Damn. Ah well close this then. Thanks anyway.

:( what's the reason for not changing the container?

I know you don't change the video.. I've explained what's happening. Quite simply the video needs to be tagged that it's bt601 in this instance in the container. Otherwise the wrong colors will show unless the video is edited as you linked on doom9. The user shouldn't have to do this, do it automatically please.

Take a screenshot of this video playing in 720P



Now download it in 720P & play in any media player. Take a screenshot of the same frame and compare it. You can see a color difference. This is because the youtube video is from a DVD/SD source (BT 601) but you don't save that info in the media file when it's downloaded, so a media player on the PC thinks it's from an HD source (being 720p) but it's not.. it thinks the colormetric is BT 709 (Blu-ray) but it's BT 601 (DVD). Here's a screenshot comparison I've already done to show you.

http://screenshotcomparison.com/comparison/129413

Any player as they tend to all follow the same rules. But specifically I use MPC-HC, MPC-BE (both with madVR) or MPDN all of which are using LAV Filters.