Jump to content


Photo

Colour-space concerns: monitoring HD on SD monitors


  • Please log in to reply
2 replies to this topic

#1 Jack Kelly

Jack Kelly
  • Basic Members
  • PipPip
  • 25 posts
  • Producer
  • London, UK

Posted 17 April 2008 - 12:01 PM

Hi there,

I have a nice Sony PVM-14L4 monitor which I feed via component YCbCr from my Blackmagic Decklink HD Extreme card. When I'm editing HD projects, the Decklink card down-converts the HD to SD while I'm editing so I can still use my SD monitor to edit and grade HD projects. However, should I be worried about colour-space issues (i.e. HD uses rec.709 whilst SD uses rec.601)?

To confuse matters further, as I understand it... rec.709 and rec.601 are standards for the digital encoding of HD and SD video (respectively). i.e. there's no such thing as "rec.709" or "rec.601" once you're in analogue land.

In other words... do I not need to worry about colour space issues when monitoring HD on my SD CRT because my monitor is being driven by an analogue (YCbCr) connection?

I'm confused, I admit it!

Any help would be greatfuly received!

Many thanks,
Jack
  • 0

#2 Walter Graff

Walter Graff
  • Sustaining Members
  • 1334 posts
  • Other
  • New York City

Posted 17 April 2008 - 12:35 PM

Nothing to worry about. You're seeing colors the way they were meant if your monitor is set up properly.
  • 0

#3 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 17 April 2008 - 01:39 PM

All the up/down converters that I know of convert correctly for the difference between the 601 and 709 luminance equations and matrices.

This was a subject of discussion a little over ten years ago, when the HD standards were in the works. At that time, I wrote a little assembly language program that would take a .BMP file and apply to it the equivalent of encoding as 601 and decoding as 709, and vice versa. Those test images were widely circulated, and the converter makers decided that getting 601/709 right was a nice bullet point to have in their feature lists, so they all did it.

I'll have to try to find that stuff again.




-- J.S.
  • 0


Rig Wheels Passport

Tai Audio

Willys Widgets

Wooden Camera

rebotnix Technologies

CineLab

Abel Cine

Gamma Ray Digital Inc

Glidecam

Broadcast Solutions Inc

Metropolis Post

Paralinx LLC

CineTape

FJS International, LLC

Visual Products

New Pro Video - New and Used Equipment

Ritter Battery

The Slider

Aerial Filmworks

Technodolly

Media Blackout - Custom Cables and AKS

Media Blackout - Custom Cables and AKS

Technodolly

Wooden Camera

FJS International, LLC

CineLab

Glidecam

Ritter Battery

Paralinx LLC

Aerial Filmworks

New Pro Video - New and Used Equipment

The Slider

Rig Wheels Passport

Visual Products

Tai Audio

Abel Cine

Broadcast Solutions Inc

Gamma Ray Digital Inc

Metropolis Post

rebotnix Technologies

CineTape

Willys Widgets