RFC: Xv field order
khc at pm.waw.pl
Tue Jun 23 08:50:39 PDT 2009
Thomas Hilber <xorg at toh.cx> writes:
> with a slight modification the patches can output BFF or TFF.
> But I'm living in PAL land so I use TFF only ATM.
I'm here as well but I routinely use PAL MPEG2 (DVD) with BFF encoding
(originating as DV which is always BFF, I could of course shift the
audio and reverse fields but it creates some minor additional problems).
>> going to implement is the BFF/TFF(/progressive) interface at XVideo and
> what do you mean with progressive here? Do you mean 2 interlaced
> fields in weaved format?
Progressive video playback on interlaced display. This means the driver
is free to sync to either field (for example, to the previously selected
> The vga-sync-fields patches effectively use these 2 weaved fields of
> softdecoder output and forward these directly to VGA/DVI output. To keep
> synchronicity between stream and video timing the output line frequency
> is continuously trimmed in very small steps. This works very well even
> for live-TV where you must adopt exactly the stream clock delivered by
> the TV station.
Right. This is well beyond my needs.
>> DRM level. Unless I'm mistaken the patches don't touch the field order
>> and sync, at least on the intel and/or i915 driver.
> moving the sync point by 20ms yields in reversed field order output
Ah... But there is a simple interrupt-based way. And it doesn't depend
on the timings, the card signals end of each field. You may want to see
intelfb for details, I was using fb because the X playback was unusable.
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