mex-thumbnailer: use fast search to nearest key frame, issue #235
mex-thumbnailer: use fast search to nearest key frame, issue #235

Accurate searching can be very slow for some video formats, resulting in the
thumbnailer code timing out and failing to generate a thumbnail.

Signed-off-by: Tomas Frydrych <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@sleepfive.com>

media-explorer/media-explorer,media-explorer/media-explorer,media-explorer/media-explorer,media-explorer/media-explorer