The top row shows the original RGB gray scale pixel swatch values.The value swatches below the graph show how input values are changed: Here is the input/output transformation curve for RGB gray scale values: The maximum deviation occurs for an input value of 88, which is increased by 12 pixel values: Each output_pixel is equal to (input_pixel) ^ 0.88. Problem #1: If you use Adobe After Effects CS5 to encode QuickTime H.264 video on a PC, After Effects will first modify the pixel values to boost the mid-tone brightness, by applying a gamma of (1/0.88). There are actually two different problems, which tend to be conflated with each other: The problem is not always possible to fix, so it’s important to understand what’s going on. It’s commonly referred to as the “QuickTime gamma bug,” but it’s really a reduction in contrast, which converts the full range of pixel values (0-255) to the more limited pixel value range defined in in rec.601: rec.601 The QuickTime player causes H.264 and MPEG-4 encoded video to look washed-out.
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