How do you choose the best video codec for YouTube uploads?

Think of the content you created as candy and the codec as the wrapper hugging your candy as it exports. Different wrappers protect your candy better depending on the candy store it sits in. H.264 is the most commonly supported codec online, it protects your candy best in the YouTube candy store, and it's recommend by YouTube!

H.264 is mainly the most industry standard exporting codec. Small file size, and widely compatible on many platforms online make this the go-to codec.

Before uploading your content in 4k consider your target audience. Remember, most movies on the big screen are finished in 2k and by the time compression occurs across the internet, very few people can view content in true 4k. Optimized content will always outperform content on the bleeding edge of image science.

For almost all use-cases, the H.264 codec is the way to go. The main question is what bitrate to encode that H.264 video for its resulting MP4 file. I export video for web everyday, and stick to the following rule. A constant bitrate of 16Mbps for polished content in HD. I'll encode at 8Mbps for less detail-critical content like a long performance or speaker session. And finally (if needed), I'll go down to 4Mbps if it's a very long piece of content and lower quality is acceptable, and file size needs to be small. I use these powers of two, (4, 8, 16...) because it creates satisfying file size results. For example, a 60 second video encoded in H.264 at 8Mbps will become exactly a 60MB file! And this 60MB file will look great on YouTube.

In my experience youtube generally adds compression to any video uploaded, so while I do use H.264 when uploading to youtube as it's a more commonly used format, I do find myself cranking up the bitrate quite high. If I need to get something out quick to a client to proof then I use 15Mbs for a smaller file size to upload quicker. Where as when I'm exporting the final version of a project I use around 50Mbs to get the best result possible while still using H.264. Granted this increases the file size substantially, but the video needs all the help it can get against youtube's compression.

It is also worth mentioning that you can upload a .mov to YouTube. This has a larger file size because it offers a more lossless compression. YT is very good at encoding. However, h.264 is the most popular way to go if you want to export that file type yourself. YT accepts several different forms and their transcoding is good, so you can always leave it to YouTube.

If you want the absolute best quality on YouTube then I would allow YouTube to do its encoding of the video. I always supply a 'master' video file to my client, in a very high broadcast spec codec like ProResHQ or something similar. The trade off is that the file sizes are a LOT bigger than exporting an H.264 file and uploading it BUT the trade off is that you will be getting the best looking file because YouTube has encoded it how it thinks. If you have a decent upload speed then I would always do it this way. Same goes for other sites like Vimeo. As others have said - if it's a 2 hour clip it's not a practical way of uploading because the file size could be insanely huge. especially at 4k etc.

If you just want to check the codec of a video, it's as simple as right clicking on the file and bringing up the file details / properties. No need for an editing software.