Attached are two screen shots of a 16:9 TV displaying the MGM Logo from a Blu-Ray disk of a 4:3 film.
When the BD Player's DVD aspect ratio is set to 'Letterbox' the 4:3 film frame is expanded [distorted] horizontally and is letterboxed on the 16:9 TV screen 'postage stamp' sized surrounded on all four sides by black bars.
When the BD Player's DVD aspect ratio is set to 'Pan and Scan' the 4:3 film frame is displayed Pillar boxed on the 16:9 screen. Cliff On 1/7/2011 6:52 PM, Manfredi, Albert E wrote:
Ron Economos wrote:No, I'm referring to the IEC-61880 signal in the VBI.Got it. Thanks. It's sent along with CGMS and other odds and ends. So here's the question. Are these IEC 61880 signals generated by the STB as a function of the display aspect ratio entered in the setup step, or are they transmitted independent of that setup step? It's easy enough to misconfigure STBs and see the results. For example, entering 4:3 in the setup, when sending the image to a 16:9 screen, results in stretched images. So, either the codes depend on the initial setup step, or perhaps none of my displays has ever decoded these bits? (I'm thinking, the codes depend on that initial setup step, where display aspect ratio is set by the user.)After the zero bit, there are two bits of aspect ratio information. 00 = 4:3 10 = 16:9 01 = 4:3 letterboxed 11 = not definedIf the codes are independent of any initial STB setup setting, I'm not sure why the 01 code would ever be required. It should be up to the display receiving these codes to determine whether to letterbox, pillarbox, or display the image full frame, no? Or maybe the 01 code is what creates the postage stamp images in 16:9 displays. (I thought those were created by the STB pillarboxing an image which already contained black bars top and bottom, as part of the image itself.)In the first picture (MGM Title displays 1 X 1 aspect ratio on 4 X 3 screen when BD player is set to pan and scan .jpg), the aspect ratio is 10 or 16:9.And Cliff's display blindly showed a horizontally compressed image, instead of panning and scanning the 16:9 image to create a 4:3 full frame image. So Cliff's display doesn't decode these, or the code was ignored upon reception due to failed checksum or other such, or the image with that code is never intended to go to 4:3 displays, but did. Second comment. In this specific case, pan and scan for a 4:3 display would have been ideal. The image content is 4:3 anyway, so pan and scan would only work to consistently eliminate the pillarboxing. Perfect, one would think.On the second picture (MGM Title displays stamp sized 4X3 aspect ratio on 4 X 3 screen when BD player is set to letter box .jpg), the aspect ratio is 01 or 4:3 letterboxed.This leads me to believe that the codes are sent based on some initial STB configuration (such as setting the STB to "letterbox," which implies a 4:3 display is in use). Otherwise, what would a 16:9 display do with a letterbox setting? To test this, Cliff might try to connect a 16:9 display on that same interface, still set to pan and scan, and see what happens. My bet? It will show a horizontally stretched postage stamp image.
Attachment:
16X9 HD set MGM Logo Letterboxed and Stretched.jpg
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16X9 HD set Pan and Scan .jpg
Description: JPEG image
