Thread Priorities in MP (DirectShow filter priority?) (1 Viewer)

[ziphnor]

It seems to me that video playback and possibly also recording in MP is much too sensitive to other processes running on the system. For example, updating the EPG results in jitter in live TV.

A related problem is that when using Compress in 'low priority' mode, its only the thread that starts the DirectShow filtergraph that runs in low priority, and judging from the resulting performance, the filter graph itself runs in a seperate thread(or possibly several threads), and for example almost completely locks the GUI.

In MCE i have noticed that video playback seems to have a much higher priority i could for example encode Xvid in the background at standard priority and still watch live TV without jitter, though the GUI was very sluggish.

I found a few discussions on the topic of DS filter thread priorities on related newsgroups:
http://shurl.org/eFEuq
http://shurl.org/EwSNZ

Does anyone here know anything about this? I would really like to see this worked on, and im prepared to look into it myself, but i would like to ask for input first.

Seems to me that any filter graphs related to recording should run at real time critical priority, while playback should run at the next highest priority, the GUI at normal, and all compress jobs etc at low or idle priority.

 

[mzemina]

ziphnor - I think you may get a better response if you get on the IRC chat and ask there, the only problem is trying to match up with timezones. It would be better to use a client instead of the webclient. The better irc client that has been recommended by various developers is hyrdairc, it is opensource and free, can be found at http://www.hydrairc.com/.

 

[tourettes]

Seems to me that any filter graphs related to recording should run at real time critical priority, while playback should run at the next highest priority, the GUI at normal, and all compress jobs etc at low or idle priority.

I'm not so sure if it's that good idea to run something as such a high priority. If thread that's running in real time priority starts to eat CPU it's pretty much impossible to kill MP then.

 

[ziphnor]

I'm not so sure if it's that good idea to run something as such a high priority. If thread that's running in real time priority starts to eat CPU it's pretty much impossible to kill MP then.

Good point, i just think its important to have recording at higher priority than playback and playback at higher priority than gui/normal stuff and i cant really remember the thread priority options. Is it normal, above normal, high and realtime or are there fewer?

 

[ziphnor]

ziphnor - I think you may get a better response if you get on the IRC chat and ask there, the only problem is trying to match up with timezones. It would be better to use a client instead of the webclient. The better irc client that has been recommended by various developers is hyrdairc, it is opensource and free, can be found at http://www.hydrairc.com/.

Thanks, ill try that when i have time. What time-zone is the developers mostly in? Im in europe and had the impression that this was also the case for most of the developers.

 

[mzemina]

ziphnor - I think you may get a better response if you get on the IRC chat and ask there, the only problem is trying to match up with timezones. It would be better to use a client instead of the webclient. The better irc client that has been recommended by various developers is hyrdairc, it is opensource and free, can be found at http://www.hydrairc.com/.

Thanks, ill try that when i have time. What time-zone is the developers mostly in? Im in europe and had the impression that this was also the case for most of the developers.

You are correct!

 

[ziphnor]

I found a relevant usenet group using Google Groups, and i have gotten some tips there. It seems its not that easy to do:

If someone else wants to read this is the URL:
http://groups.google.dk/group/micro...o/browse_thread/thread/150003ec32c9ccc9?hl=us

 

[ziphnor]

I made a hack to try this out( i find filter threads by changing the application thread to highest priority, start the graph, and then check which new threads were made, and lower priority to what it was before and adjust priority of new threads, ie not very pretty). I tested it with the DVR-MS -> MPEG-2 Compress option in TV Recordings. Before adjusting DS thread priorities i could hardly navigate the GUI while a compress job was working, and watching something else meanwhile was a joke, after applying my 'hack', things improved a lot, and while i could still 'feel' that something was working in the background(probably due to harddrive activity), i was able to watch another recording meanwhile.

Im going to check out the effect on playback and recording filters next.

 

[FlipGer]

Hi,

this sounds promising!

Keep up the great work.

Flip.