TCL TV power consumption spikes with Dolby Vision

team teri on 07/11/2020 - 19:48

I recently upgraded to a TCL 75 inch P715. Overall I am quite happy, but one detail is somewhat annoying:

When I watch content on Netflix that supports Dolby Vision, the power consumption spikes from ~100W to ~230W. That seems rather excessive.

Does anyone know why that would be the case?

The picture mode is set to 'Standard', which is described as 'Power Saving mode, recommended for daily home use'. Changing that to 'Dynamic' or 'Smart HDR' means that the power consumption is high, even for content without Dolby Vision.

I can't seem to see any way to turn off 'Dolby Vision' in Netflix. Except I found one description that suggests Dolby Vision is only available on the Premium plan, so perhaps downgrading to Standard will fix it. I'll know in 2 weeks after the change takes effect, but honestly I'd prefer to get UHD content still…

Any ideas?

Electrical & Electronics

Comments

  • Willco88 on 07/11/2020 - 19:51

    I'm sorry I can't help;

    but I'd love to know more about this actual model of TV?

    I'm very interested in possibly 65P715, just never personally owned TCL.

    EXACTLY how good is the picture full 4K HDR+
    Have you used a gaming console?
    Any issues with the picture or OS?

    Thank you

    • team teri on 07/11/2020 - 20:33
      +1

      It's my first 4K TV, other than what I saw on display in shops I have nothing to compare against. Not gaming myself. Mostly watching Netflix & Prime Video, some free to air TV.

      One negative surprise I got: things already look significantly different (losing colour brilliance) from a viewing angle of perhaps 25 degrees away from center. Not changing much if you go further out.

      • Willco88 on 07/11/2020 - 20:34

        Well I like to sit further back like 2 metres away from any TV

  • jackinyourbox on 07/11/2020 - 20:27
    +3

    The reason is that the backlight is lit brighter than usual for max visuals. Usually the tv will dynamically adjust contrast and backlights depending on the image displayed.

  • ShannonN on 07/11/2020 - 20:34

    I take it you're not concerned about the extra cost of the spike in the electricity used but just why it is happening?

    • team teri on 07/11/2020 - 20:45

      You're right, electricity cost isn't the issue. Goes from ~2.8 cents/hour to ~6.5 cents/hour.

      That said, an extra 200kWh per year (based on 4 hours a day) are a significant junk in what otherwise is an energy efficient household.

      If all new TVs exhibit the same behaviour that would be something worth addressing. I'd be quite ok with it if I could just turn it on when I feel I need it, i.e. when watching a movie where it makes a lot of difference, as opposed to when mediocre TV shows share my attention with browsing the phone…

      • ozhunter on 07/11/2020 - 21:16
        +2

        You're right, electricity cost isn't the issue

        The rest of your comment suggests otherwise.

        • team teri on 07/11/2020 - 22:16
          +2

          It's not about the cost for the individual, it's about the environmental impact that will be caused worldwide if most households have a TV that needlessly burns an extra 130W for very little gain.

          We outlawed incandescent light bulbs…

          In this case I don't think we need to outlaw anything, but perhaps the software can be changed to default to 'off'. Or it could be mandated to ask "do you want to activate the HDR feature for this movie/show, it will increase power consumption by 130W."

          • vivmahi on 09/11/2020 - 23:01
            -2

            @team teri: In this case you shouldn't have purchased a 75 inch 4k TV. A smaller Full HD TV to save the environment and to make our world a better place.

  • abb on 10/11/2020 - 15:41

    Am I understanding correctly?

    4k Netflix show without Dolby Vision: 100W
    4k Netflix show with Dolby Vision: 230W

    That's a hell of a lot. Are any other parameters changing? (frame rate?)

    How are you measuring power?

    Are you running the latest TV firmware?

    • team teri on 10/11/2020 - 18:48

      Yes correct.

      On Netflix:
      "Dark" is 4K, uses 90-100W
      "The Crown" is 4K with Dolby Vision: ~230W

      Last night I watched Prime:
      "The Matrix", basically flatlined at 175W (+- 2W for the whole 2 hours+)
      "The Good Doctor", bit more variation, but average about 95W

      So yeah, highly variable between shows, but fairly constant within a show.

      Power is measured by a Xiaomi Smart Plug (Zigbee). I believe it is quite accurate, anything with 'known' power is reported spot on.

      Firmware: no update available.

      • abb on 10/11/2020 - 20:29

        It could be just that there is more data to process, more complex encoding, etc.

        I wouldn't have guessed the difference to be so much, but it's well within the realms of possibility.

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