having issue in playing video using AVFoundation framework - iphone

Question

I am getting frame buffer one by one from video file using AVAssetReader and doing some operation on the frame and then saving new frame to temp file using AVAssetWritter.Now I have temp file path where all new frame is saving one by one. Is there any way to play video at the time frames is continuously adding to temp file?
here is code to play video from temp path(where frames is continuously adding):
(void)loadAssetFromFile {
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:[NSURL fileURLWithPath:[(mMediaReader.mCameraRecorder) tempVideoFilePath ]] options:nil];
NSString *tracksKey = #"tracks";
[asset loadValuesAsynchronouslyForKeys:[NSArray arrayWithObject:tracksKey] completionHandler:
^{
// Completion handler block.
dispatch_async(dispatch_get_main_queue(),
^{
NSError *error = nil;
AVKeyValueStatus status = [asset statusOfValueForKey:tracksKey error:&error];
if (status == AVKeyValueStatusLoaded) {
self.mPlayerItem = [AVPlayerItem playerItemWithAsset:asset];
[mPlayerItem addObserver:self forKeyPath:#"status"
options:0 context:&ItemStatusContext];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(playerItemDidReachEnd:)
name:AVPlayerItemDidPlayToEndTimeNotification
object:mPlayerItem];
self.mPlayer = [AVPlayer playerWithPlayerItem:mPlayerItem];
[mPlayerView setPlayer:mPlayer];
[self play:nil];
}
else {
// You should deal with the error appropriately.
NSLog(#"The asset's tracks were not loaded:\n%#", [error localizedDescription]);
}
});
}];
}
(IBAction)play:sender {
[mPlayer play];
}
And code inside the block never runs.

Answer 1

You can convert the CMSampleBuffer that the AVAssetReader returns into a CGImage and then a UIImage and display that in a UIImageView, to render the frames as they are pulled out of the original video file.
There is example code inside the AVFoundation Programming Guide that shows how to do this conversion.