MPC vs OGG VORBIS vs MP3 at 175 kbps
Reply #19 – 2004-07-12 12:11:49
Do you have details on the ABX tests ? If you're talking about ABX log and comments, they're all in the .zip archive, accompagning each sample. Not the best idea I must say. I'll upload the log files in a separate and slim archive.Did you do them for every sample ? Yes, but for some files, I've renounced to ABX encoded files against encoded files. Sometimes, difference is very small. These kind of tests need much more concentration. I've nevertheless try to compared encoded files each others when they're sharing the same kind of flaw, in order to have a better idea of which sounded better.Do you train before beginning ? No. I didn't use the latest ff123 ABC/HR soft (offering a training module). The only training I've done was with the Diana Krall samples. It's a sample I've discovered some times ago, when I noticed that mpc --standard produces audible distortions on the cymbals. I've first began my test mith this sample as dilettante, without ambition, comparing MPC against one Vorbis encoding and one MP3 encoding. Then, I have decided to avoid some possible criticism about bitrate by using a wider set of encodings for vorbis and mp3, in order to see how are performing these file formats even at higher bitrate: at their optimal quality (the "excellence step" for each format: --standard, --alt-preset standard, and -q 6,00).How much ABX sessions do you perform ? What were the results ? Generally, I've stopped when pval was low enough. FOr some files, I've ruined the results by doing some mistake. Angry, I've damaged even more the results. Therefore, for some files, I've went up to 50 trials in order to reach again satisfying pval. But you can find precise values by downloading the archive on my ftp.