Hello, I am needing to have AVPlayer output the video as an CVImageBufferRef in
real time instead of AVPlayerLayer. I am able to do this with QTKit and
QTPixelBufferContextCreate, however, QTKit is said to be dead and AVFoundation
is the future as well as AVFoundation is 64bit.
So far what I've came up with works, however it is not feasible as I cannot
skip time without also telling AVAssetReader to change it's position and it
takes up more CPU than QTKit does.
Another thought I had with using AVFoundation is that AVFoundation should have
GPU accelerated H.264 decoding, which this does not seem to be true in my
current testing with QuickTime X as it still uses 33% CPU with a 1080P video
(not sure if that's good or bad).
Here is what I currently have, if anyone can improve it, please tell me how.
avMovie = [[AVPlayer alloc] initWithURL:[NSURL fileURLWithPath:[theArguments
objectAtIndex:0]]];
AVPlayerItem *item = [avMovie currentItem];
AVAsset *asset = [item asset];
AVAssetTrack *videoTrack = nil;
NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
if ([tracks count] == 1) {
videoTrack = [tracks objectAtIndex:0];
NSError *error = nil;
assetReader = [[AVAssetReader alloc] initWithAsset:asset error:&error];
if (error!=nil) {
NSLog(@"Unable to create asset reader %@", [error
localizedDescription]);
} else {
NSMutableDictionary *bufferOptions = [NSMutableDictionary dictionary];
[bufferOptions setObject:[NSNumber numberWithInt:kYUVSPixelFormat]
forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[assetReader addOutput:[AVAssetReaderTrackOutput
assetReaderTrackOutputWithTrack:videoTrack outputSettings:bufferOptions]];
[assetReader startReading];
}
}
if (videoTrack!=nil) {
NSLog(@"%f", (Float64)1/[videoTrack nominalFrameRate]);
[avMovie addPeriodicTimeObserverForInterval:CMTimeMake(1001, [videoTrack
nominalFrameRate]*1001) queue:dispatch_queue_create("eventQueue", NULL)
usingBlock:^(CMTime time) {
dispatch_sync(dispatch_get_main_queue(), ^{
AVAssetReaderTrackOutput *output = [[assetReader outputs]
objectAtIndex:0];
CMSampleBufferRef sampleBuffer = [output copyNextSampleBuffer];
if (sampleBuffer!=NULL) {
CVImageBufferRef texture =
CMSampleBufferGetImageBuffer(sampleBuffer);
// Do code with the CoreVideo Image.
CFRelease(texture);
}
});
}];
}
[avMovie setRate:1.0];
P.S. I know I have leaks in there somewhere, I plan to remove them after
getting the concept completed with all of this.
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