+- PINE64 (https://forum.pine64.org)
+-- Forum: PinePhone (https://forum.pine64.org/forumdisplay.php?fid=120)
+--- Forum: PinePhone Hardware (https://forum.pine64.org/forumdisplay.php?fid=122)
+--- Thread: Questions about filming video with the Pinephone (/showthread.php?tid=13997)
Pages:
1
2
RE: Questions about filming video with the Pinephone - vortex - 06-02-2021
I dove into the datasheet for the rear camera and one manual I was able to find online and it is really really hard to figure out what the maximum frame rate at any resolution is. I've gone through many sensor and camera data sheets and manuals over the years, and this one was one of the most opaque (it seems that either they don't want tinkering or there is more documentation but it must be requested from the manufacturer). Most I can find is some information related to theoretical limits. A theoretical upper limit is set by the pixel clock and the fact that the special blank/black pixels and lines must be included. The datasheet indicates that the maximum pixel clock frequency is either 96 MHz or 192 MHz. There are 36 black lines and 20 black pixels per line. This means that if you are using the resolution A x B (A is rows, B is columns) with pixel clock C, the upper bound on the frame rate is
upper_bound_fps = C / ((A + 36) * (B + 20))
If you choose 1080p (A = 1920, B = 1080) and, you get an upper bound of 44.6 fps with a 96 MHz clock and 89.2 fps with a 192 MHz clock.
Now, note, that calculation of the upper bound assumes that there is no delay after reading one line before the next can be read, no delays when the last line has been read and the next image can begin, and that the interface the images are being read with can support that high a rate.
In reality, there will be a delay after each line is read before the next one can be read, there may be an extra delay after the last line is read and reading begins again for the next image. Also, I don't know what the limits on the camera interface are for the transfer rate.
And of course, the camera has to actually be configurable to such a limit. The settings may not allow such a thing.