1
0
mirror of https://github.com/mpv-player/mpv synced 2024-12-11 17:37:23 +00:00
mpv/TOOLS/lua/skip-logo.lua
wm4 68bbc55eda skip-logo.lua: fix skipping in the first two frames
mpv typically decodes and filters at least 2 frames before starting
playback. This happens during seeks, as well as when playback starts
from the beginning of the file.

skip-logo.lua receives notifications for all filtered frames, even
during seeking. It should interrupt during seeking, so as a crude
heuristic, it ignored all frames while the player was seeking. This does
not mean all these frames are skipped due to seeking (thus it's a "crude
hueristic"). In particular, it means that the first 2 frames of a video
cannot be skipped, since they're filtered within the playback restart
phase (equivalent to "seeking").

Fix this by making the heuristic slightly less crude. Since we observe
the property as "none", the property is not actually read until we do it
explicitly. By not reading it during seeking, we can let the frames
internally queue up (vf_fingerprint discards them in a ringbuffer-like
fashion if they're too many). Then, if seeking ends, we get the current
playback timestamp, and check queued up frames that are at or after that
timestamp. (In some ways, this duplicates what the player's seeking
logic does.)

A disadvantage is that this is racy. While playback-time is guaranteed
to be set when seeking changes from false to true, playback could
already have progressed to the next frame (or more) before the script
gets time to react. In theory, we could add a seek restart hook or so,
but I don't want to. A property that returns the last playback restart
time would also do it, but feels to special. Not an important problem
in practice anyway.
2019-10-08 21:26:43 +02:00

267 lines
9.3 KiB
Lua

--[[
Automatically skip in files if video frames with pre-supplied fingerprints are
detected. This will skip ahead by a pre-configured amount of time if a matching
video frame is detected.
This requires the vf_fingerprint video filter to be compiled in. Read the
documentation of this filter for caveats (which will automatically apply to
this script as well), such as no support for zero-copy hardware decoding.
You need to manually gather and provide fingerprints for video frames and add
them to a configuration file in script-opts/skip-logo.conf (the "script-opts"
directory must be in the mpv configuration directory, typically ~/.config/mpv/).
Example script-opts/skip-logo.conf:
cases = {
{
-- Skip ahead 10 seconds if a black frame was detected
-- Note: this is dangerous non-sense. It's just for demonstration.
name = "black frame", -- print if matched
skip = 10, -- number of seconds to skip forward
score = 0.3, -- required score
fingerprint = "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
},
{
-- Skip ahead 20 seconds if a white frame was detected
-- Note: this is dangerous non-sense. It's just for demonstration.
name = "fun2",
skip = 20,
fingerprint = "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
},
}
This is actually a lua file. Lua was chosen because it seemed less of a pain to
parse. Future versions of this script may change the format.
The fingerprint is a video frame, converted to "gray" (8 bit per pixels), full
range, each pixel concatenated into an array, converted to a hex string. You
can produce these fingerprints by running this manually:
mpv --vf=fingerprint:print yourfile.mkv
This will log the fingerprint of each video frame to the console, along with its
timestamp. You find the fingerprint of a unique-enough looking frame, and add
it as entry to skip-logo.conf.
You can provide a score for "fuzziness". If no score is provided, a default
value of 0.3 is used. The score is inverse: 0 means exactly the same, while a
higher score means a higher difference. Currently, the score is computed as
euclidean distance between the video frame and the pre-provided fingerprint,
thus the highest score is 16. You probably want a score lower than 1 at least.
(This algorithm is very primitive, but also simple and fast to compute.)
There's always the danger of false positives, which might be quite annoying.
It's up to you what you hate more, the logo, or random skips if false positives
are detected. Also, it's always active, and might eat too much CPU with files
that have a high resolution or framerate. To temporarily disable the script,
having a keybind like this in your input.conf will be helpful:
ctrl+k vf toggle @skip-logo
This will disable/enable the fingerprint filter, which the script automatically
adds at start.
Another important caveat is that the script currently disables matching during
seeking or playback initialization, which means it cannot match the first few
frames of a video. This could be fixed, but the author was too lazy to do so.
--]]
local utils = require "mp.utils"
local msg = require "mp.msg"
local label = "skip-logo"
local meta_property = string.format("vf-metadata/%s", label)
local config = {}
local cases = {}
local cur_bmp
local seeking = false
local playback_start_pts = nil
-- Convert a hex string to an array. Convert each byte to a [0,1] float by
-- interpreting it as normalized uint8_t.
-- The data parameter, if not nil, may be used as storage (avoiding garbage).
local function hex_to_norm8(hex, data)
local size = math.floor(#hex / 2)
if #hex ~= size * 2 then
return nil
end
local res
if (data ~= nil) and (#data == size) then
res = data
else
res = {}
end
for i = 1, size do
local num = tonumber(hex:sub(i * 2, i * 2 + 1), 16)
if num == nil then
return nil
end
res[i] = num / 255.0
end
return res
end
local function compare_bmp(a, b)
if #a ~= #b then
return nil -- can't compare
end
local sum = 0
for i = 1, #a do
local diff = a[i] - b[i]
sum = sum + diff * diff
end
return math.sqrt(sum)
end
local function load_config()
local conf_file = mp.find_config_file("script-opts/skip-logo.conf")
local conf_fn
local err = nil
if conf_file then
if setfenv then
conf_fn, err = loadfile(conf_file)
if conf_fn then
setfenv(conf_fn, config)
end
else
msg.warn("Lua 5.2 was not tested, this might go wrong.")
conf_fn, err = loadfile(conf_file, "t", config)
end
else
err = "config file not found"
end
if conf_fn and (not err) then
local ok, err2 = pcall(conf_fn)
err = err2
end
if err then
msg.error("Failed to load config file:", err)
end
if config.cases then
for n, case in ipairs(config.cases) do
local err = nil
case.bitmap = hex_to_norm8(case.fingerprint)
if case.bitmap == nil then
err = "invalid or missing fingerprint field"
end
if case.score == nil then
case.score = 0.3
end
if type(case.score) ~= "number" then
err = "score field is not a number"
end
if type(case.skip) ~= "number" then
err = "skip field is not a number or missing"
end
if case.name == nil then
case.name = ("Entry %d"):format(n)
end
if err == nil then
cases[#cases + 1] = case
else
msg.error(("Entry %s: %s, ignoring."):format(case.name, err))
end
end
end
end
load_config()
-- Returns true on match and if something was done.
local function check_fingerprint(hex, pts)
local bmp = hex_to_norm8(hex, cur_bmp)
cur_bmp = bmp
-- If parsing the filter's result failed (well, it shouldn't).
assert(bmp ~= nil, "filter returned nonsense")
for _, case in ipairs(cases) do
local score = compare_bmp(case.bitmap, bmp)
if (score ~= nil) and (score <= case.score) then
msg.warn(("Matching %s: score=%f (required: %f) at %s, skipping %f seconds"):
format(case.name, score, case.score, mp.format_time(pts), case.skip))
mp.commandv("seek", pts + case.skip, "absolute+exact")
return true
end
end
return false
end
local function read_frames()
local result = mp.get_property_native(meta_property)
if result == nil then
return
end
-- Try to get all entries. Out of laziness, assume that there are at most
-- 100 entries. (In fact, vf_fingerprint limits it to 10.)
for i = 0, 99 do
local prefix = string.format("fp%d.", i)
local hex = result[prefix .. "hex"]
local pts = tonumber(result[prefix .. "pts"])
if (hex == nil) or (pts == nil) then
break
end
local skip = false -- blame Lua for not having "continue" or "goto", not me
-- If seeking just stopped, there will be frames before the seek target,
-- ignore them by checking the timestamps.
if playback_start_pts ~= nil then
if pts >= playback_start_pts then
playback_start_pts = nil -- just for robustness
else
skip = true
end
end
if not skip then
if check_fingerprint(hex, pts) then
break
end
end
end
end
mp.observe_property(meta_property, "none", function()
-- Ignore frames that are decoded/filtered during seeking.
if seeking then
return
end
read_frames()
end)
mp.observe_property("seeking", "bool", function(name, val)
seeking = val
if seeking == false then
playback_start_pts = mp.get_property_number("playback-time")
read_frames()
end
end)
local filters = mp.get_property_native("option-info/vf/choices", {})
local found = false
for _, f in ipairs(filters) do
if f == "fingerprint" then
found = true
break
end
end
if found then
mp.command(("no-osd vf add @%s:fingerprint"):format(label, filter))
else
msg.warn("vf_fingerprint not found")
end