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Busted! Comcast Down-Converts native 1080i Channels to 720P!!!

Discussion in 'TiVo Coffee House - TiVo Discussion' started by HarperVision, Jul 29, 2016.

  1. Jul 29, 2016 #1 of 670
    HarperVision

    HarperVision TiVo's Italian Cuz!

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    Paradise...
    I think this deserves its own thread because it's such a severe violation to Comcast customers and the underhanded tactics of the always hated cable companies, in my humble opinion!

    http://www.tivocommunity.com/tivo-vb/showthread.php?p=10949905#post10949905
    It comes from this post when I suspected something fishy going on after reading this thread:

    http://www.tivocommunity.com/tivo-vb/showthread.php?p=10943669#post10943669
    ...and this:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=10944190#post10944190
    I think this needs to be reported and widely spread to call out Comcast on this ridiculously egregious, slimy, underhanded move on their part, just to cram in a few more crap channels that show nothing but crap reality TV! Dave Zatz maybe?
     
  2. Jul 29, 2016 #2 of 670
    tomhorsley

    tomhorsley Well-Known Member

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    The real question is: How good is their de-interlacing? If it is good enough, 720p could easily look better than 1080i.
     
    fredi likes this.
  3. Jul 29, 2016 #3 of 670
    lew

    lew Well-Known Member

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    I'm a FiOS customer. I'm happy with my picture quality, internet speed and reasonably happy with what I pay.

    I agree with almost all of your post, but let my play devils advocate for a minute:
    1. Have you read any posts anywhere from Comcast customers complaining about picture quality on the 720p Comcast encoded stations?
    2. Posters seem to love Vue and Sling TV as alternatives to traditional cable. What resolutions and bitrate are those services transmitting?
    3. Does the Comcast STB show the resolution of the station or the resolution being sent to your TV? In other words is the Comcast box changing the resolution to 1080i.
    4. You mention greed. Not sure I completely agree. Customers seem to prefer quantity (number of channels) over quality.

    That said my preference would be for fewer stations at a better quality. That's one of the things I like about HDNet movies.
     
  4. Jul 29, 2016 #4 of 670
    HarperVision

    HarperVision TiVo's Italian Cuz!

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    Not true at all. 1080i has the exact same spatial resolution as 1080p, and as you infer, with a good and properly operating de-interlacer 1080i would be and look equivilent to 1080p.

    720p does not and will not have the same resolution (pixel density) as 1080i/p.


    My answers within the quoted text, in RED
     
  5. Jul 29, 2016 #5 of 670
    lew

    lew Well-Known Member

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    Sony promises all high definition content will be available in HD.

    Says nothing. Read some of the threads on TCF. Posters talk about price and number of channels. subscribe to Vue, cut the cord and save money. Relatively few posters talk about picture quality. I can rent a Blu-ray at Redbox for a couple of bucks. I can rent the same movie streamed for $5-$10. Is there any question which has the better picture. Gas isn't that expensive.
     
  6. Jul 29, 2016 #6 of 670
    Bigg

    Bigg Cord Cutter

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    If this is, in fact, true, this is a new low for Comcast. They refuse to invest in their TV product by using SDV and plant rebuilds in combination with MPEG-4 to deliver a good TV service AND a good internet service.

    Instead they use their broadband monopoly to shove crappy TV down your throat instead of actually making it good.
     
  7. Jul 29, 2016 #7 of 670
    HarperVision

    HarperVision TiVo's Italian Cuz!

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    Well, technically 720p is still HD. I'm sure they had to explain to each network owner that due to the limitations of their streaming service, they would have to top out at 720p, at least initially until further infrastructure and technology upgrades could be made. I doubt that is the same story with Comcast and what they seem to be doing. I am sure they're trying to open up more room to increase internet speeds/bandwidth to compete with the likes of FiOS and New Charter/TWC/Bright House.

    I think someone should tip off DirecTV about this so they can market some new commercials pointing out how some "Big Cable" companies are compressing and down converting the crap out of their channels, compared to DirecTV's great h.264 HD image quality channels! :up:
     
  8. Jul 30, 2016 #8 of 670
    lew

    lew Well-Known Member

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    My point is providers don't commit to a specific resolution, only HD. Can you find anything from Comcast (or FiOS) which promises a specific resolution?

    Kind of funny if you think about it. People want faster internet so they can stream Netflix, Vue, Sling etc. Comcast seems to be offering faster internet by reducing video quality to streaming standards thereby giving informed consumers no reason to pay a premium price for cable transmission.

    Look at it this way, tivo customers who use programs like kmttg to archive shows will be able to skip the encoding step. You might not even have to encode the video for viewing on a mobile device.

    A compromise. Do we care what they do to shopping networks? Leave the primary feeds (HBO,SHO...) alone. Do the "magic" on the alternate coast feed, HBO2, HBO3....We can DVR shows off the main feed.

    I hate to say this but I think the majority of customers prefer the faster internet and increased number of channels vs video quality.

    Now optimized for iPad viewing may actually be a "good" sales piece.
     
  9. Jul 30, 2016 #9 of 670
    dlfl

    dlfl Cranky old novice

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    This is very interesting but I don't see it as the scandal implied by the OP. Picture Quality (PQ) doesn't depend only on either bit-rate (i.e. number of channels packed into a 6 MHz QAM), or on number of pixels (i.e., whether resolution is 1080 or 720). It also strongly depends on the amount of computing horsepower you're willing to devote to the H.264 encoding process. A ratio of 8:9 in bitrate could be compensated by better encoding to provide equivalent PQ. Now whether Comcast has actually compensated this way is another question. As already mentioned, there are other factors, such as overall customer satisfaction, that enter into such design decisions. Unfortunately the small percentage who are TiVo users with large screens don't have much weight in overall customer satisfaction.
     
  10. Jul 30, 2016 #10 of 670
    mschnebly

    mschnebly Member

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    I just switched back to Comcast from Dish and the picture quality is noticeably better. Actually night and day better. I don't care what they do or how they do it because my picture is great. :up:
     
  11. Jul 30, 2016 #11 of 670
    lew

    lew Well-Known Member

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    ITA I suspect most customers prefer the increased number of channels, increased internet speed and the increased DVR capacity the change permits. I'm not a Comcast customer but I'd prefer fewer channels at a higher quality.

    Are we getting to a point where 4K will be required to get picture quality equivalent to what HD is suppose to offer?


    Have you checked any of the channels Comcast is down rezing to 720p.
     
  12. Jul 30, 2016 #12 of 670
    atmuscarella

    atmuscarella Well-Known Member

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    The quality versus quantity thing doesn't really come into play for many households. They either don't have their TVs actually setup correctly or have a too small of a set for the distance they view it at. With the net effect being many people can not actually see the difference between a 1080i or a 720 down graded version of the same station. I am OTA only and have a 50 inch set, sit 12-14 feet from it, and can not see the difference between my CBS & NBC 1080i stations and my Fox 720p station (they all share their frequency with 1 or 2 SD stations). However I can see the difference between those stations and my ABC & CW stations which are 720p but share the same frequency (along with another SD station). But the ABC & CW stations don't look bad just a bit more washed out. So Pay TV providers can get away with lots of compression before the bulk of their customers are going to notice.
     
    Last edited: Jul 30, 2016
  13. Jul 30, 2016 #13 of 670
    TonyD79

    TonyD79 Well-Known Member

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    There may be more at play for abc than sharing. I get two abc stations and both are usually pretty bad on network programming. Local is fine. I think abc has a distribution problem. Same programming looks better on Hulu, etc.
     
  14. Jul 30, 2016 #14 of 670
    dishrich

    dishrich Member

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    (just found this thread over at DSLR)

    Depends on which type of STB you're using. I still have a legacy DCX-3501 DVR, which has a native P-T setting & which I always keep it on. I just checked a bunch of channels that are supposed to be 1080i & my TV is now reporting they are now 720p. BBCA, UP, MTVLive, UHD, VICE, COOKING, DIY & OWN are the ones I checked.
    Others like TV1, Weather & NFL are still reporting 1080i.

    On the X1 boxes though, none of them have a native setting...so basically EVERYTHING is converted (either up or down) to a chosen setting by the sub, so they'll probably never see a diff anyway.

    I believe all of their HD-DTA's are the same way, as I could never find a way to put them into native, either.
     
  15. Jul 30, 2016 #15 of 670
    lessd

    lessd Well-Known Member

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    You people can correct me if my following assumptions are incorrect: All flat screen TVs show the picture in the native resolution of the TV, which today is 720 lines, or 1080 lines, or 2160 lines. It does not matter if the input is 1080P or 1080i, your picture on a 1080 HDTV will be 1080P lines. A few people may be able to tell when a movie is coming into the TV at 24/frames/sec vs 30 frames/sec in action parts of the movie, so any difference will be in the detail of a given picture and color accuracy and depth. I have all HDTVs in my home and I can only tell, when I walk into a room with the TV on, if I am looking at a SD picture or a HD picture, but I can't tell anymore without looking at the TV info as to tell frame rate or resolution. (all my TiVos and Minis are set for pass through on the resolution.)
     
  16. Jul 30, 2016 #16 of 670
    atmuscarella

    atmuscarella Well-Known Member

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    That could be, no way for me to really tell. But I do know that a 1 hour prime time show on my ABC or CW station is less than half the size of a 1 hour prime time show on my Fox station, given they are all 720p the ABC & CW stations are clearly more compressed than the Fox station
     
  17. Jul 30, 2016 #17 of 670
    JoeKustra

    JoeKustra Cable only TCF Club

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    That brings up a interesting thought. When the bit rate is low (ABC) and not so low (Fox) is that because of compression? Also, I get two CW feeds, one local and one from NY. My local is 720p and DD2.0, the NY feed is 1080i and DD5.1 so how does that affect me, beyond knowing the storage difference and sound quality. No h.264 involved on my feed.
     
  18. Jul 30, 2016 #18 of 670
    atmuscarella

    atmuscarella Well-Known Member

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    Pretty hard to know if the same source material broadcast at 1080i would look better if you had a 1080p version, would have to buy some blu-ray disks of a TV show to find out.

    But compressing a 1080i TV feed to 720p stream is causing some data loss. Plus if they are cramming more channels into the same space that requires even more compression and more data loss. I really don't under stand the conversion to 720p, if the source feed is 1080i. When they first started broadcasting OTA HD a 1080i station and a 720p station's stream was about the same size. When they started to add sub channels they started compressing the streams more seems like they were able to compress 1080i streams just like they compressed the 720p. Not sure what Comcast gets out of converting to 720p and then compressing instead of just compressing the original 1080i stream.

    Are we sure these converted channels are not really 720i? That might explain allot.

    In the end what ever device (our TVs, a STB, DVR, Receiver, etc.) converts that compressed stream to the 1080p picture on our TVs is just guessing at what the lost data is.
     
  19. Jul 30, 2016 #19 of 670
    atmuscarella

    atmuscarella Well-Known Member

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    That's the way I understand it more compression equals lower bit rate or smaller file size.

    I just check some CW and Fox shows that I have transferred to this computer. While the size varies it would be basically correct to say my Fox 1 hour shows size was around 6,500,000 KBs and my CW 1 hour shows where around 3,200,000 KBs. Which indicates that the bit rate for the CW show has to be less than half that of the Fox show.

    With broadcast stations/cable companies they have to compress on the fly where streaming services can spend time conditioning the files and end up with a better looking picture for the same size stream.
     
  20. Jul 30, 2016 #20 of 670
    jth tv

    jth tv Well-Known Member

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    I am using an Antenna with a Roamio basic. With my plasma TV I think 720p looks better than 1080i. HOWEVER, Netflix "1080" per the TiVo info button does look better than "720".

    With Blu-Ray, the movies are typically the extra wide format with black bars above and below, which means that the main action part of the movie is actually smaller and less enjoyable to me than a movie/show that is in regular wide format.

    But what really matters most to me is how a show is filmed and lighted. It makes much more difference than its HD resolution, as long as its HD.
     
    Last edited: Jul 31, 2016

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