[mythtv-users] Modern ION replacement?

Paul Gardiner lists at glidos.net
Wed May 14 17:58:00 UTC 2014


On 14/05/2014 18:04, Preston Crow wrote:
> On 05/14/2014 12:15 PM, Jean-Yves Avenard wrote:
>> On 15 May 2014 02:09, John Morris <jmorris at beau.org> wrote:
>>
>>> designed so you want it to go out exactly as transmitted.  It will look
>>> perfect.  Assuming the set can also do 720p60 you would want Myth to
>>> switch modes and to also display that mode unretouched.
>> unfortunately, the automatic refresh rate selection will always favour
>> playing at 60p rather than 60i as there's also no way to detect of a
>> modeline is interlaced or not with plain xrandr.
>> so if your set can do 60p and you attempt to play 60i, the refresh
>> rate will be set to 60p.
>> you would have to disable 60p completely from the list of modelines
>> and only have 60i for that refresh rate to be selected.
>>
>> Having said that, it's not quite true what you said that you don't
>> want mythtv to do anything. If you just output the signal as-is, you
>> have 50% chance of your TV getting it wrong.
>> Hence why Paul suggested the "Interlaced 2X" deinterlacer, it's
>> specifically designed for this case, and ensure that it doesn't matter
>> if you sync on odd or even field.
> The TV is able to sync correctly to a real broadcast, so it should be
> able to sync correctly to a signal from a computer.

It's not that synchronisation that causes problems. The problem is
ensuring that the decoded images are written to the display memory at
the correct time. The software doing this sees two sync signals per
frame. If it picks the wrong one, the interlaces get reordered which
looks awful.

It's conceivable that this problem doesn't occur on some graphics cards,
so it may be worth trying without any deinterlacer, but if you see your
video playing fine half the time and looking awful the other half, then
Interlaced x2 is likely the solution.

Cheers,
	Paul.


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