Steve, Don't mind the debate at all...
480 x 360 figure came from a 4:3 aspect ratio of useable screen realestate, it's just factor of the 320x240 reality on the iPod. I will test the aspect ratios you suggest below using mp4 and report back. Agreed, that DV is a non-square pixel format (as opposed to the screencasts I referenced which were made with Snapz using a square 3:2) but in the NTSC world it is a 3:2 aspect ratio. The ratio of height to width is 66.7% for 720x480. Now, PAL DV is a 5:4 aspect ratio at 720x576. So what's going on is constraining (Chris Bevan has a neat little web app: http:// chrisbevan.com/projects/podsize#c that demonstrates this). When you contrain DV NTSC within it's native aspect ratio of 3:2 (a square version would be 720x540 which is 4:3 no contraining necessary as that factors down to 320x240) by taking the width down from 720 to 320 and multiplying by .667 you contrain the height (letterbox) to 213. Now, all this does really split hairs on a device that sits well in the palm of your hand and unless your pie charts are looking like egg charts, it really is hard to tell. Thank you for helping clarify this as it's so easy to get consumed in the gobbledeegook...I know I've been struggling with writing an Animator Action all day. BG --- In [email protected], "Steve Watkins" <[EMAIL PROTECTED]> wrote: > > Cheers and welcome, that is good info, thanks for sharing :) > > Hope you dont mind if I debate 2 points you made. > > Maximim mpeg4 res for ipod is stated by Apple to be 480x480, and it > seems the limit is actually in terms of pixels, you are allowed 230400 > pixels. So resolutions like the following should be supported: > > res aspect ratio > 720 x 304 - 2.35:1 > 624 x 336 - 1.85:1 > 624 x 352 - 16:9 > 512 x 384 - 4:3 > > (I havent actually had time to try these resolutions myself yet though) > > The second point is aspect ratios, regarding the way quicktime resizes > DV footage. We had a discussion on this a few weeks ago, and I was all > wrong and confused for a while. The mistake I (and it seems Apple) > made is to forget that DV doesnt use square pixels. So even though the > horizontal res of DV is 720, thats for rectangular pixels, and the > actual res when displayed using square pixels should be somethign > higher like 768. Anyway this makes Apples resizing maths wrong with > the export to ipod option, and the footage ends up at the wrong aspect > ratio. DV isnt 3:2. But then Im not so good at explaining this because > Im in a PAL part of the world where our DV res is a bit different to > yours, higher vertical resolution (but lower framerate). > > Anyway this page probably makes more sense than me, again it is > dealing with PAL rather than NTSC but the square vs rectangular pixels > issue is the same, just slightly different numbers: > > http://tinyurl.com/7m9ul > > So based on that sort of theory, we were assuming that Apple made a > mistake, NTSC DV footage shouldnt be resized to 320x213, but 320x240. > And therefore best to avoid the 'export to ipod' option in qt703, and > do it the more long-winded way so you can control the resolution > yourself. Though to be honest I think a lot of people are still > avoiding h264 for other compatibility (& encoding time) reasons so > they arent using that option anyway. > > Cheers > > Steve of Elbows > > --- In [email protected], "flyingchaucer" <[EMAIL PROTECTED]> > wrote: > > > > I've done some fairly extensive tests on getting video to play on > the new 5G iPods and > > here is as summary: > > > > > > Max Frame Size: 480 x 360 (Note the iPod will scale down to 320 x > 240 for playback on > > the screen, but will scale up on output to a TV via the cable adapter. > > > > Max Frame Rate: 30 > > > > Max Frame Size: 320 x 240. This is a 4:3 ratio. Lots of users are > shooting DV, that is a 3:2 > > aspect ratio so what's going to happen when you encode DV movies is > that it will be > > letterboxed on the iPod because the movie will encode to 320 x 213. > The letterboxing is > > slight so you probably won't really notice it. Now if you shot > anamorphic (16:9) then the > > letterboxing will be more aggressive--320 x 180 and that gets a > little rough to watch. > > > > Hope this helps, and I'm happy to be a new member of the group. > > BG > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get Bzzzy! (real tools to help you find a job). Welcome to the Sweet Life. http://us.click.yahoo.com/A77XvD/vlQLAA/TtwFAA/lBLqlB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/videoblogging/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
