[mythtv-users] MacOSX frontend & 1080i
gallatin at cs.duke.edu
Thu Mar 15 15:31:43 UTC 2007
Andrew Kimpton [awk at awkward.org] wrote:
> Todd Ignasiak wrote:
> > On 3/13/07, Andrew Gallatin <gallatin at cs.duke.edu> wrote:
> >>> Also, I doubt the LCD is being run at 150Hz, where does Myth show
> >>> that? I think LCDs are set to 60Hz by default, although it's hard to
> >>> tell for sure. I installed SwitchResX control panel & output the DDC
> >>> data for the display, and it showed it was running 1440x900 @ 60Hz.
> >> It is reported (for me) when using -v playback:
> >> 2007-03-12 09:52:04.014 VideoOutputQuartz::GetRefreshRate() [returning 150]
> > Hmm,. I grep'd my log for that, and it is also returning150. So, I
> > looked in videoout_quartz.cpp, and it looks like 150 is the value it
> > uses if it doesn't get a valid refresh rate:
> > // Find the refresh rate of our screen
> > CFDictionaryRef m;
> > m = CGDisplayCurrentMode(data->screen);
> > data->refreshRate = get_float_CF(m, kCGDisplayRefreshRate);
> > if (data->refreshRate == 0.0) // LCD display?
> > data->refreshRate = 150.0; // Divisible by 25Hz and 30Hz
> > // to
> > minimise AV sync waiting
> > I'm not sure how that effects playback, but it seems to be the
> > expected behavior for LCDs, and playback is okay on mine. So, I would
> > guess this is not the issue.
> I agree - it's not entirely clear what the intent of that 'magic value'
> is. Remember though that this is only used when CoreGraphics doesn't
> return a rate - and that only happens for devices such as notebooks and
> the iMac which have an integral display panel with an entirely digital
> connection between graphics adaptor and panel. For external LCD Displays
> connected through a VGA connection kCGDisplayRefreshRate is 'spoofed' to
> being 60 Hz.
> I think (from dim memory of practical experiments) that changing that
> 150 value to 60 makes no difference - in fact it may make so little
> difference that Andrew G's problems won't go away either. But it might
> be worth a shot for someone to change it and repeat the build.
For what it is worth, I changed it from 150 to 60, and my problems
went away and I have smooth playback for 1080i. Perhaps 150 is
violating some other assumption which Myth is making?
More information about the mythtv-users