Home of Professional Cinematography since 1996

Playback From The Camera

Published : 20th November 2003


Is it true that you loose picture quality when playing back directly from a Cinealta and/or Varicam, compared when playing back from a tape deck?

Esteban Camargo
Gamma Cinevideo
Bogota, Colombia



I think you do lose quality playing back from the camera as opposed to a studio deck. Also, the camera playback is not designed for the rigors of such use.

Best regards,
Leo Ticheli
Director/Cinematographer
Birmingham/Atlanta



Absolutely not

The HD SDI from either camera is identical to what comes out of a dedicated playback deck. That is inclusive of the Picture and Embedded Audio and VITC.

Dave Satin



Thanks, Dave, you are indeed correct. I checked with Panasonic and the camera has the identical chip set as the studio decks.

I still don’t think it’s a good idea, however, to use the camera as a feeder; too much wear and tear.

Best regards,
Leo Ticheli
Director/Cinematographer
Birmingham/Atlanta



>Is it true that you loose picture quality when playing back directly from a >Cinealta and/or Varicam, compared when playing back from a tape >deck?

On a Sony F900, the analog (Y`PrPb) output quality is, I have been told, not as good at that of the analog output of an F500 deck. Digital HD-SDI is, on the other hand, HD-SDI.

Noel Sterrett
Baytech Cinema
www.baytechcinema.com



>On a Sony F900, the analog (Y`PrPb) output quality is, I have been told, >not as good at that of the analog output of an F500 deck.

The F500 has no analog outs. Only a composite NTSC downconvert.

Carlos Acosta



>The F500 has no analog outs. Only a composite NTSC downconvert.


Your right. What I was thinking of was an F500 and a very good D/A. I've been told, though I don't know first hand for sure, that the F900 analog output was meant for previewing, rather than for high quality analog output.

What would be very interesting would be a way to get at the analog RGB signal from an F900 prior to A/D and signal processing.

Noel Sterrett
Baytech Cinema



>Digital HD-SDI is, on the other hand, HD-SDI.

Except on the two HD-SDI ports on the Varicam, where one is compressed out of the deck and one is not.

Mitch Gross
NYC DP



>Except on the two HD-SDI ports on the Varicam, where one is >compressed out of the deck and one is not.

Although they well may be, I can't find anything in the operators manual to indicate that the signals from the 2 Varicam BNC outs are different in terms of compression, but I would be delighted to hear that the Varicam outputs compressed DVCPRO HD. If so, it would be much easier to capture and edit, and the disk space required would be much less. No tape deck would be required. Final Cut Pro already supports DVCPRO 50.

Both a Varicam, and an F900 with the HD-SDI accessory, can output signals which have not been compressed while they are recording, and which have been compressed when playing from tape. But in either case the signals are, I believe, uncompressed full data rate HD - SDI signals when they leave the camera.

What "uncompressed" actually means is another really story altogether...

Cheers,

Noel Sterrett
Baytech Cinema



Esteban wrote :

>Is it true that you loose picture quality when playing back directly from a >Cinealta and/or Varicam, compared when playing back from a tape >deck?

Not only do you lose picture quality from the Sony F900 camera, you also lose the same quality from the Sony F500 deck when playing back directly through HD SDI. The only way that the ghostly halo goes away is to capture directly onto a hard drive. Try turning off the detail and matrix and you will see it even clearer against blue screen.

The good thing is that it is noticeable outside the edge of the key, pull the key and it is gone, replaced by whatever clean background you put in there. That does not help an in-camera shot though does it.

It seem it is the nature of HDCAM's playback heads, not the quality of the chips resolution.

Eric Adkins
DP, Los Angeles



>Both a Varicam, and an F900 with the HD-SDI accessory, can output >signals which have not been compressed while they are recording, and >which have been compressed when playing from tape.

Yes, I see my very short post was a bit unclear and a little off - topic. Although it is not in the Varicam manual, apparently with a live feed, one output is full uncompressed from the camera head end and the other is the compressed signal that is the same as would get recorded to tape. Sort of similar to the difference between the "Test Out" or "Monitor Out" vs the "Video Out" on some SD cameras. One is through the camera head section and the other is through the VTR section. If I recall correctly it is the output on the side of the camera that is full uncompressed live while the rear output is compressed.

Of course on playback it is the full signal as recorded to tape, and of course that's less than the camera head can deliver.

Mitch Gross
NYC DP



What would be very interesting would be a way to get at the analog RGB signal from an F900 prior to A/D and signal processing.

Pretty sure that's why they made the 950.

Dave Stump

vfx Supervisor/DP
LA,Calif.



>Pretty sure that's why they made the 950.

Exactly. But there aren't many of those now and there are a lot of 900's. I'm told that the CCD block on the two cameras is identical.

Noel Sterrett
Baytech Cinema



>If I recall correctly it is the output on the side of the camera that is full >uncompressed live while the rear output is compressed.

I thought both outputs on the Varicam where identical. How can we be sure
which output is the full uncompressed?

Esteban Camargo



>thought both outputs on the Varicam where identical. How can we be >sure which output is the full uncompressed?

Ask Panasonic. That's who told me about it. Jan?

Mitch Gross
NYC DP



Nope.

The 2 HDSDI outputs on the Varicam are identical.

In E/E mode, the camera signal is output to both connectors In PB/EE mode, the output of the tape deck is output to both connectors if you are playing back. If you are not playing back, the camera signal is output to both connectors.

In Off mode, no signal is output to both connectors. If you don’t want to believe me, a genuine engineer, then read pages 84-120 of the operating manual.

Dave Satin



Not Jan (SDX900) nor Jeff (Varicam), however, I can explain the situation. Varicam or SDX900 compress the 10-bit signal from the camera head to record it on tape.

The output of the Varicam’s HD-SDI out is a 10-bit uncompressed signal which you could record on a disk array, Baytech's memory array or D5-HD recorder at full res.

The SDX900's VIDEO OUT connector, the signal type is set in the menus, when set to SDI will output a 10-bit SDI signal that could be recorded on any of the above devices at full res. This presumes you have the SDI option installed in the camera. In both cases these spigots are available when shooting. If you press play on the recorder, you will get the 8-bit signal recorded on the tape out the VIDEO OUT or HD-SDI connector.

Hope that's clear.

Robert Goodman
Photographer/Author/Producer
Philadelphia
www.stonereader.net



Robert Goodman writes :

>The output of the Varicam’s HD-SDI out is a 10-bit uncompressed >signal ... If you press play on the recorder, you will get the 8-bit signal >recorded on the tape out the VIDEO OUT or HD-SDI connector.

I believe that at least on the Varicam, one output will give you the full 10-bit uncompressed signal and the other will give the 8-bit signal even when the camera is feeding live. One output is before the deck and the other is after.

Please someone prove me wrong, but this is what I was told.

Mitch Gross
NYC DP



DaveSatin wrote :

>In Off mode, no signal is output to both connectors.


Dave - I like that one....

+++ Florian Rettich +++
+++ Europe based DIT / vision control +++



Florian Rettich quoted Dave Satin as saying :

>In Off mode, no signal is output to both connectors.


Or, once could say, the same signal is output to both connectors, and that signal is modally specific.

Jeff "doesn't like to read manuals" Kreines