I want to upload a video on YouTube and was wondering what file format would be best if I want to minimize carbon emissions?

Google says all emissions of its services are offset, so let's assume hosting the video does not contribute to its footprint1.

Carbon emissions will come from people streaming the video. I can reduce the amount of data that is streamed by lowering the video's resolution. But what exactly is the influence of video format here? Some video formats will reduce file size more than others, but on the other hand more data compression will result in more CPU usage to uncompress the data and show the video? How does this balance out? Is anyone aware of research done on this topic?

1 I realize offsetting emissions is not the same as having no carbon emissions, but let's keep things simple and leave this out of the discussion.

2 Answers 2


YouTube reformats all uploaded videos:

YouTube stores whatever you upload and transcodes to other formats using their own versions of multiple compression formats including h.264 and webm

Anyway, the energy consumption needed for the user to encode the video would be negligible compared to that used to read your video by many users on YouTube.

In my opinion, by far the most efficient way to mitigate energy consumption from this process, would be that Google chooses one of the lowest resolution as a default quality when a video is played. At the moment, the default is the highest resolution that fits with your internet debit and device, even when we don't watch the image and only need the sound for instance.

  • YouTube doesn't default to the highest resolution in all scenarios. If you are on a mobile device and connected to a cellular network, YouTube will default to a lower resolution. Likewise, if your internet speed is slow, YouTube will also lower your streaming resolution.
    – Robotnik
    Commented May 18, 2022 at 10:54
  • Thanks @Robotnik, I've just edited my response
    – Noil
    Commented May 18, 2022 at 14:21

The question is unanswerable because it depends on the type of computer being used.

If the computer has hardware acceleration for the used video codec, then decoding uses practically no energy.

If the computer doesn't have hardware acceleration for the used video codec, then decoding may depending on resolution, video codec, computer age, and many other reasons use very little or very much energy.

You may not be able to choose the video codec, as YouTube has the freedom to re-encode (I'm not sure if it does). If you can choose the codec and it stays in this format, then some very common and old codec such as basic MPEG-4 may be the best as support for hardware acceleration is widespread.

The only certain choice you have is video resolution. Minimize it and the environmental impact will be minimized.

As for newer codecs requiring less data transfer because they create a smaller video file: this matters only if data transfer happens via a mobile network that is very energy-hungry. Data transfer via WLAN or data transfer via optical or electrical cable uses so little energy it doesn't matter.

Anyway, computers use electricity, not fossil fuels. Electricity generation is rapidly moving away from fossil fuels, so you can treat it as nearly emission free in few years time.

The hard-to-defossilize uses of energy are long-distance heavy transportation, large-scale heating and some industrial processes. Small scale heating is already better done using heat pumps, but large-scale heat pump installations need some large-scale heat source that may not be easily available.

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