Duration not appearing for after Video

Question

I have recorded live video from the camera using AVCaptureVideoDataOuput and AVAssetWriter but the resulting video has no duration. Can anyone give a brief idea or a point in the general direction to get the duration working?

Answer 1

What needs to be done is define an initial CMTime.

self.time = CMMakeTime( 0, 30 /* some frame time */ );

then

[instanceAVAssetWriter setSessionAtSourceTime:self.time];

on captureOutput:didOutputSampleBuffer:fromConnection:

CMSampleBufferRef sb;
CMSampleTimingInfo sampleTimingInfo;

sampleTimingInfo.duration = CMTimeMake(1,30);
sampleTimingInfo.presentationTimeStamp = self.time;
sampleTimingInfo.decodeTimeStamp = kCMTimeInvalid;

CMSampleBufferCreateCopyWithNewTiming(kCFAllocatorDefault, sampleBuffer, 1, &sampleTimingInfo, &sb);

and the end

CFRelease( sb );
self.time.value += 1;