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Brad Fitzpatrick

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MPEG artificats in analog cable!? [Oct. 11th, 2005|08:17 pm]
Brad Fitzpatrick
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Why the hell do I see MPEG artifacts during commercials on analog cable?

Is the new way to distribute commercials to studios via crappy MPEG files?

Lame. Not that I care about commercial quality much, but I hate this "digital" world being used to lower costs more than increasing quality. Kinda depressing.

[User Picture]From: moonwick
2005-10-12 03:23 am (UTC)
Don't buy an XM or Sirius radio, then. :(

(I'm glad I'm not the only one to have noticed your sentiment.)
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[User Picture]From: brad
2005-10-12 04:02 am (UTC)
I had free XM for a month with my new car and I was apalled how bad it was.... not sure how anybody could listen to it.
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[User Picture]From: newscane
2005-10-12 03:27 am (UTC)
A lot of video actually is distributed digitally these days. A system called Pathfire is used by the affiliate services of several news networks to distribute content to their affiliates. It's also used by syndicators, and I believe by some commercial distributors as well. They use MPEG files... but I've never seen MPEG artifacts result from them.

It could also be one of the digital videotape formats, like BetaSX or Digibeta. I've seen some weird digital stuff result from them.
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[User Picture]From: stevieg
2005-10-12 03:29 am (UTC)
Where I work we recieve about 10-20 new commercials a day, and about 90% of them are MPEG. So, to answer your question, yes, and I totally agree, it is lame as hell :P
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[User Picture]From: vanbeast
2005-10-12 03:32 am (UTC)
it's not new at all. commercials and most programming are delivered to local stations via satellite. They knew they were going to have to go digital so they did it years ago.
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[User Picture]From: brad
2005-10-12 04:14 am (UTC)
I guess I should've clarified "digital" a little... I have no doubt digital is used everywhere (as it should be). I have an issue with incredibly lossy digital showing up in my living room where I have to look at it.
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[User Picture]From: vanbeast
2005-10-12 04:41 am (UTC)
I was probably a step ahead of myself too. One of the natural consequences of moving to a digital distribution network is that people will start to want their content faster.

MPEG was a pretty natural choice then (and is still pretty much the only video compression standard with any industry backing) so they went with it. When it became obvious that the transmission speed wasn't going to keep up, they started moving toward higher compression.
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[User Picture]From: edm
2005-10-12 05:06 am (UTC)
_Have_ to look at it? I generally assume all adverts will make me unhappy, and try to avoid looking at them even without artifacts :-)

Here (New Zealand) pretty much all the stations (which are all analogue, all the time) have used MPEG or similar as part of their transmission process (long haul links down to the local repeaters, I think), and you see MPEG blocks/artifacts from time to time in programs when the signal to the repeater breaks up. I assume they do that with commercials too.

If you were seeing an otherwise normal picture, just with compression artifacts, then chances are the advertiser supplied a too-heavily-compressed MPEG file for screening. I used to see this effect in some adverts in the "digital" movie theatres; and it really sucked having what looked like a 320x240 heavily compressed MPEG image shown on a large-movie-theatre sized screen. I tried not to watch that too.

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[User Picture]From: maxvt
2005-10-12 06:35 am (UTC)
Bandwidth is finite. Until enough people raise hell about crappy video quality (and it is crappy), current channels are going to be squeezed even more to make space for new (and profitable) programming. However, 95% of the people either don't notice or don't care.

Also, less popular channels are also more compressed.
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[User Picture]From: pega
2005-10-12 03:34 am (UTC)
MPEG isn't standard, but a lot of studios are heading in that direction. It's cheaper and easier to e-mail an MPEG of the ad then to have dozens of copies of the Beta SP or 1/2" tapes dubbed and then messengered/mailed. And ad agencies will find the absolute cheapest way to go when it comes to distributing copy.
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[User Picture]From: kvance
2005-10-12 03:36 am (UTC)
I've wondered how far this goes. I used to see artifacts during the hi-motion introduction of iron chef america on foodtv. (I now pull my cable off of whatever Comcast pushes over QAM; it looks like crap)
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[User Picture]From: brad
2005-10-12 03:47 am (UTC)
I bet as the studios convert all their production gear over to HD/digital in prep for HDTV that they just do DA conversion as a final step late in the process, converting on the outgoing (crap) digital signal.
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From: cjensen
2005-10-12 03:57 am (UTC)
Most studios have used uncompressed digital for a decade or more now. If the artifacts are so bad that you can see them, then they were either caused by compression during transfer (as you guessed) over a satellite link or whatever, or were caused on a comcast video server if they use one for final playout.

In the new world order of HDTV, I see artifacts constantly. The Smallville title sequence, for example, is loaded with blockiness.
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[User Picture]From: brad
2005-10-12 04:13 am (UTC)
Props for the Wikipedia link!
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From: (Anonymous)
2005-10-12 03:47 am (UTC)

TiVo double-encoding

yeah, I've seen that too. I *think* it's commercial distribution to local transmission points, because I've noticed it on ads for local stuff...
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[User Picture]From: 7leaguebootdisk
2005-10-12 03:51 am (UTC)
Well, you figure most everything that comes via satellite is digital, I see glitches that are clearly digital on my analog cable, and of course damn near everything is digital for some part of its editing and distribution.

Back in 1999-2000 I worked for DG Systems, who did digital satellite distribution of commercials. Nation wide in 4 hours, guarantied. A politician can screw up at lunch, and have adds about it showing on the dinner time news. Yes, they used mpeg2, a 30 second spot was 44MB. The system at the tv stations was a 1.2.13 kernel linux box.
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[User Picture]From: 7leaguebootdisk
2005-10-12 05:04 am (UTC)
And once you start seeing it, you cannot stop. A plain wall, spread across the screen, unevenly lit, artifact city! Ugly.
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[User Picture]From: brad
2005-10-12 05:17 am (UTC)
Well, yeah, I'd expect them on digital cable. That's just ass-city. But that's one of the major reasons I've never switched away from analog cable... I'll take noise over artifacts any day.
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[User Picture]From: toast0
2005-10-12 05:13 am (UTC)
I get fun compression artifacts over my shitty antenna. (they took away the free cable, and most of the stuff i would schedule to record was broadcast, so I get it off the internet instead... sometimes they say it's 'high definition')

at least the internet makes sure it doesn't look like complete ass most of the time
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[User Picture]From: taral
2005-10-12 06:00 am (UTC)
Yeah, unfortunately too many people converted to digital without realizing that digital doesn't degrade well in the face of errors like analog does. So there's nowhere near enough ECC on those links to ensure a clear signal.

Consumers'll start to bitch soon enough. They'll find a way to fix it.
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[User Picture]From: mart
2005-10-12 07:07 am (UTC)

Cable company Telewest here in the UK produces their analogue (analog ;)) feed essentially just by stuffing their digital cable output through a modulator. Last I looked, they were even failing to properly scale widescreen transmissions leading to a distorted picture. They get their feeds from most of their upstream providers as a digital (MPEG2, I think) stream too.

The upshot of this is that bad weather or other disruption anywhere along the supply chain causes frame dropping and MPEG artifacts that you'd normally associate with digital cable. I imagine in your case too only the last little hop to your home is analogue, and that the cable company is actually putting more effort into stripping it down to an analogue signal just so they can charge you less for it. Or something.

Crazy cable companies.

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[User Picture]From: mordant
2005-10-12 08:51 am (UTC)
The upshot of this is that bad weather or other disruption anywhere along the supply chain causes frame dropping and MPEG artifacts that you'd normally associate with digital cable.

Ditto with Foxtel Digital here in Australia - I think it relates to bad frame interleaves when the carrier dips for a second and framelock dies in the ass.
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[User Picture]From: idigital
2005-10-12 03:08 pm (UTC)
People still have analog cable in the UK? Wow. I thought nearly everyone was on digital cable by now.
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[User Picture]From: mart
2005-10-12 05:08 pm (UTC)

Due to Telewest's financial troubles they are still unable to offer digital cable nor cable modem service in a bunch of their service areas. They are offering the reduced analogue service in the hope that it'll keep people interested and keep the money flowing long enough that they can eventually get them to go onto digital cable rather than jumping ship to Sky. (Beyond the first sentence this is obviously speculation.)

Aside from this, a cheap “just the terrestrial channels plus Sky One and a few cheesy shopping channels” package is quite popular in my home town since a new building in the late 80s destroyed the over-the-air reception. It's cheap enough to be negligible, so a lot of people pay it just to improve their TV picture for the basic terrestrial channels.

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[User Picture]From: grahams
2005-10-12 01:36 pm (UTC)
What are these commercials you speak of? =)

I've noticed more and more compression artifacting on cable, digital or otherwise... I think almost everyone here realizes that "digital is the future" (it's digital, it must be better)... The unfortunate side effect is that if they are going to use a lossy compression, they at least tune the bitrate so the picture isn't terrible.

I presume this corner cutting is going to be even more of a problem as resolutions rise (which implies much larger streams/files).
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