[mythtv-users] intel 24p (was: nVidia driver 304.88: problems)

[Jean-Yves Avenard]

On 17 April 2013 06:42, George Nassas <gnassas at mac.com> wrote:

>
> [ new title to avoid more thread hijacking ]
>
> On 2013-04-15, at 12:37 AM, Jean-Yves Avenard wrote:
>
> On 15 April 2013 14:25, George Nassas <gnassas at mac.com> wrote:
>
>> Sorry, brief side question: so driving your TV at 24p depends on having
>> an nVidia card? I'm using intel graphics which, of course, doesn't have
>> NVctl and I've been trying to figure out how to get myth to switch to 24p
>> on material encoded that way. Where would I look if I wanted to have a go
>> at using xrandr for intel cards?
>>
>
> Problem  with xrandr is that the frequency rate is stored as a short. So
> you'll have 24, 50, 60 and that's about it.
> NVCtrl allows much finer control: 23.976Hz (US) vs 24.00Hz (PAL), 59.976Hz
> vs 60Hz etc... as what NVCtrl reports is the full ModeLine so you can
> calculate the frequency from there.
>
> But the instructions for getting myth to switch the refresh rate to follow
> the content being played are the same across the board.
> Just that with xrandr only (Intel, AMD and others), miss will use 24Hz no
> matter if the video is 24 or 23.976Hz.
>
>
> I have the correct modeline setup as described in the wiki and it did work
> with my nvidia card but now that I'm on intel myth doesn't switch the
> refresh rate. The playback info for Big Buck Bunny says it's 24Hz and
> xrandr shows 24 as a valid refresh rate but the TV stays at 60Hz. I can
> switch the mode to 24Hz or 23.97 using xrandr and the TV status display
> does show 24p so it's clearly possible to get 24p going.
>
> The modes you put in the wiki all have @xxxHz in their name so I suppose
> one could extend DisplayResX::SwitchToVideoMode to take rates from the
> right of an @ rather than XRR's rate integer and also to switch modes based
> on mode name instead of XRRSetScreenConfigAndRate' integer parameters. That
> would accomplish the same thing as a command line xrandr.
>
> Based on a quick perusal of the source I didn't see a clean way to do this
> so it would probably be ugly and hacky and introduce a new option but,
> should I come up with something, is that something that would be accepted
> into myth as an enhancement?
>

Did you configure myth to change the refresh rate though?
this is all explained in the wiki. You need to set different GUI / Playback
mode, and set the resolution to use (set there the resolution of your
display) and set the refresh rate to "Auto".

If you can change using xrandr, then myth can change, it pretty much does
exactly what xrandr does internally.

the solution you suggest isn't feasible. There's no standard way of
questioning X for the available modelines, and you can't even know then
what the name of the modeline is.
you have to rely on xrandr or NVCtrl on linux to query which modes are
available.

Which is what myth is doing.

Plus parsing the name of a mode given by a user is totally unpractical...
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