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IDProjectCategoryView StatusDate SubmittedLast Update
0002699KdenliveUser Interfacepublic2012-08-11 11:082012-08-19 19:38
Assigned To 
Platform64 bit intelOSDebian LinuxOS Versiontesting
Product Version0.8.2.1 
Target VersionFixed in Version 
Summary0002699: Waveform display massively different from audacity
DescriptionTo synchronize our separately recorded video and audio track, we generated a synthetic soundfile with a very distinguishable waveform (rzl-video-sound.wav, I attached it to this bugreport).

When I open the file in audacity, I see the waveform as it’s supposed to be: increasing, then a gap, then decreasing. Then the pattern repeats once. Screenshot is attached.

However, when I open the file in kdenlive, the waveform display differs massively. I’m not sure what exactly is wrong here, so maybe you could shed some light on it. Note that I’ve noticed that the waveforms look weird when synchronizing in the past, but I never could put my finger on it until now.
Steps To Reproduce1. Open rzl-video-sound.wav in audacity (or see the screenshot)
2. Create a new project in kdenlive, add rzl-video-sound.wav as a clip, drag it onto the audio timeline.
3. Notice how the two waveforms differ massively.
Additional InformationI created the file with SuperCollider, here is the source code (just so that you can be sure that audacity displays the right thing here):

SwingOSC.program = "/usr/share/SwingOSC/SwingOSC.jar";
Server.default = s = Server.local;

{,0,,0.0,2.0,doneAction:2)) ! 2}.scope;
{,0,,0.5,2.0,doneAction:2)) ! 2}.scope;
TagsNo tags attached.
Build/Install MethodDistribution package
Attached Filespng file icon waveform-audacity.png [^] (46,987 bytes) 2012-08-11 11:08

png file icon waveform-kdenlive.png [^] (61,899 bytes) 2012-08-11 11:08

png file icon waveform-kdenlive-zoomed.png [^] (55,419 bytes) 2012-08-11 11:08

zip file icon [^] (997,078 bytes) 2012-08-11 11:10

- Relationships

-  Notes
MichaelStapelberg (reporter)
2012-08-11 11:11

By the way, this is not only an issue for wave files, I see the same effect when I take the recording from my camcorder (AVCHD). My observation is that it does not depend on the filetype.
vpinon (administrator)
2012-08-19 19:38

Maybe a linear/log scale mismatch?

- Issue History
Date Modified Username Field Change
2012-08-11 11:08 MichaelStapelberg New Issue
2012-08-11 11:08 MichaelStapelberg File Added: waveform-audacity.png
2012-08-11 11:08 MichaelStapelberg File Added: waveform-kdenlive.png
2012-08-11 11:08 MichaelStapelberg File Added: waveform-kdenlive-zoomed.png
2012-08-11 11:10 MichaelStapelberg File Added:
2012-08-11 11:11 MichaelStapelberg Note Added: 0008196
2012-08-19 19:38 vpinon Note Added: 0008202

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