Avoiding noise in your Youtube uploads

The latest music video by Childish Gambino for ‘This is America’, directed by Hiro Murai, is a visually stunning and provocative statement on the intersection of race, politics, music and entertainment in the United States. If you haven’t already watched (and rewatched) the video, check out the link above – content warning, contains violent imagery.

We’ll leave the political commentary to voices more qualified than ours, but one aspect of the video many people can agree upon is the noticeable noise and artifacts in the master version uploaded to Youtube.

Our users often complain that their carefully mastered, high-resolution video files end up looking far worse when they are uploaded to streaming sites. Film grain can be especially problematic – what looks like beautiful, fine-grain film emulation in your preview window in your editor can be turned into blocky mush by the inscrutable encoding gods.

So why is this happening? To begin with, it helps to understand how video compression works. Tom Scott provides a great overview of what’s going on in this video:

As Tom explains, the compression algorithms are designed to save data (and file size) by discarding information that doesn’t change much from frame to frame.

When you add film grain (or snow, or digital particle effects) to a video, there’s much more information changing from frame to frame, and the compression will usually react by ‘smushing’ the areas of common color (normally your beautiful shallow-focus background) together. This can manifest as banding or blockiness across large areas of color, or noise and muddiness in skin tones. Organic, natural-looking grain becomes artificial, digital noise.

How to prevent artifacts in your Youtube uploads

Assuming you’re not a cinematic genius like Hiro Murai and Donald Glover, you’ll want to ensure that your grading and grain settings are set to preserve your vision as much as possible.

If you’re shooting a video with snow, rain or other particle effects, or are intending to use film grain, make sure you shoot an intra-frame codec, such as All-I, ProRes, or RAW. Inter-frame codecs such as MPEG4, AVCHD and XAVC will introduce too much noise at the acquisition stage, which you will only be able to get rid of with noise reduction.

Once you’re ready to export your final master file, the key is giving Youtube the maximum amount of data in your video to work with. Regardless of your source camera’s data rate, you should render into a bigger ‘container’ for your master file, so no extra compression is being applied at the export stage.

To do this:

  1. Set ‘Maximum Bit Depth’ in your render settings
  2. Render to a high bit-rate codec such as ProRes 10-bit
  3. Upload ProRes straight to Youtube and Vimeo, rather than .h264

By exporting to a high bitrate file, the tradeoffs is that your master file may be much larger than you’re used to working with, and will take longer to render. But remember – in this online era, the streaming version will be the one 99% of your audience sees. You can always archive your master file later, but to ensure your audience see your work at the highest quality, take the time to export and upload the massive file your film deserves.

By John Parker

Senior Marketing Manager FilmConvert