[Rosegarden-bugs] [ rosegarden-Bugs-1402866 ] audio segment previews not recalculated on tempo change

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Bugs item #1402866, was opened at 2006-01-11 12:53
Message generated for change (Comment added) made by cannam
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Category: segment canvas
Group: None
Status: Open
Resolution: None
Priority: 8
Submitted By: Chris Cannam (cannam)
>Assigned to: Chris Cannam (cannam)
Summary: audio segment previews not recalculated on tempo change

Initial Comment:
  
If you add or remove a tempo change (or change an  
existing one), all audio previews that overlap or  
follow that tempo change need to be recalculated.  
  
Example: Start RG with an empty composition, add an  
existing audio file from somewhere.  Add a  
significant tempo change (say to 240bpm) somewhere  
before or during the audio segment.  Observe that the  
audio segment (correctly) changes width (because the  
fixed-duration audio file now plays in a different  
duration in our musical beat scale) but that the  
preview is not rescaled to fit, instead ending early  
or overrunning the end of the segment block.  
  
All we need to do is cause the preview to be  
refreshed -- the preview calculation code in 
paintPreviewImage handles this case correctly now.  
  
  

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>Comment By: Chris Cannam (cannam)
Date: 2006-01-29 19:46

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I've just realised that the remaining part of the problem   
is down to the fact that we store audio end time (as   
RealTime) and segment end marker time (as timeT)   
separately, rather than always deriving the one from the   
other.  When the tempo changes, one of them needs updating   
but the other does not.   
 
I already have a bug open to remove the audio end time 
field altogether.  I'm going to hold this one back until I 
look at that. 

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Comment By: Chris Cannam (cannam)
Date: 2006-01-23 10:21

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It wouldn't.  What kind of moron would think otherwise? 
 
Sorry about that, I just got a bit carried away with a 
particular train of thought. 
 
Doesn't alter the fact that this still doesn't seem to 
work correctly all the time for audio segments, I'm 
afraid. 
 

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Comment By: D. Michael McIntyre (dmmcintyr)
Date: 2006-01-22 21:50

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Huh?  Why would tempo make a MIDI segment resize?  The 
problem with audio is that it represents sound for a finite 
period of time, while a MIDI segment is always sound for a 
given fraction of the current tempo.  Increase the tempo, 
decrease the absolute time the MIDI events sound, but it's 
all still the same relative to the time signature.  Isn't 
it? 
 
One of us is confused.  Maybe it's me. 

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Comment By: Chris Cannam (cannam)
Date: 2006-01-22 21:38

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If you insert a tempo change during an audio segment, and 
the end of the audio segment _rectangle_ (never mind the 
preview) doesn't move, then yes, that's a bug. 
 
I've just tested this (with your change) on a file with 
four audio segments on four tracks.  Two of them ended 
toward the end of bar 3, the other two somewhere in bar 4.  
I changed the tempo at the start of bar 2 from 120 to 240. 
 
The first and second audio segments resized themselves 
correctly (including redrawing the previews correctly).  
 
The third and fourth audio segments remained exactly the 
same size, but the previews within them were rescaled 
correctly (and were cropped by the segment rectangle 
before the segment itself had actually stopped sounding). 
 
So, there still seems to be some problem (that I don't 
understand) with redrawing or recalculating the actual 
segment.  The previews appear to be OK.  Maybe it has 
something to do with whether or not the segment has an end 
marker previous to the end time -- I'm not sure whether 
mine do or not. 
 
There's nothing very audio-specific about this -- it's the 
segments themselves that failed to resize -- so I wonder 
if it sometimes also happens for MIDI segments? 
 

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Comment By: Guillaume Laurent (glaurent)
Date: 2006-01-22 16:52

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Tentative fix committed in cvs. 

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Comment By: Guillaume Laurent (glaurent)
Date: 2006-01-21 23:54

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I've tried that, the audio segment doesn't change a 
bit :-(. Guess that's a bug ? 

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