Failure of combination of AVAssetWriter and AVAssetWriterInputPixelBufferAdaptor appendingPixelBuffer - ios

Question

I am attempting to use a combination of the sample provided for encoding asset writer and the sample provided from pixelBufferFromCGImage to overlay a UIImage atop a AVAsset that I'm exporting.
The problem is, despite the True result of this call
[adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];
The exported avasset is corrupted, yeilding an unexpected size and a subsequent access to it failing with 'This media may be damaged'.
The export itself, if I avoid attempting to use the appendPixelBuffer call, is successful as desired. However, locating it before the dispatch queue or within it yeilds the same failure.
Hopefully not redundantly posting here, but other samples here in stack overflow don't seem to address this particular combination failure. Thanks, code below
Export code:
AVAsset *sourceAsset = [AVAsset assetWithURL:outputUrl];
NSError *error = nil;
NSString *fileName = [NSString stringWithFormat:#"non_transform_%f.mov", [[NSDate date] timeIntervalSince1970]];
NSString *combinedPath = [NSString stringWithFormat:#"file://localhost%#/%#", [[GroupDiskManager sharedManager] getFolderPath], fileName];
NSURL *outputURL = [NSURL URLWithString:combinedPath];
NSLog(#"combined path: %#", combinedPath);
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:outputURL fileType:AVFileTypeQuickTimeMovie error:&error];
AVAssetTrack *videoTrack = [[sourceAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVAssetTrack *audioTrack = [[sourceAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:1280], AVVideoWidthKey,
[NSNumber numberWithInt:720], AVVideoHeightKey,
nil];
AVAssetWriterInput* videoWriterInput = [[AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings] retain];
NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:1280] forKey:(NSString*)kCVPixelBufferWidthKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:720] forKey:(NSString*)kCVPixelBufferHeightKey];
AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:videoWriterInput
sourcePixelBufferAttributes:attributes];
NSParameterAssert(videoWriterInput);
NSParameterAssert([videoWriter canAddInput:videoWriterInput]);
videoWriterInput.expectsMediaDataInRealTime = NO;
[videoWriter addInput:videoWriterInput];
NSError *aerror = nil;
NSDictionary *videoOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
AVAssetReaderTrackOutput *asset_reader_output = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack outputSettings:videoOptions];
AVAssetReader *reader = [[AVAssetReader alloc] initWithAsset:sourceAsset error:&aerror];
[reader addOutput:asset_reader_output];
AVAssetWriterInput* audioWriterInput = [[AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeAudio
outputSettings:nil] retain];
AVAssetReader *audioReader = [[AVAssetReader assetReaderWithAsset:sourceAsset error:&error] retain];
AVAssetReaderOutput *audioReaderOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:audioTrack outputSettings:nil];
[audioReader addOutput:audioReaderOutput];
NSParameterAssert(audioWriterInput);
NSParameterAssert([videoWriter canAddInput:audioWriterInput]);
audioWriterInput.expectsMediaDataInRealTime = YES;
[videoWriter addInput:audioWriterInput];
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
[reader startReading];
CVPixelBufferRef buffer = [ImageToMovieManager pixelBufferFromCGImage:[UIImage imageNamed:#"234_1280x720_3.jpg"].CGImage size:CGSizeMake(1280, 720)];
BOOL theResult = [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];
if (theResult == NO) //failes on 3GS, but works on iphone 4
NSLog(#"failed to append buffer");
if(buffer) {
CVBufferRelease(buffer);
}
dispatch_queue_t _processingQueue = dispatch_queue_create("_processingQueue", NULL);
[videoWriterInput requestMediaDataWhenReadyOnQueue:_processingQueue usingBlock:
^{
NSLog(#"requestMediaDataWhenReadyOnQueue");
[self retain];
while ([videoWriterInput isReadyForMoreMediaData]) {
CMSampleBufferRef sampleBuffer;
if ([reader status] == AVAssetReaderStatusReading &&
(sampleBuffer = [asset_reader_output copyNextSampleBuffer])) {
BOOL result = [videoWriterInput appendSampleBuffer:sampleBuffer];
CFRelease(sampleBuffer);
if (!result) {
NSLog(#" result == nil Cancel!");
NSLog(#"videoWriter.error: %#", videoWriter.error);
[reader cancelReading];
break;
}
} else {
NSLog(#"[videoWriterInput markAsFinished]");
[videoWriterInput markAsFinished];
switch ([reader status]) {
case AVAssetReaderStatusReading:
NSLog(#"reading");
// the reader has more for other tracks, even if this one is done
break;
case AVAssetReaderStatusCompleted:
NSLog(#"AVAssetReaderStatusCompleted");
[audioReader startReading];
dispatch_queue_t mediaInputQueue = dispatch_queue_create("mediaInputQueue", NULL);
[audioWriterInput requestMediaDataWhenReadyOnQueue:mediaInputQueue usingBlock:^
{
while (audioWriterInput.readyForMoreMediaData) {
CMSampleBufferRef nextBuffer;
if ([audioReader status] == AVAssetReaderStatusReading &&
(nextBuffer = [audioReaderOutput copyNextSampleBuffer])) {
if (nextBuffer) {
[audioWriterInput appendSampleBuffer:nextBuffer];
}
}else{
[audioWriterInput markAsFinished];
switch ([audioReader status]) {
case AVAssetReaderStatusCompleted:
NSLog(#"AVAssetReaderStatusCompleted!!");
[videoWriter finishWriting];
[VideoManager videoSavedWithURL:outputURL withError:(NSError *)error];
break;
}
}
}
}
];
break;
case AVAssetReaderStatusFailed:
NSLog(#"AVAssetReaderStatusFailed");
[videoWriter cancelWriting];
break;
}
break;
}
}
}
];
pixelBufferFromCGImageCode
CGSize frameSize = CGSizeMake(CGImageGetWidth(image), CGImageGetHeight(image));
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:NO], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:NO], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, frameSize.width,
frameSize.height, kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange, (CFDictionaryRef) options,
&pxbuffer);
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, frameSize.width,
frameSize.height, 8, 4*frameSize.width, rgbColorSpace,
kCGImageAlphaNoneSkipLast);
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;

Answer 1

At the very least, the pixelFormat should be specified as kCVPixelFormatType_32BGRA not kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange.