HV20 HDMI Out = 8bit.. chance of 10bit?

[Ian G. Thompson]

Originally Posted by Peter Moretti

Do you know if anyone has done a comparison between the two signals? With the superior lens on the G1, I'd expect a better look, but you never know.

I'm not sure about that...but I do know there was a comparison on HDV and HDMI here:

http://www.dvinfo.net/conf/showthread.php?t=104431

Also look at sample pics here:

http://thomann.net/hv20/interpolation/

[Ray Bell]

Originally Posted by Ian G. Thompson

Sorry...I misquoted myself...let me rephrase... It "does" come out of the HDMI port @ 1920x1080 while shooting live. The part that is in question is whether or not that image was downsampled (to 1440x1080) while going through the DSP and then upsampled back to 1920x1080 out the HDMI port...all live. Me personally I don't believe there is any change in image size....but it really does not matter because it produces such a great image anyways. I also believe it's 8bits..simply because it does not support the new HDMI 1.3 which is 8, 10, 12 and 16 bit. The older HDMI format was only 8bit...but I could be wrong...

Well I never thought of it that way but you could be on to something...
I read somewhere that the HDMI port outputs at 1920x1080 either live or back from the tape... ( need to do some tests to verify)
If this is true then the video stream could come off the sensor at 1920 be compressed for tape at 1440 and un-compress it back out at 1920 via the HDMI port...

sounds convoluted from an engineering standpoint but who knows how they setup the DSP pipe for signal processing going in two directions....

I'll test it this weekend to know for sure....

[Robert Ducon]

Originally Posted by Peter Moretti

Robert,

You seem to be leading the way on HDMI capture front. I'm working on a documentary with a lot of indoor interviews. Of course tape would be easier to use, but external capture is a possiblility becasue the camera will be mostly stationary and indoors.

Do you find a significant improvement capturing out of the HDMI port versus using HDV tape? My subjects will not be moving much, which eliminates HDV's motion issues. I'm willing to do live capture but I'm just not sure if I'll see much of a difference.

One thing to keep in mind, is I am hoping to do a film out from the footage. This instinctively makes me say "capture," but with slow moving subjects and not very challenging lighting, is it really worth it?

Thanks VERY MUCH for your input!

Hi Peter,

For what I've done recently, yes, very much so.. I'd skip shooting HDV all the time if I could, but this is because I often do a lot of colour correction.

The Apple ProRes 422 HQ codec seems so perfect (and I imagine Cineform is as good, and a little better), but there's many a time I need a remote camera without a generator, APC, cable, computer tower, monitor, 3 extra crew, etc etc.. so I'll still shoot HDV when I need to. The HV20 footage is still cleaner than Z1U HDV footage I've shot.

Sometimes I push my footage a *lot* - with the 'uncompressed' footage (actually ProRess 422, but I find it's 99% the same thing.. yes, really I said that) I can underexpose a bit to keep the skin or other highlights from blowing too much, and still bring up the darker areas in AE with custom masks that lighten areas, and in the final rendered shot, even I can't notice that the image has been pushed! I have to review the original to make sure the change has occurred sometimes. The HDV footage however, can't be pushed nearly as far because changes become noticeable.

If you don't do a lot of colour correction or image manipulation, and your subjects are talking heads and still, then skip the investment in time and money and equipment and stick to HDV for now. All depends on your needs!

Judging from the appearance of what little grain there is, I have a feeling that the image is resized in camera from 1440x1080, but I *only* can see this if I zoom in 300% and look for it in the darker areas. It doesn't matter.. the HDMI image is incredible, and 1920x1080 sensors are rare as is, so I feel very well off indeed. I have no proof - it may very well be not resized at all in camera.

Oh, I should add, I shoot HDV for every shot of ProRes capture shot I do - 1:1 ratio, incase the computer messes things up. I'd never trust a RAID 100% of the time, so, I'm still feeding the HV20 tapes. Sorry, don't have a comparison on hand right now.

[John Hotze]

Surely whether Canon's engineers designed downrezing to 1440 in the camera is not a top secret piece of information that someone from Canon couldn't answer. I would think that someone out there has a connection to a Canon employee that could mine that information and give it to us.

[Joseph H. Moore]

Do you find a significant improvement capturing out of the HDMI port versus using HDV tape? My subjects will not be moving much, which eliminates HDV's motion issues. I'm willing to do live capture but I'm just not sure if I'll see much of a difference.

Even without high motion subject matter, HDV compression still throws away most of the color resolution and a good bit of low contrast detail. The HDMI image is definitely superior, but only you can decide if the incremental quality gain overcomes the hassle factor.

[Yi Fong Yu]

but the cam itself is so tiny that strapping external drives to capture from the hdmi still feels like a STEAL from a pro-video tool's perspective.

many prosumer/pros are using taking this little engine that could to the whole next level due to the 1920x1080 native cmos. =D.

i think the next evolution of XLH2 or whatever is next should include higher color depths either internal to solid state or hdmi-output towards as lossless as possible. this will make definitely SHAKE THINGS UP =D.

[Robert Ducon]

I absolutely agree - keeping everything else on the XL-H1 the same, and just updating the bit death to handle native, true 10-bit out, would be enough of an upgrade to warrant the name XL-H2, in my opinion.

Any manufacturer that releases 10 bit camera with the feature set of the existing XL-H1 or EX1 will stir things up very nicely. Sony could have done it with the EX1; they tend to like to lead with ‘new’ technologies. Canon’s been really impressing lately.

Someone just needs to get the ball rolling…

[Yi Fong Yu]

on the other hand, our NLE editing chain isn't really provisioned to handle anything above 8-bit yet... so while we can capture in higher color depths, having the entire chain isn't currently viable... but i hope we move towards that direction soon!!!

the next evolution of NLE is higher color depth. how strange it is that COLOR, of all things, is the FINAL frontier of 2D video editing.

after that it's all about creating holonovels for star trek TNG's holodeck ;) or DS9's holosuite.

[Ben Syverson]

FCP has supported 10 bit natively for quite some time, so editing 10 bit is not an issue. The issue is that the Intensity card is 8 bit. I think it's very safe to assume the HV20 is not outputting 10 bit anyway, since that port is mainly there so you can plug in the camera to your flat screen TV, most of which wouldn't support HDMI 1.3 (10 bit) input.

That said, the footage coming in through the Intensity is extremely high-quality (provided you have enough light for the HV20). You can push it very far without seeing any 8-bit artifacts like banding. I wouldn't hesitate to apply extreme color correction to uncompressed HV20 footage... If you're really worried, do your color correction in 32 bit, which is how most color correction apps (including Color) work.

(BTW, the advantages of 10/12/16/32 bits vs 8 bit can all be realized without high bit depth output. In other words, you don't need a 10-bit video card and monitor to appreciate the flexibility that high bit depths give you. And I think you'd be hard pressed to see any benefit from a 10 bit monitor. )

After having worked with uncompressed footage from the HV20 a bit more now, I can say there is a very real advantage to using the full 1920x1080 @ 4:2:2 rather than HDV's 1440x1080 @ 4:2:0... and not just for keying -- there's a nice bump in detail and clarity.

Now if Blackmagic would just make an Intensity To Go card that fit in an ExpressCard slot!

[Joseph H. Moore]

Now if Blackmagic would just make an Intensity To Go card that fit in an ExpressCard slot!

Here! Here!

[Robert Ducon]

I second, err, third that as well!

[Christopher Ruffell]

I've captured HV20 footage at full 4:2:2, so I'll post a shot that you can all play around - it's incredible how far one can "push' the image when it's not full of HDV macro-block compression.

Captured at 4:2:2, 24P at full 1920x1080 raster, at 10bit with the Apple Prores 422 Codec HQ. I captured into a Mac Pro with the Decklink HD Extreme, and has 10bit I/O standard, guaranteed not to truncate to 8bit.

HOWEVER, just spoke to Convergent Design, who manufactures the HDMI to HD-SDI convertor that I use, and the person I spoke to told me that their products are 8bit because all HDMI connections they've encountered are 8bit as well - HV20 included. Yes, they have one there. ;)

So they're saying my footage is 8bit because the HV20's HDMI port is 8bit, as is their HDMI to HD-SDI connector.

And it looks great - the footage in general. Regardless, take a look at the shot - push it around in photoshop with the levels.

I'm prepping a raw still .PNG from a 1920x1080 frame from the footage I captured. There was a 35mm adapter in front, and I chose a poor shot on purpose (vignette + CA) so just ignore that ;) I saved the still as a 16bit PNG, so, as far as I've been able I've kept the quality above 8bit on the post production end - the extra headroom of the codec makes me feel safer.

So, there we have it - 8bit for sure (probably).

P.S. there's an interesting thread that parallel's this one going on in the Sony EX 1 camera thread - debate over 10bit. Some users are swearing it's a 10-bit camera. Adam Wilt made no mention of it, though he did import HD-SDI footage for his review I believe. If it's true, that'd make the EX 1 the first sub $10k camera with 10-bit out.

http://dvinfo.net/conf/showthread.php?t=111417

P.S. It seems I can't attach files... shame.

[Yi Fong Yu]

i wish new HD cams would implement software internal to the cam so that u can "record to external HDMI/FW hard drives". of course, i think u'll need SSD's to record the hundreds of megabytes per second requirements.

[Christopher Ruffell]

Originally Posted by Yi Fong Yu

i wish new HD cams would implement software internal to the cam so that u can "record to external HDMI/FW hard drives". of course, i think u'll need SSD's to record the hundreds of megabytes per second requirements.

Isn't that what HDMI and FireWire outputs on the camera is already for? The Focus Enhancements FireStore exists for FireWire (HDV), and now, portable HDMI recording options are coming from Convergent Design (with HDMI-to HD-SDI convertor) and Cineform. It's great we have HDMI out :D Just a matter of time for portable support hardware to be made avaliable.

We just need a 50mb/sec HDMI 4:2:2 FireStore for HD! I'd prefer to record to hard drive too - cheap cheap $-per GB! I saw that a 250GB SATA hard disk sells for $80 now. Apple ProRes 422 is efficient enough that it'll capture to a single drive :)

[Ben Syverson]

Originally Posted by Yi Fong Yu

i wish new HD cams would implement software internal to the cam so that u can "record to external HDMI/FW hard drives". of course, i think u'll need SSD's to record the hundreds of megabytes per second requirements.

Good luck convincing the manufacturers to engineer that. ;)