iOS AVCaptureSession - How to get/set the number of frames per second recorded?

Question

I'm new to AVCaptureSession and wish to better understand how to work with it. So I managed capturing the video stream as separated CIImages and convert them to UIImages. Now I wish to be able to get the number of Frames Per Second captured and preferably to be able to set it.

Any idea how to do that?

score 22 · Answer 1 · answered May 26 '16 at 06:09

AVCaptureConnection's videoMinFrameDuration is deprecated.

You can use AVCaptureDevice properties to detect supported video frame rate ranges and can assign minimum and maximum frame rates using properties.

device.activeFormat.videoSupportedFrameRateRanges return all video frame rates ranges supported by device.

device.activeVideoMinFrameDuration and device.activeVideoMaxFrameDuration can be used for specifying frame durations.

score 14 · Answer 2 · answered Feb 11 '19 at 16:40

To set the capture session frame rate, you have to set it on the device using device.activeVideoMinFrameDuration and device.activeVideoMaxFrameDuration (if necessary).

In Swift 4 you can do something like this:

extension AVCaptureDevice {
    func set(frameRate: Double) {
    guard let range = activeFormat.videoSupportedFrameRateRanges.first,
        range.minFrameRate...range.maxFrameRate ~= frameRate
        else {
            print("Requested FPS is not supported by the device's activeFormat !")
            return
    }

    do { try lockForConfiguration()
        activeVideoMinFrameDuration = CMTimeMake(value: 1, timescale: Int32(frameRate))
        activeVideoMaxFrameDuration = CMTimeMake(value: 1, timescale: Int32(frameRate))
        unlockForConfiguration()
    } catch {
        print("LockForConfiguration failed with error: \(error.localizedDescription)")
    }
  }
}

And call it

device.set(frameRate: 60)

score 13 · Accepted Answer · edited May 23 '17 at 12:02

13

You could use AVCaptureConnection's videoMinFrameDuration accessor to set the value.

See the AVCaptureConnection documentation

Consider output be AVCaptureVideoDataOutput object.

AVCaptureConnection *conn = [output connectionWithMediaType:AVMediaTypeVideo];

if (conn.isVideoMinFrameDurationSupported)
    conn.videoMinFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND);
if (conn.isVideoMaxFrameDurationSupported)
    conn.videoMaxFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND);

More info, see my answer in this SO question

edited May 23 '17 at 12:02

Community

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answered Dec 26 '12 at 10:55

Ilanchezhian

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Is my fps guaranteed to not drop below my min/max values? How I can get my current actual fps, rather than the min and max? – Tyler Pfaff Oct 29 '14 at 19:48
@TylerPfaff did you find an answer to your question? – Crashalot Feb 01 '16 at 06:42
@Crashalot it's been too long, I don't remember :( – Tyler Pfaff Feb 01 '16 at 07:02
These properties are now deprecated. Is there any alternate method? – Shravya Boggarapu May 05 '16 at 13:28
@ShravyaBoggarapu check my answer below. I have updated it. – MouseCrasher May 26 '16 at 06:10
Also note that setting `activeVideoMinFrameDuration` and `activeVideoMaxFrameDuration` must be done _after_ adding it to your session. See https://stackoverflow.com/a/34720352/1271826. – Rob May 31 '22 at 17:49

score 3 · Answer 4 · answered Aug 01 '18 at 07:22

Do it like this

if let frameSupportRange = currentCamera.activeFormat.videoSupportedFrameRateRanges.first {
    captureSession.beginConfiguration()
    // currentCamera.activeVideoMinFrameDuration = CMTimeMake(1, Int32(frameSupportRange.maxFrameRate))
    currentCamera.activeVideoMinFrameDuration = CMTimeMake(1, YOUR_FPS_RATE)
    captureSession.commitConfiguration()
}

iOS AVCaptureSession - How to get/set the number of frames per second recorded?

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