Variable Frame rates question…

[Shane Ross]

You need to use the DVCPRO HD FRAMERATE CONVERTER. This is optional software that you install. It is located in the EXTRAS folder on the FCP install disk. This will convert the footage to proper slow motion, taking frame for frame to convert 60p to 30p or 24p.

I have a tutorial for that here:

https://forums.creativecow.net/cgi-bin/page_wrapper.cgi?forumid=8&page=https://www.creativecow.net/articles/ross_shane/dvpro_hd/index.html

Shane

Littlefrog Post
http://www.lfhd.net

[Pierrex]

Shane, thanks, that was helpful. I have a followup question.

Before I saw your response, I discovered the >Modify>Speed tool in FCP, and I found that very useful, since I had complete control over the speed variations. Does the Framerate Converter make better use of the 60 frames than the speed tool, or are they best used in conjunction…using the Framerate Converter first, then followed by the Modify>Speed tool for final speed adjustments. Naturally I want to maximize quality, and I am not sure if >Modify>Speed is using the 60 frames or not?? ( My sequence is set to 60 FPS.)

Thanks for the help.

Pierre

[Shane Ross]

The Frame Rate Converter will take all 60 individual frames and convert them to 30p or 30 frames or to 24p or 24 real frames. The Speed Change in FCP doesn’t do this, and won’t give you nearly the good results you can get with the Frame Rate Converter. And the converter can convert to 24fps or 30fps…those are your only options.

Shane

Littlefrog Post
http://www.lfhd.net

[David Battistella]

Pierre,

Do you have an understanding of film slo motion.

Film runs at 24fps.
To shoot film slo motion you can have the camera record at 48, 60, 150Fps etc. IN this case the film camera actually captures this many frames in one second. The camera is clocked to capture these frame rates in one second. This makes for amazing slom motion because UNLIKE video, which is always captured at 24 or 2.97 frames per second, it is not an interpolation of speed but actual speed.

Recently, video camera’s have been able to capture a true “film style” slo motion. The camera is capturing 60 progressive frames persecond and with the frame rate converter this is played back at 24 frames persecond. You are not slowing down time in this case but rather recording two and a half time more information to be played back at a slower frame rate.

How this differs from speed control in FCP. A video source recorded at 60FPS plays back 1 second over the course of 2.5 seconds, you are seeing every frame recorded.

With video you could say play back these 24 frames but spread it over sixty frames. They both take 2.5 seconds but one is interpreting frames and the other is actually playing back each and every frame.

That is why film style slo motion is so much nicer. It actually records enough frames in one second to show a hummingbirds wings. You could vnever do this in video at 24 or 30 fps.

You get it?

David

Peace and Love 🙂

[Pierrex]

Thanks Shane and David.

Here is why I may be thick on this issue. I see how the FrameRate Converter works, that makes complete sense. The effect is wonderful.

I hear how the Speed Modifyer deals with the video shot at 24 or 29.97.

I have been shooting at 60 however, and I am curious how FCP deals with the 60 frames in the speed modification….does it ignore the 60 frames, or spread them over the requested timeframe, thus still using the entire 60 frames….or does it ignore any frames over the 24/29.97 and just stretch using 24/29 as the starting point??
The reason this is interesting to me is that if I want to adjust the speed to something other than the 24/29 that the converter gives me, am I just destroying the final quality.

Sorry to belabour this, but I would like as complete an understanding as possible and your input is helpful.

Pierre

[David Battistella]

Piere,

The camera shoots 4 to 60 frames. This then gets decoded by the frame rate converter in FCP based on what frame rate you shot. If you soot at sixty then you can not tell it to be 24. It does not work that way.

What camera are you using?

When you record in this mode certain fields are marked on the media Or tape. This flagged frames are the ones that are removed by the software. It is a very specific and highly specialized process. I suggest you order teh Goodman’s guide to varicam. It is a good resource for eaplaining how this process works.

It is designed to be like film, ina video environment. FCP speed controls have nothing to do with this process at all. If you do change the speed then you are bound to introduce problems in teh footage.

David

Peace and Love 🙂

[David Battistella]

To take full advantage of this feature you need to run the footage throught the frame rate converter and place it in a 24 frame timeline. Why are you cutting in a 60fps timeline.

This is also covered in the manual if you read it.

David

Peace and Love 🙂

[Pierrex]

David:

Thanks for your patience, and yes I use the manual as much as possible I do not like coming here with silly questions, even if it is FCP basics. The manual is great to tell you how to do something, not how it all fits together to better understand it.

I am using the HVX200.
I have been shooting at a FrameRate of 60fps to produce slow motion.
I have not been putting n to a 24p timeline, since when I do it shows that it requires rendering, and I was under the impression that the rendering will drop many of the 60 frames and render it into 24 frames.

So you are saying that I should put it into a 24fps timeline, then run the FrameRate converter for the best results. That sounds logical.

Here is another question about the final step. I want to save the final file in the best, most flexible, format to future-proof it as much as possible. I want to use it for stock footage. I would also like to be able to bring these files back into FCP for a final edit without ruining the quality by repeated compressions.
What would you recommend? Again the manual tells me how to do it, but not which format is the best alternative for my purposes.

Thanks again for your time.

Pierre

[David Battistella]

Pierre,

OK.

I’ll try to address these as simple as I can. The Frame rate coverter works like this.

Everything is based on film frame rates. The “normal running speed” for film is 24 frames per second.

When you are using your HVX camera for slo motion it always comes back to 24 frames per second.

When you have told the camera to record footage at 60 frames per second the camera puts down special flags on the file to let that file know that it has been recorded at 60 frames per second.

In order to see these files you need to highlight the clip and choose the frame rate converter to have the clip play back as it was intended. If you do not run it through the frame rate converter, then FCP has no way of figuring out how the footage was shot. The frame rate converter looks at the file, determines the speed it was shot at and converts the file for use in a 24FPS timeline.

As I stated in an earlier post this means a one second clip file that was recorded at 60FPS will actually play back in 2.5 seconds after the frame rate conversion has occured.

Save all of your file in the format they were shot in. IE:24PN, 720 or 1080 or whatever you orginated the footage in. This preserves it best and you can up and down convert it as need be from the orignal file.

As a genreal rule, the file syou shoot at speed should be handled this way.

Place the files on a folder on your hard disk. Duplicate the folder and rename it as a backup.

1.Import the files
2. Apply the frame rate conversion to each file.
3. Use the files in 24fps timelines after steps one and two.
4. Media manage your projects properly and you can always open them with no compression, recompression at all.

David

Peace and Love 🙂

[Pierrex]

David:

Many thanks, I have a much better understanding of the frame rates issue.

Since I have gone down this road, I would ask you to indulge a couple final thoughts on the media management thread to clarify your response.

Mostly I am shooting 720p/24p.
My question relates to the final saved file. I have not been keeping the original MFX files…the reason being that the material is heavily edited and my storage requirements would be overwhelming.
I do edit in FCP on the 24 timeline, then I save and keep backups of the Quicktime Movie file, saved using the DVCPRO HD 720p60 compressor. I avoid any rendering or colour corrections etc. in creating this master backup file. The final clips are then created from these files later, and any colour work etc is done at that time.

Am I kidding myself that these files are good enough? Is saving the MFX file the only proper way to do it?

Your final thoughts please. Appreciated.

Pierre