Scene change detection is very different to av-scenechange result

[L4cache]

sc.json
an.json

It looks like some offset is introduced and get progressively worse:
120-119=1
217-215=2
354-351=3
...

Source is 24000/1001 fps YUV420P10 HEVC in MKV

[L4cache]

With FFmpeg 7.1 dlls. 7.0.2 dlls works fine.

[shssoichiro]

Do you know which one is correct?

[L4cache]

av-scenechange one is correct.
I think this could be silimilar to HomeOfAviSynthPlusEvolution/L-SMASH-Works#73
Because:

1. This problem happens with FFmpeg 7.1 dlls, but 7.0.2 dlls works fine.
2. I did more test with H.264 file and didn't saw this problem.

[shssoichiro]

I suspected something similar as well. A fix would be very important. In the meantime, there are a couple of workarounds:

• Use --chunk-method bestsource, this has a slow indexing time when it first loads the input, but it is guaranteed to be frame accurate
• Alternatively, transcode to H.264 lossless before encoding to the final format with av1an.