clip.lua

-- Copyright (C) 2017  ParadoxSpiral
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with Parabot.  If not, see <http://www.gnu.org/licenses/>.


-- Encode a clip of the current file

local mp = require 'mp'
local options = require 'mp.options'

require 'os'

-- Options
local o = {
	-- Key bindings
	key_set_start_frame = "c",
	key_set_stop_frame = "C",
	key_start_encode = "ctrl+C",

	-- Audio settings
	audio_codec = "libopus",
	audio_bitrate = "192k",

	-- Video settings
	video_codec = "libx265",
	video_crf = "24",
	video_pixel_format = "yuv420p10",
	video_width = "", -- source width if not specified
	video_height= "", -- source height if not specified
	video_upscale = false, -- upscale if video res is lower than desired res

	-- Misc settings
	encoding_preset = "medium", -- empty for no preset
	output_directory = "/tmp",
	clear_start_stop_on_encode = true,
	block_exit = false, -- stop mpv from quitting before the encode finished, if false…
		-- …mpv will quit but ffmpeg will be kept alive
}
options.read_options(o)

-- Global mutable variables
local start_frame = nil
local stop_frame = nil

function encode()
	if not start_frame then 
		mp.osd_message("No start frame set!")
		return
	end
	if not stop_frame then
		mp.osd_message("No stop frame set!")
		return
	end
	if start_frame == stop_frame then
		mp.osd_message("Cannot create zero length clip!", 1.5)
	end

	local path = mp.get_property("path")
	local out = o.output_directory.."/"..mp.get_property("media-title").."-clip-"..start_frame..
		"-"..stop_frame..".mkv"
	
	local width = mp.get_property("width")
	local height = mp.get_property("height")
	if o.video_width ~= "" and (o.video_width < width or o.video_upscale) then
		width = o.video_width
	end
	if o.video_height ~= "" and (o.video_height < height or o.video_upscale) then
		height = o.video_height
	end

	local saf = start_frame
	local sof = stop_frame
	if o.clear_start_stop_on_encode then
		start_frame = nil
		stop_fram = nil
	end

	local preset = ""
	if o.encoding_preset ~= "" then
		preset = "-preset "..o.encoding_preset
	end

	-- Check if ytdl is needed
	local input
	if not os.execute('ffprobe "'..path..'"') then
		input = 'youtube-dl "'..path..'" -o - | ffmpeg -i -'
	else
		input = 'ffmpeg -i "'..path..'"'
	end

	-- FIXME: Map metadata properly, like chapters or embedded fonts
	local command = input.." -ss "..saf.." -t "..sof-saf..
		" -c:a "..o.audio_codec.." -b:a "..o.audio_bitrate.." -c:v "..o.video_codec..
		" -pix_fmt "..o.video_pixel_format.." -crf "..o.video_crf.." -s "..width.."x"..
		height.." "..preset..' "'..out..'"'
	local time = os.time()

	mp.osd_message("Starting encode from "..saf.." to "..sof.." into "..out, 3.5)
	if o.block_exit then
		os.execute(command)
		mp.osd_message("Finished encode of "..out.." in "..os.time()-time.." seconds", 3.5)
	else
		-- FIXME: Won't work on Windows, because of special snowflake pipe naming
		local ipc = mp.get_property("input-ipc-server")
		local del_tmp = ""
		if ipc == "" then
			ipc = os.tmpname()
			mp.set_property("input-ipc-server", ipc)
			del_tmp = " && lua -e 'os.remove(\""..ipc.."\")'"
		end
		os.execute(command..' && echo "{ \\"command\\": [\\"show-text\\", \\"Finished encode of \''
			..out..'\' in $(lua -e "print(os.time()-'..time..')") seconds\\", 3500] }" | socat - '
			..ipc..del_tmp.." &")
	end
end

-- Start frame key binding
mp.add_key_binding(o.key_set_start_frame, "clip-start",
	function()
		start_frame = mp.get_property("playback-time")
		if not start_frame then
			start_frame = 0
		end
		mp.osd_message("Clip start at "..start_frame.."s")
	end)
-- Stop frame key binding
mp.add_key_binding(o.key_set_stop_frame, "clip-end",
	function()
		stop_frame = mp.get_property("playback-time")
		if not stop_frame then
			mp.osd_message("playback-time is nil! (file not yet loaded?)")
		else
			mp.osd_message("Clip end at "..stop_frame.."s")
		end
	end)
-- Start encode key binding
mp.add_key_binding(o.key_start_encode, "clip-encode",
	function()
		encode()	
	end)

-- Reset start/stop frame when a new file is loaded
mp.register_event("start-file",
	function()
		start_frame = nil
		stop_frame = nil
	end)