Frame Rate General Discussion

[James Hollingsworth]

Sorry to be a dunce but I am quite confused on frame rate. Can anyone point me in the direction of a useful guide. I understand all the basic differences but have read conflicting reports as to the restrictions of each mode. Mainly regarding transfer to DVD/Bluray. I have always shot 50i as that is what my Z1 did but with the EA50 have many more capabilities. I read that 25p is not supported by Blu ray so does that make it useless if your project was shot and edited in 25p? Can 24p be output to Pal DVD? I understand it is fine for Blu ray. How about 720p compared to 1080p? What formats are people using when wanting to have final output on both DVD and Blu-ray? I want to shoot 24 or 25p but am afraid to shoot a wedding like that until I know the output will be safe.

[James Manford]

Im not a tech head ... but I would say stick to 50p progressive. It's the absolute best quality your camera captures. Then edit in what ever format you want, but atleast you know the source file is the crem de la crem of frame rates.

[Joel Corral]

I always shoot 60p. Not matter what. Then if I need to convert to 23.976 or 29.97 no problem. (Ntsc over here)

JC

[James Hollingsworth]

So if I shoot in 50i or 50p I can just set up my timeline in fcp7 to 24 or 25p and render then export? Is it best to do the actual edit in the format shot in and then export then bring back the edited QuickTime file to final cut and place on a 25 or 24p timeline before exporting again. Thanks for all the advice, just want to make sure I have the best possible workflow.

[Joel Corral]

Don't shoot interlaced. And expect to go to 24p or 25p nicely. ... stay in 50p or 60p. Then yes drop in ur timeline and export to the frame rate you want.... even if you want interlaced delivery; shoot 50p drop in 25i timeline .... at least for premiere cs6 this is fine...

[Taky Cheung]

25p is preserved in the form of PsF (Progressive Segmented Frame) in a 50i stream. Your encoder would split a full progressive frame into two interlaced frame thus your progressive content is preserved in BluRay output.

[Jos Svendsen]

Blu ray supports HD1080i50. Most encoders will handle a 1080P25 conversion to 1080i50 with no problem. All LCD tvs are progressive by nature anyway, so it will end up being quite nice progressy anyway. The biggest issue with 50P is that you will end up using a shutter speed of 1/100 S resulting in half the usual motion blur. This might not be an issue for you.

And unless you state it explicitly to them no non-techies will notice the difference between 720P and 1080P. Believe me. The Danish cable broadcasters has been transmitting 720 P for the lest two years and nobody complained.

[Ron Evans]

Why would you shoot 50P with 1/100s shutter? I shoot 60P with 1/60s shutter. 50P and 50i are the same exposure rate and 60i and 60P are the same exposure rate. In one case they record fields in the other full frames. Camera exposure parameters will be the same.

Ron Evans

[Noa Put]

I use a shutter of 1/50th as well with 50p, don't see any negative impact on the image because of that.

[Joel Corral]

I always shoot 60p 1/60th.... no complaints here

[James Hollingsworth]

I'm still confused, gonna hit the hay! Thanks for all the advice, seems that frame rates are a pretty cloudy issue, will just have to experiment until I find the look I like best.

[Taky Cheung]

It's not that confusing. You are limited to your geographical location and what frame rate options your camera provided. If you are in the US, 30p and 24p would be a popular choice.

[Ron Evans]

If you shot 50i with your Z1 just use 50P and do what you did before in editing. You now just have the whole picture rather than half the vertical resolution ( field ) and nothing else has changed. If you need to take a still from the video file it will be full resolution.

Ron Evans

[Steve Game]

James,

If you shoot 1080p/50 you can put it on a timeline with 1080p/25 or 1080i/25 and render to 1080p/25 and 1080i/25 respectively. The process will either drop every other frame or interlace every frame as required. The only side issue as mentioned by Ron Evans is that 50fps cameras will normally use shutter speeds at least twice that of 25fps ones, so reducing the frame rate to 25fps may result in a gritty motion effect. Some editors can reduce this by applying motion blur that integrates adjacent frames to smooth the motion.

As far as 1080p/24 is concerned, unless you have a primary requirement to export to film, (i.e. the chemical stuff) or video to somebody in the 60Hz world, then don't bother. All broadcasters in Europe transmit movies created at 24fps as 25fps, (usually 1080psf/25). The 4% increase in speed is not considered an issue and if necessary the pitch of the soundtrack can be adjusted electronically.

[Noa Put]

The only side issue as mentioned by Ron Evans is that 50fps cameras will normally use shutter speeds at least twice that of 25fps ones

Why? I use 1/50th shutter all the time with 25p or 50p and don't see any disadvantages in doing so.