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MPC VBR flaws (low volume & ringing), audible under specific conditions
Frank Klemm
post Jul 9 2005, 14:47
Post #51


MPC Developer


Group: Developer
Posts: 543
Joined: 15-December 01
From: Germany
Member No.: 659



QUOTE (Gabriel @ Jul 9 2005, 12:16 PM)
Isn't the purpose of track gain to be able to use the tracks in a compilation of tracks from different albums?
In this case, why would track gain be dependant of the gain of its neighbours tracks in the original album? If someone wants to listen a full album, he would use album gain, not track gain.
*


This is not an article about Musepack, but about flaws in the current ReplayGain
concept and implementation. Low level artefacts are related to this problem,
but this article is about ReplayGain and problems with ReplayGain. ReplayGain
ist *not* perfect at all, there's a long list of problems. Actually I use only
album based ReplayGain, other modes have a lot of problems which may significantly
reduce enjoy music.

Okay?

--------------------------------------------------------------------------------------------------------------

We should (always) start from the user application side.
And there there are at least three scenarios.

1. You want to listen to an album in original order. You want to remove volume differences between albums. The aim is to avoid volume differences between albums with different reference level, which is typical for album mastered in different decades. The effect is like a computer's turn on the volume control between albums (and by the way can also implemented in this way when the computer has access to the volume control via RS-232, RS-422, Cable LAN, Wireless LAN, IR-RC, IR-DA, USB, IEEE-1394, CAN, ...).

2. You want to listen to an album in original order. You want to remove volume differences between titels. The aim ist to reduce loudness differences inside an album, maybe also inside longer or very dynamic tracks. These loudness adjustments must be inaudible at all. No clicks, no distortions, no incredible noise boosting, no obviously loudness changes.

3. You want to shuffle titles of different album and you want to remove loudness differences between the titles. The goal is again: No clicks, no distortions, no incredible noise boosting, no obviously loudness changes.

Okay? Always start from the user application side, never start from the SSE and 3DNow!
assembler code side! Even when you like assembly programming on Intel.
Okay?

--------------------------------------------------------------------------------------------------------------

Now from the programmers geek side.

Solution for 1 is the album based replaygain and this work really great.

Solution for 2 is the proposal above. There should be a free parameter (with a useful default value) which controls the speed of the AGC. Someone want only slight loudness correction especially on title borders, another people wants to remove nearly all dynamic.

For album with silence at the title boundaries title based replaygain often works.
When there's only little loudness difference inside the album also the album gain works (see examples 2)!
There are some conceptional flaws and some flaws in the implementation.
* From time to time there are titles with (psychological) much too much title based replaygain gain
** short titles
** silent titles which must be silent at all
* file boundaries not at the real title boundaries
* live albums / classic without gaps
* noisy albums with little, but audible noise between tracks
* albums with DC
When an album has one of these problems, title based replaygain works poorly.
(see also Examples 1).

Solutions for 3 are also not so easy to implement. First of all we have problems with
boundaries (shifted, no silence). But it is not the task of replaygain to find useful
cuts or to fade between live titles during playback.

Primary goal is to remove loudness differences. Secondary goal is to avoid boosting
of intentionally silent titles. Third goal is to avoid noise boosting.

Short and very silent titles should not be boosted as much as replaygain's function GetTitleGain() says. This is important to avoid boosting of short and intentionally
silent titles.

To avoid noise boosting, ReplayGain's title gain must be limited. ReplayGain's album gain makes less problems, I only found albums with gains between -12.3 dB and +9,4 dB.
Within the title gain I found gain from -13,7 dB to +30,9 dB.

--------------------------------------------------------------------------------------------------------------

Even for 2 AND for 3 the current ReplayGain title gain is a really good implementation.
There are some flaws affecting the usage of ReplayGain title gain for problem 2 AND for problem 3. These should be fixed. In combination with a solution of the cut problem then ReplayGain title gain is also a great solution for problem 3.

Problem 2 must be solved completely different. Even when the ReplayGain title gain problems are solved, there are enough problems remaining when you want to use it
with music with
* file boundaries not at the real title boundaries
* live albums / classic without gaps
* noisy albums with little, but audible noise between tracks
* albums with DC

Examples: see next posting(s)

This post has been edited by Frank Klemm: Jul 9 2005, 15:23


--------------------
-- Frank Klemm
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+Quote Post
Frank Klemm
post Jul 9 2005, 14:58
Post #52


MPC Developer


Group: Developer
Posts: 543
Joined: 15-December 01
From: Germany
Member No.: 659



Example for changing title based replaygains from title to title.
(Pause) are silent intermezzi with background noise, ends and beginning of other titles.
Some are digital null or above +36 dB (=>0 dB titlegain), some are between +31 dB and
+15 dB (=> +15...+31 dB), some has normal loudness resultig in ReplayGain of -5...-7 dB.

The title numbering on the CD and on the Cover is different!

http://www.amazon.com/exec/obidos/ASIN/B0000CNY4K/

Replaygain values:

CODE

Title | Album |
Level- | (Peak+)| Level- | (Peak+)|
Adjustment| Peak (Adjst)|Adjustment| Peak (Adjst)| Filename
----------+--------------+----------+--------------+---------------------------
-7.52 dB | 34427 (14484)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [01] Wo willst du hin%3F.mpc
+30.12 dB | 599 (19205)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [02] (Pause).mpc
-6.17 dB | 37039 (18203)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [03] Auf Herz und Nieren.mpc
+0.00 dB | 187 ( 187)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [04] (Pause).mpc
-5.93 dB | 34627 (17495)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [05] Wir gehören zusammen.mpc
+0.00 dB | 483 ( 483)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [06] (Pause).mpc
-6.84 dB | 37529 (17075)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [07] Abschied nehmen.mpc
+20.32 dB | 2571 (26674)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [08] (Pause).mpc
-9.01 dB | 36891 (13074)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [09] Kein Königreich.mpc
+14.71 dB | 3633 (19759)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [10] (Pause).mpc
-7.43 dB | 37127 (15783)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [11] Wir haben alles Gute vor uns.mpc
+0.00 dB | 73 ( 73)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [12] (Pause).mpc
-6.51 dB | 35447 (16752)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [13] Alle Männer müssen kämpfen.mpc
+28.30 dB | 861 (22387)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [14] (Pause).mpc
-5.25 dB | 35853 (19589)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [15] That's the way love is.mpc
+17.96 dB | 3587 (28361)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [16] (Pause).mpc
-9.42 dB | 34291 (11592)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [17] Brief.mpc
+0.00 dB | 309 ( 309)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [18] (Pause).mpc
-7.46 dB | 34297 (14529)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [19] Don't give up.mpc
+30.90 dB | 833 (29217)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [20] (Pause).mpc
-5.01 dB | 36825 (20684)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [21] Gut aufgepasst.mpc
+0.00 dB | 235 ( 235)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [22] (Pause).mpc
-6.60 dB | 36525 (17084)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [23] Wenn ich schon Kinder hätte (Rap-Version).mpc
+26.50 dB | 913 (19296)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [24] (Pause).mpc
-6.93 dB | 29321 (13203)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [25] Kleines Lied (Kinderlied).mpc
+26.72 dB | 879 (19054)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [26] (Pause).mpc
-5.08 dB | 31571 (17590)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [27] Die Dinge singen hör ich so gern.mpc
+25.92 dB | 4979 (98433)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [28] (Pause).mpc
-7.47 dB | 34227 (14483)| -7.14 dB | 37529 (16495)| Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [29] Keep your eyes on me.mpc
+0.00 dB | 1 ( 1)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [01] (Pause).mpc
-5.74 dB | 33169 (17129)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [02] Himmel über Deutschland.mpc
+16.33 dB | 2297 (15054)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [03] (Pause).mpc
-5.28 dB | 35303 (19222)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [04] Ich lass sie sterben.mpc
+1.95 dB | 24485 (30647)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [05] (Pause).mpc
-6.18 dB | 34891 (17128)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [06] Bevor du gehst.mpc
-8.76 dB | 34735 (12669)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [07] (Pause).mpc
-5.53 dB | 36027 (19060)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [08] I'd be waiting.mpc
+0.00 dB | 341 ( 341)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [09] (Pause).mpc
-5.09 dB | 34937 (19443)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [10] Sie ist im Viereck angelegt.mpc
-4.91 dB | 33669 (19130)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [11] (Pause).mpc
-5.30 dB | 35933 (19520)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [12] Eyes R shut.mpc
+0.00 dB | 39 ( 39)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [13] (Pause).mpc
-4.22 dB | 34461 (21199)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [14] Der Geist ist willig.mpc
+3.93 dB | 16935 (26624)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [15] (Pause).mpc
-4.20 dB | 34441 (21236)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [16] Mägde und Knechte.mpc
+1.62 dB | 31413 (37853)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [17] (Pause).mpc
-6.81 dB | 35489 (16202)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [18] Der Herr knickt alle Bäume.mpc
+0.00 dB | 349 ( 349)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [19] (Pause).mpc
-5.79 dB | 36597 (18790)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [20] Wer weiß schon, was der Morgen bringt.mpc
+8.13 dB | 6591 (16805)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [21] (Pause).mpc
-5.09 dB | 36205 (20149)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [22] Alles für den Herrn.mpc
+0.35 dB | 34581 (36002)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [23] (Pause).mpc
-4.74 dB | 38201 (22134)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [24] Wo driften wir hin.mpc
+0.62 dB | 24231 (26023)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [25] (Pause).mpc
-7.00 dB | 37661 (16822)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [26] Klagelieder.mpc
-6.75 dB | 34197 (15721)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [27] (Pause).mpc
-5.11 dB | 27527 (15284)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [28] Lied (du, nur du).mpc
+7.97 dB | 7453 (18656)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [29] (Pause).mpc
-4.56 dB | 33751 (19965)| -5.56 dB | 38201 (20140)| Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [30] Wenn du es willst (mir sind die Hände gebunden).mpc
| 38201 (98433)| | 38201 (20140)| --- maximum ---


Musepack bitrates and durations:

CODE

PCM size File size Ratio kbps Duration Param Frequency Name
44.633 6.077 7.344 192 4:13.027 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [01] Wo willst du hin%3F.mpc
0.938 0.079 120 0:05.320 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [02] (Pause).mpc
45.605 6.469 7.049 200 4:18.533 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [03] Auf Herz und Nieren.mpc
1.027 0.081 112 0:05.827 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [04] (Pause).mpc
43.608 6.227 7.002 202 4:07.213 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [05] Wir gehören zusammen.mpc
0.992 0.066 94.3 0:05.627 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [06] (Pause).mpc
73.904 10.654 6.936 203 6:58.960 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [07] Abschied nehmen.mpc
1.121 0.056 71.1 0:06.360 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [08] (Pause).mpc
36.994 4.841 7.641 185 3:29.720 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [09] Kein Königreich.mpc
0.959 0.127 7.510 188 0:05.440 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [10] (Pause).mpc
58.002 7.115 8.151 173 5:28.813 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [11] Wir haben alles Gute vor uns.mpc
0.886 0.088 141 0:05.027 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [12] (Pause).mpc
57.607 8.598 6.700 211 5:26.573 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [13] Alle Männer müssen kämpfen.mpc
1.032 0.070 96.3 0:05.853 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [14] (Pause).mpc
48.740 7.471 6.524 216 4:36.307 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [15] That's the way love is.mpc
0.896 0.049 78.1 0:05.080 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [16] (Pause).mpc
54.923 7.670 7.161 197 5:11.360 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [17] Brief.mpc
0.893 0.071 112 0:05.067 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [18] (Pause).mpc
67.862 8.823 7.691 183 6:24.707 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [19] Don't give up.mpc
0.933 0.064 97.6 0:05.293 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [20] (Pause).mpc
45.358 6.029 7.522 188 4:17.133 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [21] Gut aufgepasst.mpc
0.898 0.073 115 0:05.093 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [22] (Pause).mpc
50.490 7.080 7.131 198 4:46.227 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [23] Wenn ich schon Kinder hätte (Rap-Version).mpc
0.959 0.059 87.5 0:05.440 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [24] (Pause).mpc
36.893 4.738 7.786 181 3:29.147 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [25] Kleines Lied (Kinderlied).mpc
0.922 0.043 66.2 0:05.227 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [26] (Pause).mpc
39.727 5.820 6.825 207 3:45.213 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [27] Die Dinge singen hör ich so gern.mpc
1.070 0.087 116 0:06.067 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [28] (Pause).mpc
53.317 7.313 7.291 194 5:02.253 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 1) (2002) -- [29] Keep your eyes on me.mpc
0.705 0.001 3.52 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [01] (Pause).mpc
65.564 8.723 7.516 188 6:11.680 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [02] Himmel über Deutschland.mpc
0.705 0.070 9.954 142 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [03] (Pause).mpc
39.210 5.050 7.764 182 3:42.280 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [04] Ich lass sie sterben.mpc
0.705 0.068 137 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [05] (Pause).mpc
55.006 7.742 7.104 199 5:11.827 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [06] Bevor du gehst.mpc
0.705 0.085 8.295 170 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [07] (Pause).mpc
42.500 6.411 6.629 213 4:00.933 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [08] I'd be waiting.mpc
0.705 0.052 105 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [09] (Pause).mpc
41.522 6.177 6.721 210 3:55.387 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [10] Sie ist im Viereck angelegt.mpc
0.705 0.075 9.368 151 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [11] (Pause).mpc
58.602 8.488 6.904 204 5:32.213 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [12] Eyes R shut.mpc
0.705 0.020 40.7 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [13] (Pause).mpc
45.720 5.820 7.855 180 4:19.187 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [14] Der Geist ist willig.mpc
0.707 0.096 7.334 192 0:04.013 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [15] (Pause).mpc
48.705 5.908 8.244 171 4:36.107 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [16] Mägde und Knechte.mpc
0.740 0.061 116 0:04.200 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [17] (Pause).mpc
40.108 5.619 7.138 198 3:47.373 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [18] Der Herr knickt alle Bäume.mpc
0.705 0.061 123 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [19] (Pause).mpc
38.960 4.891 7.965 177 3:40.867 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [20] Wer weiß schon, was der Morgen bringt.mpc
0.705 0.052 104 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [21] (Pause).mpc
40.701 4.656 8.740 161 3:50.733 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [22] Alles für den Herrn.mpc
0.705 0.069 140 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [23] (Pause).mpc
43.481 5.630 7.723 183 4:06.493 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [24] Wo driften wir hin.mpc
0.705 0.070 9.968 142 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [25] (Pause).mpc
40.637 4.630 8.777 161 3:50.373 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [26] Klagelieder.mpc
0.705 0.057 114 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [27] (Pause).mpc
45.299 6.495 6.974 202 4:16.800 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [28] Lied (du, nur du).mpc
0.705 0.064 129 0:04.000 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [29] (Pause).mpc
68.523 8.974 7.636 185 6:28.453 (2x16 44100 Hz) Zwischenspiel - Alles für den Herrn (CD 2) (2002) -- [30] Wenn du es willst (mir sind die Hände gebunden).mpc
1496.373 202.080 7.405 191 141:22.827 --- 59 files ---


(HA board software reformats the first table, why???)

moderation: changed 'code' blocks to 'codebox' for better readability


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Frank Klemm
post Jul 9 2005, 15:16
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Other examples where ReplayGain makes nonsense.
Especially the last example (May be someone knows this group and this album)
is suitable to destroy the hearing. While fading from "Waiting For The Worms" to "Stop"
the loudness is switched by more than 12 dB. The result are heavy overdrives for 2 or 3 seconds and you can frightens people to death.

CODE
decoding of file 'Back To Titanic (1997) -- [11] Celine Dion -- My Heart Will Go On (with dialogue from the film).mpc'
        to device /dev/audio (Open Sound System)

        Celine Dion: Back To Titanic    (1997)
   [11] My Heart Will Go On (with dialogue from the film)

 189.4 kbps,    4:43.09, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 0.9616

    4:43.07 (runtime: 1.15 s  speed: 246.14x)

decoding of file 'Back To Titanic (1997) -- [12] Eileen Ivers -- Nearer My God to Thee.mpc'
        to device /dev/audio (Open Sound System)

        Eileen Ivers: Back To Titanic    (1997)
   [12] Nearer My God to Thee

 203.1 kbps,    2:22.34, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 9.5280

    2:22.33 (runtime: 0.51 s  speed: 279.08x)


CODE
decoding of file 'Hot Rail (2000) -- [05] Crystal Frontier.mpc'
        to device /dev/audio (Open Sound System)

        Calexico: Hot Rail    (2000)
   [05] Crystal Frontier

 204.1 kbps,    3:56.77, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 0.4222

    3:56.77 (runtime: 0.95 s  speed: 249.24x)

decoding of file 'Hot Rail (2000) -- [06] Untitled III.mpc'
        to device /dev/audio (Open Sound System)

        Calexico: Hot Rail    (2000)
   [06] Untitled III

 231.7 kbps,    4:07.48, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 2.0893

    4:07.47 (runtime: 0.83 s  speed: 298.15x)

  17 Overdrives, maximum level 36659, rerun with --scale 0.89380



CODE
decoding of file 'Osho -- Kundalini Meditation (1995) -- [01] First Stage: 15 minutes.mpc'
        to device /dev/null (Null Device)

        Osho: Kundalini Meditation    (1995)
   [01] First Stage: 15 minutes

 233.3 kbps,   14:45.84, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 0.5916

   14:45.83 (runtime: 2.83 s  speed: 313.01x)

decoding of file 'Osho -- Kundalini Meditation (1995) -- [02] Second Stage: 15 minutes.mpc'
        to device /dev/null (Null Device)

        Osho: Kundalini Meditation    (1995)
   [02] Second Stage: 15 minutes

 212.8 kbps,   14:39.18, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 0.7464

   14:39.17 (runtime: 2.84 s  speed: 309.57x)

decoding of file 'Osho -- Kundalini Meditation (1995) -- [03] Third Stage: 15 minutes.mpc'
        to device /dev/null (Null Device)

        Osho: Kundalini Meditation    (1995)
   [03] Third Stage: 15 minutes

 215.7 kbps,   14:53.02, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 1.1521

   14:53.00 (runtime: 2.69 s  speed: 331.97x)

decoding of file 'Osho -- Kundalini Meditation (1995) -- [04] Fourth Stage: 15 minutes.mpc'
        to device /dev/null (Null Device)

        Osho: Kundalini Meditation    (1995)
   [04] Fourth Stage: 15 minutes

   9.7 kbps,   14:42.02, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 22.2075

   14:42.00 (runtime: 1.58 s  speed: 558.23x)

3425 Overdrives, maximum level 241085, rerun with --scale 0.13591



CODE
decoding of file 'The Wall (CD2) (1979) -- [10] Waiting For The Worms.mpc'
        to device /dev/audio (Open Sound System)

        Pink Floyd: The Wall (CD2)    (1979)
   [10] Waiting For The Worms

 200.2 kbps,    3:56.64, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 1.3107

    3:56.64 (runtime: 0.85 s  speed: 278.40x)

decoding of file 'The Wall (CD2) (1979) -- [11] Stop.mpc'
        to device /dev/audio (Open Sound System)

        Pink Floyd: The Wall (CD2)    (1979)
   [11] Stop

 205.0 kbps,    0:34.95, SV 7.0, Profile 'Xtreme' (Beta 1.14), Gain 5.4828

    0:34.93 (runtime: 0.09 s  speed: 388.15x)

9937 Overdrives, maximum level 125247, rerun with --scale 0.26161


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Frank Klemm
post Jul 9 2005, 15:22
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A lot of albums have nearly no differences between the title based ReplayGain values.
Using album based replay gain for equalization of titles may be the better choise.

CODE
       Title            |        Album            |
 Level-  |       (Peak+)|  Level-  |       (Peak+)|
Adjustment|  Peak (Adjst)|Adjustment|  Peak (Adjst)|  Filename
----------+--------------+----------+--------------+---------------------------
-2.32 dB | 34823 (26660)| -2.98 dB | 34983 (24823)| Islands -- [01] The Wind Chimes.mpc
-3.30 dB | 31059 (21241)| -2.98 dB | 34983 (24823)| Islands -- [02] Islands.mpc
-3.10 dB | 31613 (22124)| -2.98 dB | 34983 (24823)| Islands -- [03] Flying Start.mpc
-3.09 dB | 28675 (20091)| -2.98 dB | 34983 (24823)| Islands -- [04] North Point.mpc
-3.53 dB | 34983 (23300)| -2.98 dB | 34983 (24823)| Islands -- [05] Magic Touch.mpc
-3.61 dB | 30963 (20433)| -2.98 dB | 34983 (24823)| Islands -- [06] The Time has Come.mpc
-2.75 dB | 31731 (23119)| -2.98 dB | 34983 (24823)| Islands -- [07] When the Nights on Fire.mpc
         | 34983 (26660)|          | 34983 (24823)| --- maximum ---


CODE
       Title            |        Album            |
 Level-  |       (Peak+)|  Level-  |       (Peak+)|
Adjustment|  Peak (Adjst)|Adjustment|  Peak (Adjst)|  Filename
----------+--------------+----------+--------------+---------------------------
-8.00 dB | 36787 (14645)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [01] She Is My Sin.mpc
-8.44 dB | 37953 (14363)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [02] The Kinslayer.mpc
-8.06 dB | 36125 (14282)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [03] Come Cover Me.mpc
-8.27 dB | 36675 (14153)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [04] Wanderlust.mpc
-7.38 dB | 34621 (14802)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [05] Two For Tragedy.mpc
-8.54 dB | 36245 (13559)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [06] Wishmaster.mpc
-7.76 dB | 35925 (14702)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [07] Bare Grace Misery.mpc
-8.43 dB | 35949 (13620)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [08] Crownless.mpc
-7.22 dB | 35475 (15449)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [09] Deep Silence.mpc
-8.02 dB | 35857 (14242)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [10] Dead Boy's Poem.mpc
-7.90 dB | 35909 (14461)| -8.10 dB | 37953 (14936)| Wishmaster (2000) -- [11] FantasMic.mpc
         | 37953 (15449)|          | 37953 (14936)| --- maximum ---


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mtm
post Jul 9 2005, 18:51
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Thank you for your posts, Mr Klemm. They certainly are some food for thought.

It's good to see you here again. smile.gif


Quite a lot of thread views, but not too many replies, so I'll risk mine.

From a purely practical point of view, do you think it's possible to change Musepack's RG the way it would fix problems reported by guruboolez ? You mentioned it would be more suitable for Matroska rather than SV7, and I'm curious.

Also, I don't listen to classical music nearly as much as typical classic lovers, and hence my second question is: would the practical implementation of new RG scheme have any negative influence on the idea of volume equalising between the tracks ?
I'm thinking mainly about track gain changes reported by guruboolez (about +20 dB) and a proposal of limiting the track gain to +-12 dB.

As I said, I have no idea about classic. smile.gif I'm sorry if I'm not understanding something. smile.gif


Best regards,
MTM


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ChristianHJW
post Jul 10 2005, 09:45
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QUOTE (CiTay @ Jul 8 2005, 09:19 PM)
I got a new e-Mail from Frank (he follows this thread):
For Matroska, here would be a proposition:

* Determine and apply album-based Replaygain (control range between K+26 and K-6) [with current nomenclature: +12 to -20 dB]
* Title-based Replaygain is an additional control signal, which is additionally applied
* Restrict title-based Replaygain to +-12 dB
* Title-based Replaygain can be changed steadily within a track
* For that, a control signal similar to an automatic level adjustment is calculated, with the following differences:
  - slow adjustment rate with normal levels
  - level-dependent maximum adjustment rate (e.g. 6 dB/sec at <-80 dB, 1.5 dB/sec at -60 dB, 0.4 dB/sec at -40 dB, 0.1 dB/sec at -20 dB, 0.02 dB/sec at >0 dB)
          - these levels are relative to the album-based Replaygain
  - adjustment considers volume jumps in both time directions
 

Result:

* Normal pop music with digital zero between the tracks isn't handled much differently, maybe the dynamics are lowered by max. 1 dB/minute.
    - There are differences with long titles that have bigger dynamics
* The outcome doesn't depend on where the cuts/title borders are (important!)
    - in particular, there are no problems when they're at the wrong place or when it's a live concert without cuts
* With classical music, the outcome is much more closer to what you would want when you listen to Beethoven in the subway.

But this thing is something that would be more for Matroska than for the MPC format.


Recently there hasnt been too much interest in investing time into improvement of our audio tools, as audio devs seem to be more inclined in seeing container and compression as an entity.

In a first step, you guys have to launch SV 7.5, so that we can start muxing MPC into MKA/MKV.

Christian
matroska project admin
http://www.matroska.org


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guruboolez
post Jul 10 2005, 23:22
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QUOTE
This is not an article about Musepack, but about flaws in the current ReplayGain
concept and implementation. Low level artefacts are related to this problem,
but this article is about ReplayGain and problems with ReplayGain.


I beg you pardon, but you've apparently miss an important point: the problem occurs with ReplayGain and Musepack.
ReplayGain + Lame = no problem
ReplayGain + Vorbis = no problem.
ReplayGain + AAC = no problem (checked recently with Nero and previously faac)
ReplayGain + DualStream = no problem
ReplayGain + WavPack lossy = no problem
ReplayGain + MPC = problems

I won't say that ReplayGain is the cause of the problem. It's obviously MPC which can't be used safely in some situation at some encoding profiles.

QUOTE
ReplayGain ist *not* perfect at all, there's a long list of problems. Actually I use only
album based ReplayGain, other modes have a lot of problems which may significantly
reduce enjoy music.

Okay?


What should I conclude? That a problem shouldn't be considered as relevant because you have other listening habits? That's fine as long as you consider MPC as your own tool, dedicated to your own purpose and to people sharing the same behavior, and if you don't plan to improve the obvious bug occuring in other situations. But don't wonder if musepack will quickly loose its audience with such reasoning.

This post has been edited by Dibrom: Jul 11 2005, 00:14
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rjamorim
post Jul 11 2005, 00:13
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QUOTE (Frank Klemm @ Jul 9 2005, 10:47 AM)
ReplayGain ist *not* perfect at all, there's a long list of problems. Actually I use only album based ReplayGain, other modes have a lot of problems which may significantly reduce enjoy music.

Okay?
*


Honestly, that's the first time I see that reported here. Most other complaints I have seen were about replaygaining tools having bugs (wasn't there something about MP3gain and a memory leak? It happened so long ago...) and not about the proposal itself, as well as the existing implementations of it, having issues inherent to the analytical model or the way the gain information is obtained.

There were some complaints about RG behaving in a weird fashion on some specific albums, but I wouldn't call that "a long list of problems".


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Dibrom
post Jul 11 2005, 00:15
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QUOTE
I won't say that ReplayGain is the cause of the problem. It's obviously MPC which can't be used safely in some situation at some encoding profiles.


I think in fact it is more correct to say that MPC can't be expected to provide good results in all situations where postprocessing of the encoded file might occur, unless the user intervenes at encode time and provides the encoder with some information that can correct for this after the fact.

This still shouldn't come as a big surprise for a lossy codec.

Yes, other codecs may not exhibit this problem, but at least in the case of some (e.g., the adaptive ATH Gabriel mentioned), it appears that they rely on tradeoff's as far as compression efficiency is concerned here. And furthermore, without 2-pass encoding being used, such an adaptive method is going to be much more imprecise.

QUOTE
What should I conclude? That a problem shouldn't be considered as relevant because you have other listening habits?


The inverse can be said just as well. Should we conclude that MPC is buggy because it doesn't perform as well as you'd like after you modified the encoded file, invalidating the assumptions the encoder made about masking, etc.?

QUOTE
That's fine as long as you consider MPC as your own tool, dedicated to your own purpose and to people sharing the same behavior, and if you don't plan to improve the obvious bug occuring in other situations. But don't wonder if musepack will quickly loose its audience with such reasoning.


Calling this a bug seems like a real stretch to me. It's not a problem with the encoder itself, it's a problem that arises when using the encoded file in certain situations that the encoder doesn't know about. Furthermore, it would seem definitely not to be a bug since the problem goes away if you in fact give the encoder the correct information at encode time (e.g., ath adjustment).

I agree with Frank -- this is not a problem with MPC but a problem with using Replaygain in this way. And that doesn't mean that there cannot be some sort of solution found, but I don't think that implementing some sort of imprecise changes in the psymodel to compensate for this special case -- sacrificing efficiency along the way -- is the right answer.

I think the proper solution is to implement some sort of multi-pass encoding system that allows for the encoder to interact with Replaygain more intelligently, if this is the way you plan to use your encoded files. Maybe this would be done by calculating the Replaygain values for the file before encoding, and then using the track gain as an indicator for ATH adjustment and the like. Of course this won't be an automatic process (you would have to specify some flag like --2pass), but I don't think it should be -- for people not planning to use their files this way, it should be unnecessary for them to have to make the efficiency sacrifices resulting in larger files.

Note: Sorry I accidently hit edit on your post instead of reply wink.gif
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Gambit
post Jul 11 2005, 00:22
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QUOTE (Dibrom @ Jul 11 2005, 12:15 AM)
I think in fact it is more correct to say that MPC can't be expected to provide good results in all situations where postprocessing of the encoded file might occur, unless the user intervenes at encode time and provides the encoder with some information that can correct for this after the fact.
*

Erm, we are talking about Replaygain here. In the end, it's the same as adjusting the volume knob. I would hardly call that "postprocessing".


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Dibrom
post Jul 11 2005, 00:25
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QUOTE (Gambit @ Jul 10 2005, 03:22 PM)
QUOTE (Dibrom @ Jul 11 2005, 12:15 AM)
I think in fact it is more correct to say that MPC can't be expected to provide good results in all situations where postprocessing of the encoded file might occur, unless the user intervenes at encode time and provides the encoder with some information that can correct for this after the fact.
*

Erm, we are talking about Replaygain here. In the end, it's the same as adjusting the volume knob. I would hardly call that "postprocessing".
*



Well call it what you like, but when you make significant changes to the playback level (e.g., what is happening here with classical music), it's just about as good as postprocessing as far as a psychoacoustic encoder is concerned.

The file is being processed (volume changed significantly) in a way the encoder does not expect, after the file has been encoded.
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rjamorim
post Jul 11 2005, 00:28
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QUOTE (Dibrom @ Jul 10 2005, 08:25 PM)
Well call it what you like, but when you make significant changes to the playback level (e.g., what is happening here with classical music), it's just about as good as postprocessing as far as a psychoacoustic encoder is concerned.

The file is being processed (volume changed significantly) in a way the encoder does not expect, after the file has been encoded.
*


But if something as simple as turning volume knobs is tripping the codec, then the problem can't be in the volume knob :B


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Dibrom
post Jul 11 2005, 00:33
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QUOTE (rjamorim @ Jul 10 2005, 03:28 PM)
QUOTE (Dibrom @ Jul 10 2005, 08:25 PM)
Well call it what you like, but when you make significant changes to the playback level (e.g., what is happening here with classical music), it's just about as good as postprocessing as far as a psychoacoustic encoder is concerned.

The file is being processed (volume changed significantly) in a way the encoder does not expect, after the file has been encoded.
*


But if something as simple as turning volume knobs is tripping the codec, then the problem can't be in the volume knob :B
*



Umm.. It's not "something as simple as turning the volume knob" that is "tripping the codec." If it were, this problem would be much more pervasive and would occur practically everywhere, instead of being limited to the rather specific conditions (i.e., significant boosting of highly dynamic music to levels that invalidate encode time assumptions about masking, etc.) that guruboolez has brought up.
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rjamorim
post Jul 11 2005, 00:41
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QUOTE (Dibrom @ Jul 10 2005, 08:33 PM)
Umm.. It's not "something as simple as turning the volume knob" that is "tripping the codec."  If it were, this problem would be much more pervasive and would occur practically everywhere, instead of being limited to the rather specific conditions (i.e., significant boosting of highly dynamic music to levels that invalidate encode time assumptions about masking, etc.) that guruboolez has brought up.
*


Well, since it doesn't shows up at all in other codecs, maybe it is the encoder we're discussing here that is making wrong "encode time assumptions about masking, etc."?

After all, if other codecs' psymodels can handle this issue (without two passes!), why can't Musepack's? That is what I am failing to understand. Granted it's a rare ocurrance only reported by Guru so far, but still, there's the point that no other codec suffers from it - even little tunes ones like Faac.

This post has been edited by rjamorim: Jul 11 2005, 00:44


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Dibrom
post Jul 11 2005, 00:59
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QUOTE (rjamorim @ Jul 10 2005, 03:41 PM)
Well, since it doesn't shows up at all in other codecs, maybe it is the encoder we're discussing here that is making wrong "encode time assumptions about masking, etc."?

After all, if other codecs' psymodels can handle this issue (without two passes!), why can't Musepack's? That is what I am failing to understand. Granted it's a rare ocurrance only reported by Guru so far, but still, there's the point that no other codec suffers from it - even little tunes ones like Faac.
*


There are two ways I see that this could be handled, and is probably what is going on in the other codecs:

1) Adaptive ATH like what Gabriel was talking about. It should be pretty obvious why a two pass solution is going to be better than this. The encoder has to adjust the ath according to some sort of running average, and this is something that will have to be hand tuned probably. If you adjust too fast, you lose a lot of efficiency. If you adjust too slow, the user will hear artifacts that you were trying to adjust to prevent. How do you suppose you are going to decide this? There's not going to be a perfect way because you're working with incomplete data the whole time unless you go 2-pass.

2) Simply encode with a less aggressive ath level. This is probably what is happening more of the time. The problem here should be pretty obvious too -- you're always less efficient than you could be. Maybe this isn't a problem if most people are happy with the bitrate though.

Maybe something else is going on and I'm simply missing it, but from the sound of what has been said, I don't think this is the case.
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rjamorim
post Jul 11 2005, 01:02
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Thanks for your clarification.

So, from that, one can infer that Musepack is being a little too conservative on choosing an encoding parameter (ATH) to favor on the bitrate efficiency side?


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Dibrom
post Jul 11 2005, 01:05
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QUOTE (rjamorim @ Jul 10 2005, 04:02 PM)
Thanks for your clarification.

So, from that, one can infer that Musepack is being a little too conservative on choosing an encoding parameter (ATH) to favor on the bitrate efficiency side?
*


This is what I suspect probably, yes.

'Conservative' here could actually mean 'more exact,' since things seem to sound fine until you push them into the situation guruboolez is describing. Unfortunately, when that happens there's no headroom anymore and you sometimes might hear artifacts.

This post has been edited by Dibrom: Jul 11 2005, 01:07
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CiTay
post Jul 11 2005, 01:26
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QUOTE (Dibrom @ Jul 11 2005, 02:05 AM)
'Conservative' here could actually mean 'more exact,' since things seem to sound fine until you push them into the situation guruboolez is describing.  Unfortunately, when that happens there's no headroom anymore and you sometimes might hear artifacts.
*


Yes, that was my feeling too. With that in mind, i think we should look at the possible fixes, i.e. --ath_gain -14 / Ltq_offset tweaks, and see if we can work something out from there. If it's just an increase of 3, 4 kbit (and it would only be needed for --quality 5/--standard, from what i understand), it could easily be added in a new release. After all, the bits that were shaven off in 1.06~1.1 would simply be added again for one profile.
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mtm
post Jul 11 2005, 01:35
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I just want to say I agree with everything Dibrom said. Any postprocessing has the potential to trip a psychoacoustic encoder, especially when the encoder is expected to provide high efficiency. 20 dB amplification is IMO a pretty extreme case and I'm not surprised it can cause some problems. I wouldn't be surprised in case of any codec.

I don't think it's fair to say Musepack is severly flawed and hope no one will. unsure.gif

I wonder if RG modifiactions can solve all that.

<edit (while still writing wink.gif> If not, I think CiTay is right that lowering the ath in some new release should not be a problem for any Musepack user, considering only minor bitrate increase (on avarage).


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guruboolez
post Jul 11 2005, 02:18
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QUOTE (Dibrom @ Jul 11 2005, 12:15 AM)
The inverse can be said just as well.  Should we conclude that MPC is buggy because it doesn't perform as well as you'd like after you modified the encoded file, invalidating the assumptions the encoder made about masking, etc.?


That's fair. But as other members have said it, ReplayGain is not necessary to increase the volume playback. Even at home, I'm used to modify the volume during the playback. This behaviour might hurt some purists, but it's like making a pause, or listening again and again your favorite passage. It's simply a confort introduced and allowed by recordings (sometimes, Id like to increase the volume on classical concert - and also kill my noisy neighbour, but that's another problem wink.gif).

If a problem occurs on specific conditions, then problem lies in the encoder, and not in the listener's choice. Vorbis suffers (or maybe suffered) from perceptible pre-echo which is probably only audible with headphone. The answer to this issue is not to use loudspeakers instead, but rather to tune the encoder. Nobody would say that heaphones are buggy - the encoder is immediately accused, and rightly. If a developer would maintain that listeners should avoid headphones, users would probably switch to another encoding tool more suited to their habits.


QUOTE
I agree with Frank -- this is not a problem with MPC but a problem with using Replaygain in this way. 

You mean "...but a problem with using ReplayGain and MPC in this way" I suppose. Because I've no problem with current RG implementation - only some lossy encodings leads to problem. Of course, a track adjustment of 30 dB will increase the background noise, but I wouldn't compare this annoyance to the awful ringing produced by mpc --standard on such situations.

QUOTE
And that doesn't mean that there cannot be some sort of solution found, but I don't think that implementing some sort of imprecise changes in the psymodel to compensate for this special case -- sacrificing efficiency along the way -- is the right answer.


Possibly. But I only know that some encoders could handle this situation very well without sacrificing efficiency. Some of them have even encoding tool thats would allow to stay away from this issue at very low bitrate (vorbis as example, or SBR encoders). I can't say if MPC efficiency will be sacrified by correcting this problem; but I know that other lossy encoders could perfectly handle this situation and maintain in the same time the encoding efficiency.

In my opinion, sacrifying the quality on low volume content in order to increase the efficiency on most common material is a wrong trade off. Of course, it will please people a specific category of listeners, but other could only be disappointed by the poor performance on other material/situations.

QUOTE
Note: Sorry I accidently hit edit on your post instead of reply wink.gif

I thought you've tried to correct all my grammatical and syntactic mistakes laugh.gif Don't do it, it's probably more fastidious than tuning an encoder wink.gif

This post has been edited by guruboolez: Jul 11 2005, 02:27
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guruboolez
post Jul 11 2005, 02:26
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QUOTE (mtm @ Jul 11 2005, 01:35 AM)
I don't think it's fair to say Musepack is severly flawed and hope no one will. unsure.gif

The real problem is not the words we use to qualify the issue: it's the perception of the difference between the encoded file and the reference. Currently, MPC --standard produces severe artifacts on situations ~perfectly handled by LAME at 128 kbps. Now you'e free to describe the problem with your own words.
MPC is working very well on many situations. But here, it sucks (forgive my rudeness, but it corresponds IMO to the level of the artifact).

QUOTE
I wonder if RG modifiactions can solve all that.


Possibly. Another solution is to ask to composers or instrumentists to avoid quiet passages and to play everything loud enough to not mislead MPC current implementation. It should also solve the problem wink.gif

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guruboolez
post Jul 11 2005, 11:53
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QUOTE (CiTay @ Jul 11 2005, 01:26 AM)
With that in mind, i think we should look at the possible fixes, i.e. --ath_gain -14 / Ltq_offset tweaks, and see if we can work something out from there. If it's just an increase of 3, 4 kbit (and it would only be needed for --quality 5/--standard, from what i understand), it could easily be added in a new release. After all, the bits that were shaven off in 1.06~1.1 would simply be added again for one profile.
*


I fear that this kind of fix can't be proposed as default. The increase in bitrate would probably appear as excessive. Don't forget that the current 1.15 series is not on par with previous MPC encoders: bitrate is systematically higher, for an identical quality compared to 1.14 on a wide majority of samples. Some users have already complaint about it. 1.06 was the most "efficient" encoder; but when 1.1 was released, the bitrate was highered again to reach the same level than pre-1.06 encoders.

I've tried to evaluate the impact of the --ath_gain -14 on standard preset with my 150 short samples (edit: classical ones - it might differ with other music). It should give an accurate idea of the inflation:

- 1.01j --standard = 185 kbps
- 1.14 --standard = 188 kbps
- 1.15v --standard = 196 kbps
- 1.15v --standard --ath_gain -14 = 214 kbps

As you can see, 1.15v without additional switch already increase the bitrate compared to the latest beta. The inflation could reach 15 kbps per album (tried with harpsichord music) without experiencing any gain in quality. And compared to 1.01j, the difference is even higher - and also recall that I've tested 1.01j to sound better on a panel of 15 samples.

Now the ath_gain command would probably increase the quality, but the price to pay is a bitrate, with --standard profile and 1.15v, comparable to older encoder at --extreme profile.

The html files created with MisterQuestionMan:

- mppenc 1.01j
- mppenc 1.14
- mppenc 1.15v
- mppenc 1.15v --ath_gain -14

This post has been edited by guruboolez: Jul 11 2005, 11:56
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CiTay
post Jul 11 2005, 13:01
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QUOTE (guruboolez @ Jul 11 2005, 12:53 PM)
Now the ath_gain command would probably increase the quality,
*


Probably?

QUOTE
--ath_gain -14 works very well, and solves all issues (I didn't carefully tried to hear smallest difference).



QUOTE
but the price to pay is a bitrate, with --standard profile and 1.15v, comparable to older encoder at --extreme profile.


That's why i said, we need to work something out, probably with --ath_gain -14 as a basis, and fine-tune from there. I will do some bitrate checking with pop music etc., of course 15 kbit increase would be too much, but i'm confident there is some middle ground.
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Dibrom
post Jul 11 2005, 13:11
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I think I probably agree with guruboolez. I'm not sure this sort of change should be made to the presets.

I really think probably some sort of 2-pass method would be better. Why not simply calculate the track gain first and use the resulting value as some sort of offset to the defaults for the presets, and then use the already calculated track gain for the encoded file? That way you sort of get the 2-pass 'for free' because you were going to calculate it anyway. The downside to this is that the replaygain value probably won't be exactly what it would have been since the encoded file should calculate just a little bit differently, but the difference should be negligible (I think?). But doing it this way would probably catch cases where even a preset modification might not be enough, while also allowing the bitrate for most things to stay where it's already at. The other good thing is that this is something that could be implemented 100% at the frontend side.
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ancl
post Jul 11 2005, 13:33
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QUOTE (Dibrom @ Jul 11 2005, 02:11 PM)
I think I probably agree with guruboolez.  I'm not sure this sort of change should be made to the presets.

I really think probably some sort of 2-pass method would be better.  Why not simply calculate the track gain first and use the resulting value as some sort of offset to the defaults for the presets, and then use the already calculated track gain for the encoded file?  That way you sort of get the 2-pass 'for free' because you were going to calculate it anyway.  The downside to this is that the replaygain  value probably won't be exactly what it would have been since the encoded file should calculate just a little bit differently, but the difference should be negligible (I think?).  But doing it this way would probably catch cases where even a preset modification might not be enough, while also allowing the bitrate for most things to stay where it's already at.  The other good thing is that this is something that could be implemented 100% at the frontend side.
*

The 2-pass approch seem like a good solution. Reusing the replaygain can cause problem though - you won't get correct peak information.
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