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Discussion Starter · #1 ·
I've never seen a "native" 720p game from ESPN or FOX look as good as the CBS highlights of the AFC championship game currently on ESPN. I thought that the 720p networks shot the games with 1080i (or higher resolution cameras) then downconverted, so why isn't the 720p network PQ better on live games?


Is anybody using something like the Grass Valley LDK5000? 9.2 megapixels, holy cow!
http://www.thomsongrassvalley.com/pr...meras/ldk5000/
 

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Quote:
Originally Posted by paule123 /forum/post/0


I've never seen a "native" 720p game from ESPN or FOX look as good as the CBS highlights of the AFC championship game currently on ESPN. I thought that the 720p networks shot the games with 1080i (or higher resolution cameras) then downconverted, so why isn't the 720p network PQ better on live games?


Is anybody using something like the Grass Valley LDK5000? 9.2 megapixels, holy cow!
http://www.thomsongrassvalley.com/pr...meras/ldk5000/

ESPN and the other 720p networks use cameras that are 720p native. Most HD broadcast cameras today can operate in 720p or 1080i natively.
 

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The 1920 x 4320 9.2 Mega pixels is a bit misleading as not all pixels can be output simultaneously. The HD version, the LDK6000, and the newer version LDK8000 use pixel grouping to output 1080i, 1080p and 720P at various aspect ratios.
 

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I don't think that any of you answered the question. I'll try as best I can, but it'll take a while.


I'll use my pocket digital camera as an example that'll lead up to the answer (follow along, there is a reason). With it, I can choose to take pictures at the highest resolution (2048 x 1536 I think). When I zoom in to 100%, meaning I view the image exactly how it was recorded to the CF card pixel for pixel, the edges aren't so sharp. Perhaps it's because of anti-aliasing, but for whatever reason, the edges aren't super-sharp. It's sharp, but not unbelievably sharp. The sensor that's on the camera's known as a "Bayer" sensor. Bayer-type video capuring devices, the type used by virtually every single video camera out there, aren't terribly sharp per-pixel at the "pixel-peeping" level.


Now let's say I downres the in-camera setting to 1600 x 1200 like I have on occasion. You would think that when I zoomed in to 100%, I would have super-sharp pixels because of the downres. But no -- the edges are similarly "blurry" as if I had taken them at full resolution. I don't know why -- but again that doesn't mean it's not so.


The same effect's probably going on with these cameras. The setting's put at 720p and the edges are as "blurry" pixel-for-pixel as the camera would capture it in 1080i. BUT, if that 1080i picture is externally downrezzed by an external method, then this bypasses the camera/sensor's processing unit, and allows a "per pixel" sharpness that is much sharper than it was natively captured -- and sharper per-pixel than the native 720p out of an ESPN-HD cam.


I hope that made sense. Sorry if it didn't.
 

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Besides the cameras themselves, there are many other variables that will affect the PQ that arrives at home. The lenses on the cameras, how the video operator sets certain parameters such as enhancement and masking, the method for backhaul to the network or channel broadcasting the event and the network/channel's distribution.


As far as PQ on ESPN from other networks, it depends on what their source is. Is it from a backhaul, network fronthaul etc? Some networks like ABC and CBS use high bitrate for both the backhauls and the net fronthauls. Other networks like Fox and most cable channels use only the amount required for ATSC on their network distribution. As CBS was given as an example in the OP, I know it's common for them to use both fiber and high bitrate satellite backhauls, so that may be the source of ESPN's highlights.
Quote:
Originally Posted by mikemikeb /forum/post/0


The sensor that's on the camera's known as a "Bayer" sensor. Bayer-type video capuring devices, the type used by virtually every single video camera out there, aren't terribly sharp per-pixel at the "pixel-peeping" level.

Most high end video cameras use separate RGB imagers instead of a single Bayer type. Thomson cameras use a unique vertical pixel grouping arrangement described in this white paper on page 3. Other cameras like the Sony 1500L use 1920 x 1080 imagers capable of both progressive and interlaced operation. In both the Thomson and the Sony, reduction from 1920 horizontal pixels to 1280 for 720P is performed by an internal scaler. The Sony camera also uses scaling for the 1080 to 720 vertical pixel transformation.
 

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And then there are times when I think my local RSN always goes for the lowest bidder when the do their HD hockey games. That low bidder, to save money, looks like they are up-converting 540P (or 480p). A pretty bad picture when compared to HDNET hockey games. Of course, it could be worse, the SD picture they simulcast looks even worse (it looks worse than the S-video output of my HD receiver). That makes me think the SD version is either not derived from the HD version, but is a separate system or somewhere along the path, the bitrate is set pretty low.


Ernie
 

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Quote:
Originally Posted by mikemikeb /forum/post/0


I don't think that any of you answered the question.

homcom answered the camera issue correctly.
 

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Downconverting a 1920X1080i/p source for 1280X720p delivery boosts the limiting resolution of 720p closer to the format resolution. The result is crisper images than sampling at only 720p. As mentioned above , newer HD cameras can perform this oversampling/downconversion internally, sampling at 1080/60p for 720p delivery. But there's likely still a mix of hardware in use, with 720p-only hardware being used that provides 'fuzzier' images compared to 1080i/p originated HD.


Besides boosting the final maximum resolution of 720p, downsampling from 1080i/p likely also increases the contrast of middle resolutions/frequencies, making the overall picture appear sharper. A graph (page 26) of Matt Cowan's pdf Black Paper illustrates how boosting a range of resolutions can enhance the contrast and sharpness of the same image. Mark Schubin also outlines this image-sharpening effect near the end of this archived post . -- John
 

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Discussion Starter · #9 ·
I'm resurrecting this thread because I was stricken at how sharp 1080i highlights of yesterday's baseball games looked on ESPN SportsCenter last night. The highlights of the 1080i YES coverage of Yankees/White Sox at US Cellular were outstanding. When the highlights were done and they returned to the SC studio, it was the typical grainy "blah" 720p look.

More surprising was the fact that I was watching ESPNHD over DirecTV's "old" MPEG2 encoding, but the 1080i highlights still looked spectacular.

So I ask why don't ESPN and Fox do everything internally at 1080i, and save the final reduction to 720p for distribution to the affiliates and sat/cablecos? They'd end up with a much better looking product and silence the 720p complainers like myself.



Should also mention my display is a Panny commercial 50" 1080p plasma connected to a D* HR20.
 

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Quote:
Originally Posted by paule123 /forum/post/13713981


So I ask why don't ESPN and Fox do everything internally at 1080i, and save the final reduction to 720p for distribution to the affiliates and sat/cablecos?

Perhaps 1080/60p cameras, capable of internal downconversion to 720/60p, aren't that widespread. I've noticed reports about them only in the past few years. Using a 1080i60/720p camera without internal downconversion to 720/60p would require external 1080i deinterlacing, possibly less desirable.


When networks split 1080i and 720p coverage weekdays and weekends, like the last golf Masters or the U.S. Open (ESPN/CBS/NBC), I've noticed PQ is noticeably closer than most 720p versus 1080i broadcasts, and assume that's from internal 1080/60p camera downconversion for the 720/60p. On my 9"-gun 64" RPTV at 8' (via NYC's TW cable), most 720p appears less crisp than 1080i ever since hooking the display up 8 years ago. With movies, usually effective resolution limited already, the crispness difference isn't always that distinct. -- John
 

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Quote:
Originally Posted by ziltomil /forum/post/13717468


simple answer: 1080i is better than 720p, and an oversampled image looks better than a native resolution image.

But you'd think that ESPN is using cameras that do 720p and 1080i natively. In other words, the camera is downsampling internally. If that weren't the case - if the cameras were 720p only - it would explain why ESPN productions look worse than 1080i highlights on ESPN.
 

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Quote:
Originally Posted by paule123 /forum/post/13713981


So I ask why don't ESPN and Fox do everything internally at 1080i, and save the final reduction to 720p for distribution to the affiliates and sat/cablecos? They'd end up with a much better looking product and silence the 720p complainers like myself.

Because 10 years ago Fox and ABC made the decision to abandon interlaced and go with a progressive format for the digital transition. Their entire infrastructure is 720p based so it's not that easy to introduce 1080i into these facilities.


It's also highly political. Those two networks engineering heads, Andy Setos for Fox and Preston Davis for ABC both announced publically their disfavor of interlaced formats. They claim it is obsolete going forward in an digital world. So they aren't about to change their stand to imply CBS (Joe Flaherty) was right! And is he right? Even Joe has calimed 1080P/60 is the holy grail in ATSC could support it.
 
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