Roamio plus vs cable company dvr - PQ

Discussion in 'TiVo Roamio DVRs' started by davidg716, Jan 22, 2015.

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  1. davidg716

    davidg716 Member

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    So funny story. I upgraded the harddrive today And had to reinstall everything, well, I think the picture actually looks better now than it did before. Still set to 1080 60p so no change in resolution. But watching the superbowl and the picture is really good.
     
  2. Bigg

    Bigg Cord Cutter

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    Some setting must have changed, new HDD alone isn't changing PQ...
     
  3. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Agreed, and he would also have to compare it directly to the MSOs box on the same channel with all the same settings.

    OP, It could've just been that NBC and/or the MSOs used the highest bitrate, resolution and equipment for the most watched TV show in history, don'tcha think?
     
  4. CoxInPHX

    CoxInPHX COX Communications

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    FWIW: When I got my first TiVo I also thought that the SA8240HDC HD DVR had a better PQ, I kept both DVRs attached to the same TV for about a year, finally getting rid of the cableco DVR.
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=8645457#post8645457
     
  5. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Well, it is a believable scenario, considering the MSO boxes from Cisco, Motorola, etc. are probably built using MILSPEC or close to it parts so they have high quality, high tolerance components and they're rugged and can withstand Bubba throwing it in the back of his pick 'em up truck as well as changing owners on a regular basis.

    I'm sure TiVo uses the cheapest stuff from Asia and Mexico that barely meets tolerances and saves on manufacturing costs. Heck I just hooked up my Premiere XL that's THX certified and I swear it has better picture quality than my Roamio plus. I think that's the last unit I mentioned earlier that I tested with my i1 Pro colorimeter too.
     
  6. Bigg

    Bigg Cord Cutter

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    Yeah. The affiliates may also have cut the subchannels back hard. Some cable companies just take the OTA channels bit for bit, subchannels and all, and stick two of them on a QAM, so that extra bandwidth for the main feed would also affect cable. Even if the cable company were compressing it on their own from a high-bitrate feed, I would think they would "juice" the statistical multiplexer a bit to be biased and give more bandwidth to the Superbowl and less to whatever was sharing the QAM.
     
  7. Roveer

    Roveer Member

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    Without knowing exactly how Tivo's technology works your statements could be slightly inaccurate to dead wrong. We all wish the world was that easy.

    First, the video processor might be (and probably is) totally different in Tivo than the STB's that could account for a lot. We don't know if it's passing the data stream straight through (I kind of doubt that it is), or if it's being processed or possibly compressed in order to be transmitted over CAT5 or MOCA to Mini's. Lots of things probably ARE happening to that stream inside the Tivo and it could have a huge difference on how the picture looks.

    I'm happy that lots of people say the PQ is exactly the same or better with Tivo, but my experience is that it is not. And depending on the load on the Tivo can vary quite a bit. Remember I have a total of 6 mini's connected to my Tivo with probably 4 or more running/recording at times. The chart below shows some of the data rates for different kinds of 1080 video. As you can see, there is uncompressed, compressed (implied), 8 bit, 10 bit, RGB (4:4:4) and a bunch more. All of these things do make a difference and I don't believe any of us (especially me), know exactly what is happening inside a Tivo Box. Do we even know what data rate Tivo streams video to a mini? I bet its a lot lower than some of the numbers below. Remember I have my Roamio running on a 100 mbps switch running 6 mini's. The numbers below are all almost 100mbps or more for 1 HD stream. Tivo may be compressing the heck out if it's stream to allow the technology (multiple mini's) to work. Inside the STB the datarate can be potentially much higher because it's only got to move inside the box and then to HDMI. Oh, my original remarks were all made when I had the entire setup on a 1gbps switch. I went to the 100 meg because it was Cisco enterprise grade and I really haven't seen any difference. So, it's just not as easy as saying, "It's taking the same MPEG-2 signal, recording it bit for bit, and spitting it back bit for bit, and then decoding it." Maybe it does, do any of us know for sure? Why am I seeing 3-5 times more artifacts on my Tivo setup than when I had STB's? And I'm not using the wrong resolution. Some of the SD channels almost look like 90's stile first gen AVI files. I really don't remember that when we had the STB's.

    Back in the infancy of video devices, there was great debate about the quality of different video processing chips. Sigma chips being one of them. All the heavy geeks talked about color space, bit depth etc. They all talked about how all of these things had effects on how things looked when they finally got to the screen. It does make a difference. Tivo is NOT the same as a STB.

    Here's a post from back in 2013 with folks making similar complaints about PQ. And like this thread, it devolved into Your wrong, no your wrong. It's just too subjective to get everyone to agree but as I've said before. It's just not the same. Still love my tivo. Family took to it better than I thought too.

    Another thread about Tivo Picture Quality

    1080i and 1080p HDTV uncompressed
    8 bit @ 1920 x 1080 @ 24fps = 95 MB/s, or 334 GB/hr.
    10 bit @ 1920 x 1080 @ 24fps = 127 MB/s, or 445 GB/hr.

    8 bit @ 1920 x 1080 @ 25fps = 99 MB/s, or 348 GB/hr.
    10 bit @ 1920 x 1080 @ 25fps = 132 MB/s, or 463 GB/hr.

    8 bit @ 1920 x 1080 @ 29.97fps = 119 MB/s, or 417 GB/hr.
    10 bit @ 1920 x 1080 @ 29.97fps = 158 MB/s, or 556 GB/hr.

    1080i and 1080p HDTV RGB (4:4:4) uncompressed
    10 bit @ 1280 x 720p @ 60fps = 211 MB/s, or 742 GB/hr.
    10 bit @ 1920 x 1080 @ 24fps = 190 MB/s, or 667 GB/hr.
    10 bit @ 1920 x 1080 @ 50i = 198 MB/s, or 695 GB/hr.
    10 bit @ 1920 x 1080 @ 60i = 237 MB/s, or 834 GB/hr.
     
  8. slowbiscuit

    slowbiscuit FUBAR

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    Yeah LOL, this also pretty well debunked any claim you made.
     
  9. Bigg

    Bigg Cord Cutter

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    There could be a slightly different video processor that's doing something to the video coming out of the box, but it's not going to make a big difference, and it's not going to fix the inherent problems with over-compression that many cable companies (I'm looking at you, Comcast) have. I run my TV through a DVDO EDGE, which is an order of magnitude above what you will find in any STB, and it cleans up the video somewhat, and hides some of the bad artifacts, but when it comes down to it, Comcast's over-compression is still really obvious, and the PQ wasn't any different using an HTPC or their crappy DVR.

    TiVo DOES NOT re-compress the stream for the Minis. The Mini gets the MPEG-2 exactly as it was sent by the MSO (or OTA). TiVo doesn't have anywhere near the horsepower required to do that much re-compression. So the only difference would be how the TiVo Roamio/Premiere vs. the Mini is decoding and processing the video before it goes out the HDMI port, but again, those would be miniscule differences, if any.

    You clearly have no clue what you're talking about. TiVo records the MPEG-2 or MPEG-4 (on FIOS and a select few cable companies) stream as it comes in from the MSO. That stream is streamed without modification, other than some sort of file wrapper and metadata and whatnot, to the Minis exactly as it came from the MSO. We know this for a fact, since many TiVos, like my XL4 have no ability to transcode the video in the first place.

    Typical MPEG-2 bitrates range from 8mbps (on the really low end on Comcast, they look atrocious) to 19mbps on the high end, most are between 12 and 16mbps or thereabouts. 12mbps is starting to get really shady if there's a lot of motion, 15+mbps looks really good. There theoretically cannot be cable video channels available to a TiVo that exceed 38mbps. No way, no how. Can't happen. Doesn't exist.

    As far as I know, there is nothing available on any QAM system in the US that exceeds 19mbps, which is also the limit for OTA, and I'm not positive if it's even possible to have an MPEG-2 channel over 19mbps on a QAM system. Doesn't exist, isn't going to happen in the near future until we're looking at 4K, and that's limited to 38mbps, because that's the width of a 6mhz QAM channel. Bandwidth beyond that will have to be running over IP on top of DOCSIS.

    Even with Verizon FIOS, where many channels are 19mbps MPEG-2 (although some are now tri-muxed at around 12mbps per channel, and even the ones that are close to 19mbps usually aren't quite there), you would need 5 Minis streaming simultaneously to encounter problems on a 100mbps network, and if you put one on MoCA, and the others one 100mbps Ethernet, you'd have enough bandwidth even under the most extreme hypothetical situation. Or put a gigabit switch in. All 5 would work fine in a good MoCA installation as well.

    Even my older XL4 can spit out 3 live streams to Minis, plus be used locally. Yes, it slows down a bit in terms of remote responsiveness, as it's running completely flat out, but the video is fine. With the video streams already encoded and sitting that way on the hard drive, there is no way for the quality to degrade if there are bandwidth problems. If the network doesn't have enough bandwidth available, the Minis either freeze or drop entirely, there's basically no in-between.

    So the bottom line is that other than minute differences in the processing happening after the stream gets to the TiVo it is being played back on, the video stream is the same, irregardless of whether it's going through an MSO box, a TiVo Roamio, a TiVo Premiere, or a TiVo Mini.
     
  10. Roveer

    Roveer Member

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    See the blue on the right side. Pulsing in the live video on my Mini. As a matter of fact most solid colors on shows do some kind of pulsing if you look closely enough. I've set this to record and will see how it displays on my computer and will try to upload a sample. Never saw this type of junk on my STB. Also, picture is "soft" overall compared to my STB.

    [​IMG]

    Video Link of Pulsing Blue Background on Right Side

    Another Example of Pulsing. Look at McCain's suit right hand side

    Same McCain Video but downloaded from Tivo Very clean compared to what comes out of the Mini. Negligible pulsing

    Just did not have this PQ on a STB...

    Roveer
     
  11. trip1eX

    trip1eX imo, afaik, feels like to me, *exceptions, ~aprox

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    Yeah he got used to it and forgot about his previous box.

    People get a new something or other. Then they sort of notice it isn't quite the same. Then they start looking for sht. Something they never did before with their old watchamacallit. And when they start looking for stuff then they find it. And then declare it was never there before. ONly they forget they never looked for it before. And then they conclude the new thing must be worse.

    They drive themselves nuts for awhile until they finally wake up one day and forget about it all.
     
  12. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    What you are seeing in those samples is a compression effect called "macro-blocking." One of the things that MPEG-2 compression does to save space is average together the color values of adjacent pixels. Then, instead of having to send 30 different color values, the data just says "repeat this pixel color value 30 times). That's a gross oversimplification, but captures the essence.

    This is 100% a result of either the source content (Fox News in your example) or your cable company feed being over compressed. That was absolutely the same on your cable company box. It is NOT something the TiVo is doing. As Bigg points out, no TiVo DVRs have compressed the recorded video themselves since broadcasters and cable companies went digital. The transcoding capability of the Stream is only inside the Roamios and is absolutely not used by the Minis. If it were, you couldn't watch MPEG-4 channels on a mini because the Stream can not take in an MPEG-4 channel (at least not until they update the firmware).

    I have no idea why you didn't see it previously. I can only say that we don't see anything that bad on FiOS, and never saw it that bad on DirecTV HD channels. Macro-blocking exists in all compressed video, it is just a matter of how bad it gets, and that is directly related to how small a bitstream is allocated to the channel.
     
  13. Roveer

    Roveer Member

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    My Provider is FIOS

    When you look at the Tivo Recorded stream on a computer you really don't see it at all. So that leaves me to believe the video processing chips in the Tivo Equipment are doing a BAD job at displaying the content. The STB video processing chips do a better job. I still have STB's at my office. I guess I'll try and do some side by side comparisons and see if I can visually quantify the difference. At this point, nothing is going to change and I do like my Tivo setup. We are starting to use the pause live tv more and more now that we have it. We are starting to use the Amazon prime streaming app as well. Those are all plus's in my book.

    Roveer
     
  14. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    I guess then it's because I don't watch Fox. ;)
     
  15. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Have you tried using the component video out on your Roamio plus to rule out any HDMI issues?
     
  16. Jed1

    Jed1 Well-Known Member

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    Roveer,
    If you have the 1080p box checked in your video settings of your DVR, uncheck it and then see if this changes the video on the mini. Since there is no content made in 1080p60 there is no reason to use this setting.
    Make sure your have 480i, 480p, 720p, and 1080i selected in the menu on the main DVR and then do the same on the mini. Do not select 1080p60 even if your display is native 1080p60. Let your display do the conversion for both the DVR and mini .
     
  17. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Good idea! :up: Then you take the TiVo's scalar out of the equation. Great troubleshooting tip! FYI, I don't think 1080p on the mini does anything to broadcast channels. It only allows pass thru of 1080p24 streaming content if your display is compatible.
     
  18. Jed1

    Jed1 Well-Known Member

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    Old School troubleshooting!;)

    I remember when I had my cable company DVR (Pace RNG200) it had a 1080p60 option. I tried it and I noticed I had some minor artifacts on my Kuro on the 720p channels. I never used this option since then.

    Another thing is his TV settings. If his TVs are not calibrated and has those stupid enhancement features turned on this will also produce artifacts like he has.
     
  19. HarperVision

    HarperVision TiVo's Italian Cuz!

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    Yeah, but then the artifacts would've also showed up when he used his MSO box too.
     
  20. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    FWIW, while the video looks okay on a small monitor, I pushed the downloaded video from my PC to our 55" plasma TV and it looks just like the samples of TiVo output the OP posted (tons of macro blocking in McCain's jacket). I also looked at Fox News Channel live on our 65" 1080p set and saw the same macro blocking shown in the closeup samples. I did not, however, see any such artifacts on Al Jezeera America. FNC broadcasts in 720p and AJA broadcasts in 1080i, but that alone would not cause such severe artifacts on FNC. Either Fox is just over-compressing FNC before Verizon ever gets it or Verizon (for some reason) is re-compressing FNC to a lower bit rate. I still can't explain why the Verizon STB didn't look the same.
     
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