gbrp pixel format gets "End of file" error

[bczhc]

Maybe a follow-up of #395. Demonstration file (audio muted).

Hello. I use ffmpeg x11grab to record lossless rgb videos like this:

ffmpeg -f x11grab -framerate "$framerate" -i "$DISPLAY" \
        -f pulse -i "$pulse_device" \
        -c:v libx264rgb -r "$framerate" ${=FF_ARGS} \
        -crf 0 \
        -preset ultrafast \
        -c:a libopus -b:a 96k \
        "$output_file"

But when using av1an, it gives "End of file" error during scene scanning.

~/screenrecord ❯ ~/av1an --sc-only -s scenes.json -i 1.mp4                                                                                                                                 07:50:46
INFO [av1an_core::context] Input: 2560x1440 @ 30.000 fps, GBRP, SDR
Scene detection
⠒ 00:00:01 ▕                                                                                                                                                      ▏   0%  0/300 (0 fps, eta unknown)
Error: End of file

Also, if hevc gbrp (Rext profile) is used, e.g.:

ffmpeg -i 1.mp4 -c:v hevc_nvenc -b:v 50M -pix_fmt gbrp 2.mp4

Then for 2.mp4, av1an gives the same error.

av1an --version:

av1an 0.4.1-unstable (rev e69826f) (Release)

* Compiler
  rustc 1.75.0-nightly (LLVM 17.0)

* Target Triple
  x86_64-unknown-linux-gnu

* Date Info
  Commit Date:  2024-04-23

* VapourSynth Plugins
  systems.innocent.lsmas : Not found
  com.vapoursynth.ffms2  : Not found
  com.vapoursynth.dgdecodenv : Not found
  com.vapoursynth.bestsource : Not found

[master-of-zen]

Try converting to yuv420p lossless with ffmpeg, or use vapoursynth script that use your video as input and converts to yuv420p, and set that script as input

[bczhc]

Actually what does "yuv420p lossless" mean please? If I first convert it to yuv420p (or yuv420p10le) using ffmpeg, and then set it as the input of av1an, it will work.

For screenrecords I prefer rgb instead of yuv, and ffmpeg can do this. That's, these two ffmpeg commands will work:

# gbrp
ffmpeg -i 1.mp4 -c:v libaom-av1 -row-mt 1 -tile-rows 2 -tile-columns 2 -tune psnr -cpu-used 5 -crf 50 -threads 16 -pix_fmt yuv420p a.mkv

# yuv420p
ffmpeg -i 1.mp4 -c:v libaom-av1 -row-mt 1 -tile-rows 2 -tile-columns 2 -tune psnr -cpu-used 5 -crf 50 -threads 16 -pix_fmt yuv420p b.mkv

I used to hear of, that aomenc cannot output rgb videos, and this is a limitation of aomenc the CLI but not libaom-av1 the library which ffmpeg uses? May be related to aomenc?

[master-of-zen]

Actually what does "yuv420p lossless" mean please?

It means convert video with something like ffmpeg x264 yuv420p for compatible color space, and using crf 0 for lossless encoding, so there is no quality loss.

ffmpeg -i input -c:a copy -c:v libx264 -crf 0 -pix_fmt yuv420p input_for_av1an.mkv will suffice

In case when ffmpeg gets RGB as input, it does the conversion internally

[bczhc]

Yes, I tried and this worked.

ffmpeg -i 1.mp4 -c:a copy -c:v libx264 -crf 0 -pix_fmt yuv420p input_for_av1an.mkv
<ffmpeg outputs>
/mnt/nvme/av1/3 ❯ ~/av1an -i input_for_av1an.mkv                                19:46:30
INFO [av1an_core::context] Input: 2560x1440 @ 30.000 fps, YUV420P, SDR
Scene detection
INFO [av1an_core::context] scenecut: found 1 scene(s) [with extra_splits (300 frames): 1 scene(s)]
  00:00:02 ▕█████████████████████████████████████████▏ 100%  300/300 (133.32 fps, eta 0s)Queue 1 Workers 1 Passes 2
Params: --threads=8 --cpu-used=6 --end-usage=q --cq-level=30 --tile-columns=1 --tile-rows=0
/mnt/nvme/av1/3 ❯

Seems the error encounters only with RGB inputs.