Fix swscaler warning : "deprecated pixel format used ..."

Hi,
It's my first contribution, so I hope this is the good process.

Here's a fix of the warning raised by ffmpeg lib swscaler
["deprecated pixel format used, make sure you did set range correctly"]
when we open or convert a frame with a deprecated source pixel format.
From now, it use the couple [pixel_format, color_range]

PS : there is a TODO. I didn't find the deprecation start libswscale/libavutil version. So I use respectively 2.1.0/52.17