This might sound like a fairly uneducated question, but I'm asking the question because I'm uneducated. My uncle works in the visual effects industry, and he told me that Avid makes a video codec that has great quality and can even render with an alpha channel. Does this codec exist (I haven't been able to find it)? If so, how can I install it on a Linux Mint machine for use in Blender? Thanks!
The later era Avid format is DNxHD, with the more recent DNxHR.
FFMPEG is capable of decoding DNxHD. If using proper libraries, Blender would import DNxHD as an 8 bit per channel image, likely sub-optimal. Blender relies on swscale from FFMPEG to convert the (typically) YCbCr planes to RGB, at 8 bits per channel.
DNxHD is not a reliable format for visual effects, nor is any codec for that matter.