CODEWITHSUNDEEP
objective-ciosavfoundationavcapturesessionavassetwriter
NebulaFox
NebulaFox

Reputation: 8323

Duration not appearing for after Video

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?

Upvotes: 0

Views: 866

Answers (2)

Steve McFarlin
Steve McFarlin

Reputation: 3596

This is what I do which is similar to NebulaFox's answer. This code is in the callback for the capturing of video data. The writer has already been initialized and setup.

switch (writer.status) {
        case AVAssetWriterStatusUnknown:

            startTime = CMSampleBufferGetPresentationTimeStamp(sample);

            [writer startWriting];
            [writer startSessionAtSourceTime:startTime];

            if (writer.status != AVAssetWriterStatusWriting) {
                break ;
            }  
....

Upvotes: 0

NebulaFox
NebulaFox

Reputation: 8323

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;

Upvotes: 2

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