video: add vf_fingerprint and a skip-logo script

skip-logo.lua is just what I wanted to have. Explanations are on the top
of that file. As usual, all documentation threatens to remove this stuff
all the time, since this stuff is just for me, and unlike a normal user
I can afford the luxuary of hacking the shit directly into the player.

vf_fingerprint is needed to support this script. It needs to scale down
video frames as part of its operation. For that, it uses zimg. zimg is
much faster than libswscale and generates more correct output. (The
filter includes a runtime fallback, but it doesn't even work because
libswscale fucks up and can't do YUV->Gray with range adjustment.)

Note on the algorithm: seems almost too simple, but was suggested to me.
It seems to be pretty effective, although long time experience with
false positives is missing. At first I wanted to use dHash [1][2], which
is also pretty simple and effective, but might actually be worse than
the implemented mechanism. dHash has the advantage that the fingerprint
is smaller. But exact matching is too unreliable, and you'd still need
to determine the number of different bits for fuzzier comparison. So
there wasn't really a reason to use it.

[1] https://pypi.org/project/dhash/
[2] http://www.hackerfactor.com/blog/index.php?/archives/529-Kind-of-Like-That.html

1 files changed, 1 insertions, 0 deletions

diff --git a/wscript_build.py b/wscript_build.py
index 56668f1a09..63cd7538ec 100644
--- a/wscript_build.py
+++ b/wscript_build.py
@@ -389,6 +389,7 @@ def build(ctx):
         ( "video/decode/vd_lavc.c" ),
         ( "video/filter/refqueue.c" ),
         ( "video/filter/vf_d3d11vpp.c",          "d3d-hwaccel" ),
+        ( "video/filter/vf_fingerprint.c",       "zimg" ),
         ( "video/filter/vf_format.c" ),
         ( "video/filter/vf_sub.c" ),
         ( "video/filter/vf_vapoursynth.c",       "vapoursynth" ),