Why does my movie from UIImages gets distorted?

After a lot of experiments with different image sizes, and with the help of this article, I've got to the conclusion that the width of the images must be a multiple of 16.

I'v encountered this problem too, and I found the reason is the image's size is not the multiple of 16, you can change the size and have a try.

For those still doing the journey in 2020, and getting distortion in their movies because its not width 16px

change

CGContextRef context = CGBitmapContextCreate(pxdata,
                                             width, height,
                                             8, 4 * width,
                                             rgbColorSpace,
                                             kCGImageAlphaNoneSkipFirst);

to

CGContextRef context = CGBitmapContextCreate(pxdata,
                                             width, height,
                                             8, CVPixelBufferGetBytesPerRow(pxbuffer),
                                             rgbColorSpace,
                                             kCGImageAlphaNoneSkipFirst);

Credit to @Bluedays Output from AVAssetWriter (UIImages written to video) distorted