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-   -   50mbit/s for ex1/3 - like panasonics new cam? (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/147058-50mbit-s-ex1-3-like-panasonics-new-cam.html)

Craig Seeman March 31st, 2009 02:20 PM

DV50 it a data rate tied to a codec rather than simply a data rate. BIG difference.

Quote:

Originally Posted by Gints Klimanis (Post 1037108)
DV50 is probably their minimum, but it's an intraframe codec. There is no way a 50 mbit codec, even for SD video, will compete with 35 mbps intraframe EX1 codec.


Brian Luce March 31st, 2009 02:50 PM

Quote:

Originally Posted by Alister Chapman (Post 1037208)
Most of the broadcasters that are specifying a minimum of 50Mbps 4:2:2 are also specifying a minimum of 1/2 inch, full raster 1920x1080 sensors.

There is a very good reason for this and it's called diffraction. Cameras with small sensors suffer from diffraction issues at apertures less than f6. The severely limits the way lenses can be used.

Is there a thread here that talks about this issue?

Chris Hurd March 31st, 2009 09:18 PM

Yes. See these threads for starters:

http://www.dvinfo.net/conf/open-dv-d...d-filters.html

http://www.dvinfo.net/conf/canon-xh-...re-values.html

http://www.dvinfo.net/conf/canon-xh-...unprecise.html

and http://www.dvinfo.net/conf/623697-post131.html

Some of those are written for Canon XH but these matters apply to all 1/3rd-inch (and smaller) sensors no matter what the camera model is... use our Search function to bring up many more threads which discuss diffraction to an even greater degree. Hope this helps,

David Heath April 1st, 2009 02:52 PM

Quote:

Originally Posted by Craig Seeman (Post 1036999)
It's a bit more complex than what I'm stating but the short of it is it's technically absurd to claim a data rate alone as a specs sans taking the codec into account.

Indeed, and the EBU have tried to set a baseline with a series of highly involved tests - an attempt to set a reasonable "to be worked towards" standard than set any hard and fast "less than this should never be used, regardless of content" laws.

In brief, they've given full approval for general use to 50Mbs XDCAM422 and 100Mbs AVC-Intra as a minimum for the future, and the expectation is that formats such as HDCAM, DVCProHD and 35Mbs XDCAM-HD should be phased out in future. That's nowhere near the same as saying "should never be used". But hopefully it also gives manufacturers some clarity as to what to work towards.

Equally, even higher end formats such as HDCAM SR may be sensible for top end productions such as expensive broadcast drama.

The issue is not what the pictures look like straight after recording, but how they stand up to a broadcast chain, including post work and compression for transmission. Errors, insignificant in themselves, can build up down the chain.

Thomas Diehl April 1st, 2009 03:20 PM

Very good contribution, David! I think, that is exactly what it is all about. That is also why I think, the new Panasonic AG-HPX301E camera is one important step into the right direction. (even though I still prefer 1/2inch chips and find P2 way too expensive and too slow). Canon might come up with something quite interessting next year, i heard ... combining the best of both "worlds". we'll see ..

David Heath April 1st, 2009 05:52 PM

Quote:

Originally Posted by Thomas Diehl (Post 1040794)
That is also why I think, the new Panasonic AG-HPX301E camera is one important step into the right direction...

Yes, I agree. It ticks a lot of right boxes (fully approved codec being just one), but I find it frustratingly leaves a lot unticked. For that sort of money, I'd really want 1/2" sensors as you get with the (much cheaper) EX - nothing to do with "quality" in a technical sense, far more issues such as diffraction and dof as Alistair says. And now people have got used to the wide use of SDHC in this sector of the market, P2 just seems less and less attractive.

What I'd like to see is something similar to the 301 - but with (at least) 1/2" chips, and able to use SDHC. My suspicion is that's most likely to come from Sony, in which case I can only hope they go for the other EBU approved codec - 50Mbs XDCAM-HD422 - instead of 35Mbs. It shouldn't add much onto the price, and (unlike 100Mbs codecs) still be recordable to SDHC.

Alister Chapman April 2nd, 2009 02:05 AM

Brings us back around to the EX plus a nano flash, or maybe even Sony will bring out a SxS recorder with HDSDi in at 50Mbps. Not sure how the unit for the PDW-700 will get it's input yet, wether it will somehow take the Mpeg stream from the camera (not sure where this would come out) or take the cameras HDSDi output and record that. My suspicion is HDSDi as I've heard rumors that the box will also work with HDCAM cameras.

David Heath April 2nd, 2009 03:34 PM

Quote:

Originally Posted by Alister Chapman (Post 1042007)
Brings us back around to the EX plus a nano flash, or maybe even Sony will bring out a SxS recorder with HDSDi in at 50Mbps.

Maybe, but something like a nano-Flash won't help the EX handheld ergonomics. It's also quite a bit of extra money.

Yet shouldermount styling and a 50Mbs bitrate option needn't add much onto the camera cost at all, which is why there's so much hope for an "EX5" at NAB. If such a thing should come about, it's conceivable it could cost less to upgrade an EX3 to an "EX5" than buy such as a nano-Flash. Get the increased data rate and (hopefully) better ergonomics as well.

Olof Ekbergh April 2nd, 2009 04:06 PM

I think we are in for a few interesting years in cam development.

Consumers love to not think about focus 1/4" chips are great at that, maybe we will see even smaller chips with greater DOF.

Storytelling is great with selective focus, but a lot more work. Pros love it. Canon 5dmkII is a great cheap example of generation 1 of full 35mm chips, RED is coming out with lots of different size chips.

I think in the future pros will have a great variety of chips and lenses, you will have modular cams a la RED. Pick your chip and your lens to fit what you want to conway.

I also think we will soon see an end to HD's, everything will be solid state. We still deliver a lot of SD 4:3 BetaSP, but that is about the only tape we use much any more. We now deliver a lot of comercials etc by FTP MPG streams.

There will be lots of new codecs and compression schemes.

Enjoy the ride.


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