Hello all, picked this up on: http://bboard.mp3.com/mp3/ubb/Forum1/HTML/003127.html author is Timothy, someone I respect the opinion of. I must say I pick up other artifacts, so maybe this is valuable. :) > Hi all, > I've done some more listening tests and these are merely > subjective. > > First comments are regarding the famous command line: -V 1 -b 128 -m > j -h > > Well, the same comments that I once had are again the same feelings > upon listening. Joint Stereo still leaves out certain spacial depth, > "presence", and lower midrage/upper bass filling. The sound in the > midrange sounds accurate, the highs have no apparent artifacts. In > my strong opinion, I'd say that it's damn near impossible to hear > artifacts on most material encoded with this command line on many of > the most recent LAME versions. VBR is doing a good job, but not as > good as I feel it could. As far back as LAME version 3.58, I > remember complaining that the lower mids and upper bass sounded thin > and the highs were dry as a result of that thinning (while using > joint-stereo). The same analogy applies now as then in my critique > of the most recent LAME versions. > > Comments on the "dry" factor. It seems localized with the > joint-stereo mode only. It's the only contributing command line > factor regardless of how hard I tried to get around it with > different settings and experimental modes. Only bitrates of 224 > kb/sec and higher can make joint-stereo sound "full" at the bottom > end of the sound. Also, stereo image seems to be missing certain > cues at times. Imagine hearing a sound position left, right, and > then center. Now, imagine a sound that is left of center, but not > quite left. The joint-stereo mode seems to put this sound to the > center very often for no reason, other times it does the job > correctly. This seems to leave gaps at times when certain > instruments/sounds pan or fill up the sound image. It's not very > apparent, but it's there if you critically listen on good speakers. > I found this anomally while trying out orchestra music which carries > many spacial cues. Again, as always, the point of transparency for > me is at 224 kb/sec either in VBR average or CBR mode. LAME does an > admirable job with joint-stereo at the middle bit-rate averages, but > it's not transparent to me. Every frequency range seems to be done > justice except in the lower mid-range/upper bass area. In stereo > mode, it sounds fine at any bit-rate, even the artifact filled 128 > kb/sec range. > > Achieving "Fullness" with joint-stereo should be a priority for the > LAME team. Even with -V 1, the problems is there. > > Some suggestions maybe that could work: > > -Allow joint-stereo to select more "stereo" frames. Maybe put in a > new criteria for selection of the modes within js. > > -I recommend that sf-band 22 be cutoff while using 160 kb/sec in CBR > mode as a default. My reasoning for this is that artifacts can still > be heard at 128 kb/sec CBR, and this stands to reason that artifacts > exist in 160 CBR. The difference is in the available bits. At 160 > CBR, a removal of sfb 22 should allow enough bits for > near-transparent sound up to 15KHz. That is a more appealing middle > ground for that bitrate. > > -Please insert a command line option to completely disable sfb-22 > (16KHz-22KHz), not just a lowpass filter option, but an option to > disable sfb-22 completely and insert a 15.5KHz filter. The reason > for this is that some users might like to try and test out the > removal of high frequencies to see if audible resolution improves at > certain bitrates. You can use it as an "experimental" option. Also, > in this experimental mode, can you re-structure bit distribution to > "fill-in" areas like lower-mid range scale-factor bands? I'd like to > experiment with this option more fully, especially in joint-stereo > mode. > > -masking and noise thresholds could use more improvement. Using LAME > 3.86 (-V 1 -b 128 -m j -h) I encoded Pink Floyd - Money (off the > Dark Side of the Moon album). Around the 3:00 mark, a set of guitars > solo (famous moment too). I referenced an old mp3 of this that I > made with LAME 3.36 in full stereo and VBR 3 mode. I compared the > mp3 made by LAME 3.86 in js mode, the mp3 made by LAME 3.36 in full > stereo mode, and the original wav file. Here are my results: > > -The LAME 3.36 mp3 was superior in terms of masking noise and > maintaining quality on the guitars when compared to LAME 3.86 in js > mode and using the wav file as a means of comparison. LAME 3.86 was > "tinty" or "tinny" sounding. Any metallic clink or clack was > over-emphasized and seemed tinty, not full. Vocal sybillances were > alos emphasized in the high frequencies. > > -The LAME 3.86 mp3 in js mode was flawed. I could hear a static > (crackling white noise) sound on the guitars during certain moments. > Clear noise that wasn't in the original wav file or on the LAME 3.36 > mp3. This must have been a masking/psycho acoustic flaw either/or > both. It needs work. > > -LAME 3.86 included the characteristic that the recent LAME versions > have in that there is clear "dryness" in the sound. An overly crisp > sounding high frequency range that I believe is brought on by an > empty lower mid/upper bass scalefactor area. (That's what I'm > percieving, correct me if it's technically wrong). It's isolated to > the joint-stereo mode. > > This comparison was done using the fraunhofer decoder in Winamp > version 2.22. Please let me know if other people are noticing this > as well. > > Timothy -- Best regards, Roel mailto:[EMAIL PROTECTED] -- MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
