RE: [backstage] Why are iPlayer SD programmes encoded at funky resolutions?
I had wondered about this myself a while ago. So use to the underground scene of resolutions, it always seems strange when looking at others methods of distribution's choice of rez. Although I think Brian might be right about the aspect ratio Secret[] Private[x] Public[] Ian Forrester Senior Backstage Producer BBC RD North Lab, 1st Floor Office, OB Base, New Broadcasting House, Oxford Road, Manchester, M60 1SJ From: owner-backst...@lists.bbc.co.uk [mailto:owner-backst...@lists.bbc.co.uk] On Behalf Of Brian Butterworth Sent: 29 March 2010 08:38 To: backstage@lists.bbc.co.uk Subject: Re: [backstage] Why are iPlayer SD programmes encoded at funky resolutions? Isn't it because of the difference in pixel shapes between TVs and monitors? On TV, 16:9 in 720x576 the pixels are 1:1.89, on a computer monitor the pixels are 1:1. 832x468 is therefore the profile nearest the desired output of 1:1.89? http://www.ukfree.tv/fullstory.php?storyid=1107051225 On 29 March 2010 01:19, Christopher Woods chris...@infinitus.co.uk wrote: I've noticed for a while that the HQ iPlayer stuff (not the HD) is encoded at 832x468. (recent example: Australian F1, or pretty much every single high quality iPlayer video you look at). No complaints about the actual PQ, just really curious as to the technical decisions that led to this target output res. Is it some convoluted compromise to do with broadcast Pixel Aspect Ratios and square pixel conversion for H.264 encode or is there some other reason? Part of me always gets angsty not seeing 720x404 as the resolution if I measure whatever I'm watching ;) All insight appreciated... - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/ -- Brian Butterworth follow me on twitter: http://twitter.com/briantist web: http://www.ukfree.tv - independent digital television and switchover advice, since 2002
RE: [backstage] Why are iPlayer SD programmes encoded at funky resolutions?
What bothers me is whether it's actually the most efficient way of encoding - does the equipment doing the capture have the ability to extract the true square pixel 'quality' from the nonsquare 'broadcast' pixels, thus resulting in a dimensionally larger, but equal quality, video... Or is the quality still being lost because the the encoder can't actually transcode the full quality and ends up extrapolating interpixel data? If the latter is true (which I hope it's not), if the dimensions are mostly due to legacy and there's no real advantage to be gained, is there still an argument against encoding at a smaller WxH resolution (e.g., 720x404) which might make better use of the available bits? (thinking aloud again) _ From: owner-backst...@lists.bbc.co.uk [mailto:owner-backst...@lists.bbc.co.uk] On Behalf Of Ian Forrester Sent: 30 March 2010 11:24 To: backstage@lists.bbc.co.uk Subject: RE: [backstage] Why are iPlayer SD programmes encoded at funky resolutions? I had wondered about this myself a while ago. So use to the underground scene of resolutions, it always seems strange when looking at others methods of distribution's choice of rez. Although I think Brian might be right about the aspect ratio Secret[] Private[x] Public[] Ian Forrester Senior Backstage Producer BBC RD North Lab, 1st Floor Office, OB Base, New Broadcasting House, Oxford Road, Manchester, M60 1SJ _ From: owner-backst...@lists.bbc.co.uk [mailto:owner-backst...@lists.bbc.co.uk] On Behalf Of Brian Butterworth Sent: 29 March 2010 08:38 To: backstage@lists.bbc.co.uk Subject: Re: [backstage] Why are iPlayer SD programmes encoded at funky resolutions? Isn't it because of the difference in pixel shapes between TVs and monitors? On TV, 16:9 in 720x576 the pixels are 1:1.89, on a computer monitor the pixels are 1:1. 832x468 is therefore the profile nearest the desired output of 1:1.89? http://www.ukfree.tv/fullstory.php?storyid=1107051225 On 29 March 2010 01:19, Christopher Woods chris...@infinitus.co.uk wrote: I've noticed for a while that the HQ iPlayer stuff (not the HD) is encoded at 832x468. (recent example: Australian F1, or pretty much every single high quality iPlayer video you look at). No complaints about the actual PQ, just really curious as to the technical decisions that led to this target output res. Is it some convoluted compromise to do with broadcast Pixel Aspect Ratios and square pixel conversion for H.264 encode or is there some other reason? Part of me always gets angsty not seeing 720x404 as the resolution if I measure whatever I'm watching ;) All insight appreciated... - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/ -- Brian Butterworth follow me on twitter: http://twitter.com/briantist web: http://www.ukfree.tv - independent digital television and switchover advice, since 2002
Re: [backstage] Why are iPlayer SD programmes encoded at funky resolutions?
On 29-Mar-2010, at 01:19, Christopher Woods wrote: I've noticed for a while that the HQ iPlayer stuff (not the HD) is encoded at 832x468. (recent example: Australian F1, or pretty much every single high quality iPlayer video you look at). No complaints about the actual PQ, just really curious as to the technical decisions that led to this target output res. Not 100% sure, but I have a feeling it’s down to the dimensions of the bbc.co.uk site design. M. - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
Re: [backstage] Why are iPlayer SD programmes encoded at funky resolutions?
Isn't it because of the difference in pixel shapes between TVs and monitors? On TV, 16:9 in 720x576 the pixels are 1:1.89, on a computer monitor the pixels are 1:1. 832x468 is therefore the profile nearest the desired output of 1:1.89? http://www.ukfree.tv/fullstory.php?storyid=1107051225 On 29 March 2010 01:19, Christopher Woods chris...@infinitus.co.uk wrote: I've noticed for a while that the HQ iPlayer stuff (not the HD) is encoded at 832x468. (recent example: Australian F1, or pretty much every single high quality iPlayer video you look at). No complaints about the actual PQ, just really curious as to the technical decisions that led to this target output res. Is it some convoluted compromise to do with broadcast Pixel Aspect Ratios and square pixel conversion for H.264 encode or is there some other reason? Part of me always gets angsty not seeing 720x404 as the resolution if I measure whatever I'm watching ;) All insight appreciated... - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/ -- Brian Butterworth follow me on twitter: http://twitter.com/briantist web: http://www.ukfree.tv - independent digital television and switchover advice, since 2002
