I am writing an MP4 video file with AVAssetWriter using AVAssetWriterInputPixelBufferAdaptor .
The source is a video from the UIImagePickerController , either fresh captured from the camera, or from the resource library. Quality right now is UIImagePickerControllerQualityTypeMedium .
The writer fails several times. Its status is AVAssetWriterStatusFailed , and the error property of AVAssetWriter objects AVAssetWriter :
Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo=0xf5d8990 {NSLocalizedFailureReason=An unknown error occurred (-536870210), NSUnderlyingError=0x4dd8e0 "The operation couldn't be completed. (OSStatus error -536870210.)", NSLocalizedDescription=The operation could not be completed
The error occurs in about 20% of cases when the code starts. It seems that it no longer works on the iPhone 4 / 4S than on the iPhone 5.
This also happens more often if the quality of the original video is higher. Using the UIImagePickerControllerQualityTypeLow error does not occur so often. Using the UIImagePickerControllerQualityTypeHigh, the error occurs a little more often.
I also noticed something else: It seems to be waves. When it fails, the following runs will often fail, even if I uninstall the application and reinstall it. This makes me wonder if my program will lose some memory, and if this memory remains alive, even if the application is killed (is this possible?).
Here is the code that I use to render my video:
- (void)writeVideo { offlineRenderingInProgress = YES; /* --- Writer Setup --- */ [locationQueue cancelAllOperations]; [self stopWithoutRewinding]; NSError *writerError = nil; BOOL succes; succes = [[NSFileManager defaultManager] removeItemAtURL:self.outputURL error:nil]; // DLog(@"Url: %@, succes: %i, error: %@", self.outputURL, succes, fileError); writer = [AVAssetWriter assetWriterWithURL:self.outputURL fileType:(NSString *)kUTTypeQuickTimeMovie error:&writerError]; //writer.shouldOptimizeForNetworkUse = NO; if (writerError) { DLog(@"Writer error: %@", writerError); return; } float bitsPerPixel; CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions((__bridge CMVideoFormatDescriptionRef)([readerVideoOutput.videoTracks[0] formatDescriptions][0])); int numPixels = dimensions.width * dimensions.height; int bitsPerSecond; // Assume that lower-than-SD resolutions are intended for streaming, and use a lower bitrate if ( numPixels < (640 * 480) ) bitsPerPixel = 4.05; // This bitrate matches the quality produced by AVCaptureSessionPresetMedium or Low. else bitsPerPixel = 11.4; // This bitrate matches the quality produced by AVCaptureSessionPresetHigh. bitsPerSecond = numPixels * bitsPerPixel; NSDictionary *videoCompressionSettings = [NSDictionary dictionaryWithObjectsAndKeys: AVVideoCodecH264, AVVideoCodecKey, [NSNumber numberWithFloat:videoSize.width], AVVideoWidthKey, [NSNumber numberWithInteger:videoSize.height], AVVideoHeightKey, [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInteger:30], AVVideoMaxKeyFrameIntervalKey, nil], AVVideoCompressionPropertiesKey, nil]; writerVideoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoCompressionSettings]; writerVideoInput.transform = movie.preferredTransform; writerVideoInput.expectsMediaDataInRealTime = YES; [writer addInput:writerVideoInput]; NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:kCVPixelFormatType_32ARGB], kCVPixelBufferPixelFormatTypeKey, nil]; writerPixelAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerVideoInput sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary]; BOOL couldStart = [writer startWriting]; if (!couldStart) { DLog(@"Could not start AVAssetWriter!"); abort = YES; [locationQueue cancelAllOperations]; return; } [self configureFilters]; CIContext *offlineRenderContext = [CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer : @NO}]; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); if (!self.canEdit) { [self createVideoReaderWithAsset:movie timeRange:CMTimeRangeFromTimeToTime(kCMTimeZero, kCMTimePositiveInfinity) forOfflineRender:YES]; } else { [self createVideoReaderWithAsset:movie timeRange:CMTimeRangeWithNOVideoRangeInDuration(self.thumbnailEditView.range, movie.duration) forOfflineRender:YES]; } CMTime startOffset = reader.timeRange.start; DLog(@"startOffset: %llu", startOffset.value); [self.thumbnailEditView removeFromSuperview]; // self.thumbnailEditView = nil; [glLayer removeFromSuperlayer]; glLayer = nil; [playerView removeFromSuperview]; playerView = nil; glContext = nil; [writerVideoInput requestMediaDataWhenReadyOnQueue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) usingBlock:^{ @try { BOOL didWriteSomething = NO; DLog(@"Preparing to write..."); while ([writerVideoInput isReadyForMoreMediaData]) { if (abort) { NSLog(@"Abort == YES"); [locationQueue cancelAllOperations]; [writerVideoInput markAsFinished]; videoConvertCompletionBlock(NO, writer.error.localizedDescription); } if (writer.status == AVAssetWriterStatusFailed) { DLog(@"Writer.status: AVAssetWriterStatusFailed, error: %@", writer.error); [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithInt:1] forKey:@"QualityOverride"]; [[NSUserDefaults standardUserDefaults] synchronize]; abort = YES; [locationQueue cancelAllOperations]; videoConvertCompletionBlock(NO, writer.error.localizedDescription); return; DLog(@"Source file exists: %i", [[NSFileManager defaultManager] fileExistsAtPath:movie.URL.relativePath]); } DLog(@"Writing started..."); CMSampleBufferRef buffer = nil; if (reader.status != AVAssetReaderStatusUnknown) { if (reader.status == AVAssetReaderStatusReading) { buffer = [readerVideoOutput copyNextSampleBuffer]; if (didWriteSomething == NO) { DLog(@"Copying sample buffers..."); } } if (!buffer) { [writerVideoInput markAsFinished]; DLog(@"Finished..."); CGColorSpaceRelease(colorSpace); [self offlineRenderingDidFinish]; dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ [writer finishWriting]; if (writer.error != nil) { DLog(@"Error: %@", writer.error); } else { DLog(@"Succes!"); } if (writer.status == AVAssetWriterStatusCompleted) { videoConvertCompletionBlock(YES, nil); } else { abort = YES; videoConvertCompletionBlock(NO, writer.error.localizedDescription); } }); return; } didWriteSomething = YES; } else { DLog(@"Still waiting..."); //Reader just needs a moment to get ready... continue; } CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(buffer); if (pixelBuffer == NULL) { DLog(@"Pixelbuffer == NULL"); continue; } //DLog(@"Sample call back! Pixelbuffer: %lu", CVPixelBufferGetHeight(pixelBuffer)); //NSDictionary *options = [NSDictionary dictionaryWithObject:(__bridge id)CGColorSpaceCreateDeviceRGB() forKey:kCIImageColorSpace]; CIImage *ciimage = [CIImage imageWithCVPixelBuffer:pixelBuffer options:nil]; CIImage *outputImage = [self filteredImageWithImage:ciimage]; CVPixelBufferRef outPixelBuffer = NULL; CVReturn status; CFDictionaryRef empty; // empty value for attr value. CFMutableDictionaryRef attrs; empty = CFDictionaryCreate(kCFAllocatorDefault, // our empty IOSurface properties dictionary NULL, NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 1, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionarySetValue(attrs, kCVPixelBufferIOSurfacePropertiesKey, empty); CFDictionarySetValue(attrs, kCVPixelBufferCGImageCompatibilityKey, (__bridge const void *)([NSNumber numberWithBool:YES])); CFDictionarySetValue(attrs, kCVPixelBufferCGBitmapContextCompatibilityKey, (__bridge const void *)([NSNumber numberWithBool:YES])); status = CVPixelBufferCreate(kCFAllocatorDefault, ciimage.extent.size.width, ciimage.extent.size.height, kCVPixelFormatType_32BGRA, attrs, &outPixelBuffer); //DLog(@"Output image size: %f, %f, pixelbuffer height: %lu", outputImage.extent.size.width, outputImage.extent.size.height, CVPixelBufferGetHeight(outPixelBuffer)); if (status != kCVReturnSuccess) { DLog(@"Couldn't allocate output pixelBufferRef!"); continue; } [offlineRenderContext render:outputImage toCVPixelBuffer:outPixelBuffer bounds:outputImage.extent colorSpace:colorSpace]; CMTime currentSourceTime = CMSampleBufferGetPresentationTimeStamp(buffer); CMTime currentTime = CMTimeSubtract(currentSourceTime, startOffset); CMTime duration = reader.timeRange.duration; if (CMTIME_IS_POSITIVE_INFINITY(duration)) { duration = movie.duration; } CMTime durationConverted = CMTimeConvertScale(duration, currentTime.timescale, kCMTimeRoundingMethod_Default); float durationFloat = (float)durationConverted.value; float progress = ((float) currentTime.value) / durationFloat; //DLog(@"duration : %f, progress: %f", durationFloat, progress); [self updateOfflineRenderProgress:progress]; if (pixelBuffer != NULL && writerVideoInput.readyForMoreMediaData) { [writerPixelAdaptor appendPixelBuffer:outPixelBuffer withPresentationTime:currentTime]; } else { continue; } if (writer.status == AVAssetWriterStatusWriting) { DLog(@"Writer.status: AVAssetWriterStatusWriting"); } CFRelease(buffer); CVPixelBufferRelease(outPixelBuffer); } } @catch (NSException *exception) { DLog(@"Catching exception: %@", exception); } }]; }