vaapidecode: make reverse playback smoothly
Submitted by Víctor Manuel Jáquez Leal @vjaquez
Link to original bug (#768692)
Description
Right now, reverse playback in vaapidecode is rough: only the key-frames are shown. This is because the element runs out of VA surfaces (4 or so depending on the codec).
The purpose of this report is to think how we can improve this situation, how we can make reverse playback smoothly.