Question on adjusting frame rate of pipeline

[Marianna Smidth Buschle]

> Hi thanks
>
>>> Use your command or a variant  -- v4l2-ctl --list-formats-ext -d /dev/video0
> This are the result
>
> ioctl: VIDIOC_ENUM_FMT
>          Index   [ 5628.245685] ov5640_mipi 3-003c: Please assign pixel format, t
>      : 0
>          Type        : Video Capture
>          Pixel Format: 'YUYV'
>          Name        : YUYV 4:2:2
>                  Size: Discrete 640x480
>                          Interval: Discrete 0.033s (30.000 fps)
>                  Size: Discrete 320x240
>                          Interval: Discrete 0.033s (30.000 fps)
>                  Size: Discrete 720x480
>                          Interval: Discrete 0.033s (30.000 fps)
>                  Size: Discrete 1280x720
>                          Interval: Discrete 0.033s (30.000 fps)
>                  Size: Discrete 1920x1080
>                          Interval: Discrete 0.033s (30.000 fps)
>                  Size: Discrete 2592x1944
>                          Interval: Discrete 0.067s (15.000 fps)
>                  Size: Discrete 0x0
>
> I do not think the camera would support 25 fp/sec.
No, as you can see it only seems to support 30 and 15 fps.
>
> Btw is there way we can control the frame rate in the downstream, like when encoding to save file or send it to another src

You can use a videorate element, but it can't do magic. It can only 
duplicate or drop frames.

So you can only get "multiples": like from 30 you can get 30/2, 30/3, 
30/4, 30/5, ... By selecting how many frames you drop.

You can also get fx 20fps from 30 or a different value, but in this case 
that will only give you an "average fps". The time differences between 
the frames will vary: 33ms, 66ms, 33ms, 66ms, ... Instead of 50ms, 50ms, 
50ms. Because of the frame dropping.

>
>
> Regards

-- 
Best regards / Med venlig hilsen
“Marianna Smidth Buschle”

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