Here's a quick comparison between the protune mode in m GoPro Hero HD2.
If protune mode is set to off, the bitrate is about 14 Mb/s The image has a profile with a lot of contrast and a red hue.
If protune is set to on, the bitrate is about 34 Mb/s. The profile is much flatter and softer. After importing in Premiere Pro CS6, you have to sharpen the image to take back details. The color correction is much more efficient with this mode.
You can download the original mp4 file 110Mo (25 Mb/sec).
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