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

[Henrikki Almusa]

On 2013-12-15 06:27, Vincent PINON wrote:
> Hello,
>
> Thanks for your involvement !

No problem. I'm trying to learn c++ so best way to do that is code and I 
do use kdenlive.

> I would take option 2, allowing any value of fps, 1 being a workaround
> for a design limitation...
> displayed fps should be made a float for this case (0.33), or a fraction
> (1/3)? As you prefer/have time to do...

The return formats assume 2 numbers for frames, so I might have to 
change that to accommodate the larger numbers, here's hoping nothing 
breaks. Is there a preference to float or fraction?

> Once done can you send a git-formatted patch?

Yes. I have a clone of master.

> BR,
>
> Vincent
>
> Le 15/12/2013 00:08, Henrikki Almusa a écrit :
>> 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?
>>
>
>
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-- 
Henrikki Almusa