You set every parameter to its absolute maximum (e.g., me=tesa, subme=7, ref=16). The result: A 10-second video takes an hour to encode, yet looks identical to a preset=medium encode. Solution: Start with preset=slow, then adjust only 2-3 parameters based on visual inspection.
Despite its power, the userhevc ecosystem has drawbacks:
The most common tool for deploying UserHEVC is FFmpeg with the libx265 encoder. Below is a baseline command, followed by a "UserHEVC-enhanced" version. userhevc
Baseline (Preset-based):
ffmpeg -i input.mkv -c:v libx265 -preset medium -crf 23 -c:a aac output.mp4
Advanced UserHEVC Command (Custom parameters): You set every parameter to its absolute maximum (e
ffmpeg -i input.mkv -c:v libx265 -preset slow -crf 20 \
-x265-params "aq-mode=3:no-sao=1:deblock=-3,-3:psy-rd=1.5:psy-rdoq=4.0:me=umh:subme=5:rc-lookahead=40" \
-c:a aac -b:a 128k output.mp4
What these UserHEVC parameters do:
UserHEVC isn’t always in standard repositories yet, but you can find community builds on GitHub (search for "UserHEVC builds") or through encoding forums like Doom9. What these UserHEVC parameters do: UserHEVC isn’t always
A typical command line might look like this:
userhevc --input input.mkv --output output.mkv --preset medium --tune grain-synthesis --aq-mode 4
Notice --tune grain-synthesis—that’s the signature feature not found in vanilla x265.
Modern GPUs include dedicated media encoders. They are blazing fast but expose very few UserHEVC parameters. You might adjust bitrate, maxrate, bufsize, and profile. However, advanced parameters like psy-rd, aq-mode, and me are either fixed or nonexistent. For real-time streaming (OBS, Twitch), hardware encoding is sufficient. For archival, UserHEVC software encoding wins.