Question

我尝试过多次在上面的iOS 7版本中捕获240fps视频。但所有尝试都失败了。我的代码如下。

CGFloat frameRate = 240.f;

for (AVCaptureDeviceFormat *videoFormat in [self.inputCamera formats]) {
    CMFormatDescriptionRef videoFormatDescriptionRef = videoFormat.formatDescription;
    Float64 maxFrameRate = ((AVFrameRateRange *) [videoFormat.videoSupportedFrameRateRanges objectAtIndex:0]).maxFrameRate;

    if (maxFrameRate >= frameRate && CMFormatDescriptionGetMediaSubType(videoFormatDescriptionRef) == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) {

        if ([self.inputCamera lockForConfiguration:nil]) {

            self.inputCamera.activeFormat = videoFormat;
            [self.inputCamera setActiveVideoMinFrameDuration:CMTimeMake(600.f/(CGFloat)_frameRate, 600)];
            [self.inputCamera setActiveVideoMaxFrameDuration:CMTimeMake(600.f/(CGFloat)_frameRate, 600)];

            [self.inputCamera unlockForConfiguration];
        }
    }
}

AVCaptureConnection *connection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];
if ( connection ) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    if ([connection respondsToSelector:@selector(setVideoMinFrameDuration:)])
        connection.videoMinFrameDuration = CMTimeMake(1, _frameRate);

    if ([connection respondsToSelector:@selector(setVideoMaxFrameDuration:)])
        connection.videoMaxFrameDuration = CMTimeMake(1, _frameRate);
#pragma clang diagnostic pop
}

如果我尝试直接将帧速率设置为240fps，它会崩溃。所以我必须在iOS和240 fps支持的值之间设置最小值。

有人可以帮助我吗？

问候。

Answer 1

我认为最大值是60 fps，它取决于您选择的捕获设备。

https://developer.apple.com/library/ios/documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/04_MediaCapture.html#//apple_ref/doc/uid/TP40010188-CH5-SW5

AVFoundation不允许以240fps的速度捕获视频

1 个答案: