What kind of compression does YouTube use?

H.264 as video codec. HandBrake can do that, as your 3 GB video probably uses an editing codec like ProRes (FCP) or Apple Intermediate Codec (iMovie or FCE),

In order to find out, what codec is used with your videos, you can use the following three applications to analyse a sample video file.

• VideoSpec (free)
• MediaInfo (free)
• Media Inspector (2.99 USD € in the Mac App Store (MAS))

When done, you can use the "Report" (VideoSpec) and "Export" (Media Inspector) button to export a report,
attachable to your next post via the button.
In MediaInfo you have to go to the Menu Bar, select View > Text and copy the text via CMD+A > CMD+C and paste it via CMD+V into your next post.​

Video Compression
Why It Matters & How To Make The Most Of It

which includes the following sections:

• GOPs, Macroblocks & Wavelets
• Acquisition Formats
• Editing & Post Formats
• Final Cut Pro
• Avid Media Composer
• Adobe Premiere Pro
• Which Codec Should I Edit With?
• Conclusion
• Camera Codec Summary
• Apple ProRes Variations
• Avid DNxHD Codecs

​

 

Although the videos on youtube look really good and might appear to have the same quality, to say that they are identical is not true.

I know I'm just nagging, and I guess you do understand (and just quickly used the word "identical") but the real quality won't be identical. Just to make sure there's is no misunderstanding.

A lot of data is lost and once you start editing on youtube videos, or a have a keen eye for details. You'll notice some data is lost.

This becomes notable, for example, when you export your video as a compressed video, and then upload it to youtube. The video will be encoded twice, but the second time information will be missing (because it was compressed the first time). It still might not be very noticeable. But my point is, it's always best to use a file with as much details (with low or no compression) in your workflow, until you come to the final product.

They don't edit a movie in Hollywood with DVD like compression and use that all the way through. No, they use uncompressed and then compress it for the DVD (and for iTunes, Netflix, TV Stations etc). That's why they can "upgrade" and sell the older movies on Blu-ray. And still, the movies are compressed to fit on Blu-ray. (and sometimes they rescan the actual film material in a higher resolution).

Again, sorry for waisting your time with something I think is important, just wanted to share.