PBS switching to H.264?

Discussion in 'TiVo Coffee House - TiVo Discussion' started by ggieseke, Nov 12, 2019.

  1. ggieseke

    ggieseke Well-Known Member

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    Just noticed that my local PBS station (KUHT in Houston) switched from MPEG-2 to H.264 sometime in the last week or so. That's the first time I've seen that on OTA broadcasts.
     
  2. silversurfer2k7

    silversurfer2k7 New Member

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    Yeah, I noticed the improved picture. Channel 8.4 looks better for sure
     
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  3. Bigg

    Bigg Cord Cutter

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    That's... fascinating. For all of the channels, or only subchannels?
     
  4. silversurfer2k7

    silversurfer2k7 New Member

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    Maybe the main PBS channel looks a little sharper, too. But I noticed the biggest difference on subchannel 8.4. It was pretty horrible before.

    EDIT: I noticed this picture improvement maybe a month or so ago. Channel 8.2 (Create) looks sharper as well.
     
    Last edited: Nov 13, 2019
  5. collin

    collin Member

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    Did ATSC get updated to allow this? And it works automatically on our Tivo's?
     
  6. ggieseke

    ggieseke Well-Known Member

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    I don't see a huge difference visually on the main channel from last weekend's Austin City Limits, but I'll get a better idea tonight when I record Nova. It went from 1080i at about 8Mbps to 720p at about 3.5Mbps. Obviously that frees up a lot of subchannel space (that I never watch).

    ATSC has always supported H.264, I've just never seen it used in the Houston market. Any TiVo newer than the original Series 3 with the OLED display should be fine.
     
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  7. astrohip

    astrohip Well-Known Raconteur TCF Club

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    Can I assume this only affects OTA? Those of us enjoying the over-compressed Comcast signal still get the same pixels?
     
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  8. JoeKustra

    JoeKustra in the other Alabama TCF Club

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  9. jacktechie

    jacktechie New Member

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    Start worrying. Just north of San Jose, Comcast has started MPEG4 encoding some OTA at ~4.2Mbps. 717 (60.1 Independent owned by 22.1 PBS), 704 (4.1 MyNetwork), 709, 710 (9.1/54.2, 54.1/9.2 PBS). ABC, FOX, CBS remain MPEG2 and 10-13Mpbs. I didn't check the other channels I do not watch. Of the ones I watch, OTA transmission is still MPEG2. Most of the subchannels are still SD.

    About half the shows I download are missing the video track.
    Audio only on some linked Comcast broadcast channels - SF Bay Area
     
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  10. dishrich

    dishrich Active Member

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    Except most HDTV's do NOT support H.264...so I guess this means those viewers (w/out H.264 capable TV's) get zip now from this station... :eek:
     
  11. ggieseke

    ggieseke Well-Known Member

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    Just watched my recording of Nova (Decoding DaVinci) from last night. The engineers at Comcast and other cable companies could learn a LOT about H.264 encoding from the folks at PBS.

    Edit: I was wrong about Nova. See post #19.
     
    Last edited: Nov 14, 2019
  12. Charles R

    Charles R Active Member

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    I noticed a while back my PBS "looked better"... I'm wondering if they switched as well.
     
  13. wmcbrine

    wmcbrine Well-Known Mumbler

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    Not always. Per Wikipedia, "In July 2008, ATSC was updated to support the ITU-T H.264 video codec." Prior to now, I've only seen it on a single local subchannel here, Stadium (45.4 Baltimore). It's been there a while. Only newer TVs can pick it up. When I mentioned it on DSLReports, some dumbass refused to believe me. :)
     
  14. Slumpert

    Slumpert Member

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    I am getting 72 signal strength on my OTA PBS here in a suburb of Houston, I will record that Nova tonight to see how it looks.
     
  15. ggieseke

    ggieseke Well-Known Member

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    I stand corrected, but apparently the DTV implementation in the US didn't happen for another year or so. I would assume that most TVs built with an ATSC tuner should be fine.

    Digital television transition in the United States - Wikipedia
     
  16. shwru980r

    shwru980r Well-Known Member

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    How would compressed video look better than uncompressed video?
     
  17. wmcbrine

    wmcbrine Well-Known Mumbler

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    You don't get uncompressed video over broadcast or cable, ever.* So, that's not the issue. The issue is, given a fixed amount of bits, how do you best make use of them? H.264 can, generally, make better use of them than MPEG-2 can. They're both lossy codecs, but H.264 will, for a given bit rate, tend to come closer to reproducing the original image than MPEG-2 will.

    Now, if you started from an MPEG-2 source and recompressed it with H.264, then yeah, that's gonna be worse, because each step is lossy. But if you start from the uncompressed source, and just compress it once with each codec, separately, to about the same size -- then H.264 will look better. The latter would, presumably, be what the TV stations are doing. (Comcast is another issue.)

    * Uncompressed video is measured in gigabits per second -- almost 1.5 Gb/s for 1080i. It has to be compressed to 19.2 megabits per second, or less, to fit into an ATSC TV channel. That's about 78:1.
     
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  18. wmcbrine

    wmcbrine Well-Known Mumbler

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    That's not the DTV implementation, that's the analog shutdown. ATSC was on air since the late 1990's. I personally have HD OTA recordings dating to 2002.
     
  19. reneg

    reneg Well-Known Member

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    I recorded Nova this week on both Comcast & OTA in Houston area this week. Nova on OTA was MPG-2 with a 1920x1080 resolution, 29.970 fps w/ 7.36 kb/s stream and Comcast was their normal overly compressed 1280x720 resolution, 59.950fps w/ 3.5 kb/s stream.
     
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  20. ggieseke

    ggieseke Well-Known Member

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    Upon further review you're absolutely right - Nova was MPEG-2. After seeing my latest Austin City Limits recording (s45e06 Vampire Weekend) I just assumed that the switch to H.264 was a done deal. My bad, but both recordings were made on the same OTA Roamio. Maybe it's a work in progress.
     

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