Clean transcoding when htsp based transcoding is used

[Flole998]

@perexg There was an issue when HTSP clients like kodi used a transcoding profile (especially nvidia based profiles) so the transcoder was never cleaned up which caused more and more GPU memory to be used. This fixes it for me but I have absolutely no idea if this is a proper fix or if run should evaluate to true in this case and the cleanup code from above should be used instead. There is no profile sharer thread started in this case if I saw that correctly, so it should be correct that run evaluates to 0 but it could be that a profile sharer thread should be started in this case. Really not sure about this and I would appreciate if you could look over this and approve this or reject this is this is not a proper fix (and I believe that this is not a proper fix).

[pinkflozd]

Helps with growing memory with vaapi encoding too, but tvheadend segfaults when a second user that watches the same channel stops playback

[Flole998]

Then this is not the correct implementation as I already assumed....

[Saentist]

May be, because no one monitor session usage.
Session process must be keep alive until there is active client/s/ exist,
and terminated 2-5 sec after last leave.

[Flole998]

A fix was provided at the Forum and I have updated this PR now to use that fix. Please check if this fix is better.

[pinkflozd]

Confirming it fixed, no memory buildup with htsp+vaapi

[susadmin]

I would just like to add +1 vote for adding this fix to the master branch as this (expanding GPU memory usage) is still happening for me. I have to use the fix-htsp-transcode branch until it is included.

[Flole998]

This fix is not correct yet though. There's a potential race condition in it, so that needs fixing first.

[susadmin]

Ok thanks for the update and for all your hard work on this project.

[susadmin]

Hi. Just wondered if this fix can be added to the master branch yet? It would be really great as the master branch has some important fixes since the fix-htsp-transcode branch I am currently using . Thanks

[woooow1]

@Flole998 changes that you made, works without any problems. If you decide, close this PR!

[Flole998]

What changes? I'm not aware of fixing this yet (or I forgot).

[woooow1]

fc3759a