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The Sorry State of Youtube HDR Video
  • markr041markr041

    HDR video is a big step in quality, with much better color and dynamic range than the current REC709 standard. And, it is possible to shoot videos with existing consumer equipment and edit them in HDR (e.g., Resolve). Moreover, YouTube recently made it possible to share HDR videos, publishing the requirements for the video, which conform to the basic HDR standards. They even provide instructions how to inject metadata to inform YouTube the video is HDR. Nice.

    When you upload the correctly-spec'ed video YouTube also converts it to an SDR version, so people without HDR capabilities can see the video in a reasonable way. Otherwise an HDR video in SDR will look very washed out. This is also nice.

    Here is an HDR video (10bit, 10+ stops of D, 4:2:2, REC202 color gamut) not converted to SDR because it does not have metadata that YouTube recognizes:

    You are seeing it in SDR of course, so it looks faded - no contrast or color. If you could switch your viewer to HDR mode, the video would then look great in HDR.

    An HDR video with the correct metadata, however, will display nicely in SDR, because of the conversion by Youtube. This is also an HDR video, same specs as above, but with the correct metadata so that YouTube has converted it to SDR:

    It looks nice and colorful on your SDR screen, but it is REC709 all the way (8bit, 4:2:0, limited color gamut, 5-6 stops of DR).

    Here is the bad news: so, how do you see the HDR version? If you switch your TV/monitor to HDR mode will you see the video in HDR? No. You need to have YouTube show the HDR version instead of the SDR version. But there is no way to do that - there is no option to choose the version - HDR or SDR - in the YouTube player.

    Does that mean you cannot see the HDR version? No. There is one way, and one way only: Buy the new $69 Google Chromecast Ultra. It will play HDR YouTube videos in HDR, on any wifi-enabled HDR TV. No other device will do that - not the Amazon stick, not any Roku, nothing. It is also possible that Google has made a deal with Samsung (license fee) so that the YouTube player on some Samsung HDR TV's will play YouTube HDR videos in HDR, but this is not confirmed.

    As someone on this web site might say, capitalism is so predicable - Google is not around to help us share videos, it is here to make a profit.

  • 12 Replies sorted by
  • Vitaliy_KiselevVitaliy_Kiselev

    Our HDR topic - http://www.personal-view.com/talks/discussion/14402/hdr-new-marketing-idea/p1

    I think that very soon we can see independent players that download proper files.

  • markr041markr041

    This, quoted in the "HDR" topic from Youtube PR:

    "Starting today, you can watch YouTube videos in HDR on supported devices, such as HDR TVs with the new Chromecast Ultra, PCs hooked up to an HDR monitor and soon on all 2016 Samsung SUHD and UHD TVs."

    is not correct - my appropriately-equipped PC hooked up to an HDR monitor (which can play true HDR videos on my computer using Resolve as a player) cannot get YouTube to switch to the HDR version. There is nothing I see in the YouTube player on the YouTube web site that enables the switch. Maybe I need to use Chrome, but nowhere is that stated. And if Chrome is required, yet another attempt at a closed system. And why only Samsung TV's? Exclusive deal? Sony TV's are now pure Android, and Google won't give them an app that plays YouTube HDR?

    Downloading files as a means of sharing is Twentieth-Century. Do we really want someone to download a multi GB file to see our HDR video, or should we mail them a platter or usb stick? Streaming is necessary to maximize viewing; anything the lowers the barrier to viewing is good for dissemination.

  • karlkarl

    You don't have to wait: You can already both download and stream/play the Youtube HDR files using free software:

    Download:

    youtube-dl -f 337 'htt ps://youtu.be/9WRW3f8ZGWQ'

    Play directly from stream:

    mpv -vf format=colormatrix=bt.2020-cl:primaries=bt.2020:gamma=st2084 -vo opengl-hq --ytdl-format=337 'htt ps://youtu.be/9WRW3f8ZGWQ'

    (I inserted a space in "https" to avoid the forum software to display a player instead of the URL.)

    As you can see, the only difficulty left is that players like mpv (using ffmpeg for decoding VP9) are unable to recognize the VP9.2 flags that indicate the EOTF and colorspace, but you can specify them manually as displayed above.

  • davedvdavedv

    The impression I got was that HDR playback support in the browser isn't supported yet. Here is the announcement blog post: https://youtube.googleblog.com/2016/11/true-colors-adding-support-for-hdr.html

    "Starting today, you can watch YouTube videos in HDR on supported devices, such as HDR TVs with the new Chromecast Ultra, and soon on all 2016 Samsung SUHD and UHD TVs."

    I'm not sure that other quote that mentions PCs came from, but the post on YouTube's site has no mention of this.

    My guess is that support for HDR playback will be added to other streaming devices and TVs in the future. It seems likely that YouTube just hasn't gotten to it yet. They have a lot of different versions of their streaming apps across various platforms that need to be updated, so it's not surprising that it might take a while to update them all.

    YouTube makes its money from advertising, so they want as many people watching as possible. That's why YouTube has a presence on all of the various streaming devices and TVs in the first place (they are not just on their own devices and smart TV platform, for example). And several of the TV vendors (Sony, Sharp, Philips) now use Android TV as their smart TV platform. Given that this is Google platform, it would be pretty surprising if Android TV didn't get updated for YouTube HDR playback.

    And clearly if the HDR versions of the file are easily downloadable, there is not much to stop playback of these files in third party players either.

    It's still relatively early days for HDR.

  • tonalttonalt

    What encoder youtube uses for HDR?

  • markr041markr041

    "And clearly if the HDR versions of the file are easily downloadable, there is not much to stop playback of these files in third party players either."

    HDR videos are much bigger than SDR videos; they need higher bitrates to accommodate 10bit, for example. So they are less "easily" downloadable. And where does one post these videos to download? Vimeo is not HDR compatible. So if I upload an HDR video to Vimeo it will display it SDR, unconverted, and it will look flat like the above. Not an option. Rent cloud storage?

    We want to stream in HDR; that is the most efficient means of sharing.

    More importantly, the idea that you can just download the "HDR" video from Youtube fails to take into account that there are two versions of the video - SDR and HDR. So how do you know which video you are downloading? Only the Chromacast Ultra can differentiate the two. That is the true state of YouTube HDR right now.

    I hope it is correct that this is an interim state. But is not the way YouTube operated before - you did not need to buy something to stream 4K using Youtube; you could choose within the app or on the browser what resolution you wanted to stream. You cannot choose between the SDR and HDR YouTube versions. Why?

    Oh, and YouTube encodes in nonstandard VP9, and will not accept H265 videos. Have fun playing downloadable perhaps-HDR videos from YouTube.

  • Vitaliy_KiselevVitaliy_Kiselev

    @markr041

    As I understand 337 defines the format to download.

  • eatstoomuchjameatstoomuchjam

    @markr041 If HDR videos are too big to download, as you state in your first paragraph, why would they be the right size to stream (which is effectively the same as downloading, but with more rigid latency requirements)?

  • markr041markr041

    Thanks Vitaliy on 337. Thats important, and i can test.

    As to the streaming question i'll pretend it's serious. For streaming, you click and the video starts immediately no matter how long the video. When you download you have to wait until the download is finished, leaving aside that you must leave room to store it.

  • karlkarl

    @markr041: HDR videos are not much bigger than SDR videos. Youtube videos are never really "big", they are always smaller than would allow for visual transparency, but to take your video as an example, excerpt from "youtube-dl -F ..." output:

    313 webm 3840x2160  2160p 20124k , vp9, 30fps, video only, 520.71MiB
337 webm 3840x2160  2160p 20963k , vp9.2, 30fps, video only, 558.04MiB

    That's just 7% more data Youtube used for encoding.

    "And where does one post these videos to download?" - You could publish them on e.g. archive.org, where, unlike Youtube, everybody could download them in original (or any derived) quality.

    "how do you know which video you are downloading" - apart from using "youtube-dl -F URL" you can, of course, lookup the colorspace info in the container - see https://www.webmproject.org/docs/container/ for a documentation of the .webm container format, you will find flags for indicating bt.2020 and SMPTE-2084 in there.

    BTW: My information from above is already outdated: mpv has been capable of auto-detecting HDR material in .webm containers for a few days already in its source code repository.

    Regarding VP9: VP9 is well standardized, openly documented and free of licensing cost. Youtube/Google/Alphabet certainly don't want to pay the (multiple) HEVC licensing pools $$$ per every minute streamed to their users. It makes perfect sense for them to use a video codec that does not incur such costs.

    Regarding streaming: Especially if you want to enable users to watch high quality videos - and 4k HDR videos certainly seem to go into that direction - it's a bad idea to require an excellent, glitch-free InterNet connection. Even somebody with a lagging 1mbit/s connection can download a 4k HDR video for later offline viewing in perfect quality - while streaming would be bound to fail.

    And if a video is not worth waiting while it downloads - how important can it be?

  • markr041markr041

    @Karl This is absolutely terrific info. However, you provide it as if any of this is common knowledge, so you provide it cryptically. So, what the heck exactly are these programs? You just give us commands from command lines.

    You will have to excuse the fact that I have a mental handicap evidently, because I cannot discern from your posting of commands what programs you are using. Maybe you said and I missed it? Is "mpv" a program? Where do we get it, what OS is needed? Is it the only program to do these wonderful things, or the only one you know?

    Please let us know. Btw the way, the HDR video I uploaded is 54GB's - want to download it? :)

  • karlkarl

    @markr041: Regarding mpv, I wrote about that player on this forum not long ago: http://www.personal-view.com/talks/discussion/15488/mpv-player-now-able-to-replay-v-log-and-hdr-content-directly-with-tone-mapping/p1

    Regarding youtube-dl - just click this link for more information.

    Both are free, open-source, cross-platform tools available for different operating systems (but yes, meant for starting them from a command line, which is my favourite way of starting software :-) )

    Regarding the 54GB download: If I had specific interest in that particular video, I wouldn't hesitate to download the 54GB version of it for maximum quality.

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