[opendtv] Re: Format Independence
- From: Tom Barry <trbarry@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Sat, 24 Dec 2005 09:02:16 -0500
MPEG-2 encoders and
> decoders know how to recognize 24P material that is doubled (3/5) to
fit in
> 60P, so very little bandwidth is actually wasted.
Maybe some encoders do, and maybe more today, but when I checked back in
Detroit 2-3 years ago none of the OTA broadcasters were using any
telecine flags. I think here in Jax I may have seen one (NBC?) that
does but I have not systematically checked them all recently.
- Tom
Stephen W. Long wrote:
> Dan,
>
> An engineer at a major network explained it to me this way - do you want to
> risk losing eyeballs (customer changes the channel) every time you go to a
> commercial or come back to a program? Since there is no guarantee
> whatsoever that consumer equipment will properly behave when different
> formats are received (my CRT HDTV goes blank every time the format changes
> BTW), the broadcaster can only control his end - thus upconvert or cross
> convert every signal to your base "master" signal. MPEG-2 encoders and
> decoders know how to recognize 24P material that is doubled (3/5) to fit in
> 60P, so very little bandwidth is actually wasted.
>
> Stephen
>
> At 06:21 PM 11/9/2005 -0800, you wrote:
>
>>In response to some of the discussion about formats, I have another
>>question. Why do broadcasters put out a fixed format stream when at the
>>production level the format is different. For instance, if Fox puts out
>>720@60P all the time, and the original production content is 24P, why would
>>the broadcaster waste bits by sending several frames of the same picture?
>>Why not send out 720@24P and use the 19Mb/s to send a less compressed
>>picture? Or how about when a 640x480@30i is sent out 720@60P? Is it a
>>problem with the master control switcher only switching one format, or the
>>server, or is the problem on the customer's end (like the monitor won't
>>naturally switch)? Is it simply easier that way? I would think a lot of
>>efficiency could be gained there.
>>
>>Dan
>>
>>
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