briantist: > > Obviously I'm hoping that everything that's on the iPlayer Radio will come >> as MP3s and the existing podcasts will be better quality (I would personally >> prefer a VBR stereo "In Our Time" than the current mono one). > > > VBR is something we've not actually looked at, as far as I'm aware. That's > a good and interesting thought - I'll consult with the clever people to see > if there are benefits for downloads. We are, though, not encoding everything > that the same rate; it depends on what the content is; there are four > different encoding profiles that we've identified. More though will need to > wait for the blog - and don't read this into saying that we're making > everything available as MP3 downloads; naturally, we're not. We can't. > VBR in MP3s just simply allows the encoder to pick the appropriate level of compression for each block in the MP3 stream contained in the .MP3 file. I did loads of tests (some years ago) on lots of different material, and VBR generally speaking comes out very well. But it is particularly good for speech radio (comedy and drama in particular) because it allows any short silence to be compressed (by dropping the bitrate towards zero), by using lower bitrates for speech and then automatically upping the bitrate for fully stereo music, sound effects etc. If you want to run some tests, I would have thought that "The Now Show" would be a great test, but any speech audio that contains short sections of music benefits greatly from VBR. -- Brian Butterworth http://www.ukfree.tv - independent digital television and switchover advice, since 2002
