Vertical position of subtitles playbin and subtitleoverlay

Submitted by Luis de Bethencourt @luisbg

Link to original bug (#744056)

Description

Created attachment 296209
01- patch for subtitleoverlay

Two nights ago I went to an event hosted by a spanish academy where they projected a spanish film at a pub. Since most of the people in the room are learning spanish, they had english subtitles for educational purposes. And since the venue wasn't designed for this (group of chairs in flat floor) most people had their view of the bottom of the screen blocked. After some failed starts somebody changed a setting in the video player to move the subtitles to the top of the screen, and everybody could read them and was happy.

This made me think doing this in playbin is not possible. I don't think there are any GStreamer players that offer this feature.

I attach a solution for this :)

(some people call it opera-style subtitles since the same solution has been used in the opera)

Patch 296209, "01- patch for subtitleoverlay":
0001-subtitleoverlay-add-vertical-position-property.patch