Why you need to sort out your post production monitoring!

workshops-275 Why you need to sort out your post production monitoring!

One of THE most common complaints I hear, day in, day out, is: There is banding in my footage.

Before you start complaining about banding or other image artefacts ask yourself one very simply, but very important question: Do I know EXACTLY what is happening to my footage within my computer or playback system? As an example, editing on a computer your footage will be starting of at it’s native bit depth. It might then be converted to a different bit depth by the edit or grading software for manipulation. Then that new bit depth signal is passed to the computers graphic card to be displayed. At this point it will possibly be converted to another bit depth as it passes through the GPU and then it will be converted to the bit depth of the computers desktop display. From there you might be passing it down an HDMI cable where another bit depth change might be needed before it finally arrives at your monitor at goodness knows what bit depth.

The two images below are very telling. The first is a photo of a high end TV connected to my MacBook ProRetina via HDMI playing back a 10 bit ProRes file in HD. The bottom picture is exactly the same file being played back out of an Atomos Shogun via HDMI to exactly the same TV. The difference is striking to say the least. Same file, same TV, same resolution. The only difference is the top one is playing back off the computer, the lower from a proper video player. I also know from experience that if I plug in a proper video output device such as a Blackmagic Mini-monitor to the laptops Thunderbolt port I will not see the same artefacts as I do when using the computers built in HDMI.

And this is a not just a quirk of my laptop, my grading suite is exactly the same. If I use the PC’s built in HDMI the pictures suck. Lots of banding and other unwanted artefacts. Play back the same clip via a dedicated, made for video, internal PCI card such as a Decklink card and almost always all of the problems go away. If you use SDI rather than HDMI things tend to be even better.

So don’t skimp on your monitoring path if you really want to know what your footage looks like. Get a proper video card, don’t rely on the computers GPU. Get a decent monitor with an SDI input and try to avoid HDMI for any critical monitoring.

20170620_091235-1024x576 Why you need to sort out your post production monitoring!
Shot viewed on a good quality TV via HDMI from the computers built in graphics card. Notice all the banding.
20170620_091347-1024x576 Why you need to sort out your post production monitoring!
Exactly the same shot/clip as above. But this time played back over HDMI from an Atomos Shogun Flame onto the very same TV. Not how all the banding has gone.

 

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One thought on “Why you need to sort out your post production monitoring!”

  1. Hi Alister,

    What Display Profile were you using for the HDMI monitor connected to your Mac? See System Preferences > Displays > Color tab > Display profile. I wonder if a sub-optimal display profile was selected. Some of the options available include:

    ACES CG Linear
    Adobe RGB (1998)
    Generic RGB Profile
    HD 709-A
    Rec. ITU-R BT.2020-1
    Rec.ITU-R BT.709-5

    I have an HDTV connected to my Mac, and am using the HD 709-A display profile. I haven’t noticed any banding issues, but I would be curious if you could post the still frame that exhibited the issue to see if it happens on other systems too.

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