Standard timing/modeline for 720p50 1280x720 at 50 Hz 50Hz

[tte at cs.fau.de]

Sorry if this is too inappropriate for this list, but i was hoping to
find the best expert here to help. It's not really about a problem with
Xorg itself, but using it:

I am trying to connect a native 720p projector (PT-AX100E) via HDMI or VGA
to a Linux/Xorg-7.2 PC, but so far i have been un able to produce a modeline
that will make it synchronize with 1280x720 @ 50Hz (720p50). The projector
claims to officially support this resolution, and even lists 74.25 Mhz
for it in the user manual.

The modelines i tried where from various places i found on the Internet
and what i got calculated from online modeline calculators, and they where
all different - as opposed to the modelines for the various ATSC resolution, 
which where pretty close together.

Unfortunately, i do not have a consumer HDMI device that produces 720p50
and with which i could try to see whether the projector manufacturers claim
is actually correct (that it supports this resolution), but i wonder if
there is actually any standard specifying the official resolution details
that a consumer device must support for 720p50. I guess for the US resolutions
this is somewhere in the ATSC standards or similar (correct ?), but where
would i find this for the european 50Hz ? My hope is that i could then 
generate a modeline from this timing and if the projector does not synchronize
to that, then i could reasonably complain to the manufacturer.

Given that the projector shows the same 74.25 Mhz for 50Hz that it lists
also for 60Hz, and given that it also has in paranthesis (750) for both,
i guess that the total number of rows needs to be 750 for both resolutions,
to achieve standard timings, and i tried tat, so maybe it was just the sync
values that xtiming did not compute standards compliant.

And no, the projector does not provide EDID information.

And yes, it would be great to include 720p50 and 1080i80 standard timings
into Xorg itself *grin* Assuming as i do that there is such a thing as
these standard timings.

Thanks
    Toerless