subtitle is still outputing while video abnormally freezed for some reason

[Churchy Zheng]

subtitle is still outputing while video abnormally freezed for some reason.

for some reason, for example helix dbus server crashed, the video is freezed on front, but the subtitle is still outputing at the bottom of video area.

this bug is hard to reproduce. but if you try many times, you will be lucky to happen it.

steps:
 1. copy a same name subtitle file as video media to ~/media/video
 2. plyaback it
 3. if the helix dbus server crashed at the back end, then you will see the subtitle is still outputing.

[Churchy Zheng (changqiu-zheng)]

the bug is hard to reproduce and depends the stability of helix dbus server. so set low level.

[Halley (halley-zhao)]

however, I think the scenario is:
CIP codecs has hanged (for example: due to switch back from other application. "Xlib Async)
but sw codec (real text render) still works for some time.

[donald (donald-wei)]

What's the expected result? Since the sub title show and video playback are two pipleline. It's right for subtitle to keep playing.

[donald (donald-wei)]

This seems not a bug in subtitle, it is a bug in playback, may cip codec