0002699: Waveform display massively different from audacity

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Project

Category

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Date Submitted

Last Update

0002699

Kdenlive

User Interface

public

2012-08-11 11:08

2012-08-19 19:38

Reporter

MichaelStapelberg

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

new

Resolution

open

Platform

64 bit intel

Debian Linux

OS Version

testing

Product Version

0.8.2.1

Target Version

Fixed in Version

Summary

0002699: Waveform display massively different from audacity

Description

To 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 Reproduce

1. 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 Information

I 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";
SwingOSC.default.waitForBoot({s.makeGui});
Server.default = s = Server.local;
s.boot;

{SinOsc.ar(440,0,Line.kr(0.5,0.0,2.0,doneAction:2)) ! 2}.scope;
0.25.wait;
{SinOsc.ar(440,0,Line.kr(0.0,0.5,2.0,doneAction:2)) ! 2}.scope;
)

Tags

No tags attached.

Build/Install Method

Distribution package

Attached Files

waveform-audacity.png [^] (46,987 bytes) 2012-08-11 11:08

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

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

rzl-video-sound.wav.bz2.zip [^] (997,078 bytes) 2012-08-11 11:10

Relationships

Notes
(0008196) 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.

(0008202) vpinon (developer) 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: rzl-video-sound.wav.bz2.zip
2012-08-11 11:11	MichaelStapelberg	Note Added: 0008196
2012-08-19 19:38	vpinon	Note Added: 0008202