Blackmagic Forum

Hi there, I wonder if someone else can do a check on this for me. I am finding that a clip that is, for example, 10 seconds long, indicates it is about 12 seconds long according to the scale in the Color Page Window/Stabilizer/Fx view-window. However, if I turn the clip into a compound clip, the scale is correct.

Here are two screen shots taken moments apart. I have two V tracks, V1 is a 10 seconds clip, and V2 is the same clip converted to a compound clip, also 10 seconds long. The clips are on top of each other.

Screenshot One - Track 1 is selected. I have placed the cursor at the 8 second 11 frame point. On the scale in the Stabilzer Window, you can see the cursor is shown to be at 10 seconds 13 frames. That doesn't seem quite right.



Screenshot Two - Track 2 is selected. I have placed the cursor at the same point, 8 seconds 11 frames, and you can see that it is correctly positioned along the scale.



Here is an enlargement of the scales: -



So, it is not just a display problem either. The real problem is that when I copy tracking data from one to the other, the tracking data is offset.

Can anyone else do this quick test and see if they get the same result

Cheers,
Cass.

So, if this may help someone help me, who may have seen this before, this is what I have found out thus far...

I have my timeline frame rate set to 24, and playback to 24 fps. I have clips from many sources with assorted frame rates, such as 30 and 29.97. What I have found is that the Stabilize window scale appears to use the frame-rate of the source clip, instead of my chosen working frame-rate.

Does anyone know if there would be a setting to fix this, or are we talking about a bug. I just can't imagine the latter, or else everyone would notice this problem, right? Has anyone ever noticed this?

C'mon, more than 120 people have viewed this message. Is there not one kind person out there that either could do a quick 1 minute test to see if they see the same thing, or throw me a suggestion of where I might better investigate the issue...

My habit is to use a single resolution and frame rate for all my media.

Jim Simon wrote:My habit is to use a single resolution and frame rate for all my media.

Hi Jim, thanks for the comment. I appreciate that, but sometimes one has to go with the formats they're given, and I have multiple for this project. Of course I could encode them all first to something the same, and live with the slight quality loss, and the time, but to be honest, I only noticed this issue with the project half way completed and started with stabilization and motion tracking.

I just wish someone could tell me whether what I am seeing is 'normal' behavior, and why that is so. Doesn't make sense that everything else appears to be designed to handle multiple frame-rates, why not the stabilizer window?

Ah well, maybe someone else will let me know if at least they can try it...

Cheers again...

Probably because the stabilizer needs to work with every single frame, while the timeline is dropping frames, blending or synthesizing them. You could conform the odd clips with the "Clip Attributes" to the target rate, but you'll get mild slo-mo (for 30 fps sources). Might look even better, given the fact that you want to stabilize.

Uli Plank wrote:Probably because the stabilizer needs to work with every single frame, while the timeline is dropping frames, blending or synthesizing them. You could conform the odd clips with the "Clip Attributes" to the target rate, but you'll get mild slo-mo (for 30 fps sources). Might look even better, given the fact that you want to stabilize.

Yes, I can imagine that the design is such that Resolve would use the clip's raw frame data to handle the internal calculations for stabilisation, but to display the time scale on a different time scale to the main timeline should not be necessary.

So, the interesting thing is that, as I mentioned above, if I turn it into a compound clip, the clip scale is displayed consistently with the main timeline scale.

So, I am not sure if this is a bug or feature, but to put this concisely: -

1. When a clip that has a frame-rate different from the timeline frame-rate is viewed using the Color Page Stabilizer/Tracker, the time scale on the Stabilizer/Tracking window reflects that of the original frame rate of the clip, not of the timeline.

2. Given the situation in point 1, the time indicated by the timeline play-head will not line up with the time-scale displayed in the tracker window. Additionally, if one attempts to take tracking data from that clip and copy it to another clip that has a different frame-rate, the tracking data is mismatched and therefore not synchronized in time/frame.

3. One way to copy tracking data between two clips of different frame-rate, is to convert any clip that has a different frame-rate from the timeline frame-rate into a compound clip. When this compound clip is viewed on the Color Page Stabilizer/Tracker, the time scale is then consistent with the timeline time-scale, and any tracking data generated for the compound clip can be copied and will be in sync with other clips that share the timeline frame-rate.

In a nutshell, it is a workaround, but since all clips that are mismatched to the timeline frame-rate are automatically adjusted by Resolve to appear in sync with the timeline frame-rate in every other respect, I still do wonder whether displaying the clip using an 'inconsistent' time scale in the Stabilizer/Tracker display is a bug.

I will submit to BM Support.

Glenn, stabilization is performed on source clips therefore source frame rate.

Peter Chamberlain wrote:Glenn, stabilization is performed on source clips therefore source frame rate.

Hi Peter, thanks for that. Just what I wanted to know.

This does mean that, essentially, tracking data from a clip cannot be copied to another clip with a different source frame-rate.

However, as a workaround, for anyone reading this thread in the future, if one turns a clip into a compound clip, this results in one that is at the timeline frame-rate, allowing its tracking data to be copied between clips that share this frame-rate.

Thank you.