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#1 Alex Worster

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Posted 09 May 2008 - 07:45 PM

So I'm ACing this feature with the RED (build 15) and during prep I couldn't get the HDMI out to work with the monitor we're using. The monitor is a TVLogic, can't remember what model it is but it does have a HDMI in along with all the usual suspect, HDSDI, DVI, and analog. So is there a reason the camera and monitor aren't working together? I just get a no signal warning on the monitor. I've tried two different cables, still the same problem. The monitor is not a dub because I ended up running cable from the onboard monitor's SDI out (we're not using a red monitor, its a small TVLogic that we're feeding from the HD/SDI out on the camera) to the big TVLogic SDI in and we get picture. Anyone have any bright ideas?

Also, another question... When we pointed the camera at the sun we get this sweet red and black circle/artifact in the middle of the sun. I think I remember reading that this may have something to do with the rolling shutter or something. Is it correctable in camera or is that just something you have to live with and fix in post?

Thanks for all your help in advance.
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#2 Hal Smith

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Posted 09 May 2008 - 08:05 PM

So I'm ACing this feature with the RED (build 15) and during prep I couldn't get the HDMI out to work with the monitor we're using. ..............

There are different versions of HDMI which can bite you - like it bit me. I've got an HDMI to VGA (RGB + H&V sync) converter that will not recognize the HDMI coming out of a Canon HV30 but works just fine with both a Directv HR20 HD receiver and a Toshiba HD-DVD's HDMI output.
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#3 Keith Walters

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Posted 09 May 2008 - 08:08 PM

So I'm ACing this feature with the RED (build 15) and during prep I couldn't get the HDMI out to work with the monitor we're using. The monitor is a TVLogic, can't remember what model it is but it does have a HDMI in along with all the usual suspect, HDSDI, DVI, and analog. So is there a reason the camera and monitor aren't working together? I just get a no signal warning on the monitor. I've tried two different cables, still the same problem. The monitor is not a dub because I ended up running cable from the onboard monitor's SDI out (we're not using a red monitor, its a small TVLogic that we're feeding from the HD/SDI out on the camera) to the big TVLogic SDI in and we get picture. Anyone have any bright ideas?

Also, another question... When we pointed the camera at the sun we get this sweet red and black circle/artifact in the middle of the sun. I think I remember reading that this may have something to do with the rolling shutter or something. Is it correctable in camera or is that just something you have to live with and fix in post?

Thanks for all your help in advance.

HDMI is a bit of a trainwreck technology at the moment.
It has always been promoted as a "one plug" alternative to hooking up eight or more cables to an HD Home Theatre system.
In reality it's really just another lame attempt at enforcing so-called "Digital Rights Management" entirely for the benefit of the movie companies.
Many of the design engineers in China who have been given the task of designing HDMI interfaces, simply do not understand how DRM is supposed to work
The result is that many HDMI equipped monitors refuse to display perfectly legitimate HDMI source material, because they thnk it's a pirate copy of a Blu-Ray movie or similar.
See this thread for more information and a possible solution
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#4 Phil Rhodes

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Posted 10 May 2008 - 02:18 AM

I agree that the lack of standardisation among HDMI and DVI devices can be a problem, and the copy protection is more about making you buy a new TV from Sony (who owns a major studio, anyone?) than it is about preventing piracy. After all, it's been possible to pirate DVDs by recording them from DVI for years, and it is certainly not a serious vector for piracy even if, in fact, it has ever been done at all. The way HDCP works, as well as the way its implementation is intended to be controlled, is insidious and unnecessary and does the studios no good at all.

That said, I'm forced to admit that the presence or lack of HDCP encoding on a DVI or HDMI connection is generally fairly well advertised.

More likely, in my experience, you're asking for a rate (such as 48Hz) that the monitor you're using is not capable of displaying. This situation is directly analogous to the one faced by people using SDI to DVI converters, such as Blackmagic Design's HDLink. These boxes usually have to go some way out of their way to offer 3:2-pulldown-style features to double and triple fields up to get to 60Hz, since many TFT monitors (especially computer monitors as opposed to TVs) are quite picky in this regard.

If all else fails, you could get an HDlink and monitor the SDI outputs.

P
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#5 Keith Walters

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Posted 10 May 2008 - 05:21 AM

. After all, it's been possible to pirate DVDs by recording them from DVI for years, and it is certainly not a serious vector for piracy even if, in fact, it has ever been done at all. The way HDCP works, as well as the way its implementation is intended to be controlled, is insidious and unnecessary and does the studios no good at all.


P


"After all, it's been possible to pirate DVDs by recording them from DVI for years"

Why would anyone want to do it that way, when there are any number of programs available that can defeat the various attempts at copy protection, and copy the disc directly?

Unless you are talking about HD discs, which have not really been around for "years". Apparently the rationale there is that because the movie has been "degraded" by converting it to an Analog format, it is of little value to consumers! In practice I seriously doubt anybody would even notice the difference.

The venerable freeware program DVD Shrink will still efficiently copy most copy-protected SD DVDs (as well as shrinking them down to fit on a single layer DVD if required). More recent attempts at "uncrackable" copy protection systems have been defeated with almost laughable ease, and some software vendors even offer free upgrades, rather like the suppliers of anti-virus sofware :rolleyes: )

An increasing number of movies are now released with no copy protection at all, the distributers presumably refusing to pay royalties for systems that clearly do not work!

I think the only thing that has thus far inhibited the wholesale copying of Blu-Ray discs is simply that the drives and the movie discs are still relatively uncommon.

Whether this is a real problem for the studios or not, they are going to eventually going have to live with the fact that there is no practical solution to it, and try to move on from there.

.
More likely, in my experience, you're asking for a rate (such as 48Hz) that the monitor you're using is not capable of displaying.
P


I have seen numerous HDMI monitors that refuse to accept certain HDMI outputs, even when the source format has been set to one that the monitor is advertised as capable of handling.

Edited by Keith Walters, 10 May 2008 - 05:25 AM.

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#6 Phil Rhodes

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Posted 10 May 2008 - 06:50 AM

> Why would anyone want to do it that way, when there are any number of programs
> available that can defeat the various attempts at copy protection, and copy the disc
> directly?

Well exactly.

> have seen numerous HDMI monitors that refuse to accept certain HDMI outputs, even
> when the source format has been set to one that the monitor is advertised as
> capable of handling.

So have I. The difficulty here is in ensuring that both the devices speak the same revision of EDID, the Extended Display Identification Data. This information is sent on pins 6 and 7 of a DVI connector as part of the Display Data Channel, based on I2C bus specification, and is standardised - a bit - by VESA. Its purpose is to avoid exactly this sort of problem, and to be fair, in the main it works - ever noticed how a modern PC will automatically size its desktop to suit a modern monitor immediately it's plugged in?

It tends to not work so well when you're dealing with things which aren't computers, including SDI converters, cameras, etc. The safest bet is that almost all DVI and HDMI devices will support 60p modes in 1080 and try to get to that. A disturbingly large number of devices (such as the Dell 24" flat panels, and in fact almost all 24" flat panels) will certainly not do 48 or 72Hz modes and will require special tricks to display 24p anything like correctly. If in doubt, assume 60.

Phil
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#7 Alex Worster

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Posted 10 May 2008 - 01:51 PM

Thanks for all the responses so far. So what I'm gathering is that the RED and this specific monitor (and probably a lot of other monitors) just wont work with the RED's HDMI out if we're shooting 23.98 fps. I also tried using an HDMI to DVI converter to go into the monitor's DVI in, no luck. I believe the RED has an option to change monitoring from 50Hz to 59.98Hz, would that solve any problems? Really I guess it's not such a big deal because we can use the HD/SDI camera out and monitor in to get picture but I get curious when things don't work.

I don't suppose anyone out there has used one of these new TVLogic monitors with the RED's HDMI out and gotten it to work?
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#8 Phil Rhodes

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Posted 10 May 2008 - 02:25 PM

> So what I'm gathering is that the RED and this specific monitor (and probably a lot of other
> monitors)

I wouldn't be terribly surprised. It is up to Red to put appropriate EDID on its HDMI output. However, Nattress knows this, and I suspect it is probably acting correctly. What I suspect it isn't doing is negotiating with the monitor on what it is capable of displaying and providing a realtime pulldown to make the situation work.

> I also tried using an HDMI to DVI converter to go into the monitor's DVI in, no luck.

I'm sure you were using the same decoders in the end anyway, but worth a try.

> I believe the RED has an option to change monitoring from 50Hz to 59.98Hz, would that solve
> any problems?

Very possibly. You didn't try it?

Life gets simpler with whole-number frame rates.

Phil
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#9 Alex Worster

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Posted 10 May 2008 - 03:25 PM

Thanks for all the help Phil and no, I didn't mess with changing the Hz and seeing if there was an effect on the monitor issue, not the smartest I know. I'll also try playing with the frame rates during some down time to see if that would solve the problem. More than anything now I want to be able to tell them why it doesn't work. If anyone has/does get a TVLogic monitor to work out of the HDMI I'd be interested to hear about it.

Thanks to everyone else that's given it some thought as well.
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#10 Keith Walters

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Posted 10 May 2008 - 07:45 PM

A disturbingly large number of devices (such as the Dell 24" flat panels, and in fact almost all 24" flat panels) will certainly not do 48 or 72Hz modes and will require special tricks to display 24p anything like correctly. If in doubt, assume 60.

Phil


Again, a lot of this can be put down to inept software design. Rather than designing a signal processing system that can cope with a wide and continuous input range, the designers simply assume that only certain parameters will ever be encountered.

Actually I have a 17" LCD screen that is basically a VGA-type analog input computer monitor that has had an analog TV tuner and A-V inputs fitted as well. It works very well as either a PC monitor or a TV set, but it was only after I had laboriously mounted it on my bedroom wall, ran cables through the ceiling and so on so there were no connections visible, that I discovered it is extremely intolerant of VCR signals! (I mostly record on DVDs but my wife still prefers the convenience of VHS).

It will display the pictures well enough in normal play mode, but on some tapes, if you select "pause" or fast picture search, it will blank the screen for several seconds every time you enter or leave that mode. Sometimes, for reasons best known to itself, it also switches out the subcarrier trap when normal play resumes, and you have to pause and un-pause it to get it right!

I bought it for a very good price, now I know why!
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#11 Phil Rhodes

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Posted 11 May 2008 - 08:33 AM

I think that's a slightly different issue to the one we were previously discussing, since it's an issue of DSP and ADC design, a discipline somewhat removed from concerns over I2C bus communications.

That said you're not wrong. I have enormous trouble with 2.4Ghz "preview-quality" video links, which miniDV recorders frequently barf on horribly when they're unstable. I usually have to insert some sort of timebase corrector, such as a digitally sampling vision mixer.

P
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