View Full Version : A clue regarding HDMI output?


John Vincent
September 6th, 2011, 07:46 PM
A minor clue regarding the HDMI output from B&H (who just updated their VG20 page to include stats)? Many people have been asking if the HMDI will be clean - here's a possible hint:

"HDMI Output for HD Viewing

Enjoy HD movies and stunning still images on a compatible HDTV or HDMI-enabled field monitor via the camera's HDMI output (mini-HDMI-to-HDMI cable not included). The VG20 continues to show live video on its LCD screen even as video is output via HDMI"

Wouldn't seem to be "stunning" if it wasn't a clean... Also, as some one who's been using Canon's for two years, it will be very nice to still be able to see the image on the LCD screen while outputting to HMDI.

I know I'm grasping at straws a bit here, but there's been very little new info since August 24th...

Steve Mullen
September 6th, 2011, 07:52 PM
"The VG20 continues to show live video on its LCD screen even as video is output via HDMI"

That's a very good sign the hardware is different than the NEX cameras.

The field monitor output indicates that data is sent via the HDMI and the picture is centered. On the VG10, the Display button could turn-off all data.

Wish the VG20 would arrive because I've got a Ninja I'm reviewing.

John Vincent
September 7th, 2011, 02:48 PM
Looks like no clean output, and the HDMI port itself broke after one day (according to an outside source) of the IBC.

Yikes.

Henry Williams
September 8th, 2011, 07:49 AM
John, it might be worth treating some of the contents of that particular negative report with a degree of caution. The author did sound like they had something of an axe to grind. Apart from anything else the NEX-5 and VG-10 were both pretty solidly put together. The only major build quality issue people found was a weak locking plate on the VG10, although I can't say I've had any problems with that myself. The VG20 seems to be pretty much the same body with a few enhancements so I'd be surprised if it was any less robust than it's predecessor.

John Vincent
September 8th, 2011, 09:34 AM
Absolutely - the source's veracity has been questioned by others as well. And that model was almost certainly a pre-production unit. But there's been a near total lack of other new information available - an interesting omission on Sony's part given that the camera hits shelves in 2 months (or less). No true reviews, no additional info from Sony. And given the uproar VG10 owners are in over a lack of firmware upgrades, Sony has to be aware of what potential buyers of the VG20 want.

Here's the thing - the VG20 either has a clean HDMI out or not. It either has the same picture profiles as the 5n, or it doesn't (Sony's site does list them as being there in the VG20's specs). I've read contradictory things regarding the VG10's (which I don't own) ability to output a clean signal via HDMI, so not sure if not having that feature would be a step back for the line or not...

Regardless, at $1,600 (body only) I do think that the VG20 aught to have at least the same functionality/picture profiles as a camera in the same line costing a third as much and it should have clean HDMI (given consumer desires and market place conditions).

Now do I expect it to have 20 buttons? No. Do I expect SDI or even a full sized HDMI port? Nope. XLRs? No. Programmable buttons? Well, that's a tougher call, but I can live without them. But IMO the same functionality of a much cheaper camera and clean HDMI isn't too much to ask.

Sony would go far if they addressed issues which virtually every serious shooter is asking about. I'd love to pre-order the camera, but can't until I know what the camera can/can't do.

Glen Vandermolen
September 8th, 2011, 11:40 AM
Explain "clean" HDMI to me. What does it mean?
I have a VG10 and I regularly connect it to my 55" flatscreen through the HDMI to review my footage.

Henry Williams
September 8th, 2011, 12:49 PM
I completely understand your concerns John. Sadly, the VG10 release was also rather bungled from a PR perspective - (the only way we figured out that the camera shot it's own particular form of interlaced was by importing the footage and working with it!) so I wouldn't be surprised if we again had to rely on a slow dripfeed of often contradictory info. Which is a shame, as the VG10 was an underrated piece of kit and the VG20 looks to have corrected most of the shortcomings we've highlighted on the forums over the last year. I'll be a day one buyer myself for those reasons, but I can see why many have a lot of questions they still need answered first.

Michael Bray
September 8th, 2011, 01:14 PM
Explain "clean" HDMI to me. What does it mean?
I have a VG10 and I regularly connect it to my 55" flatscreen through the HDMI to review my footage.

Someone please correct me if I'm wrong, but I believe "clean" HDMI means (for example) when you use an external recorder for uncompressed recording, you want the HDMI output to be "clean" as in no video information overlay. In other words, you want the video information overlay in your viewfinder or LCD screen but not output via HDMI into your external recorder. At least that's my understanding.

John Vincent
September 8th, 2011, 01:44 PM
That's pretty much it - having the option to switch of the overlays so you can record to something like a Ninja (which should result in a 4:2:2 recording vs a 4:2:0) via a HDMI cable.

Henry Williams
September 8th, 2011, 02:08 PM
As Steve says, this is possible with the VG10 - you can adjust whether information is displayed or not. As the VG20 seems to be adding features it would be strange if they omitted it.

Robert Young
September 8th, 2011, 06:51 PM
...you can record to something like a Ninja (which should result in a 4:2:2 recording vs a 4:2:0) via a HDMI cable.

This is the part that I have never been clear about.
The raw video comes off of the chip, into the DSP, and then out the other side as 4:2:0 AVCHD.
The signal can be recorded to the camera card and/or output via the HDMI.
I don't understand where or how the 4:2:0 signal becomes 4:2:2 for external recording in a Ninja, etc.
How does that work??

John Vincent
September 8th, 2011, 10:04 PM
My understanding of the issue is this: For the AF100, FS100, F3, VG10, VG20 to record to a SD memory card, the camera must compress the images as it records them. Apparently, there's just not enough processing power in these cameras to record at a rate higher then 4:2:0 (although this might also be partly due to a limitation of recording to an SD card - even a fast one).

The HDMI output feed is essentially what the camera's sensor is "seeing" as you photograph without any compression being added. My understanding is that the AF100, the VG10/20 can record 4:2:2 to an outboard recording device via the HDMI socket. The FS100 and the F3 can actually output 4:4:4 via the HDMI input (SDI on the F3), although there is no sub $10,000 recorder on the market that is capable of doing so.

I'm no color correction guy, but my understanding is that it's much easier to push around a 4:2:2 image vs a 4:2:0. And it's much easier to pull a key from a 4:2:2 recoding as well.

So as a matter of practicality right here and now, most AF100/FS100/VG10 shooters wanting better quality then 4:2:0 are going to something like the Ninja via the HDMI plug. But that's worthless if you can't selectively turn off the overlays. Thus all the angst.

Hope that clears it up a bit...

Steve Mullen
September 8th, 2011, 10:40 PM
Sensor outputs RGB that is not 4:4:4 because of the Bayer sensor. Half of the Red and half of the Blue information is not present.

RGB is debayered to 4:2:2 YUV or 4:2:0 YUV. There is no reason to create 4:2:2 because AVCHD is 4:2:0 and the LCD resolution is only about 720x480 PER COLOR. There's no reason for 10-bits because AVCHD is 8-bits and the LCD is only 8-bits.

So assuming the HDMI delivers 4:2:2 10-bits is risky as there is no need for such a signal. Connecting a Sony camera-top monitor doesn't require anything but RGB sent over HDMI.

Remember, HDMI can carry RGB or YUV. I strongly suspect that Sony feeds RGB to its tiny monitor.

Thus, the HDMI output hardware must be able to sense that you have connected a recorder that needs YUV. It also must be able to not overlay information when it switches to YUV.

Bottom-line to be able to record 4:2:2 Sony must design a camera to support it. Outputting 10-bits of information, is a separate decision.

John Vincent
September 8th, 2011, 11:13 PM
"Bottom-line to be able to record 4:2:2 Sony must design a camera to support it."

They already have in the FS100 and F3. I have no idea about the VG10/20 however.

Beyond better color correction and keying, the use of an outboard recording device also allows for much longer recording times if needed - something event shooters are usually keen to have.

The FS100 allows for simultaneous recording to SD card and outboard recorder - meaning you have the potential for a backup right off the bat. Again, not sure if the 10/20 allow for this.

So, there's 3 potential benefits to being able to record off of the HDMI spigot - better color rendition for post, longer potential recording times (esp as you can't hot swap on the FS100 or VG20), and double redundancy... Assuming it's clean.

Steve Mullen
September 9th, 2011, 03:13 PM
Exactly the same conclusions I had when I compared the two. Panasonic builds a camera for those who need to get real work done. Sony builds a sexy camera for those who want to look like they are going to get work -- someday.

Same conclusion I came to on the VG10 verses NEX-5.

Clearly the VG20 is much better than the VG10. But ergonomics, IMHO, are still bad. No ND filter!!! Not at $1600.

The Samurai now offers both ProRes and DNxHD, but uses HD-SDI. No go with VG20 or FS100.

The F3 is the way to go and one should be able to pay it off with a few jobs. And, it will last years -- if you don't need 3D or 4K2K. Plus PL mount lenses will last years.

I'm curious if Pana and Canon will offer a $2000 camera to compete with the VG20.

Dave Blackhurst
September 9th, 2011, 06:04 PM
I'm a little curious as to why it keeps coming up that "there's no ND filter" - I think that's at least to some degree inherent in the design of an interchangeable lens camera?

While traditional video cameras with sealed construction can easily have a bit of glass slide into place to provide ND filtering between the sensor and the lens, in the case of these large sensors, you can't exactly have a chunk of glass come flying in from somewhere, can you??

I see two problems, one being the physical size of an INTERNAL ND filter would prohibit you from finding a good place to put it, along with a sufficiently substantial mechanism to fling said glass around inside the camera...

Second this would mean another piece of glass that is susceptable to dust... one that could not be easily accessed/cleaned, as presumably it would mostly be out of the way... but potentially exposed each time the lens was off...

For those reasons, I don't think an ND filter could have been incorporated internally? Other than electronically reducing the sensitivity of the sensor ("anti-gain", if you will, which would seem to make sense at first glance, if counterintuitive to the goal of a sensor that performs well in low light), the obvious "solution" is a ND, either fixed or variable, mounted to the FRONT of the lens... which of course is the solution that SLR shooters have to and do use.



The VG20, as the VG10 was, is a strange little animal - part still camera (moreso now that it has RAW stills), yet with one paw (two? three?) firmly in the video camera realm. It takes a bit to wrap one's head around shooting video with a still camera, as there are some things that just aren't "videocamera like". The "reward" is of course the ability to achieve large sensor, shallow DoF, and a choice of lenses instead of being "stuck" with whatever lens was attached at the factory.

I'm sure at least a few of us saw a short NEX7 clip with the new translucent alpha adapter, and a HUUUUUUGE professional lens attached... anyone else go "where's the camera?!" Point being that the IMAGING MODULE, be it a NEX still camera, or a VG10/20 is but ONE part of an image acquisition equation...

With the new adapters and the improved user controls, I think Sony may have hit a home run, or more like several innings of home runs. Just a matter of whether enough people start thinking outside the box as to how they can be used. Sony certainly pushed the walls off the box when they released the 1st generation NEX cameras, this time looks like they blew the walls clean off...

Now we just have to figure out how these new toys fit into whatever creative schemes we all have!

Steve Mullen
September 9th, 2011, 10:47 PM
The AF100 performs at the same quality as the FS100. Yet it has an ND filter, large chip, and interchangeable lens. There's no reason not to have an ND filter. Note the wonderful F3 has an ND filter plus it has a big sensor and an inter-changable lens. Sony doesn't fool around with it's pro products.

Read the AF100 vs FS100 review and see what a bit of extra money buys you.

Bill Bruner
September 10th, 2011, 04:46 AM
I agree, Steve. If I get a VG20, I will have to spend a couple of hundred bucks for a matte box or screw in ND filter, $299 for a JuicedLink for XLR inputs and a $384 HDMI to HD-SDI adapter (assuming the HDMI out is clean). Total price will still be less than an out-of-the-box AF-100 or FS100, but Sony could have put all of these features in the camera and charged me for them instead of giving up the money to accessory manufacturers. Maybe in the VG30 :-)

Cheers,

Bill
Hybrid Camera Revolution (http://hybridcamerarevolution.blogspot.com)

Bill Bruner
September 13th, 2011, 11:12 PM
"We also managed to record from the new Sony VG-20 at the Sony booth. It has clean out and unlike other bloggers I’m quite interested in this camera as the Sony A77 and the 5N both didn’t offer a clean hdmi out to us"

John Vincent
September 14th, 2011, 02:42 PM
That alone starts to justify the price difference between the VG20 and the 5n...

Bill Bruner
September 14th, 2011, 05:06 PM
Don't tell Sony, but for recordable HDMI out, manual sound levels and a headphone jack, I'll gladly pay the extra $1K ;-)

Steve Mullen
September 14th, 2011, 06:16 PM
It has clean out and unlike other bloggers I’m quite interested in this camera as the Sony A77 and the 5N both didn’t offer a clean hdmi out to us"

Interesting because the 5N has a display setting that offers the option of NO DATA.

Bill Bruner
September 15th, 2011, 02:37 AM
Interesting because the 5N has a display setting that offers the option of NO DATA.

That setting is most likely for clean playback from the camera to an external display after recording. I am much more interested in clean HDMI in record mode.


"...We had even worse issues with the new Sony NEX-5N. The camera menu is constantly displayed on the right hand side of the feed."

and

"Only the new and yet unreleased Sony VG-20 offers a clean hdmi output. I will post a detailed report and test results in the next days."

Really looking forward to that report.

James Saradetch
September 16th, 2011, 12:59 AM
So it does have clean HDMI out.... but the results are indeed disappointing. I still hope that somehow, Sony can rectify, or else - what's the point?

Bill Bruner
September 16th, 2011, 01:20 AM
James -- I really appreciate the work that Sebastian put into this test, but I'm reserving judgment on his conclusions. It is sometimes a challenge to get clean progressive video straight out of HDMI on the Ninja, even from the FS100.

Here is the explanation from Atomos: ATOMOS News+Updates / Edition 1. May 2011 (http://atomos.com/news/V1_052011.html#hdmi)

Many cameras output their video signals differently through HDMI than they do to their own internal storage. Cameras “wrap” their progressive internal signals as an interlaced video output for transmission over HDMI.

This is simply to ensure compatibility with all displays new and old even though HDMI supports 24, 25 and 30p natively.

The Ninja can and does record and store your 24, 25 and 30p images perfectly, “wrapped” in an interlaced signal. You will see some different frame-rates reported by your Ninja compared to the settings on your camera. This is normal.

For example, if your camera is set to 25p (in Europe) you may see 1080i50 on your Ninja. Or (in America and former NTSC countries) you may see 1080i59.94 on your Ninja instead of 23.98p.

It’s worth repeating this.You will probably find that the framerate you have your camera set to record to is not the same as the video signal coming out of the HDMI connection.

The situation in Europe and other parts of the world where 25/50 frames/fields are the standard is simple.

The 1080i50 footage recorded from 25p is identical in 50i form. A single progressive frame is split into 2 progressive fields making the format 50i. There are no interlace artifacts because there is no movement between the fields.

In NTSC regions (eg the USA and Japan) it can be more complicated, because a 24p signal is turned into a 60i one using a process called 3:2 pulldown, which maps the 24 fames in the progressive footage into a 60i stream using a 3:2 pattern (or “cadence”).

You can use the interlaced signal produced by your camera as it is, or you can remove the pulldown using a “reverse telecine” program like Cinetools, supplied with Final Cut Pro, or our fast, simple “Stripper” application that will be available soon.

I'm still waiting for a review from someone who has a few days with the camera outside of a convention hall ;-)

Cheers,

Bill
Hybrid Camera Revolution (http://hybridcamerarevolution.blogspot.com)

John Vincent
September 16th, 2011, 01:31 AM
Still some reason for hope - just like the reviled 1st review from an outside website, this footage was sourced from a pre-pro camera on a demo floor. No handbook, no real alone time with the camera, no full blown review from a place like this one.

In other words, worst possible scenario. With a pre-pro camera (well, most likely).

The image is going to be massaged, that much is already certain. What remains to be seen is just pleasing that process will be to the eye.

It's still encouraging that the signal is clean at all - otherwise, the whole issue of quality would be moot.

John McCully
September 16th, 2011, 01:32 AM
Pardon me if I am perhaps a little more blunt than Bill. I would take this report, if you can call it that, with a huge grain of salt. The comment is made in the text referring to ‘the bad internal AVCHD compression’ that being the 28mbps codec also used in the FS100 as I understand it and he also admits that this was ‘not a scientific test, just a quick grab of some footage’ and then concludes ‘I’d suggest not to buy this camera’.

Scary huh!

While the text is sensational, and that’s perhaps the nature, the deliberate style employed at this web site, I would suggest not to not buy this camera based on this information.

I for one will hold my horses on a decision awaiting a review. No offense to James and the web site. Sort of hilarious really.

James Saradetch
September 16th, 2011, 02:50 AM
No, not all.... no offense taken! I really like this camera, and hope to get it. There's nothing like it at this price point. So we shall see how it performs in a proper review - and at least take heart that the hdmi out is clean.

Steve Mullen
September 16th, 2011, 11:58 AM
1) Looking at video that's been uploaded (how?) and compressed again (how) is not a great way to check camera quality. For example the macroblocking on the dark wall.

2) However, the fact that the Canon always looks "better" suggests that no matter what he may have done wrong -- the VG20 PROTOTYPE is not doing all that well.

3) I think he's using ProRes LT which is exactly what I would try for 4:2:0 HDMI output. (Note, I am assuming only 4:2:0 8-bit because there is no need to compute 4:2:2 during recording.) If it is 4:2:2, he should have recorded using ProRes 422.

4) It makes no sense to output video that has been compressed UNLESS Sony decided that it wanted to have the LCD and VF have data display while outputting a clean HDMI. Circuitwise it might be cheaper not to use the NEX LCD and VF recording circuit which is not clean RGB and use the playback YCrCb circuit to feed the HDMI jack since it is designed to be clean. Since the playback circuit inputs compressed video, Sony could feed it with compressed video while recording. When you attach a Sony monitor it would switch to RGB with the overlays. This would need to be confirmed with a shipping model.

5) I'm not totally surprised there is so little DIFFERENCE between AVCHD and ProRes at 1080i60 because 24Mbps is very good. On the other hand, why does it look so bad?

And, why would Sony allow recording on a PROTOTYPE?

PS; And I still want to know why Juan told us that Sony would not reveal the full set of specs for the FS100/F3 chip? (I continue to think the same 16MP is being used but with 4x4 binning to get the 2-stops of extra sensitivity for the FS100/F3.) Marketing games?