Are You Being Cheated by Digital Cable? 291
Lauren Weinstein writes "Even though your cable company may claim that a channel is in a digital tier that you're paying for, they may be sending it to you in analog form, with associated negative effects. Surprise! Are You Being Cheated by Digital Cable? 'You're paying for digital, you should get digital. Outside of the lower video and audio quality that can be present on many analog feeds, third-party devices (like cableCARD TiVos) which could otherwise record a digital signal directly, will be forced to re-digitize an analog signal, with inevitable quality loss in the process. But how to know for sure if a channel is digital or analog as received?'"
Audio (Score:2, Informative)
On Comcast it's easy (Score:5, Informative)
Re:Shocking? (Score:1, Informative)
Look at the noise (Score:5, Informative)
Look at the noise characteristics. Analog and digital respond to noise differently. Digital pixilates and stutters but otherwise displays a perfect picture. Analog ghosts and snows.
If you're not getting enough noise to tell the difference then smile and be happy because you have a better cable TV signal than most of the rest of us.
How to know... (Score:5, Informative)
Begin unscrewing the coax cable from your cable box. As you very, very slowly pull it away, if the signal starts to fade/shows static/etc., it's certainly analog. If, instead, it suddenly goes from perfect, to black, it's digital. Also, in the latter case, it will probably start to show artifacts, perfectly square 16x16 pixel macroblocks that stand out in sharp contrast to the rest of the picture.
Re:Who actually pays more for digital cable? (Score:4, Informative)
Re:Analog is better here. (Score:5, Informative)
Bandwidth is not really a problem for HDTV: from what I read, most current HDDVD and BluRay titles are encoded at less than 10Mbps total. Since a DOCSIS modem can pull over 40Mbps from a single 6MHz NTSC channel bandwidth, a digital cable box should be able to squeeze at least three very good quality HD channels in the same bandwidth as one analog channel. With about 900MHz worth of usable downstream bandwidth on coax, there is room for up to 450 high-quality HD channels. Of course, about half of that spectrum is used by analog channels, SD/ED digital channels and cable-modems so there should still be room for 150-200 HQ-HD channels.
As for the processing equipment, the heavy-lifting is at the source where initial encoding is done and at the head-end if there is transcoding to be done. The rest is standard fare digital broadcast over an HFC network just like it is for all other digital cable broadcasts. Since head-ends already have quite a bit of equipment dedicated to each channel they support on their networks, having an extra transcoding/scaling unit in loops that require it is (usually) a minor hurdle.
Re:Incessant whining! Argh! (Score:4, Informative)
I had this problem a few years ago and called the cable provider. The technician who came out identified a simple barrel connector in the cable demarc box was attenuating the signal by about 12 db instead of the expected 0.5 db. It took him just minutes to trace out the wires and replace the connector (he also replaced the cable ends while he was at it,) and it didn't cost me a cent.
So I agree that you should do a bit more investigation before calling shenanigans.
Re:On Comcast it's easy (Score:5, Informative)
Many of these boxes can only output the signal as analog (on a user-specified frequency, for arbitrary placement in the channel map), some of them are capable of outputting MPEG-2 data using ASI as the physical link. In order to cram multiple channels in one frequency, the MPEG-2 streams have to be changed (PID numbers must be changed to be non-duplicates, PAT and PMT packets need to be updated), then these MPEG-2 streams need to be muxed together and encoded into QAM.
Seeing as this is an expensive process (that cable companies might not have planned for, especially in the case of smaller operators), I believe that many of them are waiting for the migration to MPEG-4, to get the most bang for the buck.
-- Joe
Re:Analog is better here. (Score:4, Informative)
The problem is not bandwidth, it is that the cable operators are locked into their antiquated equipment due to politics within the industry (for example, the CableLabs cabal/consortium), or due to the cost of the equipment (although I only do software at a company that makes this equipment, I have heard estimates of hundreds of dollars per channel in costs).
-- Joe
Re:Very interesting ... (Score:4, Informative)
If you are using something like VLC or mplayer (or even Media Player Classic on Windows), it shouldn't be too hard to get it to look right. Most feeds should have the MPEG aspect ratio flag set and it should Just Work. Otherwise you should be able to force the aspect ratio (4:3 or 16:9) in your playback software.
Re:How to know... (Score:1, Informative)
Composite video has a maximum bandwidth (Score:5, Informative)
Re:HD is Better - Digital just gets you more chann (Score:4, Informative)
Not true.
Not True.
I think what the grandparent was saying is its not neccessarily better
. If the transmitted program was recorded digitally, ie. recently, it does look better, and is mpeg2 standard (DVD) with bit rates up to 15 Mbs (thats the highest I've seen so far).
I'm sure that would look better. What if it were transmitted at 256 kbps instead? Would the quality still surpass a virgin dub from a high quality master onto broadcasters professional tapes (1/2" Beta as I recall)? No way in hell. And broadcasters I'm pretty sure don't generally use DVD's to store their material. So the bitrates you see on you DVD player are irrelevant. Actually, in general the quality of the source material is irrelevant. Yes, good tranmission won't help bad source material, nobody is arguing that. Assume pristine best case source material.
Now think, does an CD (digital representation of an analog sound wave) or an MP3 (compressed digital represntation of an analog sound wave) sound better? At higher bandwiths the compression losses (MP3 is part of the MPEG2 standard, a "lossy" standard) become negligible, sure. But almost nobody argues it is better than the original source.
Now lets think bandwidth. An analog signal consumes some amount of bandwidth (I think 38 Mbps). By compressing it via MPEG2, the cable company can now fit 7 (very good quality) to 12 (Ok quality) channels. With all the bandwidth pressure though (more channels, faster internet, HDTV), cable companies are being tempted to add even more channels in each slice, I've heard of up to 24 less popular digital channels being squeezed into 1 "analog" channel.
So why is "digital" sold as cleaner? Interference. While a very clean signal is injected at the head end, By the time it runs through all the splitters, amplifiers, it can be very muddled. The benefit of digital assuming about 85% of the signal can be ressurected at the far end, and near ideal picture can be constructed. Problem is, at about 75% loss, no picture can be reconstructed. Analog pictures can yield usable content with much higher loss level (we used to what OU football games out of NYC (OTA) with maybe 40% of the signal surviving. A staticy mess, yes, but we knew what was happening on the field.
Re:Very interesting ... (Score:3, Informative)
With the box on, press Power (turns it "off") then press Select within 4 seconds. This should take you to the User Settings menu.
If Power/Select takes you to the diagnostics, try Power/Menu. It's one or the other, I just cant recall which right now.