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Broadcast Quality: What it Means For Non-Broadcast Content Delivery


2017 NAB Show Editorial Submission
by Rush Beesley, President RUSHWORKS

“Broadcast Quality”, my friends, is a relative term. For reasons that will become apparent in this discourse, I’ve always defined “broadcast quality” as “the quality of what you broadcast”. That concept is generally enough to short circuit a two-dimensional discussion and let you resume a meaningful dialog.

So how do you define broadcast quality? Presuming it requires something more insightful than the quality of what is being broadcast, let’s review the many variables contributing to this ephemeral notion. In no particular order.

  1. Film vs. Video

So do you think that film is higher quality than video? A lot of people do. Or rather did. Not many years ago the majority opinion favored film, citing video as never being able to handle the dynamic range of exposure and color available through film acquisition. And they were correct. The ‘resolution’ of analog video was extremely limited, with 525 “lines” of video from the top of the screen to the bottom, no matter what size the screen. The bigger the screen, or the closer you got to it, you could actually start counting those lines.

People flocked to movie theatres to see Big Screen productions, ones not limited by the limited capabilities of electronic television technology. How times have changed. With the emergence of digital video, and vertically ascendant advancements in expanded pixel density, what you’re watching on the Big Screen is just as likely to shot on video and delivered to the theatre via satellite.

And people are making commercials and feature films with smartphones. I challenge anyone to watch an episode of “Hawaii’ Five-O” and not swear that it’s shot on film. Gosh. It sure looks like film, doesn’t it? Heck … then it must be. Right? Huge range in contrast, vibrant colors. Not a hint of what I grew up with and recognized as video. No spoiler alert here. Just say, “OK, Google”.

  1. Frame Rate

Remember, we’re talking about “broadcast quality”. The frame rate for video in the US for more than seventy five years has been 29.97 frames per second. What the? Where the heck did that number come from? TMI for this discussion. Suffice to say it’s the NTSC standard (which some of us venerable old dogs call Never The Same Color). Add to that the frames were “interlaced”, meaning there are actually 60 individual fields comprising one frame.

So during playback the motion is very smooth. Interestingly, when folks see it they typically recognize it as video and not film. Why that? Because film doesn’t deal with the electronic hocus pocus of interlacing fields. The shutter opens for 1/24th of a second and captures a full frame of the action. So the frame rate is 24 frames per second, not 30. That means there is 20% less “action” recorded in each frame.

When you see 24 fps playback, your brain actually perceives a slight stutter between the frames. You don’t think about it, but it happens. And that, my friends, is why it was traditionally pretty easy to discern between film and video playback.

But we’re talking about broadcast quality here. To broadcast content originally acquired on film, you must transfer the film using a special video camera with a shutter that does some real hocus pocus, adding duplicate fields every other frame to synchronize the time differences.

Since you can’t “broadcast” film, this is what you see. An artificial video reproduction of film. And you lose the huge dynamic range of film and its theatrical subtleties in the process.

But that too has been eclipsed by video technology (actually computer technology) in the cameras that allows images to be recorded at virtually any frame rate, emulating the physics of capturing film. Notably, the “film look” can now be achieved by using 24fps in “progressive” mode, which means full frame and not interlaced.

  1. Broadcast quality according to TV engineers

Decades ago I was producing some low-cost video commercials in a TV station, and took one of the copies to a station which was scheduled to air the spot. This station was an affiliate of a major network (of which there were three at the time).

I took the 2” tape to the engineer for ‘quality control’ so it could be deemed fit for broadcast. He threaded the tape on a Volkswagen-sized VTR, hit the play button, and looked closely at his electronic scopes. He then stopped the tape, turned to me and said, “We can’t accept this tape. It’s not broadcast quality.” I was actually very proud of what I’d shot, and it looked stunning on the engineer’s super high-quality video monitor, playing flawlessly.

I said, “Uh … what do you mean … not broadcast quality? It looks great to me!” He then issued forth an explanation in a language I can only call jabberwoky. Something about the “sync tip and the front porch”. He rejected the tape. And he never once looked at the monitor.

  1. Size matters. Depending.

Fast forward. People are now driven to produce content in 4K … and Beyond. While I understand that more pixels are “better”, think about it. Sure, if you’re watching a huge screen in a movie or home theatre. Proponents of 4K suggest we move very close to a modest sized 4K display in order to “appreciate” the difference. Really? Who wants to sit close to a big TV to appreciate it?

And here’s the most important consideration, given that traditional “broadcast” as we’ve known it is being rapidly displaced by migration to alternate means of content distribution. The new term is “OTT”, I believe, which I’m told signifies “Over The Top”. Funny how meaningless things stick. At any rate, these subscription services like Netflix, Hulu and dozens more use inexpensive internet ‘boxes’ like Roku for ‘reception’, removing broadcast towers and linear programming from the viewer equation.

So it’s suggested that the term “broadcast quality” be replaced. RIP. OTT quality, maybe? Where signals are compressed and resolutions decimated so that millions of people can tap available and evermore in-demand bandwidth and hope for minimal pauses, video stuttering, and highly compromised video quality while chanting, “Isn’t Technology great???”

Don’t get TOO close to your big screen monitor, though. You’re liable to see a bunch of little squares in the picture when something moves too fast. Quality is always trumped by expediency in delivering less to more.

And finally, size REALLY matters if you’re among the legions who’ve turned to their ‘smart devices’ to watch content when they want, where they want. You can take that 4K and shove it to Topeka when it comes to image quality on small screens. Sure the screens have great resolution. But do this for me. Grab some ‘high quality’ video content and start watching. You’ve got your ‘phone’ about 12” from your face, right? Look at the size of that rectangle, and imagine yourself parked in the very last row of the Admiral Twin Drive-In Theatre and watching that projected film image from 300’ away. That image could be one tenth the resolution and it will look the same to you from the driver’s seat. Or wherever.

And that’s the point. If the image is small … or you’re a long way off … you just don’t need all that resolution to enjoy the show. So next time you download something to watch, be sure and check the available quality options. If one of them is “Broadcast” … please re-read this article before you purchase.

 

 

 

 

Broadcast Beat Magazine

Broadcast Beat Magazine is an Official NAB Show Media partner and we cover Broadcast Engineering, Radio & TV Technology for the Animation, Broadcasting, Motion Picture and Post Production industries. We cover industry events and conventions like BroadcastAsia, CCW, IBC, SIGGRAPH, Digital Asset Symposium and more!

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