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Video seeking webm doesn't cut straight to the point in question, it fast forwards. It's doing this in the final render too.

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Wed, 01/09/2013 - 02:07
#1
j
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Joined: 04/21/2012
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Video seeking webm doesn't cut straight to the point in question, it fast forwards. It's doing this in the final render too.

Basically, if I view a webm file (produced by my webcam with cheese) in kdenlive and skip to the middle, the last few minutes will fast forward until the video catches up, rather than just skipping to the point in question.

This would be fine if it only happened in the preview window but it happens when rendering too. I fixed this once before as I have a kdenlive project where it skips to the correct part, but that was months ago and I forgot how I did it (Or just did it with luck somehow)

By looking at the .kdenlive xml files I can see the one that's working is set to "55 fps" in various places while the one that's not is set to "1000 fps" though don't ask me why.

Here are the lines from the file I think might be related to the problem.

<property name="meta.media.1.stream.frame_rate">1000.000000</property>
<property name="meta.media.frame_rate_num">1000</property>
<property name="meta.media.frame_rate_den">1</property>
<property name="source_fps">1000.000000</property>

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Wed, 01/09/2013 - 10:02
#2
ttguy
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Joined: 09/15/2009
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Re: Video seeking webm doesn't cut straight to the point in ...

Does the project profile match the .webm files properties?
Use the Clip properties on the clip in the project tree to see its properties.

Try Project>Adjust Profile to Current clip to make Kdnelive set you projects properties to one that matches the clips you have.

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Wed, 01/09/2013 - 13:49
#3
j
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Re: Video seeking webm doesn't cut straight to the point in ...

There are no profiles for 1kfps. Even if there were I'd rather not record like that.

It seems to me that's just a default value as the video itself looks more like 10fps.

Simply scrubbing to the middle of the clip makes it offset and speed all over the place and makes it impossible to time clips together. What is kdenlive doing to my webm clips?...

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Wed, 01/09/2013 - 14:31
#4
ttguy
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Re: Video seeking webm doesn't cut straight to the point in ...

You are saying your source video is 1000 frames per second ?

That is a pretty crazy frame rate isn't it?

You could create a custom profile though with that frame rate if that is really what you have - and see how it goes.

http://userbase.kde.org/Kdenlive/Manual/Settings_Menu/Manage_Project_Pro...

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Wed, 01/09/2013 - 15:24
#5
j
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Re: Video seeking webm doesn't cut straight to the point in ...

No, webm video has no frame rate as far as I can see. Webcam recordings, ffmpeg/avconv outputs all show up as 1kfps in kdenlive.

Meanwhile vlc shows the codec doesn't have a specific framerate set (probably variable for html5 stuff) but renders 470 frames in 30 seconds so I'd think my webcam is recording at about 15fps.

kdenlive just isn't handling it properly and I'm wondering if anyone knows the workaround.

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Wed, 01/09/2013 - 19:08
#6
yellow
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Re: Video seeking webm doesn't cut straight to the point in ...

Kdenlive uses MLT framework which in turn uses ffmpeg. So its ffmpeg thats having issue with your file regarding establishing a frame rate, whether its variable or not etc. MLT has the ability to adjust the frame rate to your project settings. Sounds like that too is having issue.

Have you tried a different codec in Cheese? Can you set a recording frame rate a forget the vfr?

What does ffplay or ffprobe on the command line say about the file?

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Wed, 01/09/2013 - 21:01
#7
j
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Re: Video seeking webm doesn't cut straight to the point in ...

You can't set codec or framerate in cheese.

ffplay/ffprobe say:


Input #0, matroska,webm, from '/media/data/Videos/output/kdenlive/cube26/26sec.webm':
Duration: 00:26:31.86, start: 0.000000, bitrate: N/A
Stream #0.0(eng): Audio: vorbis, 44100 Hz, mono, s16 (default)
Metadata:
title : Audio
Stream #0.1(eng): Video: vp8, yuv420p, 640x480, PAR 1:1 DAR 4:3, 1k tbr, 1k tbn, 1k tbc (default)
Metadata:
title : Video

VLC (using ffmpeg backend) and ffplay can both seek the video fine, the problem is either in mlt or kdenlive.

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