Digital Delivery

[Mark Suszko]

I know there are several different companies that do this sort of thing, not just DG Fastchannel. They accept the programs on various media and can do the conversions themselves, so it is not 100 percent certain that YOU have to do the initial compression, if you have the time to send them a master tape they can read.

Have you asked the service you’re considering using for their specific tech preferences yet? Or did you mean you were going to do all the FTP stuff “in-house” yourselves? In whch case it may take a few test runs to develop a “recipe” that works best for your specific users. Biggest Issues I’ve heard of involve a compression pass that reverses the field order.

[Todd Terry]

[Mark Suszko] “several different companies that do this sort of thing, not just DG Fastchannel.”

Yeah, I go back two decades with them (God I’m old) back when they were DGS and just doing radio delivery… but haven’t used them in years.

Comcast is just requesting direct FTP delivery. In this particular instance, there’s no point in bringing in (and paying for) DG Fastchannel… if I have to FedEx someone a dub, I might as well just send it right to Comcast rather than a middle-man.

[Mark Suszko] “Have you asked the service you’re considering using for their specific tech preferences yet?”

Yes… well the “service” is Comcast itself, and they couldn’t be sketchier. All we get from them is to send “mpeg2 or .mov files” and to make sure to put plenty of black at the head and tail. Oh, and “You might send a test file, first.” They seem clueless. Obviously not a Bob Zelin client.

[Mark Suszko] “In whch case it may take a few test runs to develop a “recipe” that works best for your specific users.”

That’s the biggest problem. We’ve tried countless setting and output combinations, and can’t find that elusive recipe that works and always looks good.

I know it’s the wave of the future, but right now it’s a big pain in the rear.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Chris Blair]

Todd,

We output for Comcast in Nashville and Louisville. I’ll send you the specs from out output settings on our NLE system (VelocityQ).

We send them mpg2 files and the setting are really pretty basic, but I’m not at the office at the moment. When I get there later I’ll send them to you.

Where most of the TV stations and cable companies screw up digital deliveries is with field ordering, so if you work in progressive or have a way of deinterlacing interlaced projects and sending them progressive, I’d do it. Or, just send them a couple test spots with different field order and see which one they say works.

I’ll post later this evening with more specifics. Are you coming out of Premiere CS4 and Matrox Axio? Is that correct?

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com

[Daniel Low]

We are pretty well 100% file delivery and one of the biggest in Europe.

Our chosen format is MXF wrapped IMX 50MB/s I-frame OP1a at 720×608 (PAL)

We get nothing refused.

Bottom line is that if you stick to an I-frame only (Contrained) 50Mb/s MPEG-2 file and you’ll be fine. For SD only, obviously.

__________________________________________________________________
“There’s no chance that the iPhone is going to get any significant market share. No chance.”

Steve Ballmer To USA Today

[Chris Blair]

I fear broadcasters here in the U.S. aren’t quite as savvy as our friends from across the pond. We have a spreadsheet we have to keep that lists the dizzying array of file formats and settings local network affiliates and cable companies require.

Many take MPEG2, some require various flavors of Quicktime, some require really specific containers and codecs (one has to have a specific Matrox AVI codec).

Once delivered, many (if not all) of them re-encode your already heavily compressed spots, and the results can be frightening. We send test after test and still see our spots run with fields reversed, color space screwed up, squished vertically or stretched horizontally, and with so much compression you can’t read large block text based graphics.

There are some that are so bad, we just gave up and resorted back to delivering tape based dubs and letting them encode them into their system.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com

[Daniel Low]

[Chris Blair] “Once delivered, many (if not all) of them re-encode your already heavily compressed spots”

I guess that’s why most of the stuff we get from ‘over there’ looks terrible! And then we have to standards covert it. Jeez!

__________________________________________________________________
“There’s no chance that the iPhone is going to get any significant market share. No chance.”

Steve Ballmer To USA Today

[Chris Blair]

Todd,

Here are the settings we use for Comcast:

Width=720
Height=480
Aspect=4:3 (They don’t accept 16:9 as far as I know)
FrameRate=29.97
Color sampling=4:2:2 (Use 4:2:2 if you have that option. Otherwise just use the DVD spec of 4:2:0)

Fields=lower field first, which matches our NLE system
(this may differ depending on your editing system. I’d send them 2 tests with one using upper and the other lower. 24P video with pulldown also often causes problems so if you shoot/edit using that be sure to also send a test of a 24P based spot. You may need different presets for each. When we send 24P spots to some stations/cable systems, their encoders reverse the fields, so we have special presets that resize the video instead of cropping the top and bottom 3 lines. This effectively reverses the fields which makes the 24P video play smoothly)

Multiplexed Stream
(Video/Audio encoded in same file, sometimes called Program Stream I believe)

PFrames=2 BFrames=2 (We just use the defaults on this coming out of our NLE system, which comes from a DVD compliant MPEG2 preset)

Variable Video Bitrate (VBR)
VideoMaxBitrate=20Mb/sec
VideoMaxAvgBitrate=18Mb/sec
VideoMinAvgBitrate=15Mb/sec

AudioBitrate=224
(MPEG Layer2, AC3 or linear PCM, basically anything supported within DVD specs. AC3 generates smaller sizes at no real loss in quality)

CloseGOP=3
Audio BitsPerSample=16
SamplesPerSec=48000khz
Channels=2 stereo

If you include a 2 seconds bars/tone, 2 seconds of a slate and a second of black before and after the spot, this usually generates a file about 60-75MB in size depending on the visual content. If there’s a lot of white (or black) space, the files are smaller. If there’s a lot of detail and motion, the files are bigger.

If you use 4:2:2 sampling, your files will be bigger since there’s more color info, but your quality will be a little higher. But the 4:2:0 encoded files look pretty darn good at the data rates above.

You can also use constant bitrate (CBR) at about 10-12Mb/sec and the resulting files are about the same size, but we’ve never seen any significant visual difference in quality doing that.

Hope that helps.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com