How could I avoid recording moving streaky noise, when using a projector?
How could I avoid recording moving streaky noise, when using a projector?
You can see the noise in the coloured background from the middle of this YouTube video.
https://youtu.be/kQomeGo6L_E
In the real world, I don't see that noise with my eyes.
I guess it has something to do with qmetro rate (@interval 60Hz), camera setting (shutter speed 30, 29.97 fps), and projector setting .
Many thanks for your advice,
Masa
Hi Masa
with me it happened a lot more when using a DLP projector! It is because the DLP projector uses little mirrors to make the image and it therefore builds up the image within a frame. The refresh rate of the projector you cannot change (other than fixed settings on the projector), and the metro will not change the refresh rate of the projector (only the refresh rate of the computer) so the only thing you can change is the shutter speed and fps on the camera.
Shutter speed and frame rate of a video camera are two different things. A photo camera only uses the shutter speed, because it has no frame rate (it doesn't record a succession of frames). For photo's I remember that 1/60 gives good photo's or projection. The faster the shutter speed the more pronounced the stripe will be.
I don't remember the right shutter speed for video exactly but you can see it in the view finder. Try 1/60 for the shutter.
Then the frame rate: rule of thump is 1/2 FPS of the shutter for good looking video (it's called 180 deg shutter speed, meaning double that of the FPS). This only matters for a 'filmic look', but if you can set it like that why not, if you can't it doesn't matter as long as the picture is clear.
Typical frame rates are 25 (Europe) or 30 (US) sometimes they get doubled in 50 or 60 halframes (interpolated) (those are called i-frames or 1080i) but they count as 25/30 FPS and should be converted to such. Some camera have a in 50 or 60 full/ progressive FPS setting (you can get slow motion by playing it back at 25 or 30 resp). Those are called 50 or 60p.
Hope it is clear: mostly shutter speed should matter and therefor set the camera to a fixed shutter speed and let it calculate the appropriate exposure (diaphragm) for it.
Here is some more explanation:
https://vimeo.com/blog/post/frame-rate-vs-shutter-speed-setting-the-record-str
Thank you very much Mrmaarten! Your post is so helpful.
I forgot to mention which projector I use. This is Acer H6510BD, and yes, it's a DLP projector unfortunately...!
I will do my best in experimenting more thanks to your information, and hope I don't have to buy another non-DLP projector (or is it the quickest way?).
No problem ;-)
I think it should work out if you have a camera with manual controls.
An other option is to record you render in the computer itself. Better not with max itself for perforance reasons (see forum), there are third party screen recorders that are very good. Quicktime 10 on mac can also do it for free. (The quality is not the best but quite good).
Another option is syphon on the mac and syphon recorder. Syphon shares a 3D texture accross the whole computer (so it can be recorder or used by an other program). You have to capture your scene and send it to syphon.
http://syphon.v002.info
Last option would be a hardware recorder, eg by HDMI. The blackmagic shuttle can do such a thing.
Test camera shutter speed and frame rate settings to find optimal settings. It can be hard or impossible to prevent 100%, depending on hardware. Refresh rate of the graphics output of the video card might be a factor too, depending on how the projector handles it. Jitter qmetro setting has nothing to do with it.
What kind of camera are you using?
Hopefully you have a Clear Scan type setting.
Adjusting shutter and frame rate can do much but Clear Scan is made specifically for this.
What kind of projector are you using?
I would guess it's a "single chip" dlp projector. These use a single chip and a spinning color wheel to produce images. A better quality 3-chip projector, dividing up work between 3 chips, one each for red blue and green, would also probably give better results but they are not inexpensive.
Thank you very much all.
My current setup is:
-
The projector is Acer H6510BD
The camera is Panasonic GH3
-
The reason I chose H6510BD is because of its mobility ((5.5 lbs (2.5 Kg)). I would appreciate any recommendation or advice.
I tried several screen recording software, but it introduced more latency to my visual unfortunately, as the patch is quite CPU/GPU intensive already.
I have heard of syphon, but haven't tried it. I will try and hope it's a light software.
It seems I can only choose between 'automatic', 'underscan' and 'overscan' regarding to the scan rate of H6510BD.
Didn't it work to have your shutter speed the same or a bit below the refresh rate of the projector?
I will get back to this topic the next time I have an opportunity to shoot projection.