[Kdenlive-devel] Bug #3181, Crash from setting slow frame rate

[Henrikki Almusa]

Hi all,

I've been looking into bug 3181.
http://www.kdenlive.org/mantis/view.php?id=3181

The bug is triggered when framerate is set to 3/1 or slower (so 3 
seconds per frame). What happens is division by 0 error from 
Timecode.cpp line 414:

     int frames = framenumber % m_displayedFramesPerSecond;

In there the m_displayedFramesPerSecond is 0. This is set earlier:

void Timecode::setFormat(double framesPerSecond, Formats format)
{
     m_displayedFramesPerSecond = (int)(framesPerSecond + 0.5);
     m_dropFrameTimecode = (framesPerSecond / 1.00 != 
(int)framesPerSecond) ;
     m_format = format;
     m_realFps = framesPerSecond;
     if (m_dropFrameTimecode) {
         m_dropFrames = round(m_realFps * .066666); //Number of frames 
to drop on the minute marks is the nearest integer to 6% of the framerate
         m_framesPer10Minutes = round(m_realFps * 600); //Number of 
frames per ten minutes
     }
}

So in situations where framesPerSecond is less than 0.5 (eg. 3/1 in the 
dialog -> framesPerSecond is 0.3333...) the m_displayedFramesPerSecond 
becomes 0, leading to crash.

So I can figure out two ways to solve this:
1. Profile dialog could prevent giving more than 2 for first value in 
frame rate (or just set it 1 and disallow changing it)
2. The Timecode.cpp needs to be changed to allow 0 in 
m_displayedFramesPerSecond.

Which one would be better (or a third option)? If 1, where should I poke 
my head to do this?

-- 
Henrikki Almusa