Where are your videos? Encoding is a more complicated problem in that the source and destination would impact things. Bandwidth transfer can cost more than the compute on some clouds (and impact speeds).
If it's on S3 it might still be best to use AWS EC2 in the same region.
Oracle is definitely a good choice with 10TB free tier.
Hetzner cloud likely has cheaper compute than Oracle.
Specifically for Video encoding I'd look into benchmarks about what certain ARM architectures can do. Not all encoders can correctly utilize them and they may end up very slow.
If it's on S3 it might still be best to use AWS EC2 in the same region.
Oracle is definitely a good choice with 10TB free tier.
Hetzner cloud likely has cheaper compute than Oracle.
Upcloud has the fastest CPU.