How to reduce the size of a .mov video file created with AVCaptureSession?
I can record video using AVCaptureSession
. But I want to reduce its size. How can i do this? I get the final URL
in the delegate's captureOutput method.
VideoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
VideoInputDevice = [AVCaptureDeviceInput deviceInputWithDevice:VideoDevice error:&error];
if (!error)
{
if ([CaptureSession canAddInput:VideoInputDevice])
{
[CaptureSession addInput:VideoInputDevice];
}
else
{
NSLog(@"Couldn't add video input");
}
else
{
NSLog(@"Couldn't create video input");
}
}
else
{
NSLog(@"Couldn't create video capture device");
}
AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
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2 answers
You want to use AVAssetExportSession. The code will look something like this:
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:myAsset presetName:exportPreset];
exporter.videoComposition = _videoComposition;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = NO;
url = [url URLByAppendingPathExtension:CFBridgingRelease(UTTypeCopyPreferredTagWithClass((__bridge CFStringRef)(exporter.outputFileType), kUTTagClassFilenameExtension))];
exporter.outputURL = url;
[exporter exportAsynchronouslyWithCompletionHandler:^{
// handle the completion in a way meaningful to your app
}];
Export preset must be one of the following:
AVF_EXPORT NSString *const AVAssetExportPreset640x480 NS_AVAILABLE(10_7, 4_0);
AVF_EXPORT NSString *const AVAssetExportPreset960x540 NS_AVAILABLE(10_7, 4_0);
AVF_EXPORT NSString *const AVAssetExportPreset1280x720 NS_AVAILABLE(10_7, 4_0);
AVF_EXPORT NSString *const AVAssetExportPreset1920x1080 NS_AVAILABLE(10_7, 5_0);
AVF_EXPORT NSString *const AVAssetExportPreset3840x2160 NS_AVAILABLE(10_10, NA);
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Hope this method is helpful for u
- (void)compressingVideoWithSoundWithInputURL:(NSURL*)inputURL outputURL:(NSURL*)outputURL andResolution:(CGSize)resolution
{
self.myVideoWriter = nil;
[[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
//setup video writer
AVAsset *videoAsset = [[AVURLAsset alloc] initWithURL:inputURL options:nil];
AVAssetTrack *videoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
NSDictionary *videoWriterCompressionSettings = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:1250000], AVVideoAverageBitRateKey, nil];
NSDictionary *videoWriterSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey, videoWriterCompressionSettings, AVVideoCompressionPropertiesKey, [NSNumber numberWithFloat:resolution.width], AVVideoWidthKey, [NSNumber numberWithFloat:resolution.height], AVVideoHeightKey, nil];
AVAssetWriterInput* videoWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoWriterSettings];
videoWriterInput.expectsMediaDataInRealTime = YES;
videoWriterInput.transform = videoTrack.preferredTransform;
NSError* writerError = nil;
self.myVideoWriter = [[AVAssetWriter alloc] initWithURL:outputURL fileType:AVFileTypeQuickTimeMovie error:&writerError];
if (writerError) {
NSLog(@"Writer error: %@", writerError);
NSString *message = [NSString stringWithFormat:@"VideoEditor. compressingVideoWithInputURL: outputURL: andResolution:. Writer error: %@", writerError];
FLog(message);
return;
}
[self.myVideoWriter addInput:videoWriterInput];
//setup video reader
NSDictionary *videoReaderSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
AVAssetReaderTrackOutput *videoReaderOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack outputSettings:videoReaderSettings];
AVAssetReader *videoReader = [[AVAssetReader alloc] initWithAsset:videoAsset error:nil];
[videoReader addOutput:videoReaderOutput];
//setup audio writer
AVAssetWriterInput* audioWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeAudio
outputSettings:nil];
audioWriterInput.expectsMediaDataInRealTime = NO;
[self.myVideoWriter addInput:audioWriterInput];
//setup audio reader
AVAssetTrack* audioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
AVAssetReaderOutput *audioReaderOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:audioTrack outputSettings:nil];
AVAssetReader *audioReader = [AVAssetReader assetReaderWithAsset:videoAsset error:nil];
[audioReader addOutput:audioReaderOutput];
[self.myVideoWriter startWriting];
//start writing from video reader
[videoReader startReading];
[self.myVideoWriter startSessionAtSourceTime:kCMTimeZero];
dispatch_queue_t processingQueue = dispatch_queue_create("processingQueue1", DISPATCH_QUEUE_SERIAL);
[videoWriterInput requestMediaDataWhenReadyOnQueue:processingQueue usingBlock:
^{
while ([videoWriterInput isReadyForMoreMediaData]) {
CMSampleBufferRef sampleBuffer;
if ([videoReader status] == AVAssetReaderStatusReading &&
(sampleBuffer = [videoReaderOutput copyNextSampleBuffer])) {
[videoWriterInput appendSampleBuffer:sampleBuffer];
CFRelease(sampleBuffer);
}
else {
[videoWriterInput markAsFinished];
if ([videoReader status] == AVAssetReaderStatusCompleted) {
if ([audioReader status] == AVAssetReaderStatusReading || [audioReader status] == AVAssetReaderStatusCompleted) {
}
else{
//start writing from audio reader
[audioReader startReading];
[self.myVideoWriter startSessionAtSourceTime:kCMTimeZero];
dispatch_queue_t processingQueue = dispatch_queue_create("processingQueue2", NULL);
[audioWriterInput requestMediaDataWhenReadyOnQueue:processingQueue usingBlock:^{
while (audioWriterInput.readyForMoreMediaData) {
CMSampleBufferRef sampleBuffer;
if ([audioReader status] == AVAssetReaderStatusReading &&
(sampleBuffer = [audioReaderOutput copyNextSampleBuffer])) {
[audioWriterInput appendSampleBuffer:sampleBuffer];
CFRelease(sampleBuffer);
}
else {
[audioWriterInput markAsFinished];
if ([audioReader status] == AVAssetReaderStatusCompleted)
{
[self finishWritingAction];
break;
}
}
}
}
];
}
}
}
}
}
];
}
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