在处理奇数宽度的ProRes422视频时,AVPlayer和AVAssetReader可能会产生伪影。这是因为ProRes422视频要求宽度为偶数,而当输入奇数宽度的视频时,这些库会在渲染或解码过程中产生问题。
解决这个问题的一种方法是在渲染或解码之前,将奇数宽度的视频进行处理,将其宽度调整为偶数。这可以通过裁剪奇数列或在视频末尾添加一个黑色像素来实现。
以下是一个示例代码,展示了如何使用AVPlayer和AVAssetReader来处理奇数宽度的ProRes422视频并避免伪影:
import AVFoundation
func processProResVideo(url: URL) {
// 创建AVAsset对象
let asset = AVAsset(url: url)
// 创建AVAssetTrack对象
guard let videoTrack = asset.tracks(withMediaType: .video).first else {
print("Video track not found.")
return
}
// 检查视频宽度是否为奇数
if Int(videoTrack.naturalSize.width) % 2 != 0 {
// 获取视频的原始尺寸
let originalSize = videoTrack.naturalSize
// 裁剪奇数列或在视频末尾添加一个黑色像素来将宽度调整为偶数
let adjustedSize = CGSize(width: ceil(originalSize.width / 2) * 2, height: originalSize.height)
// 创建视频轨道的输出设置
let outputSettings = [
kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA
]
// 创建AVAssetReaderTrackOutput对象
let output = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: outputSettings)
// 创建AVAssetReader对象
guard let reader = try? AVAssetReader(asset: asset) else {
print("Failed to create AVAssetReader.")
return
}
// 添加输出到AVAssetReader对象
reader.add(output)
// 开始读取
reader.startReading()
// 处理每个采样缓冲区
while let sampleBuffer = output.copyNextSampleBuffer() {
// 获取图像像素缓冲区
guard let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
continue
}
// 创建一个新的像素缓冲区
var newPixelBuffer: CVPixelBuffer?
let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(adjustedSize.width), Int(adjustedSize.height), kCVPixelFormatType_32BGRA, nil, &newPixelBuffer)
if status == kCVReturnSuccess {
// 将原始像素缓冲区复制到新的像素缓冲区中
CVPixelBufferLockBaseAddress(imageBuffer, .readOnly)
CVPixelBufferLockBaseAddress(newPixelBuffer!, [])
let srcBaseAddress = CVPixelBufferGetBaseAddress(imageBuffer)
let dstBaseAddress = CVPixelBufferGetBaseAddress(newPixelBuffer!)
memcpy(dstBaseAddress, srcBaseAddress, CVPixelBufferGetDataSize(imageBuffer))
CVPixelBufferUnlockBaseAddress(imageBuffer, .readOnly)
CVPixelBufferUnlockBaseAddress(newPixelBuffer!, [])
// 使用新的像素缓冲区创建一个新的采样缓冲区
var newSampleBuffer: CMSampleBuffer?
let timingInfo = CMSampleTimingInfo(duration: CMSampleBufferGetDuration(sampleBuffer), presentationTimeStamp: CMSampleBufferGetPresentationTimeStamp(sampleBuffer), decodeTimeStamp: CMSampleBufferGetDecodeTimeStamp(sampleBuffer))
CMSampleBufferCreateCopyWithNewTiming(allocator: kCFAllocatorDefault, sampleBuffer: sampleBuffer, sampleTimingEntryCount: 1, sampleTimingArray: [timingInfo], sampleBufferOut: &newSampleBuffer)
if let newSampleBuffer = newSampleBuffer {
// 更新新的采样缓冲区的图像像素缓冲区
CMSampleBufferSetDataBufferFromAudioBufferList(newSampleBuffer, kCFAllocatorDefault, kCFAllocatorDefault,