Lux ex Tenebris HQ – The art of maximising your YouTube upload

For the last week or so I have worked tirelessly in finding a way of upolading my first camera test movie entitled Lux ex Tenebris with as high quality to the image retained as possible. Iv’e done all of my editing and grading in DaVinci Resolve 12.5 and when it was time to render the finished project for streaming on the Web I first decide to try out my free Vimeo account. DaVinci Resolve offers presets for both YouTube and Vimeo (which match each other perfectly) and I pressed 1080p for Vimeo in the Delivery page. It was rendered using QuickTime as a wrapper or container, and H.264 as a video compression codec in 1920 × 1080 resolution and two channel PCM as audio codec, by default. But in trying to upload the file from my HDD to Vimeo the site wouldn’t accept it as my weekly 500MB limit was exceeded by approximately 1.5 GB! So I went over to YouTube to upload that same file (as said, DaVinci Resolve renders a file with the same default presets for both YouTube and Vimeo) but after a couple of hours uploading I was heartstruck at the bad image quality when watching playback; the H.264 file looked allright on my computer playing from the HDD but YouTube had managed to decompose the file with its own compression algorithm ruining the image in the process. Gone was the filmic and dynamic CinemaDNG RAW image and what I saw instead was plain ugly video. The compression artefacts and the washed out picture was awful to watch, especially in the night scenes. Consequently, I immediately removed it from public display – my creative vision as a director and DoP wasn’t coming through to the screen. It was quite depressing to say the very least; what’s the point of making movies if you cannot show them to a general public?

Setting values for output to YouTube
Setting values for output to YouTube

Searching for information on the Web and asking question on all the relevant fora I realised that it’s better to upload your video from a much less compressed codec than standard video H.264; ProRes or DNxHD / DNxHR was recommended as a high-end alternative. Abandoning Vimeo entirely, as I didn’t want to pay them a penny, I rendered a new file for YouTube, this time changing the compression codec to DNxHR HQ. This time the upload of approximately 30GB took me five hours to complete. But as I for some reason decided to change the default audio setting from PCM to AAC, prior to the render, no audio came through (must have pressed some strange button on the Delivery page). Again, the video looked washed out as before and terrible during the night scenes as the entire picture was pulsating with a few seconds interval createing ugly compression artefacts that burnt into the image and retained for a second or so. Banding and blocking was generally terrible as well. Because of the lost audio I did a new try using the DNxHR SQ video codec and PCM for audio, which resulted in a four hour upload; the sound came through allright but the image was as bad as in the previous try. Again I had to remove the file from public display. Then I found out that YouTube offers enhancement of the picture, changing the parameters for Fill Light, Contrast, Saturation and Color Temperature. Raising Contrast +5 and Saturation +5 removed much of the compression artefacts, and thankfully the pulsating ugliness, but the image became way to saturated and to dark. So I changed the settings to +1 for both Contrast and Saturation; colour was good but the image was still to dark preventing the viewer to see important details in the night scenes. So I changed Contrast back to 0 and retained Saturation at +1 to compensate for badly adjusted monitors that desaturates the image (such as my laptop) but prevented to push the colours to much on well calibrated monitors and computers (such as my workstation).

Alas, I could finally present a version of the camera test movie that transmitted my original vision onto the screen, approximating what I had come to know on my DaVnci Resolve workstation, good enough. This was the official 1080p version of Lux ex Tenebris. Still, although the day scenes looked really good the compression artefacts were still quite visible in the form of blocking and banding in the night scenes. A few days ago someone suggested to upload the rendered file as a Ultra HD 4K file, upscaling the Cinema DNG workflow from its native 1920 × 1080 to a 3840 × 2160 resolution. This is easily done in the DaVinci Resolve Delivery page using the video controls. I finally made a second upload to YouTube using the DNxHR HQ video compression codec and two cannel PCM audio codec wrapped in QuickTime and Ultra HD 4K, enhancing Saturation +1. This is the official 2160p version of the movie. It took me circa 33 hours to finish the entire uploading process, which is hardly a surprise considering that the .MOV file was approximately 90 GB in size (compared to the 15 GB .MOV file of the 1080p version). YouTube now presents Lux ex Tenebris HQ in 720p, 1080p, 1440p and 2160p. Finally YouTube does justice to the native CinemaDNG RAW 1080p footage coming from the Blackmagic Pocket Cinema Camera and the LOMO Meteor 5-1 lens! I’m happy again that my audience may watch my movies as I intended them to look. (I have chosen to save the original 1080p YouTube clip for comparison, but in the future I will always use the highest possible image resolution and the least possible compression.)

To reiterate, based upon my own experience and that of others, use the following instructions if you have shot a movie in a native 1080p resolution as a quick-start guide for creating optimal image quality files rendered from DaVinci Resolve 12.5, uploaded to YouTube or Vimeo, using the golden rule of providing YouTube or Vimeo with as large a file as possible, using the least compressed codec you can find, knowing well that it will swallow almost anything regardless of the size:

  1. In the Deliver page, choose (highlight) either the YouTube or Vimeo output preset and click 1080p, and then check if the Video tab is highlighted.
  2. Under the  Format drop-down choose (or rather leave the default setting at) QuickTime which is a very good and solid wrapper-container.
  3. Under the Codec drop-down choose DNxHR HQ which is the least compressed codec for 8-bit 4:2:2 or choose DNxHR HQX for 12-bit 4:2:2 Ultra HD 4K Broadcast-quality delivery. If you are a Apple / Mac user, you could also use ProRes HQ for that matter, which is equivalent in quality. (Apple doesn’t allow Blackmagic Design to support ProRes as an export option for Window users, only as an import.)
  4. Under the Resolution drop-down choose 3840 × 2160 Ultra HD which will scale your native 1080p resolution to 4K. That’s it; no more adjustments are needed in the Video tab.
  5. Leave the Audio tab as it is. It is set by default to Linear PCM as a Codec, 2 Channels, 16 as Bit Depth and Single Tracks. The uncompressed PCM format is to be preferred over the ACC audio compression codec.
  6. Check that the Single Clip is chosen as Format, that the Entire Timeline is highlighted in the Render drop-down, and then click the Add to Render Cheque button and finally click the Start Render button as per the Installation and Operation Manual: Blackmagic Design Compact Cameras. The render will take approximately as long as the lenght of the movie clip, perhaps a bit longer depending on the capacities of your workstation. The resulting .MOV file will be huge – a 15 minutes movie clip will have a approximate file size of 90GB (or more if you choose DNxHR HQX)!
  7. Go to YouTube and click on the Upload button and follow the usual instructions. The uploading process will take a huge amount of time, probably one whole day or more. During this time, you cannot turn off your computer; it cannot even go into sleep mode, so make shure to turn that feature off on Windows (I learnt that the hard way). When everything is finished and you are able to see the uploaded video, check that everything is o.k. Put in all necessary information about the clip.
  8. Click on the Enhancements tab and raise Saturation to +1. You may also raise contrast to +1 if the clip doesn’t contain any night scenes, which would darken the shadows to much and could crush the blacks; day scenes will probable look better with a little raised Contrast. The reason for this enhancement of the image is that YouTube seems to flatten the image somewhat when it compresses the file, and to compensate for this quirk you are recommended to do the adjustment, but only one unit as +2 and above would saturate the colours (and darken the image) to much for most screens.


Two words of warning, however: (a) For Vimeo you would have to pay lots of money for the Business version to get unlimited file sizes, for an amount equal to half the price of a Blackmagic Pocket or Micro Cinema Camera. Vimeo may have a marginally better image quality (it supposedly has a higher bitrate) compared to YouTube but is it really worth all of that money, which you could better spend on film gear and film production? In my opinion, it’s more about snobbery and rubbing yourself with a coating of “professionalism”; I myself refuse to fall for that trap out of my guerilla film soldier codex. ¡No pasarán! (b) Depending on your broadband bandwith, YouTube may not accept a Ultra HD file for upload. Sorry to say, but if this is the case you are limited to upload your rendered file in 1920 × 1080 HD. Besides this limitation, you should be able to follow the same uploading process per the instructions above. Good luck with your broadcasting efforts!


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