I can't exactly answer your question, frustratingly, but I am working on code that does essentially the same thing. And, mine happens to get further than the error you have been getting; it gets all the way to the point where it's attempting to add the images to the movie and then simply fails by never getting a successful result from appendPixelBuffer() -- and I'm not sure how to figure out why. I'm posting this in the hopes that it helps you get further, though.
(My code is adapted from AVFoundation + AssetWriter: Generate Movie With Images and Audio, and I used your post to help navigate som e of the pointer interop shenanigans...)
func writeAnimationToMovie(path: String, size: CGSize, animation: Animation) -> Bool {
var error: NSError?
let writer = AVAssetWriter(URL: NSURL(fileURLWithPath: path), fileType: AVFileTypeQuickTimeMovie, error: &error)
let videoSettings = [AVVideoCodecKey: AVVideoCodecH264, AVVideoWidthKey: size.width, AVVideoHeightKey: size.height]
let input = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: videoSettings)
let pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: input, sourcePixelBufferAttributes: nil)
input.expectsMediaDataInRealTime = true
writer.addInput(input)
writer.startWriting()
writer.startSessionAtSourceTime(kCMTimeZero)
var buffer: CVPixelBufferRef
var frameCount = 0
for frame in animation.frames {
let rect = CGRectMake(0, 0, size.width, size.height)
let rectPtr = UnsafeMutablePointer<CGRect>.alloc(1)
rectPtr.memory = rect
buffer = pixelBufferFromCGImage(frame.image.CGImageForProposedRect(rectPtr, context: nil, hints: nil).takeUnretainedValue(), size)
var appendOk = false
var j = 0
while (!appendOk && j < 30) {
if pixelBufferAdaptor.assetWriterInput.readyForMoreMediaData {
let frameTime = CMTimeMake(Int64(frameCount), 10)
appendOk = pixelBufferAdaptor.appendPixelBuffer(buffer, withPresentationTime: frameTime)
// appendOk will always be false
NSThread.sleepForTimeInterval(0.05)
} else {
NSThread.sleepForTimeInterval(0.1)
}
j++
}
if (!appendOk) {
println("Doh, frame (frame) at offset (frameCount) failed to append")
}
}
input.markAsFinished()
writer.finishWritingWithCompletionHandler({
if writer.status == AVAssetWriterStatus.Failed {
println("oh noes, an error: (writer.error.description)")
} else {
println("hrmmm, there should be a movie?")
}
})
return true;
}
Where pixelBufferFromCGImage
is defined like so:
func pixelBufferFromCGImage(image: CGImageRef, size: CGSize) -> CVPixelBufferRef {
let options = [
kCVPixelBufferCGImageCompatibilityKey: true,
kCVPixelBufferCGBitmapContextCompatibilityKey: true]
var pixBufferPointer = UnsafeMutablePointer<Unmanaged<CVPixelBuffer>?>.alloc(1)
let status = CVPixelBufferCreate(
nil,
UInt(size.width), UInt(size.height),
OSType(kCVPixelFormatType_32ARGB),
options,
pixBufferPointer)
CVPixelBufferLockBaseAddress(pixBufferPointer.memory?.takeUnretainedValue(), 0)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapinfo = CGBitmapInfo.fromRaw(CGImageAlphaInfo.NoneSkipFirst.toRaw())
var pixBufferData:UnsafeMutablePointer<(Void)> = CVPixelBufferGetBaseAddress(pixBufferPointer.memory?.takeUnretainedValue())
let context = CGBitmapContextCreate(
pixBufferData,
UInt(size.width), UInt(size.height),
8, UInt(4 * size.width),
rgbColorSpace, bitmapinfo!)
CGContextConcatCTM(context, CGAffineTransformMakeRotation(0))
CGContextDrawImage(
context,
CGRectMake(0, 0, CGFloat(CGImageGetWidth(image)), CGFloat(CGImageGetHeight(image))),
image)
CVPixelBufferUnlockBaseAddress(pixBufferPointer.memory?.takeUnretainedValue(), 0)
return pixBufferPointer.memory!.takeUnretainedValue()
}