Originally posted by cinemagotham
Would I be getting any digital channels even if I only subscribed to basic?
....This TV has a built in QAM cable tuner and a built in HD receiver, so all you have to do is plug an HD antenna right into it and get OTA HD channels.
I think it's the analog local stations that look a lot cleaner than ther digital counterparts.
....By the way, I think TWCNYC's bandwidth argument is nonsense. They are lazy sods and if they wanted to get it together they could.
TWC NYC delivers analog and digital signals. There are about 100 analog channels with perhaps 30 not sync-scrambled (no converter needed). Most of the analog channels were duplicated in digital format a few years back. (Channels 31, 21, 25, last I checked, were still only analog.) Some digitals are encrypted, requiring a subscription. TVs with QAM tuners can pick up unencrypted digitals. Generally I find that digital channels have better fidelity than the analog source, although the opposite is true at times if the source is poor quality. Composite analog is ~440X480 resolution, while SD digital can be ~720X480 (possible with this fiber/satellite delivery to TWC headends).
TWC out of bandwidth? Each analog channel needs a 6-MHz-wide cable slot (frequency). So that's 600-MHz bandwidth out of TWC's 860-plus-MHz total. Non-H/DTV digital channels each get <5 million bits per second (Mbps) out of the ~40 Mbps available in each 6-MHz slot with 256 QAM (most digital channels; a few here are 64 QAM). That's about 8 SD channels for each 6-MHz slot. H/DTV channels use ~19 Mbps per slot, or about 2 channels/slot. To calculate how much of the remaining bandwidth SD channels occupy (~860 - ~600 = ~260 MHz), count all the special sports tiers, subscription foreign-language channels, etc. and divide by 8.
The bandwidth requirement of the huge Spanish-language block of channels is uncertain IMO. Using the diagnostic mode
with my 3100HD converter I noticed the Spanish Discovery Science channel has the same frequency as the English version. So, unless TWC is putting both channels on the same frequency (2 of 8/slot), it appears the Spanish version could just be remapped video, requiring no additional bandwidth, with the audio, needing little spectrum, changed. Perhaps a really energetic subscriber will enter all the channels/frequencies on a spreadsheet data base and sort it on the frequencies to help determine what's going on.
TWC here has been using rate shaping
and statistical multiplexing to maximize bandwidth use.
Seems that's just a starting point for bandwidth use, though. Video-on-demand (VOD) delivers streaming video from TWC disk servers to local cable hubs or optical-fiber nodes, (not to each NYC subscriber when you order VOD). But for peak VOD demand periods, how much spectrum must be reserved? How much spectrum is being used for broadband Internet, both private and businesses? How much spectrum is being set aside for upcoming cable telephone use? That ~260-MHz block of non-analog available spectrum seems fairly limited.
One method of freeing up bandwidth, eliminating the analog block and using digital-to-analog converters
for subscribers requiring analog, might be too costly--even with low-cost converters--if too many subscribers need analog. These special converters, BTW, are smaller than regular cable boxes. Whether TWC is planning this converter approach, or other techniques (link above), it's puzzling why one of the largest cable systems apparently couldn't plan for HD's current rapid expansion. -- John