[mindweaver]

Will this maybe fix the sync issue when playing a video with the same refresh rate as the TV?

referring to this ticket/issue:

http://trac.xbmc.org/ticket/5755

[tslayer]

And did you checkout the correct branch? It isn't the linuxport branch.

[Hitcher]

Maybe I am crazy but I do not see anything new in the options? I am running SVN18044. Is not a late enough build to see the oprions in "Configure audio hardware"

Check the Timeline and you'll see you'll need 18060.

[SlaveUnit]

Ok yeha I just saw that bobo made some changes from 18020-18022 and thought those might be them. Thanks.

[Nazgulled]

I've been following this and other threads about smooth playback and you guys talk a lot about v-sync and triple buffering, but I'm not sure what's the best configuration for this:

1) Changing these settings (v-sync and triple buffer), only have effect on the "xbmc-smoothvideo" branch or it will also do good on other branches, namely the "linuxport" one?

2) I own a GeForce 8300, which is the best setting for v-sync in XBMC and triple-buffer/v-sync at the drivers level for OpenGL?

3) How does the work done here compares to the "adjust video framerate" option in the "linuxport" branch?

I really appreciate it if someone can answer me these three questions

[PolliSoft]

I checked out the smoothvideo branch, but I get a build error using Visual C++ 2008. I will send a message to Bobo1on1 to see if that is something he can fix.

[bobo1on1]

I've been following this and other threads about smooth playback and you guys talk a lot about v-sync and triple buffering, but I'm not sure what's the best configuration for this:

1) Changing these settings (v-sync and triple buffer), only have effect on the "xbmc-smoothvideo" branch or it will also do good on other branches, namely the "linuxport" one?

2) I own a GeForce 8300, which is the best setting for v-sync in XBMC and triple-buffer/v-sync at the drivers level for OpenGL?

3) How does the work done here compares to the "adjust video framerate" option in the "linuxport" branch?

I really appreciate it if someone can answer me these three questions

For smoothvideo to work you need vsync, it relies on it heavily.
I don't have an option called "adjust video framerate", do you mean "Adjust refreshrate" ? That changes the refreshrate of the monitor to match the framerate of the movie playing.
Smoothvideo adjusts the fps of the movie to play at a rate that is exactly matched to the refreshrate, it should be a very good combination with "Adjust refreshrate", I can't test it though, so I hope the refreshrate is detected correctly (you might have to restart the movie).

I've got this option on my card but never knew what it did or if it even helps XBMC. Hopefully get a chance to try this out later.

Usually you have two buffers with opengl, on one you draw everything and the other is what the user sees, triple buffering adds a third buffer, this increases performance when vsync is on at the cost of having a greater delay between drawing and displaying on the screen, which is really only an issue for games.

Yes i turned it on. Except i have costom modelines in my xorg.conf with 23.98hz. If is set it to this refresh rate, the fps is arround this value but with a little variation. Shouldn' it be fixed to this fps with no change at all ? Shouldn't the a/v time difference number be 0 all the time ?

I found this resampler if you are interested. This is the one they use for winows Reclock also.

libsamplerate
http://www.mega-nerd.com/SRC/

I think you have an old revision that doesn't sync the fps to the refreshrate yet, so the gui option is only an option with no logic behind it (I hope you enjoyed the placebo effect ).

[alanwww1]

I think you have an old revision that doesn't sync the fps to the refreshrate yet, so the gui option is only an option with no logic behind it (I hope you enjoyed the placebo effect ).

:-) No actualy i have a very good eye on this. My wife always says she doesn't see any difference and i make her mad with all the tuning of the sytem :-))

with fresh svn18062 revision i get a missing library called libsamplerate. Where can i get that ?

TIA

Edit: Sorry I found it: it is called libsamplerate0 and libsamplerate0-dev

[Nazgulled]

For smoothvideo to work you need vsync, it relies on it heavily.
I don't have an option called "adjust video framerate", do you mean "Adjust refreshrate" ? That changes the refreshrate of the monitor to match the framerate of the movie playing.
Smoothvideo adjusts the fps of the movie to play at a rate that is exactly matched to the refreshrate, it should be a very good combination with "Adjust refreshrate", I can't test it though, so I hope the refreshrate is detected correctly (you might have to restart the movie).

Yes, sorry, I mean "adjust refreshrate". I'm not at my XBMC box at the moment and I couldn't remember the proper string.

Still, isn't the "adjust refreshrate" feature supposed to fix all the issues with smooth playback? I mean, as far as I look at it, we shouldn't be needing what you are trying to implement as long as we have "adjust refreshrate", but maybe I'm missing something here?

Anyway, should I turn v-sync on the OpenGL settings of my graphic card drivers or on the XBMC settings? And if I turn v-sync on (either on XBMC, or OpenGL settings), I should turn triple buffer on too, right? That's really what I want to know, what turn on and where.

[alanwww1]

Still, isn't the "adjust refreshrate" feature supposed to fix all the issues with smooth playback? I mean, as far as I look at it, we shouldn't be needing what you are trying to implement as long as we have "adjust refreshrate", but maybe I'm missing something here?

Setting the refresh rate "near" your fps is not enough, becuase it is only near the same, but because your audio hardware and video hardware running to a different clock and/or the movie audio was encoded to a certain fps, xbmc always has to resync your video to audio unless you will be out of sync with the two. And this is the point where you can have dropped frames. On windows it is also a problem. There is a great directshow filter called reclock where this is explained very well why it is necesarry:

http://forum.slysoft.com/showthread.php?t=19931

[bobo1on1]

I found this resampler if you are interested. This is the one they use for winows Reclock also.

libsamplerate
http://www.mega-nerd.com/SRC/

with fresh svn18062 revision i get a missing library called libsamplerate. Where can i get that ?

LOL

Anyway, should I turn v-sync on the OpenGL settings of my graphic card drivers or on the XBMC settings? And if I turn v-sync on (either on XBMC, or OpenGL settings), I should turn triple buffer on too, right? That's really what I want to know, what turn on and where.

I'm not really into the vsync quirks people have mentioned, but I think turning both triple buffering and vsync on in the driver should be fine, probably can't hurt to turn it on in xbmc as well.

[PolliSoft]

Here is a fresh build of the latest (Rev18065) version of the smoothvideo branch. I cannot tell which linuxbranch version it is based on, maybe bobo1on1 can tell?
I havn't tested it myself, so if you have any problems, please contact bobo.

edit by bobo1on1: Post any problems in the thread, I'm not supporting an untested windows build.

http://www.megaupload.com/?d=K803FMQ0

[bobo1on1]

It's based on linuxport revision 17926.

[Nazgulled]

One last thing...

The audio thread should check how far off sync it is, and resample the audio so it will play faster/slower to keep the audio in sync with the video.

Won't this change the audio pitch?

[ArtVandelae]

Won't this change the audio pitch?

Not necessarily. Pitch changes are only audible when there is a change of more then about 0.35%. The tiny changes needed to compensate for the discrepancy between the video and audio clocks, provided the display refresh rate is reasonably close to the video frame rate, shouldn't even come close to this amount. For example, if you are running a 59.94fps video on a display that is running at exactly 60.0hz the change is only 0.1%. Now, if you are resampling by a large amount in the case of converting a 25fps PAL video to 24fps, which is a full 4% change, then, yes, there will be an audible difference.