ffmpeg scene detection

11. 3. 2019

ffmpeg -hide_banner -i "$file" -an \
-filter:v "select='gt(scene,0.2)',showinfo" \
-f null \
- 2>&1

More complex version (detection is the same), that shall produce a lil timeline/stats like

/media/b/data/trailers/Captain.mkv timeline
||------------|----|-----|----|----|||||||||||||||----|-|--|--|-|-||||||||||||||---|----|--|-|-|-|||-|---|--|---|--|-|-|-|-|||||||||-|-|-||-----|-|-|--|-|-|-|--|-||||---|-||-|||-||-|-|-||||-|--|--||--||||
average clip length: 1.06221 seconds
103 clips, 1 min 56 s 641 ms

https://raw.githubusercontent.com/brontosaurusrex/stretchbang/master/bin/sceneDetection

Note: ffmpeg scene detection filter fails prety much every time, needs replacement with something better.

Update: The old way, abusing x264 debug info, unfortunately the results are in frames

ffmpeg -i "$file" -vf scale=100:100 -sws_flags neighbor -an -pix_fmt yuv420p -f yuv4mpegpipe - 2>/dev/null | x264 - --demuxer y4m --bframes 0 --min-keyint 10 --scenecut 45 --preset superfast --crf 30 --threads 1 -v --output /dev/null 2>&1 | grep scene

Ffmpeg only version, still abusing x264 (unclear on how to pass parameters to x264, -preset ultrafast not working for example)

ffmpeg -v debug -an -i "$file" -vf scale=100:100 -sws_flags neighbor -c:v libx264 -f null - 2>&1 | grep "scene cut at" | cut -d ' ' -f 7 | uniq

43
78
109
140
163
181
204
268
306
351
391
465
494
552

Increasing detection threshold with -sc_threshold 90 might detect fade-in/fade-out situations, but will also place I frames in the middle of long shots.

diff -y Captain.txt Captain90.txt 
1                                 | 2
36                                  36
                                  > 57
                                  > 59
63                                  63
534                               | 269
                                  > 397
                                  > 505
                                  > 601
611                                 611
                                  > 711
720                                 720
                                  > 723
                                  > 726
729                                 729
                                  > 732
                                  > 735
738                                 738
842                                 842
854                                 854
                                  > 856
901                                 901
                                  > 950

video bash