Hi all,
Does Gem (or OpenGL in general) have any support for interlaced output? The extra temporal resolution would be nice when rendering for display on a TV, as the spatial resolution would suck anyway.
Here's an IRC log from #dataflow :
09:56 < ClaudiusMaximus> anyone got any tips for generating interlaced video in Gem? i think i need to set the gemwin to 2x the framerate and 1/2x the vertical resolution, and do some small vertical translations up/down depending on which field is the current one 09:56 < ClaudiusMaximus> it's the last step that i'm not sure exactly how to do 09:57 < ClaudiusMaximus> rather i know how, but just not what values i should put in.. 10:29 < rdz> ClaudiusMaximus, i once thought about the same.. 10:29 < rdz> ClaudiusMaximus, actually it would suffice to have only half of the vertical resolution (the scan lines) 10:30 < ClaudiusMaximus> rdz: i'm not sure, because the different fields are displayed at slightly different vertical positions.. 10:30 < rdz> ClaudiusMaximus, yeah exactly.. 10:30 < rdz> ClaudiusMaximus, this could be accomplished by shifting half a line 10:32 < ClaudiusMaximus> rdz: what about OpenGL line widths being measured in pixels? wouldn't that cause problems like "fat horizontal lines"? 10:35 < rdz> ClaudiusMaximus, sorry.. i didn't understandyour last line 10:35 < rdz> what do you mean by fat lines? 10:36 < ClaudiusMaximus> rdz: well, if you do "draw line, width 1" you get a 1pixel line, right 10:36 < rdz> yeah 10:36 < rdz> understood 10:36 < ClaudiusMaximus> and 1pixel at half the vertical resolution is 2x as fat as 1pixel at the full horizontal resolution 10:36 < rdz> hm... 10:36 < rdz> yo........ 10:36 < rdz> seems like there should be native support for that in gem/openGL 10:38 < ClaudiusMaximus> i'm currently leaning towards rendering 720x576 @ 50fps and using a field-aware downscaler 10:39 < ClaudiusMaximus> especially as i want to blur everything slightly to avoid horrible compression artifacts 10:39 * ClaudiusMaximus been reading this page http://www.adamwilt.com/Tidbits.html#CGs 10:40 < rdz> ClaudiusMaximus, are you producing for tv ? ;-) 10:40 < ClaudiusMaximus> rdz: well, i want to make any dvds i produce look better than they do currently... 10:40 < rdz> ClaudiusMaximus, i see 10:40 < ClaudiusMaximus> rdz: so that's a sorta-yes ;) 10:40 < rdz> ClaudiusMaximus, have you already asked gem-dev about it? 10:41 < rdz> ClaudiusMaximus, interlaced 3d renderings....... sounds very promising... 10:41 < rdz> i'd love to see a way to be able to do that 10:41 < ClaudiusMaximus> rdz: not yet, will post something today I think
Thanks,
Claude
Claude Heiland-Allen a écrit :
Hi all,
Does Gem (or OpenGL in general) have any support for interlaced output? The extra temporal resolution would be nice when rendering for display on a TV, as the spatial resolution would suck anyway.
I think rendering at 50fps on the TV out should do that.
if you want to make a DVD, the best is probably to have a 50fps movie. then, you should be able to downgrade the quality to 25i with a good DVD authoring software.
cyrille
Here's an IRC log from #dataflow :
09:56 < ClaudiusMaximus> anyone got any tips for generating interlaced video in Gem? i think i need to set the gemwin to 2x the framerate and 1/2x the vertical resolution, and do some small vertical translations up/down depending on which field is the current one 09:56 < ClaudiusMaximus> it's the last step that i'm not sure exactly how to do 09:57 < ClaudiusMaximus> rather i know how, but just not what values i should put in.. 10:29 < rdz> ClaudiusMaximus, i once thought about the same.. 10:29 < rdz> ClaudiusMaximus, actually it would suffice to have only half of the vertical resolution (the scan lines) 10:30 < ClaudiusMaximus> rdz: i'm not sure, because the different fields are displayed at slightly different vertical positions.. 10:30 < rdz> ClaudiusMaximus, yeah exactly.. 10:30 < rdz> ClaudiusMaximus, this could be accomplished by shifting half a line 10:32 < ClaudiusMaximus> rdz: what about OpenGL line widths being measured in pixels? wouldn't that cause problems like "fat horizontal lines"? 10:35 < rdz> ClaudiusMaximus, sorry.. i didn't understandyour last line 10:35 < rdz> what do you mean by fat lines? 10:36 < ClaudiusMaximus> rdz: well, if you do "draw line, width 1" you get a 1pixel line, right 10:36 < rdz> yeah 10:36 < rdz> understood 10:36 < ClaudiusMaximus> and 1pixel at half the vertical resolution is 2x as fat as 1pixel at the full horizontal resolution 10:36 < rdz> hm... 10:36 < rdz> yo........ 10:36 < rdz> seems like there should be native support for that in gem/openGL 10:38 < ClaudiusMaximus> i'm currently leaning towards rendering 720x576 @ 50fps and using a field-aware downscaler 10:39 < ClaudiusMaximus> especially as i want to blur everything slightly to avoid horrible compression artifacts 10:39 * ClaudiusMaximus been reading this page http://www.adamwilt.com/Tidbits.html#CGs 10:40 < rdz> ClaudiusMaximus, are you producing for tv ? ;-) 10:40 < ClaudiusMaximus> rdz: well, i want to make any dvds i produce look better than they do currently... 10:40 < rdz> ClaudiusMaximus, i see 10:40 < ClaudiusMaximus> rdz: so that's a sorta-yes ;) 10:40 < rdz> ClaudiusMaximus, have you already asked gem-dev about it? 10:41 < rdz> ClaudiusMaximus, interlaced 3d renderings....... sounds very promising... 10:41 < rdz> i'd love to see a way to be able to do that 10:41 < ClaudiusMaximus> rdz: not yet, will post something today I think
Thanks,
Claude
cyrille henry wrote:
Claude Heiland-Allen a écrit :
Hi all,
Does Gem (or OpenGL in general) have any support for interlaced output? The extra temporal resolution would be nice when rendering for display on a TV, as the spatial resolution would suck anyway.
I think rendering at 50fps on the TV out should do that.
if you want to make a DVD, the best is probably to have a 50fps movie. then, you should be able to downgrade the quality to 25i with a good DVD authoring software.
Any suggestions for such downgrading software? I'm running Linux on a no-budget; links to algorithms would be ok too, so I could implement them myself if no Free tool exists already.
cyrille
Thanks,
Claude
Here's an IRC log from #dataflow :
09:56 < ClaudiusMaximus> anyone got any tips for generating interlaced video in Gem? i think i need to set the gemwin to 2x the framerate and 1/2x the vertical resolution, and do some small vertical translations up/down depending on which field is the current one 09:56 < ClaudiusMaximus> it's the last step that i'm not sure exactly how to do 09:57 < ClaudiusMaximus> rather i know how, but just not what values i should put in.. 10:29 < rdz> ClaudiusMaximus, i once thought about the same.. 10:29 < rdz> ClaudiusMaximus, actually it would suffice to have only half of the vertical resolution (the scan lines) 10:30 < ClaudiusMaximus> rdz: i'm not sure, because the different fields are displayed at slightly different vertical positions.. 10:30 < rdz> ClaudiusMaximus, yeah exactly.. 10:30 < rdz> ClaudiusMaximus, this could be accomplished by shifting half a line 10:32 < ClaudiusMaximus> rdz: what about OpenGL line widths being measured in pixels? wouldn't that cause problems like "fat horizontal lines"? 10:35 < rdz> ClaudiusMaximus, sorry.. i didn't understandyour last line 10:35 < rdz> what do you mean by fat lines? 10:36 < ClaudiusMaximus> rdz: well, if you do "draw line, width 1" you get a 1pixel line, right 10:36 < rdz> yeah 10:36 < rdz> understood 10:36 < ClaudiusMaximus> and 1pixel at half the vertical resolution is 2x as fat as 1pixel at the full horizontal resolution 10:36 < rdz> hm... 10:36 < rdz> yo........ 10:36 < rdz> seems like there should be native support for that in gem/openGL 10:38 < ClaudiusMaximus> i'm currently leaning towards rendering 720x576 @ 50fps and using a field-aware downscaler 10:39 < ClaudiusMaximus> especially as i want to blur everything slightly to avoid horrible compression artifacts 10:39 * ClaudiusMaximus been reading this page http://www.adamwilt.com/Tidbits.html#CGs 10:40 < rdz> ClaudiusMaximus, are you producing for tv ? ;-) 10:40 < ClaudiusMaximus> rdz: well, i want to make any dvds i produce look better than they do currently... 10:40 < rdz> ClaudiusMaximus, i see 10:40 < ClaudiusMaximus> rdz: so that's a sorta-yes ;) 10:40 < rdz> ClaudiusMaximus, have you already asked gem-dev about it? 10:41 < rdz> ClaudiusMaximus, interlaced 3d renderings....... sounds very promising... 10:41 < rdz> i'd love to see a way to be able to do that 10:41 < ClaudiusMaximus> rdz: not yet, will post something today I think
Thanks,
Claude
On Wed, 2008-03-12 at 12:19 +0000, Claude Heiland-Allen wrote:
cyrille henry wrote:
Claude Heiland-Allen a écrit :
Hi all,
Does Gem (or OpenGL in general) have any support for interlaced output? The extra temporal resolution would be nice when rendering for display on a TV, as the spatial resolution would suck anyway.
I think rendering at 50fps on the TV out should do that.
if you want to make a DVD, the best is probably to have a 50fps movie. then, you should be able to downgrade the quality to 25i with a good DVD authoring software.
Any suggestions for such downgrading software? I'm running Linux on a no-budget; links to algorithms would be ok too, so I could implement them myself if no Free tool exists already.
just for the record: while discussing in #dataflow we found a way:
mencoder -vf tinterlace=<0/4> (one of those modes should work)
roman
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Claude Heiland-Allen -
cyrille henry -
Roman Haefeli