Opened 2 years ago
Last modified 2 years ago
#10124 new defect
NVENC h.264 reference frames >4 causes error
| Reported by: | CaptainObvious | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | undetermined |
| Version: | 5.1.2 | Keywords: | NVENC, reference frames, refs |
| Cc: | CaptainObvious | Blocked By: | |
| Blocking: | Reproduced by developer: | no | |
| Analyzed by developer: | no |
Description
Trying to use FFmpeg/NVENC to encode 1080p 23.976fps Blu-ray AVC files that don't need re-encoding in Architect Pro (unsuccessfully, so far). Hardware is a 2080 Ti, current drivers 527.56.
In trying to emulate a known working file, one of the things I need to do is produce a video with 5 reference frames. As I understand it, h.264 spec allows up to 16 reference frames, so this shouldn't be an issue.
When "-refs 5" or higher is specified, FFmpeg fails with error: "[h264_nvenc @ hhhhhhhhhhhhhhhh] InitializeEncoder failed: invalid param (8): Invalid Level."
When "-refs 4" or lower is used, no problem. Have tried this on the current release version 5.1.2-full_build-www.gyan.dev and the latest nightly from Dec 25, 2022.
I've simplified the following command-line significantly:
ffmpeg -y -i "input.mp4" -c:v h264_nvenc -bluray-compat 1 -b:v 1500000 -bufsize 1500000 -maxrate 3000000 -level 4.1 -profile:v high -refs 5 "output.264"
Change History (2)
comment:1 by , 2 years ago
| Summary: | NVENC h.264 reference frames over 4 causes error → NVENC h.264 reference frames >4 causes error |
|---|
Blu-ray supports maximum 4 CABAC ref frames. Offcially that is, some geniuses put 5 refs.
Blu-ray does support slicing though.
"As I understand it, h.264 spec allows up to 16 reference frames, so this shouldn't be an issue."
Not that simple. In Level 4.1 H.264 allows 9 reference frames for 720p and 4 reference frames for 1080p. See table https://en.wikipedia.org/wiki/Advanced_Video_Coding