[mythtv-users] Modern ION replacement?

[Paul Gardiner]

On 15 May 2014 20:26:04 GMT+01:00, John Morris <jmorris at beau.org> wrote:
>On Wed, 2014-05-14 at 18:58 +0100, Paul Gardiner wrote:
>
>> 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.
>
>If the hardware/driver/Myth/whatever can't detect the difference
>between
>fields and frames then it is obviously broken and you are right that
>doing the deinterlace in software would be the only option.

That's not quite it. Using the Interlaced x2 option isn't "doing the deinterlacing in software" Interlaced x2 isn't really a deinterlacer. What it has in common with a deinterlacer is that it takes frames in at one rate and outputs frames at twice that rate. Also it fits into MythTV exactly where a deinterlacer would fit, but the frames it produces aren't deinterlaced.  Half the frames that are output are identical to those coming in. The other half are just recombination of the scan lines. The purpose is purely synchronization. Unlike a deinterlacer, there are no artifacts. The results are perfect.

Also it's not that the hardware is broken. I'd agree that something is broken, but I think it's the defined behavior of X that syncs are signalled on every field, although possibly nvidia have a workaround for this now.