VLC Extension - Skip Chapter

chapter_skipper.lua

-- chapter_skipper.lua -- VLC extension
--[[
Feel free to mail me with suggestions/improvements!

INSTALLATION:
Put the file in the VLC subdir /lua/extensions, by default:
* Windows (all users): %ProgramFiles%\VideoLAN\VLC\lua\extensions\
* Windows (current user): %APPDATA%\VLC\lua\extensions\
* Linux (all users): /usr/share/vlc/lua/extensions/
* Linux (current user): ~/.local/share/vlc/lua/extensions/
* Mac OS X (all users): /Applications/VLC.app/Contents/MacOS/share/lua/extensions/
(create directories if they don't exist)
Restart the VLC or in the VLC "Tools | Plugins and Extensions" item,
select "Reload Extensions"

USAGE:
	Go to the "View" menu and select "Chapter Skipper".

LICENSE:
	Go wild!
--]]

function descriptor()
return {
title = "Chapter Skipper",
author = "Victor Pascu <victor.pscu@gmail.com>",
version = 0.1,
shortdesc = 'Chapter Skipper',
url = 'https://github.com/VictorPascu',
description = "This extension will skip a specified chapter when your video reaches it.",
capabilities = {"input-listener"}
}
end

keep_checking = true --to disable the check loop on deactivation
sleep_duration = 5 --seconds apart to run check
chapterToSkip = -1

--Run on plugin activation
function activate()
vlc.playlist.pause()
d = vlc.dialog("Chapter Skipper")
d:show()
d:add_label( "This extension will periodically check the chapter your video is at, with the first chapter being 0. ", 2, 1, 1, 1 )
d:add_label( "It cause VLC to become unresponsive, but it will return to normal after the skip.", 2, 2, 1, 1 )
d:add_label( "You can move the 'extension not responding' screen to another monitor to minimize viewing impact.", 2, 3, 1, 1 )

fullscreenOption = d:add_check_box( "Go to fullscreen", true, 2, 4, 1, 1)
restartOption = d:add_check_box( "Restart video", true, 2, 5, 1, 1)

d:add_label( "Chapter # to skip", 1, 1, 1, 1 )
chapterToSkipInput = d:add_text_input( 1, 1, 2, 1, 1 )
d:add_button("Enable", click_Start,1,3,1,1)
d:add_button("Disable", click_Disable,1,4,1,1)
end

--Verify input options and enter check loop
function click_Start()
vlc.msg.info("Enabling chapter skipper.")
chapterToSkip = tonumber(chapterToSkipInput:get_text())
vlc.msg.info("Target chapter:")
vlc.msg.info(chapterToSkip)
vlc.playlist.play()

if restartOption:get_checked() then
vlc.var.set(vlc.object.input(), "time", 0)
end

if fullscreenOption:get_checked() then
	vlc.video.fullscreen()
end	

d:hide()

start_checker()
end

--Disable check loop.
function click_Disable()
d:hide()
vlc.msg.info("Disabled chapter skipper.")
deactivate()
end

--Start chapter skip loop
function start_checker()
keep_checking = true

vlc.msg.info("Running chapter skipper")

recheck_chapter_skip()
end

--Run on plugin deactivation
function deactivate()
keep_checking = false
vlc.msg.info("Deactivated chapter skipper.")
end

--[[
OS-based sleep - this is why the extension triggers not responding prompts. 
Could be fixed if a way is found to get access to FFI from the bundled VLC lua or if VLC re-allows callbacks in it.
There is a new chapter internal callback that would greatly simplify the checks (see debug messages), 
but it's not available to extensions.

Right now, because extensions are single-threaded, and this loop makes os.time() calls to the CPU 
and because VLC has a timeout check for extensions, it thinks the extension has crashed after
a while.
--]]
function sleep(s)
  if keep_checking == true then
  vlc.msg.info("Sleeping...")
  
  local ntime = os.time() + s
  repeat until os.time() > ntime
  
  vlc.msg.info("Sleep done...")
  end
end

--Will re-run check between sleeps.
function recheck_chapter_skip()
if keep_checking then
	vlc.msg.info("Rechecking chapter skip...")
	sleep(sleep_duration)
	chapter_skip_check()
end
end

-- If the current chapter matches the one we want to skip, skip it.
-- There's room for improvement here with chapter lists (instead of just one),
-- but that's probably for a future version.
function chapter_skip_check()
if get_chapter() == chapterToSkip then
	vlc.msg.info("Skipping chapter")
	skip_chapter()
	deactivate()
	else 
	vlc.msg.info("Not at target chapter")
	recheck_chapter_skip()
	end
end

-- Get chapter number
function get_chapter()
return vlc.var.get(vlc.object.input(), "chapter") 	
end

-- Skip wrapper
function skip_chapter()
titlechap_offset('chapter', 1)
end

-- VLC's function for changing chapters
function titlechap_offset(var,offset)
    local input = vlc.object.input()
    vlc.var.set( input, var, vlc.var.get( input, var ) + offset )
end

function meta_changed()
end

Is it possible to get the chapter names and use those to skip? Or maybe even multiple chapters?

@ActuallyGiggles I wrote this many years ago and haven't kept up with changes in VLC's functions. It's possible that the calls you can do have expanded to support such functionality.