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seminewbie
Yahoo HD Trailers
on Feb 5, 2007 at 1:13:42 am

I thought I might open up some discussion on something I just discovered.
I went to the Yahoo HD Movie Trailers page (http://movies.yahoo.com/feature/hdtrailers.html) and besides the fact that
that my connection is WAY too slow for this heavy duty stuff I noticed the following.

Each trailer is listed as having a 480p, 720p and 1080p version. Now unless I am misreading the info panel on my Quicktime player (which is very possible) the frame sizes that they are actually streaming are 852x354, 1280x532 and 1920x728.

Like I said I could be getting faulty data but if I am not I would like to hear what other people feel about non-standard sizes and their experiences with same. Thanks Dan



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Charles Simonson
Re: Yahoo HD Trailers
on Feb 5, 2007 at 5:44:58 am

There is nothing really non-standard about these sizes. Basically, the reason for the encoded vertical sizes not being actual 480, 720, or 1080 lines is that the tape the trailers are delivered on have letterboxing. The typical frame sizes for storing video on tape are 720x480, 960x720, 1280x720, 1280x1080, 1440x1080, and 1920x1080. But often times, the actual images on the tape only consumes a certain number of lines if the original source was film, which can use a custom aspect ratio. So in the case of the 1080p trailer, the remaining 352 lines were likely black in order to letterbox the content to conform to the tape standards. And when the tape was encoded, there was no reason for the compressionist to compress and waste bits on the letterboxes for web output, so they cropped those out.


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seminewbie
Re: Yahoo HD Trailers
on Feb 5, 2007 at 6:39:00 am

Thanks Charles a truly amazing and thorough answer which is much appreciated

Dan


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