Blackmagic Forum

In Resolve 15 is it possible to combine two clips with different frame rates - say 30 fps and 60 fps and both will play at their native frame rates?

Thanks-

Right click on media file - Attributes. You can change the frame rate to match the project frame rate. The clip will then play frame by frame, without any frame rate conversion.
If you just drop each clip on the timeline the frame rate gets converted automatically to match the project frame rate. So the clip plays at realtime speed. The method for converting frame rates is in Project Settings/Master Settings.

Thanks George. I'm a bit confused:

"You can change the frame rate to match the project frame rate. The clip will then play frame by frame, without any frame rate conversion."

Does this mean a clip of 60 fps will play at 30 fps if 30 is the project frame rate? So it will drop every other frame?

"If you just drop each clip on the timeline the frame rate gets converted automatically to match the project frame rate. So the clip plays at realtime speed. " Meaning 30 plays at 30 and 60 plays at 60?

Thank you and sorry for the confusion.

tspence wrote:In Resolve 15 is it possible to combine two clips with different frame rates - say 30 fps and 60 fps and both will play at their native frame rates?

It's 2018 and it is not so far out to expect a video to be able to smoothly play different segments at different frame rates but as far as I know that technology is not (yet) available.

What would be the purpose of that? It all ends up a single clip.
If it becomes necessary to render masters at different frame rates, pick 120fps project frame rate.

tspence wrote:Does this mean a clip of 60 fps will play at 30 fps if 30 is the project frame rate? So it will drop every other frame?

It will drop every other frame in a 30fps project if it plays at 60fps, not 30. Timelines can't just switch frame rates, they are locked to one frame rate, so if 1 second of a 60fps source clip is to play back in real time in a timeline of a lower frame rate then it will have to skip frames at regular intervals.

If you do NOT want it to skip frames then a source clip of 60fps will only have the first 30 of those played back in 1 second of a 30fps timeline, and so it will effectively play back at half speed.

George Deierling wrote:What would be the purpose of that? It all ends up a single clip.
If it becomes necessary to render masters at different frame rates, pick 120fps project frame rate.

Practically, though, you're looking at 705,600,000fps, because 120fps can't, for instance, hold 72fps content.

I get the point... Hopefully BM will tackle the locked project frame rate issue and let us deliver at different frame rates. Then source frame rate won't matter. But I suspect of all the things that need work, its not the most hard pressing.

Selection bias. Anyone who does work at different framerates isn't using the beta because they aren't using Resolve.

Chad Capeland wrote:

George Deierling wrote:What would be the purpose of that? It all ends up a single clip.
If it becomes necessary to render masters at different frame rates, pick 120fps project frame rate.

Practically, though, you're looking at 705,600,000fps, because 120fps can't, for instance, hold 72fps content.

Not really, 360fps would be sufficient.

Thanks all.

Here is the clip in question:


The 1st part was recorded at 30 fps. At 3:51, the 2nd clip starts - was recorded at 60 fps. The project setting was 30 fps. It is playing back at normal speed - so Resolve dropped every other frame correct?

What would have happened if I had the project settings set at 60 fps? 2nd clip would have been fine but the 1st would have played 2x faster than recorded?

tspence wrote:Thanks all.

What would have happened if I had the project settings set at 60 fps? 2nd clip would have been fine but the 1st would have played 2x faster than recorded?

You should try :
A project / TL at 60 fps:

- install the 2nd clip (60 fps) first,
- install the 1st clip (30 FPS) in a project at 60 FPS (keep the clip at 30 fps)

Leave the clip attribute of the clip at 30 fps (clip 1st).
Change the project setting: master settings => Frame Interpolation:
Retime Process : Optical Flow
Motion Estimation: Enhanced Better
Motion Range: (?) Larger? Medium? Small?

In your example: (in theory)
From 60 fps to 30 FPS: There is (according to the project setting: master settings => Frame Interpolation)
Blend, nearest or interpolation (which has been improved for a long time but has never been an exact science)

If shooting is by far, you will not have much difference, but if it's close: depending on the angle and speed of action: you will have different results: especially on certain verticals.

You might have to start over with a fresh project.
Before you do anything set project frame rate to 60fps (or 59.94)
Once you add clips to the media page you cannot change the frame rate anymore.

Jean Claude & George -

Thank you both.

+1

I need to be able to reformat and retime for multiple outputs
yes some projects need both a PAL and an NTSC out

If you want possibility to mix any fps (and then have any fps output) then forget about it as it requires fps conversion and this is crazy difficult.
People for whatever reason don't understand that 25p or 23.976p source can't be just like that dropped into eg 29.97p timeline (well it can if you're happy with crappy blended output). This can be done (easily) only if files have the same time base, so eg. 25p, 50p, 50i etc.

BM can enable fps change, but this will be the biggest cause of crappy masters as people will use it in "bad way". They will do eg 25p timeline (with 25p source assets) and when asked for 29.97 output they will simply switch fps and export and think that it's as simple as this. It's not! Such a thing would only work if someone had created 99% reliable motion adaptive fps conversion engine, but this atm. doesn't exist. It's crazy difficult to do and this is the reason why Alchemist and Tachyon cost serious money (even if they are not always perfect either). If such a engine would exist we could also shot everything at 1 fps and then create all needed masters. Good luck with it It will be probably simpler to agree on 1 new fps for worldwide use than this

Andrew Kolakowski wrote:If you want possibility to mix any fps (and then have any fps output) then forget about it as it requires fps conversion and this is crazy difficult.

I am curious about your opinion on this. It's 2018 what technically stops us form having a codec and video player support different segments having different frame rates in the same file?

This is a different subject.
Variable frame rate idea has been/is "present", but it comes with its own problems also. It would require some special approach to metadata, sync etc (not mentioning TVs and need for adaptive refresh rate engine). Atm. we can't even store color space info reliably I don't know when it will happen, but taking into account that broadcast is still far from being at least HD (due to all legacy hardware and lack of investment) it won't be any time soon.
Codec is not a problem here.

Cary Knoop wrote:

Chad Capeland wrote:

George Deierling wrote:What would be the purpose of that? It all ends up a single clip.
If it becomes necessary to render masters at different frame rates, pick 120fps project frame rate.

Practically, though, you're looking at 705,600,000fps, because 120fps can't, for instance, hold 72fps content.

Not really, 360fps would be sufficient.

Not for 75fps content.

705,600,000 covers a lot of framerates without the precision issues of float.

The least common denominator between 1/120 and 1/72, which is what we were talking about, is 360.

So let me make sure I understand the workflow here...

I want to edit a music video. The first cameraman/director shot at 23.976 fps.

I was the director/camerman for the rest of the shoot. I wanted to get the slo-mo-in-real-time looks, so I shot at 60p with the band members miming to a double-speed onset music playback. The idea is that when this footage is shown at 30p, it will have an interesting look and still be "in time" with the music.

Some footage was also shot at 30p.

So... I need to convert the "24p" footage to 30p to edit it in the same timeline as the 30p footage, Okay.
But what would I do to the 60p to get it to play back at the "right" speed in 30p?

A timeline that could handle different playback frame rates in one timeline would be very useful for projects like this one.

Imagine as well a project that needs to deliver at multiple framerates. Currently can't do that in Resolve.

Re-conform that faster footage to your timeline fps and then play with the speed options.

What would be the use of throwing 60 fps into a 24 fps timeline and just drop all the extra frames?

And a timeline with changing fps in it? What would be the final delivery? I don't know of any format that is adapting it's speed dynamically at playback.