Re: [Audacity-devel] Automatic Volume Feature
A free multi-track audio editor and recorder
Brought to you by:
aosiniao
From: Gale A. <ga...@au...> - 2009-08-07 02:25:40
|
| From André Pinto <est...@gm...> | Thu, 6 Aug 2009 12:41:57 +0100 | Subject: [Audacity-devel] Automatic Volume Feature > On Thu, Jul 30, 2009 at 2:13 AM, Gale Andrews <ga...@au...> wrote: > > | From André Pinto <est...@gm...> > > | Wed, 29 Jul 2009 15:32:35 +0100 > > | Subject: [Audacity-devel] Automatic Volume Feature > > > On Wed, Jul 29, 2009 at 1:08 AM, Martyn Shaw < > > mar...@go...>wrote: > > > > > > > Hi André > > > > > > > > I've had a play with this and it seems like a good idea. A few > > > > comments however: > > > > > > > > André Pinto wrote: > > > > > Hi, > > > > > > > > > > As planed, I've been working during this week on Automatic Volume > > > > Feature. > > > > > > > > > > I've just committed the initial implementation. To test it you > > should: > > > > > - Uncomment #define AUTOMATIC_VOLUME in src/Experimental.h to test > > it. > > > > > - Activate and configure it on Preferences->Recording and then > > proceed > > > > > to a normal Record. > > > > > > > > > > Brief configuration options description: > > > > > - Checkbox: Enable/Disable Automatic Volume > > > > > - Best Peak Volume slider: desired max peak volume (from 0 to 100) > > I'm on Windows XP at the moment. I'll admit I have not followed > > this feature much, but using it with "stereo mix" I have issues > > (and certainly confusion as to the extent this feature is supposed > > to interact with the Audacity input slider). > > > > If I: > > > > * set Audacity input slider to 0.7 > > * turn up my Wave output to maximum > > * play a classical orchestral piece in Windows Media Player > > that starts ppp and ends up fff > > * press Record in Audacity > > > > the fortissimos clip severely at default settings (Best Peak = 92). > > There is no adjustment of the Audacity input slider at any time. > > > > If you are using the default settings then Automatic Volume will stop after > 5 analysis (Default number of consecutive analysis = 5). If you want it to > run all the time change the value to 0 in the Preferences. In this case is > possible that 0.7 is considered a nice volume in the beginning and only > after the 5 analysis (after Automatic Volume stopped) the volume becomes too > high. To add this, if you were using the old version of Automatic Volume, > the feature would immediately stop just after finding the first acceptable > volume. Hi André Setting "Number of Consecutive Analysis" to "0" does not prevent clipping I'm afraid with this same piece of music. With Wave Volume 100%, Target Peak = 92, "endless analysis" and Audacity Input Slider= 0.7, I get clipped recording as soon as the loud passage is reached. There is less clipping, though. In the first passages it records clipped (8 seconds or so), AV is indicating it has reduced to circa 0.8. A bit further on (the music is a little less loud here) it seems to be preventing clipping and says typically "reduced to 0.3". I can see messages in the quieter opening part that AV has "increased to 0.8", even a few times to "increased to 1.1", as well as "decreased" messages. Would I expect an "increased to 1.1" figure? Comparing to recording with AV unchecked in Preferences, it seems at the above settings that AV is messing with the volume of the quiet passage when it has no need to do so to avoid clipping. It is giving me a generally louder recording of it with higher peaks, but it's also audibly decreasing the level of some bars relative to the rest. Can you confirm this is expected, and that I can't use it just to prevent clipping when it would otherwise occur, and leave the dynamics of everything else alone? This, in my ignorance, was what I was expecting. There does not seem any positive indication if AV has turned "off" when recording, except for the Status Bar messages indicating it is still affecting the volume. If analysis number is set to 5, would I expect to see "AV has stopped" messages? I have never seen those. At some later stage, does this need some kind of On/Off Status indicator, say in the Mixer Toolbar, so people can figure if they may need to change the number of analyses? What are the benefits of AV stopping when it thinks it needs no more information - lower CPU use? And what is the rationale for a default setting that it stops, given it has no idea what level of input is to come? Generally, default settings should (IMO) prevent clipping even with a difficult test with wide dynamic range. Is it any help if I upload this piece somewhere so you can play with it and figure why it is so troublesome? We certainly need an explanation of how the feature interacts with the Audacity input slider. Is AV meant to interact with the input slider (for example, so that when it needs to reduce the input level this will be seen in that slider)? Sometimes, re-recording the same passage at the same AV settings, with similar Status Bar messages, the input slider will not move off 0.7; other times it will shoot around rapidly. On a more general point, could you please put up on your Wiki page: http://wiki.audacityteam.org/index.php?title=Bugfix_Automatic_Volume_Wiki a section on "How to use Automatic Volume Recording " explaining what its features should currently do? This was a requirement in last year's GSoC so I'm not sure why this has not been asked for yet (I appreciate this is something of an "optional" element). When you have written a user-level explanation of its purpose, how the volume is adjusted, plus what each control does, we can transfer that to the Manual. Writing some user-level input may help suggest better wording for some of the interface text than we have now. One other query (I've not tested this at all). Do you expect this feature to have any problems if run with Sound Activated Recording? > > About the type of slider used in these two features, I don't get > > good feedback about it - its also in the AAC export options. > > I think it's very confusing to have a dynamic centrally positioned > > value that can make you think you are looking at a log scale. > > It would be OK if it actually looked like a counter or something. > > I can see some point in the AAC options due to limited space, > > and I know there is a problem seeing the set value with the > > normal sliders, but Leland is I think onto a solution for that. > > Can we not use regular sliders here that behave the same as > > the others (click in the scale and the handle goes there)? > > > > So you are sugesting using LWSlider (the one that is used on Gain sliders > and many other places) right? If it's that one that's the only solution for > float values that I know, so I'll definitely be trying to use those. Yes, the slider we normally use for adjusting gain. I've left in below the other two troublesome "scenarios" for reference. Thanks, André :=) Gale > > If I now set the Audacity input slider to 0.2, play and record, > > the input slider jumps to 1.0 after 2 seconds, and stays there > > throughout the fortissimos, yet there is no clipping. I have > > extra volume compression between the pianissimo and the > > fortissimo that I was not expecting (I did not ask for a massive > > boost on the quiet passage). The highest peak recorded is > > -6.4 dB. Does this seem correct for "92" given the above? I > > completely agree that 0 > 1 is a better range for Best Peak > > and think an explicit dB scale would be better still. > > > This might be caused by the same issue I've referred above. A scale of 0>1 > probably would be better but I was reading some wxwidgets documentation and > I think there is no wxSlider for floats, I'll try to use Audacity's LWSlider > instead. > > > > > > > If I set Audacity input slider back to 0.7 and turn "Best Peak" > > down to "13", I consistently get only the first two seconds recorded. > > The rest is silence (New Peak Amplitude = Infinity according to > > "Amplify"), irrespective of the volume of the incoming audio. > > I do not have Sound Activated Recording on. This seems to happen > > because Audacity resets the input slider to 0.0 after that length of > > automated recording. Same happens if I set "Best Peak" to "50". > > > > The silence should be caused by the way your soundcard deals with 0.0 input > volume, maybe it mutes the input like Martyn said. The fact that it goes to > 0.0 is probably caused by the bad interpretation of values that is being > done as Martyn already reported. |