Combining different video outputs

[Longimanus]

I have always tried to use the same video output from gopro, camera etc in the past, I assume that its possible to combine different outputs to make a combined video, e.g. output from gopro and output form Oly EM1, but what are the downfalls? Will I even notice it?

I ask as I am off on hols and will do some filming with my gopro and my Oly if needs be, but I also have 2 others joining me who could have different outputs that I want to combine.

Any help/advice would be very grateful

 

[CSB]

In an ideal situation every camera that you are using with be set to the same resolution, frame rate, white balance and colour profile, otherwise:

• In Europe I would use 1080p and 25 fps (I prefer not to use 1080i if I have the choice).
• If your GoPro is set higher than 25fps for slow motion later on that is ok, but ideally you want to avoid mixing 25fps and 30fps (29.97) footage in the same sequence, otherwise when you export your finished edit, you may notice a quality drop from frame blending.
• You will still notice some differences like the colours may not match (each manufacturer will have its own colour profiles), you can try to colour correct these when you edit your footage if the differences are too noticeable.
• Anything that you film in a lower resolution (e.g. 720p) will have to be stretched to fit which will loose a bit of quality.

Other things to bare in mind are maintaining a similar shutter speed (1/50) where you can so that motion looks smooth and if you have enough memory cards use the Protune setting on your GoPro to make it easier to match with the rest of your footage.

If this is just a family holiday video I may be going into too much detail so I apologise for that.

 

[Longimanus]

Sam, this is great information, many thanks for this.

This is for a dive holiday out in Mexico, 4 of us going, we have a few gopro's and a selection of different still cameras. I normally use the protune setting on the gopro when diving as it allows me to set the white balance once back on the boat.

So if we all have the 1080p and either 25fps or 50fps for slowmo set we should all be ok. I think one of the gopros is the new black version so that may have super slow mo on it.

If I were to do some filming in 720p do you really think you would notice? I'm thinking for super slowmo on the hero 3

I appreciate your advice

 

[st599]

All HD video has the same colour primaries and white point (ITU-R BT.709 aka Rec709) so the only difference should be how accurately you white balanced the camera.

50p is not a slow-mo framerate - you use it to reduce jerky motion caused by shooting 25p without losing some of the spatial resolution that you get with interlaced video.

Also - if shooting 50p, use 1/100 shutter.

 

[CSB]

If I were to do some filming in 720p do you really think you would notice? I'm thinking for super slowmo on the hero 3

I would notice if it was my project but I'm a pixel peeper, most won't know the difference, especially if you are putting it onto Youtube or a DVD

All HD video has the same colour primaries and white point (ITU-R BT.709 aka Rec709) so the only difference should be how accurately you white balanced the camera.

50p is not a slow-mo framerate - you use it to reduce jerky motion caused by shooting 25p without losing some of the spatial resolution that you get with interlaced video.

Also - if shooting 50p, use 1/100 shutter.

Some points about what you have said

• Regardless of BT.709, cameras from different manufacturers will render colours differently even when properly white balanced due to different CCI from the lens, Spectral Response from the sensor and processing via the camera electronics.
• Conforming 50fps to 25fps may smooth out motion but it will give you 1/2 speed playback, anything slower than real time is slow motion, irrespective of whether it is half speed or 1/100 speed.
• Putting a 50fps clip straight into a 25fps timeline will end up with every other frame being skipped or the frames being blended (depending on your software & settings), so you either loose the point of 50fps or you loose quality by blending the frames, either way you will not smooth out any motion.

Sorry to be a pedant but I'm always a bit anal about technical stuff. I'm more than up for a technical discussion with like minded people, but I do think some of your statements needed to be unpacked further.

 

[st599]

Who said anything about conforming to a 25 fps timeline? I meant shoot and view at 50 fps.

I could have long discussions on the colour stability of cameras, colour correction and the effect of observer metameric failure, but for the OP's usage, white balanced cameras will be close enough.