Force Shotcut to use Frame Number rather than Timecode?

Help/How To
1

I am writing an app that produces an MLT file with a series of clips with in-out points shown as frame numbers like shown below.

This works fine when the video frame rate and total number of frames match up (e.g. a 60sec 25fps clip holds 1500 frames). However, my IPCam seems to drop frames over my network so that each minute maybe holds 1200 frames, but it still reports 25fps in Shotcut Info.

It seems that Shotcut takes my frame numbers and then converts them to timecode using the reported frame rate. The playlist in-points confirm this. This means my clips are shown incorrectly in Shotcut.

I can get over this problem by first converting my clips to a constant frame rate. However, I wondered if there is any way I can force Shotcut to use the frame counts rather than timecode?

Thanks in advance
Dave

<producer id = "producer0">
	<property name = "resource">C:\Ascans\drive 1 hour\1_12.36.33.avi</property>
</producer>
<playlist id="playlist0">
	<entry producer="producer0" in="3124" out="3234"/>
	<entry producer="producer0" in="9757" out="9882"/>
	<entry producer="producer0" in="10513" out="10587"/>
	<entry producer="producer0" in="16985" out="17056"/>
	<entry producer="producer0" in="22960" out="23070"/>
	<entry producer="producer0" in="24624" out="24709"/>
	<entry producer="producer0" in="28133" out="28225"/>
	<entry producer="producer0" in="30491" out="30541"/>
</playlist>
2

Shotcut and MLT does not support variable frame rate.

You should declare the frame rate in your MLT XML using , then MLT can reliably convert all frame counts. Otherwise, it might be interpreting them at the current Shotcut project frame rate or Settings > Video Mode.

On XML input, it already should, but again, perhaps only when you include <profile>.
For output XML, I have no plans to offer that choice.

3

Many thanks Dan. My app logs the actual frames per video so I can use that to calculate the real (rather than reported) FPS for each clip. Applying this in the XML file should fix my problem, as long as the rate of dropped frames is reasonably constant over the clip. I will let you know how I get on.

btw, Kudos to you and your team for Shotcut. It copes effortlessly with my app’s output files which consist of several hundred clips with video and audio transitions between each clip. I hope to upload some sample videos shortly.

Dave