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Poser - OFFICIAL F.A.Q (Last Updated: 2025 Jan 27 9:18 am)



Subject: Pixel aspect -> rendering 16:9


botti ( ) posted Tue, 06 March 2001 at 9:52 AM · edited Sun, 26 January 2025 at 1:12 PM

I want to render with poser4 for dvd. So I want to render in 16:9 (pixel aspect ratio = 1.33). But I don't know how I can do 'non-letter-box-rendering' with poser. Is there any way to tweak poser to do that? If not, what can I do? Or is there any option, I don't know? Thnx botti


Robert Belton ( ) posted Tue, 06 March 2001 at 10:06 AM

I haven't tried it to output to a widescreen format BUT if you set the x scale of the camera to 133% it squeezes the image so on playback on a widescreen system it should be unsqueezed to normal on a widescreen moniter. just like anamorphic lenses in movie making. worth a test prehaps.


botti ( ) posted Tue, 06 March 2001 at 1:11 PM

Thanks, Robert! botti


petercat ( ) posted Tue, 06 March 2001 at 3:46 PM

Hmm, but I think the squeezing is just a visual effect -- the pixels are still square, not rectangular as used by DV. So if it's stretched out in conversion, you'll end up with less resolution. It's a hardware issue... computer pixels are square, video pixels are rectangular (0.888:1 pixel aspect ratio). I know for DV tape the frame resolution is 720 by 480. This is for non-letterboxed, 4:3 frame aspect ratio video; on a TV screen the 720 pixels are squeezed into the same width 640 pixels occupy on a computer screen of identical size. So you'd still need to render at 720 to avoid losing horizontal resolution. I would try setting the camera X scale to 88.88%, rendering at 720 by 480, saving as an uncompressed QuickTime movie, and using QuickTime Pro to convert the result to DV Stream format. (N.B. I know this would work on Mac, and presume QuickTime Pro for Windows can do the same conversion.) On a computer screen, the frame would look stretched, but once converted to video it would look normal. For real widescreen, find out what resolution is needed (in pixels) and render to that resolution. You'll have to figure out a compensation for the camera X scale, based on the aspect ratio of the pixel, not the frame. It may look stretched out on a computer monitor, but on DVD it should be correct.


Robert Belton ( ) posted Wed, 07 March 2001 at 3:58 AM

Well yes the pixels are still square. And yes you'd lose horizontal resolution. My idea is based around the prefered solution for widescreen in low-end DV cameras that do not have true 16:9 but a kludge that looks good enough for the home user. Here the wisdom is you use an anamorphic adapter on the taking lense and record 4:3. Playback on widescreen looks correct with less resolution loss than using the cameras widescreen feature. But I like the sound of rendering to a widescreen frame and compensating for the pixels aspect ratio. As this should give you the best resolution possible, restoring the horizontal ratio lost in my previous kludge. I'd love to test it. Its the sort of thing I'm interested in but as yet don't have access to widescreen moniters. What I tend to do is either full screen or letterboxed. As a side issue for botti. Will a viewer without widescreen be able to see your production in a letterbox? I have one DVD myself (Ghost in the Shell) that's anamorphic widescreen and won't letterbox in 3:4 so on my computer I have to play with the moniter display to get a more true rendition of it. Bear in mind that most people in a potential audience are probably still using 3:4 TV sets. (Although thats changing ) Mind you I've seen people watching 3;4 programmes stretched out to 16:9 (everyone short and fat) and a video store playing back a DVD letterboxed but stretched on a widescreen moniter (very thin band of picture!). Sometimes I wonder what the punter really notices. (My day job is camera and lighting so I suppose I tend to overlook the possibilities of postproduction in favour of physical solutions on set. That's my story and I'm sticking to it ;-)


botti ( ) posted Fri, 09 March 2001 at 3:13 AM

I'm a bit confused... Because when I export an image with our video editing system (FAST Silver, comparable to Avid or Media100 systems) from a 16:9 movie (not letterboxed), it looks exactly like my results in Poser, I think -> 720x576 (PAL). So is there really a loss in horizontal resolution if the movie is made for 16:9 TV's only? Maybe I misunderstood your last two posts, but you are talking about viewing the movie on a device that's not a 16:9 TV, right? How can I avoid this problem you mentioned when working with Poser4 (and Digital Fusion)? Thanks for your posts! You really helped me, but can you please explain to me what you're thinking of exactly? Maybe the problem is my only middle-class, school-learned English.


Robert Belton ( ) posted Fri, 09 March 2001 at 7:43 AM

Oops! Sorry to confuse you rather than help solve your problem. Resolution issues. The logic seems to be that there are more pixels horizontaly in a widescreen picture. ie more sample points. Therefore rendering squeezed to a 4:3 frame means you are using less sample points than the maximum available for display and therefore getting slightly less resolution. (I think this loss is much more acceptable than a loss of vertical resolution you'd get rendering to a letterbox and zooming it in hardware.). (However I'm not sure if the extra pixels are in the current widescreen display technology with DVD and if what you get on a widescreen DVD isn't just a 4:3 anamorphic image being stretched out to fill the screen) As a solution this "anamorphic" technique has the virtue of being relativly quick and simple. If it works and you like the results -- just get on with the more important things like story, good sound, interesting pictures. ;-). As I said before I don't work in widescreen. So I don't have much to say about the non square pixels thing or how the image works on a widescreen TV. I'll think about it, do a bit of research and ask the video engineer at work and see if I can come up with anything. However in the end it'll come down to a) how and what the end device can display and more importantly b) what quality/resolution the user can notice (different from maximum available resolution.) Widescreen on 4:3 sets I believe the way 16:9 works on DVD is there is an anamorphic version for those that have 16:9 sets and a letterboxed version for those that don't. You set up your home equipment to view the appropriate version. The audio tracks are common to both versions and don't have to be saved twice. I would assume that this would be set up in the DVD authoring program. Since my proposed solution squeezes a widescreen image to a standard frame and relies on the 16:9 hardware to unsqueeze it, the picture will remain squeezed (tall and thin) on a normal 4:3 set. Is this a problem? Maybe not. If you have a known audience with specific hardware you just make the widescreen version for them and not worry about people watching it on 4:3 sets. But if the audience is supposed to be more general, I think you should test your disk on a 4:3 set. Then, if needs be, try to make it work there too. There's lots of room on a DVD maybe you could have three versions -- 16:9 anamorphic, letterboxed 16:9, and full screen 4:3. Depends how long the film is I guess and means extra rendering. DV.com has an article about mastering to multiple formats for TV at http://www.dv.com/magazine/1999/0899/hdtv0899.pdf Interesting site and magazine if you're interested in digital video. I'm not sure if I've made anything clearer ;-( Its a complex area not made any easier by shifting stanards and new technologies coming out every month. Exciting though in what individuals can now make! When I were a lad it was much easier; we just had bits of film , everything was physical -- you could touch it. But no-one could afford to make movies at home in the way I can now with my Mac.


botti ( ) posted Fri, 09 March 2001 at 9:44 AM

Thanks again! I'm just downloading the pdf. Hmm, I think what you say about providing different versions for different output-devices/viewers really makes sense. What do you think: Could it be ok to work fully in 16:9 anamorphic and after everything is finished just scale/stretch the movie to get the other versions? It's clear that therefore in 4:3 fullscreen the screen layout should stay well-positioned. I'm just talking about the change of the pure image quality. There will be no extremely total shots with many details. So could the quality-loss be tolerated? Or would you recommend to render every version in it's own size. By the way, the animation will be about 2,5 minutes. OK, I know you can hardly generalize this, but I'm interested about your opinion/experience. Another question: It's not possible to render fields in Poser4, right? And because ProPack german is not yet released, I even can't render with motion blur, directly. At the moment I'm using Digital Fusion to make motion blur manually by blending 3 times the same clip each 1 frame delayed with different transparency settings. It works Ok but I think that there must be programs/plugins or whatever that have better results. Can you recommend me anything? I heard that Reelsmart Blur works very well. Any opinions/tips?


Robert Belton ( ) posted Fri, 09 March 2001 at 12:20 PM

Multiple versions. Real world logic for live action is shoot in 16:9 and take care to frame the important action centrally for 4:3. Then cut off the sides for 4:3 transmission. An example of this is Stargate SG1, in full screen 4:3 on C4 in the UK (with a different title sequence) but a very nice 16:9 on DVD. I don't see why resizing the anamorphic version shouldn't work. The 4:3 should be about the same resolution but with the sides cut off and the letterbox would have the same horizontal res but resampled vertical res, but as you're downsampling it'll be OK I think. I'd say try some test frames and see what you get. Best quality would be seperate renderings. One squeezed and one full frame height but widescreen proportions, then crop this one for 3:4 and reduce it with black bars for letterbox. At 2.5 mins (3750 frames at 25fps) it seems possible. (The hard bit is the animation -- the rendering usually just needs time and processing power) No field renders in Poser that I've found. but two things to consider here. Classical animation shot on film is usually 2 frames per cell for most things maybe going to 1 frame a cell for fast motion to smooth it a bit. (now only 1875 different frames for 2.5 mins, on a ninety minute feature this really mounts up.) Apparently the information on DVD disks is at 24 frames non interlaced. The hardware sorts out how it should send it to the TV. (source -- Quantel Digital Fact Book Edition 9). (How region 0 disks can work I suppose). So for DVD-video field rendering doesn't seem to make sense. (3600 frames at 24fps for 2.5 mins) Motion Blur. Can't recommend anything myself. It seems something that sanely should be handled as a post-rendering process via a plug-in. It'd be best to blur only those items moving and the amount of blur depending on the speed of movement across the frame. Maybe you should post a request for motion blur help as a seperate topic here or in the 3D forum. Other Words of Wisdom. Don't underestimate sound. It can have a huge impact on the percieved quality of your project but often gets forgotten in favour of the visuals.


Robert Belton ( ) posted Sat, 10 March 2001 at 7:10 AM

Sorry to be writing so much on this, but its been bugging me and Ie found the research useful. After doing some reading and looking at edit programs Ie found this out about pixel ratios Computers have square pixels. CCIR601 video has rectangular ixelsPAL 625/50 576 active lines / 702 viewable samples x 3/4 screen aspect = 1:1.094 (approx 10% wider than tall) NTSC 525/60 486/711 x 3/4 = 1:0.911 (approx 10% taller than wide pixels) (viewable samples allows for blanking signal.) 601 video has no extra pixels for widescreen, therefore anamorphic widescreen is the best you can get. Widescreen TVs stretch the picture out. With digital and high definition standards there will be extra pixels for widescreen. (and hopefully a global standard) So why does pixel aspect ratio matter? If youe using live footage without DVE and going back out to the same system it doesn really. At worst the pictures may be slightly distorted while viewed on the computer. If youe producing computer graphics to go to video you have to compensate to maintain true geometry in the graphics when theye output. In professional use, everything is checked on a video moniter anyhow. Therefore from what I understand to get (PAL) widescreen from Poser you can compensate in poser by putting the camera x-scale to 133% and render to 576 x 768 (PAL fullscreen) or you can render in poser to 576 x 1024 (PAL square pixel 16:9) and compensate in the edit software for pixel aspect ratio. The Digital Factbook is available free from Quantel. (www.quantel.com) The10th edition is out in June and will also have an online version. www.terran.com also has good resources on codecs and architectures for web based video, Quicktime etc.


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