I need to reproduce a video indefinitely (restarting the video when it ends) in my OpenGL application. To do so I'm trying to utilize AV foundation. I created an AVAssetReader and an AVAssetReaderTrackOutput and I utilize the copyNextSampleBuffer method to get CMSampleBufferRef and create an OpenGL texture for each frame.
NSString *path = [[NSBundle mainBundle] pathForResource:videoFileName ofType:type];
_url = [NSURL fileURLWithPath:path];
//Create the AVAsset
_asset = [AVURLAsset assetWithURL:_url];
//Get the asset AVAssetTrack
NSArray *arrayAssetTrack = [_asset tracksWithMediaType:AVMediaTypeVideo];
_assetTrackVideo = [arrayAssetTrack objectAtIndex:0];
//create the AVAssetReaderTrackOutput
NSDictionary *dictCompressionProperty = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id) kCVPixelBufferPixelFormatTypeKey];
_trackOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:_assetTrackVideo outputSettings:dictCompressionProperty];
//Create the AVAssetReader
NSError *error;
_assetReader = [[AVAssetReader alloc] initWithAsset:_asset error:&error];
if(error){
NSLog(@"error in AssetReader %@", error);
}
[_assetReader addOutput:_trackOutput];
//_assetReader.timeRange = CMTimeRangeMake(kCMTimeZero, _asset.duration);
//Asset reading start reading
[_assetReader startReading];
And in -update method of my GLKViewController I call the following:
if (_assetReader.status == AVAssetReaderStatusReading){
if (_trackOutput) {
CMSampleBufferRef sampleBuffer = [_trackOutput copyNextSampleBuffer];
[self createNewTextureVideoFromOutputSampleBuffer:sampleBuffer]; //create the new texture
}
}else if (_assetReader.status == AVAssetReaderStatusCompleted) {
NSLog(@"restart");
[_assetReader startReading];
}
All work fine until the AVAssetReader is in the reading status but when it finished reading and I tried to restart the AVAssetReading with a new call [_assetReader startReading], the application crash without output. What I'm doing wrong? It is correct to restart an AVAssetReading when it complete his reading?
AVAssetReader
doesn't support seeking or restarting, it is essentially a sequential decoder. You have to create a new AVAssetReader
object to read the same samples again.