That's how YouTube reports them in their DASH manifest.
Closes #6370.
[letv] fix height
[youtube] Extract start_time
For a couple of days now rtlXL's non-DRM adaptive (m3u8) streams don't work anymore. By undoing the adaptive -> flash workaround youtube-dl returns the DRM streams again. Too bad for foreigners (geoblock). The progressive streams still work fine.
Closes #6343.
In some videos the base_url already ends with '/'.
Currently they give a 403 Forbidden error.