如何解决在使用 iphone 4s、ipad 2 以 60fps 录制视频时出现的问题？

Question

Question in short:

Getting exception while trying to record at 59fps. How to resolve it?

2014-09-16 15:16:27.740 RosyWriter[2294:60b] ** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'The activeVideoMaxFrameDuration passed is not supported by the receiver's active format. Use -activeFormat.videoSupportedFrameRateRanges to discover valid ranges.

My Question in detail:

What i am trying to do?

Trying to record the video in 30+ fps(60 fps or more fps ).

What have i tried so far?

1. Initially tried with " AVCaptureConnection "'s property as below and later understood that the properties i used were depreciated.

---

AVCaptureConnection *conn = [output connectionWithMediaType:AVMediaTypeVideo];

CMTimeShow(conn.videoMinFrameDuration);
CMTimeShow(conn.videoMaxFrameDuration);

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

reference: According to the header file (AVCaptureSession.h),

This property is deprecated on iOS, where min and max frame rate adjustments are applied exclusively at the AVCaptureDevice using the activeVideoMinFrameDuration and activeVideoMaxFrameDuration properties.

2. Then, i tried with "AVCaptureDevice" as below:

    -(void)setupCaptureSession { if ( _captureSession ) { return; } _captureSession = [[AVCaptureSession alloc] init]; AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; .................................... .................................... _videoConnection = [videoOut connectionWithMediaType:AVMediaTypeVideo]; int frameRate; NSString *sessionPreset = AVCaptureSessionPreset640x480; CMTime frameDuration = kCMTimeInvalid; // For single core systems like iPhone 4 and iPod Touch 4th Generation wI //use a lower resolution and framerate to maintain real-time performance. if ( [[NSProcessInfo processInfo] processorCount] == 1 ) { if ( [_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720] ) { sessionPreset = AVCaptureSessionPreset1280x720; } frameRate = 59; } else { // USE_GPU_RENDERER is set in the project's build settings #if ! use_gpu_renderer // When using the CPU renderer we lower the resolution to 720p so that all devices can maintain real-time performance (this is primarily for A5 based devices like iPhone 4s and iPod Touch 5th Generation). if ( [_captureSession canSetSessionPreset:AVCaptureSessionPreset640x480] ) { sessionPreset = AVCaptureSessionPreset640x480; } #endif // ! use_gpu_renderer frameRate = 59; } _captureSession.sessionPreset = sessionPreset; frameDuration = CMTimeMake( 1, frameRate ); NSError *error = nil; if ( [videoDevice lockForConfiguration:&error] ) { videoDevice.activeFormat = bestFormat; [**videoDevice setActiveVideoMaxFrameDuration:frameDuration]; [videoDevice setActiveVideoMinFrameDuration:frameDuration**]; [videoDevice unlockForConfiguration]; } else { NSLog(@"videoDevice lockForConfiguration returned error %@", error); } self.videoOrientation = [_videoConnection videoOrientation]; [videoOut release]; return;

   }

   My issue:

   1. I got the exception

---

2014-09-16 15:16:27.740 RosyWriter[2294:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'The activeVideoMaxFrameDuration passed is not supported by the receiver's active format.  Use -activeFormat.videoSupportedFrameRateRanges to discover valid ranges.'
        *** First throw call stack:
        (0x2da2ff83 0x385d2ccf 0x2c919e4f 0xb4c7d 0xb4317 0x38aba81f 0x38ac07cb 0xb42b1 0xb2539 0x302676df 0x30258e89 0x3025864d 0x302584bf 0x30257fe5 0x30255827 0x302bf33d 0x302bbfad 0x302b656b 0x302526e9 0x30251851 0x302b5ca9 0x3288baed 0x3288b6d7 0x2d9faa67 0x2d9faa03 0x2d9f91d7 0x2d963ebf 0x2d963ca3 0x302b4ed1 0x302b014d 0xb1b4d 0x38adfab7)
        libc++abi.dylib: terminating with uncaught exception of type NSException

Am i doing anything wrong here?

2. Later,I changed the code as

   ---

    AVCaptureDeviceFormat *bestFormat = nil; AVFrameRateRange *bestFrameRateRange = nil; for ( AVCaptureDeviceFormat *format in [videoDevice formats] ) { for ( AVFrameRateRange *range in format.videoSupportedFrameRateRanges ) { if ( range.maxFrameRate > bestFrameRateRange.maxFrameRate ) { bestFormat = format; bestFrameRateRange = range; } } } NSError *error = nil; if ( bestFormat ) { if ( [videoDevice lockForConfiguration:&error] ) { videoDevice.activeFormat = bestFormat; videoDevice.activeVideoMinFrameDuration = bestFrameRateRange.minFrameDuration; videoDevice.activeVideoMaxFrameDuration = bestFrameRateRange.maxFrameDuration; [videoDevice unlockForConfiguration]; }}

But I get the video that gets recorded at 30fps with bestFrameRateRange, but not at 59fps..

Answer 1

Here is a working example how to use higher frame rate:

Find and set active mode to use maximum frame rate available.

float maxFrameRate = 0.0;
int maxIndex = 0;
for(int i=0;i<_videoCaptureDevice.formats.count;i++) {
    AVCaptureDeviceFormat *format = [_videoCaptureDevice.formats objectAtIndex:i];
    AVFrameRateRange *frameRateRange = [format.videoSupportedFrameRateRanges firstObject];
//You can add hard coded checking for specific format like if(frameRateRange.maxFrameRate == 240) etc I am using the max one
    if(maxFrameRate<frameRateRange.maxFrameRate) {
        maxFrameRate = frameRateRange.maxFrameRate;
        maxIndex = i;
    }
}

AVCaptureDeviceFormat *format = [_videoCaptureDevice.formats objectAtIndex:maxIndex];
AVFrameRateRange *frameRateRange = [format.videoSupportedFrameRateRanges firstObject];
[self.videoCaptureDevice lockForConfiguration:nil];
self.videoCaptureDevice.activeFormat = format;
self.videoCaptureDevice.activeVideoMinFrameDuration = frameRateRange.minFrameDuration;
self.videoCaptureDevice.activeVideoMaxFrameDuration = frameRateRange.maxFrameDuration;
[self.videoCaptureDevice  unlockForConfiguration];

After that change the frame rate

if(YourFrameRate<=frameRateRange.maxFrameRate && YourFrameRate>=frameRateRange.minFrameRate) {
    if([device lockForConfiguration:&error]) {
        [device setActiveVideoMinFrameDuration:CMTimeMake(1, YourFrameRate)];
        [device setActiveVideoMaxFrameDuration:CMTimeMake(1, YourFrameRate)];
        [device unlockForConfiguration];
    } else {
        [self passError:error];
    }
}

Got the answer from here

Answer 2

You should set a valid format to AVCaptureDevice .

You can do this

// get device what you like
let device = xxxxx

// list all default formats for this device
for format in device.formats {
    var founded = false

    // check what you want and pick a perfect format. 
    let formatDesc = format.formatDescription

    // mediaType / SubType
    let mediaType = format.mediaSubType
    // if your target is above(equal) iOS 13. use formatDesc.mediaSubType
    let mediaSubType = CMFormatDescriptionGetMediaSubType(formatDesc) 

    // dimensions
    // if your target is above(equal) iOS 13. use formatDesc.dimensions
    let dimensions = CMVideoFormatDescriptionGetDimensions(formatDesc) 

    // fps
    let ranges = format.videoSupportedFrameRateRanges.first
    for supportedFPSRange in ranges {
        if supportedFPSRange.maxFrameRate == 60 {
            founded = true
        }
    }

    // support Multi cam
    let isMultiCamSupported = format.isMultiCamSupported

    ....

    if founded {
        // Set activeFormat for device! Your capture device is up and loaded.
        do {
            try device.lockForConfiguration()
            device.activeFormat = format
            device.unlockForConfiguration()
        } catch {
            // catch some locking error
        }

        // Don't forget break the loop.:p
        break
    }
}