Experiments with the Time Remap filter

[brian]

@ejmillan

On the track, there is a vertical time scale with the detected value of the clip.
At the last keyframe, I adjusted the input time to set to 1.0 X before it (I used the arrow buttons next to the time value in the filter settings). Then the keyframe disappeared.
Lengthening the track height to the maximum did not help.
I guess this happens because I go out of the time range of the original clip (vertical scale on the left of the track marked with the yellow rectangle).
To avoid undoing everything, I used the next frame and delete button, red and yellow arrows. This way I recovered the line to modify it.

You found a tricky bug and you found a good workaround to fix it. The “Set Speed” buttons can circumvent the maximum and minimum value constraints. I will make a note of this, but I do not know if I will make it a priority to fix for the next build.

@MusicalBox

If other Time related filters are added, would it be feasible to create a keyframe timeline dedicated to those filters ?

That may be something to consider. The current UI design is a direct response to many historical requests for “Where is the speed filter?”. So I expect many people expect time related features to be among the rest of the filters in the UI.

@Austin

Unless I misunderstand some mechanics, the absolute nature of the time curve is likely to be a common problem for any modification that specifically needs to lengthen or shorten the duration of the clip

@Austin

Without ripple, a user has to work left-to-right and get it perfect on the first try, because going back to modify the curve would require manual ripple work.

I have not used a lot of other video editors. But I have watched tutorials of time remap features in other editors. I have observed the following things about time remap features in other editors:

1. The workflow is often iterative - going back and making changes as the output unfolds
2. They almost always start by extending the clip way longer than they need and then they end by reducing the clip length back to where they want it to finally end
3. They almost always work left to right - which stands to reason because that is how our minds perceive the timeline

So I am not so sure if the Shotcut implementation is very different from other implementations.

@bentacular

This is what makes it hard to grasp, more importantly, hard to teach.

This makes me curious to understand:

• Are the difficulties with time remapping caused because Shotcut has implemented it so differently than other tools?
  OR
• Are the difficulties with time remapping because these users are generally unfamiliar with time remapping and they happen to be learning for the first time in Shotcut

I know that the Shotcut implementation doesn’t have all the bells and whistles of other editors (yet). But I was kind of expecting someone with some experience to make a tutorial video showing a productive workflow. Maybe someone will get around to that.

@ejmillan

This filter reminds me of a Linux application called slowmoVideo.
…
Reading this documentation I understood a little better (just a little) certain concepts.
The explanation about the interpretation of the two axes helped me a lot to understand why a straight line means freezing of the video.

Maybe we can map some of those concepts into the Documentation. It looks like Dan has been making some improvements to it already:

Time Remap Filter

The Time Remap filter is the first filter that allows altering the timing of the underlying source clip. It maps clip time to output time. [image] Limitations It can only be added onto clips with NO B-frames. If you try to add it to such a clip, it shows the Convert to Edit-friendly dialog. A proxy clip can mask the above check for B-frames and then export may be very slow or give bad results. However, it may also be a very convenient workaround for the check and dialog mentioned above if you…

@MusicalBox

@DRM

The point I am making is that I see that there is a lot of activity here in this thread about figuring out Time Remap when the best time for that really was in the several threads that were made on it before its official release.

It’s hard to work with a new tool, test it and give feedback when you have no clue on how to use that tool and even what exactly it’s suppose to do…

I understand that people are volunteers, and busy, and at different places in their learning journey. So I am happy to accept comments/suggestions any time. Just because the feature has been released does not mean we can not improve upon it. But we are somewhat limited by the capacity of the volunteer developers