I'm wondering whether this sample will have an influence on further mp3 development.
Quote from: UltimateMusicSnob on 20 September, 2013, 10:40:34 AMOn the tests above, what were you listening for? Is this listening for a noise floor? If noise floor is just white noise, then the only thing to listen for is levels of noise, yes? A difference in how much white noise you hear below the music, when the volume is cranked way up? And of course, if not for the noise floor, then what is the audible cue?Yes, noise floor. The noise floor of the recording isn't quite white. With dither there's perfectly white noise added on top. Without dither (truncation) the added noise is quieter but fractionally less uniform. All fairly subtle though and very hard to detect without a reference.Volume was cranked up, but I would happily listen to the full 30 second clip at that volume - it's not loud. I wouldn't dream of listening to anything else at anywhere near that volume though!It's interesting that lossyWAV doesn't even touch the first 5 seconds of the file (it maintains the full 16-bits unchanged), and throughout the rest of the file it never knocks off more than 1-bit from the right channel.Cheers,David.
On the tests above, what were you listening for? Is this listening for a noise floor? If noise floor is just white noise, then the only thing to listen for is levels of noise, yes? A difference in how much white noise you hear below the music, when the volume is cranked way up? And of course, if not for the noise floor, then what is the audible cue?
Quote from: greynol on 20 September, 2013, 01:48:19 PMI'm wondering whether this sample will have an influence on further mp3 development.This seems to be a real corner case, and even the OP doesn't seem to feel that it needs to be fixed or improved in any way. Personally I would treat it as a curious anomaly and leave it at that.What I am much more interested in is the OP's ability to hear the subtlest of details. He could possibly be a valuable asset in assessing codec differences.
I think David often likes to use lossyWAV as a tool to determine how many LSBs can be tossed without affecting audibility, based on a setting that hasn't yet been shown not to be transparent?
These research questions are of great interest to me.
Quote from: UltimateMusicSnob on 20 September, 2013, 02:31:57 PMThese research questions are of great interest to me.Is that you, or just a link showing what you're interested in?
... Personally I would treat it as a curious anomaly ...
Quote from: pdq on 20 September, 2013, 02:06:07 PM... Personally I would treat it as a curious anomaly ...An anomaly?We're used to considering issues in stuff like electronic music, harpsichord music, or other relatively special contents as an anomaly (as long as we are not very much into these genres), and we ignore them more or less, or use very high quality mp3 which brings even these issues pretty close to transparency.But this is a sample without any special a priori characteristics for being an issue to mp3. And the issue has been confirmed.The good news is that this can be considered not relevant in practical listening situations, in case I understand UltimateMusicSnob correctly (please tell us if I'm wrong). UMS: This is correct, Well, I think in the end it's nothing that essentially changes our attitude towards the usage of mp3. We have known before that there are spots in the music where we can get only near-transparency. What's new is that this doesn't happen only to special stuff, but also to pretty 'normal' music.An interesting question is:Claiming the issue being irrelevant is (hopefully) correct for people who use very high quality mp3.But what about the people who use say -V2, a setting which is considered to yield a very good quality/filesize relation?UltimateMusicSnob, would you mind trying -V2 and tell us what you think about quality in practical listening situations?(sorry I can't contribute myself with listening here - I cannot hear any deviation from the original even with lower quality settings than -V2).
foo_abx 1.3.4 reportfoobar2000 v1.2.82013/09/20 21:05:44File A: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_2_short.wavFile B: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_6.mp321:05:44 : Test started.21:06:37 : 01/01 50.0%21:06:53 : 02/02 25.0%21:07:34 : 03/03 12.5%21:08:04 : 03/04 31.3%21:08:38 : 04/05 18.8%21:09:12 : 05/06 10.9%21:10:01 : 06/07 6.3%21:10:32 : 07/08 3.5%21:11:37 : 08/09 2.0%21:12:19 : 09/10 1.1%21:12:55 : 10/11 0.6%21:14:30 : 10/12 1.9%21:14:35 : Test finished. ---------- Total: 10/12 (1.9%)Cues used:WAV bass has smooth, focused crescendo.MP3 bass crescendo seems to proceed by plateaus, diffuse.
foo_abx 1.3.4 reportfoobar2000 v1.2.82013/09/21 09:22:12File A: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_2_short.wavFile B: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_6.mp309:22:12 : Test started.09:22:36 : 00/01 100.0%09:22:46 : 01/02 75.0%09:23:02 : 02/03 50.0%09:23:14 : 03/04 31.3%09:23:29 : 04/05 18.8%09:23:54 : 05/06 10.9%09:24:15 : 06/07 6.3%09:25:18 : 07/08 3.5%09:27:23 : 08/09 2.0%09:28:27 : 09/10 1.1%09:29:55 : 10/11 0.6%09:31:14 : 10/12 1.9%09:31:25 : Test finished. ---------- Total: 10/12 (1.9%)Cues used:Treble is just a bit brighter in MP3, plus some room sound seems to be missing. Can't hear the same reverb reflections in the MP3.
foo_abx 1.3.4 reportfoobar2000 v1.2.82013/09/21 11:25:15File A: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_2_short.wavFile B: C:\Users\KiarkAudio\Documents\Ravel Listening Tests\Ravel_Test_File_6.mp311:25:15 : Test started.11:25:38 : 01/01 50.0%11:25:52 : 01/02 75.0%11:26:08 : 02/03 50.0%11:26:23 : 03/04 31.3%11:26:36 : 04/05 18.8%11:28:11 : 05/06 10.9%11:30:40 : 06/07 6.3%11:32:42 : 07/08 3.5%11:33:24 : 08/09 2.0%11:35:39 : 09/10 1.1%11:37:26 : 10/11 0.6%11:39:20 : 10/12 1.9%11:39:22 : Test finished. ---------- Total: 10/12 (1.9%)Cues used:MP3 Flute attack at 8.0 seconds is less crisp than WAV. Flute timbre a [u]little[/u] blurred, compared to focused sound of WAV. Bass is diffuse, like the other trials.
Thanks a lot for your test.So it looks like -V2 quality is also okay for this sample in practical listening situations.I'd like to add that other than with --bCVBR 316 special version lame3100l has no influence on this result. I've looked it up, and because of the low volume lame3100l does not increase SNR (with the exception of the last two frames which contain short resp. mixed blocks). As was to be expected. So Lame 3.100a2 should work just as fine.
Since that short sample has a headroom of more as 22dB it may be worth to shift it losslessly 18dB louder so no dither can influence the noise. UMS may test if the encode suffers by its pure loudness or by other things when brought back to higher levels.Edit: Anyone noticed the left channel only being 15bit in that sample from he beginning? No wonder lossywav can't throw away much. Very srange to have it only on one channel.
You didn't download it, did you?
It's obviously a quiet moment in a full range classical recording.
Whether it peaks at full scale I couldn't say, but it obviously goes louder than this. Maybe UMS can confirm the track and album peaks.
The only "badly made" issue is the 15bits in the left channel. That's quite weird, and probably audible. Truncating or dithering the right channel to 15 bits is audible (see above), though that would be an insane listening level for the whole piece (I assume).
Please read the entire discussion. We already had this conversation and the peak value was revealed.FFS!
Quote from: greynol on 23 September, 2013, 09:48:23 AMPlease read the entire discussion. We already had this conversation and the peak value was revealed.FFS!Did that too. Seems like an obvious disqualifiying fact was being overlooked for some reason.The clip is also pathological in that its background noise level is something like less than 30 dB below its peak level.
We already had this conversation and the peak value was revealed.
It's conceivable that classical labels could choose to normalize to -1.0db instead of -6.0, but I would bet if that range were to become standard...