streamsave updated; some caching fixes (may be)

src/mpv_control.py

@@ -7,13 +7,14 @@ from shutil import get_terminal_size
 from shlex import quote
 import mpv
 import time
-import sys
 import re
 
 fzf = FzfPrompt()
 
 if get_config('enable_persistent_cache'):
-    player = mpv.MPV(cache=True, scripts='src/mpv_scripts/mpv_cache.lua:src/mpv_scripts/streamsave.lua')
+    player = mpv.MPV(cache=True,
+                     scripts='src/mpv_scripts/mpv_cache.lua:src/mpv_scripts/streamsave.lua',
+                     script_opts='streamsave-save_directory=cache,streamsave-dump_mode=continuous,streansave-force_extension=.mkv,streamsave-autostart=no,output_label=overwrite')
     player.command('script-message', 'streamsave-path', 'cache')
 else:
     player = mpv.MPV(cache=True, demuxer_max_bytes=25*1024*1024)

src/mpv_scripts/mpv_cache.lua

@@ -25,18 +25,22 @@ end
 
 
 function make_cache_track(url)
+    mp.command('script-message streamsave-autostart no')
     find_uuid = "%x+-%x+-%x+-%x+-%x+"
     uuid = string.sub(url, string.find(url, find_uuid))
     host = get_url_host(url)
     cache_path_file = 'cache/' .. host .. '/' .. uuid .. '.mkv'
+    cache_path_named_file = 'cache/' .. host .. '/' .. uuid .. '.mkv'
     if false == file_exists(cache_path_file) then
 	createDir('cache/' .. host .. '/')
 	msg.verbose('Caching ' .. cache_path_file .. '')
 	mp.command('script-message streamsave-title ' .. uuid .. '')
+	mp.command('script-message streamsave-force_title ' .. uuid .. '')
+	mp.command('script-message streamsave-label overwrite')
 	mp.set_property('script-opts/media-uuid', uuid)
 	mp.command('script-message streamsave-extension .mkv')
 	mp.command('script-message streamsave-path cache/' .. host .. '')
-	mp.command('script-message streamsave-rec')
+	mp.command('script-message streamsave-autostart yes')
     else
 	msg.verbose('Already cached ' .. cache_path_file .. '')
 	os.execute('touch ' .. cache_path_file .. '')
@@ -52,3 +56,11 @@ mp.add_hook("on_load", 11, function()
 	 make_cache_track(url)
     end
 end)
+
+mp.register_event("file-loaded", function()
+    msg.verbose('reusable cache post-hook activated')
+    local url = mp.get_property("stream-open-filename", "")
+    if true == (url:find("https?://") == 1) then
+	 make_cache_track(url)
+    end
+end)

src/mpv_scripts/streamsave.lua

@@ -1,10 +1,9 @@
 --[[ 
 
 streamsave.lua
-Version 0.20.6
+Version 0.23.2
-2022-10-13
+2023-5-21
 https://github.com/Sagnac/streamsave
-NOTE: Modified
 
 mpv script aimed at saving live streams and clipping online videos without encoding.
 
@@ -12,10 +11,12 @@ Essentially a wrapper around mpv's cache dumping commands, the script adds the f
 
 * Automatic determination of the output file name and format
 * Option to specify the preferred output directory
-* Switch between 3 different dump modes (clip mode, full/continuous dump, write from beginning to current position)
+* Switch between 5 different dump modes:
+ (clip mode, full/continuous dump, write from beginning to current position, current chapter, all chapters)
 * Prevention of file overwrites
 * Acceptance of inverted loop ranges, allowing the end point to be set first
 * Dynamic chapter indicators on the OSC displaying the clipping interval
+* Option to track HLS packet drops
 * Automated stream saving
 * Workaround for some DAI HLS streams served from .m3u8 where the host changes
 
@@ -51,15 +52,27 @@ and only set the first loop point then press the cache-write keybind.
 
 dump_mode=current will dump the cache from timestamp 0 to the current playback position in the file.
 
+dump_mode=chapter will write the current chapter to file.
+
+dump_mode=segments writes out all chapters to individual files.
+
+If you wish to output a single chapter using a numerical input instead you can specify it with a command at runtime:
+script-message streamsave-chapter 7
+
 The output_label option allows you to choose how the output filename is tagged.
 The default uses iterated step increments for every file output; i.e. file-1.mkv, file-2.mkv, etc.
 
-There are 3 other choices:
+There are 4 other choices:
+
 output_label=timestamp will append Unix timestamps to the file name.
+
 output_label=range will tag the file with the A-B loop range instead using the format HH.MM.SS
 e.g. file-[00.15.00 - 00.20.00].mkv
+
 output_label=overwrite will not tag the file and will overwrite any existing files with the same name.
 
+output_label=chapter uses the chapter title for the file name if using one of the chapter modes.
+
 The force_extension option allows you to force a preferred format and sidestep the automatic detection.
 If using this option it is recommended that a highly flexible container is used (e.g. Matroska).
 The format is specified as the extension including the dot (e.g. force_extension=.mkv).
@@ -78,6 +91,8 @@ Once the A-B points are cleared the original chapters are restored.
 Any chapters added after A-B mode is entered are added to the initial chapter list.
 This option is disabled by default; set range_marks=yes in streamsave.conf in order to enable it.
 
+The track_packets option adds chapters to positions where packet loss occurs for HLS streams.
+
 Automation Options:
 
 The autostart and autoend options are used for automated stream capturing.
@@ -88,6 +103,8 @@ to stop at that time.
 The hostchange option enables an experimental workaround for DAI HLS .m3u8 streams in which the host changes.
 If enabled this will result in multiple files being output as the stream reloads.
 The autostart option must also be enabled in order to autosave these types of streams.
+The `on_demand` option is a suboption of the hostchange option which, if enabled, triggers reloads immediately across
+segment switches without waiting until playback has reached the end of the last segment.
 
 The `quit=HH:MM:SS` option will set a one shot timer from script load to the specified time,
 at which point the player will exit. This serves as a replacement for autoend when using hostchange.
@@ -122,14 +139,16 @@ local unpack = unpack or table.unpack
 -- change these in streamsave.conf
 local opts = {
     save_directory = [[.]],         -- output file directory
-    dump_mode = "continuous",               -- <ab|current|continuous>
+    dump_mode = "ab",               -- <ab|current|continuous|chapter|segments>
-    output_label = "overwrite",     -- <increment|range|timestamp|overwrite>
+    output_label = "increment",     -- <increment|range|timestamp|overwrite|chapter>
-    force_extension = ".mkv",         -- <no|.ext> extension will be .ext if set
+    force_extension = "no",         -- <no|.ext> extension will be .ext if set
     force_title = "no",             -- <no|title> custom title used for the filename
     range_marks = false,            -- <yes|no> set chapters at A-B loop points?
-    autostart = true,              -- <yes|no> automatically dump cache at start?
+    track_packets = false,          -- <yes|no> track HLS packet drops
+    autostart = false,              -- <yes|no> automatically dump cache at start?
     autoend = "no",                 -- <no|HH:MM:SS> cache time to stop at
     hostchange = false,             -- <yes|no> use if the host changes mid stream
+    on_demand = false,              -- <yes|no> hostchange suboption, instant reloads
     quit = "no",                    -- <no|HH:MM:SS> quits player at specified time
     piecewise = false,              -- <yes|no> writes stream in parts with autoend
 }
@@ -141,8 +160,12 @@ local file = {
     title,           -- media title
     inc,             -- filename increments
     ext,             -- file extension
+    loaded,          -- flagged once the initial load has taken place
     pending,         -- number of files pending write completion (max 2)
     queue,           -- cache_write queue in case of multiple write requests
+    writing,         -- file writing object returned by the write command
+    quitsec,         -- user specified quit time in seconds
+    quit_timer,      -- player quit timer set according to quitsec
     oldtitle,        -- initialized if title is overridden, allows revert
     oldext,          -- initialized if format is overridden, allows revert
     oldpath,         -- initialized if directory is overriden, allows revert
@@ -155,42 +178,49 @@ local loop = {
     b_revert,        -- B loop point prior to keyframe alignment
     range,           -- A-B loop range
     aligned,         -- are the loop points aligned to keyframes?
+    continuous,      -- is the writing continuous?
 }
 
 local cache = {
     dumped,          -- autowrite cache state (serves as an autowrite request)
     observed,        -- whether the cache time is being observed
     endsec,          -- user specified autoend cache time in seconds
-    prior,           -- previous cache time
+    prior,           -- cache duration prior to staging the seamless reload mechanism
     seekend,         -- seekable cache end timestamp
     part,            -- approx. end time of last piece / start time of next piece
     switch,          -- request to observe track switches and seeking
     use,             -- use cache_time instead of seekend for initial piece
-    restart,         -- hostchange interval where subsequent reloads are immediate
+    id,              -- number of times the packet tracking event has fired
+    packets,         -- table of periodic timers indexed by cache id stamps
 }
 
-local convert_time
+local track = {
-local observe_cache
+    vid,             -- video track id
-local continuous
+    aid,             -- audio track id
-local write_file
+    sid,             -- subtitle track id
-local reset
+    restart,         -- hostchange interval where subsequent reloads are immediate
-local title_change
+    suspend,         -- suspension interval on track-list changes
-local container
+}
+
+local segments = {}     -- chapter segments set for writing
 local chapter_list = {} -- initial chapter list
 local ab_chapters = {}  -- A-B loop point chapters
-local chapter_points
-local get_seekable_cache
-local reload
-local automatic
-local quitseconds
-local quit_timer
-local autoquit
 
-function convert_time(value)
+local title_change
-    local i, j, H, M, S = value:find("(%d+):(%d+):(%d+)")
+local container
-    if not i then
+local get_chapters
-        return
+local chapter_points
-    else
+local reset
+local get_seekable_cache
+local automatic
+local autoquit
+local packet_events
+local observe_cache
+local observe_tracks
+
+local function convert_time(value)
+    local H, M, S = value:match("^(%d+):([0-5]%d):([0-5]%d)$")
+    if H then
         return H*3600 + M*60 + S
     end
 end
@@ -199,16 +229,19 @@ local function validate_opts()
     if opts.output_label ~= "increment" and
        opts.output_label ~= "range" and
        opts.output_label ~= "timestamp" and
-       opts.output_label ~= "overwrite"
+       opts.output_label ~= "overwrite" and
+       opts.output_label ~= "chapter"
     then
-        msg.warn("Invalid output_label '" .. opts.output_label .. "'")
+        msg.error("Invalid output_label '" .. opts.output_label .. "'")
         opts.output_label = "increment"
     end
     if opts.dump_mode ~= "ab" and
        opts.dump_mode ~= "current" and
-       opts.dump_mode ~= "continuous"
+       opts.dump_mode ~= "continuous" and
+       opts.dump_mode ~= "chapter" and
+       opts.dump_mode ~= "segments"
     then
-        msg.warn("Invalid dump_mode '" .. opts.dump_mode .. "'")
+        msg.error("Invalid dump_mode '" .. opts.dump_mode .. "'")
         opts.dump_mode = "ab"
     end
     if opts.autoend ~= "no" then
@@ -216,15 +249,15 @@ local function validate_opts()
             cache.endsec = convert_time(opts.autoend)
         end
         if not convert_time(opts.autoend) then
-            msg.warn("Invalid autoend value '" .. opts.autoend ..
+            msg.error("Invalid autoend value '" .. opts.autoend ..
                      "'. Use HH:MM:SS format.")
             opts.autoend = "no"
         end
     end
     if opts.quit ~= "no" then
-        quitseconds = convert_time(opts.quit)
+        file.quitsec = convert_time(opts.quit)
-        if not quitseconds then
+        if not file.quitsec then
-            msg.warn("Invalid quit value '" .. opts.quit ..
+            msg.error("Invalid quit value '" .. opts.quit ..
                      "'. Use HH:MM:SS format.")
             opts.quit = "no"
         end
@@ -249,17 +282,22 @@ local function update_opts(changed)
         if opts.range_marks then
             chapter_points()
         else
+            if not get_chapters() then
+                mp.set_property_native("chapter-list", chapter_list)
+            end
             ab_chapters = {}
-            mp.set_property_native("chapter-list", chapter_list)
         end
     end
     if changed["autoend"] then
         cache.endsec = convert_time(opts.autoend)
         observe_cache()
     end
-    if changed["autostart"] or changed["hostchange"] then
+    if changed["autostart"] then
         observe_cache()
     end
+    if changed["hostchange"] then
+        observe_tracks(opts.hostchange)
+    end
     if changed["quit"] then
         autoquit()
     end
@@ -268,6 +306,9 @@ local function update_opts(changed)
     elseif changed["piecewise"] then
         cache.endsec = convert_time(opts.autoend)
     end
+    if changed["track_packets"] then
+        packet_events(opts.track_packets)
+    end
 end
 
 options.read_options(opts, "streamsave", update_opts)
@@ -281,6 +322,10 @@ local function mode_switch(value)
             value = "current"
         elseif opts.dump_mode == "current" then
             value = "continuous"
+        elseif opts.dump_mode == "continuous" then
+            value = "chapter"
+        elseif opts.dump_mode == "chapter" then
+            value = "segments"
         else
             value = "ab"
         end
@@ -297,8 +342,16 @@ local function mode_switch(value)
         opts.dump_mode = "current"
         print("Current position mode")
         mp.osd_message("Cache write mode: Current position")
+    elseif value == "chapter" then
+        opts.dump_mode = "chapter"
+        print("Chapter mode (single chapter)")
+        mp.osd_message("Cache write mode: Chapter")
+    elseif value == "segments" then
+        opts.dump_mode = "segments"
+        print("Segments mode (all chapters)")
+        mp.osd_message("Cache write mode: Segments")
     else
-        msg.warn("Invalid dump mode '" .. value .. "'")
+        msg.error("Invalid dump mode '" .. value .. "'")
     end
 end
 
@@ -321,12 +374,13 @@ function container(_, _, req)
     local file_format = mp.get_property("file-format")
     if not file_format then
         reset()
+        observe_tracks()
         return end
     if opts.force_extension ~= "no" and not req then
         file.ext = opts.force_extension
         observe_cache()
         return end
-    if string.find(file_format, "mp4")
+    if string.match(file_format, "mp4")
        or ((video == "h264" or video == "av1" or not video) and
            (audio == "aac" or not audio))
     then
@@ -339,6 +393,7 @@ function container(_, _, req)
         file.ext = ".mkv"
     end
     observe_cache()
+    observe_tracks()
     file.oldext = nil
 end
 
@@ -395,6 +450,8 @@ local function label_override(value)
             value = "timestamp"
         elseif opts.output_label == "timestamp" then
             value = "overwrite"
+        elseif opts.output_label == "overwrite" then
+            value = "chapter"
         else
             value = "increment"
         end
@@ -408,8 +465,10 @@ end
 local function marks_override(value)
     if not value or value == "no" then
         opts.range_marks = false
+        if not get_chapters() then
+            mp.set_property_native("chapter-list", chapter_list)
+        end
         ab_chapters = {}
-        mp.set_property_native("chapter-list", chapter_list)
         print("Range marks disabled")
         mp.osd_message("streamsave: range marks disabled")
     elseif value == "yes" then
@@ -418,17 +477,12 @@ local function marks_override(value)
         print("Range marks enabled")
         mp.osd_message("streamsave: range marks enabled")
     else
-        msg.warn("Invalid input '" .. value .. "'. Use yes or no.")
+        msg.error("Invalid input '" .. value .. "'. Use yes or no.")
         mp.osd_message("streamsave: invalid input; use yes or no")
     end
 end
 
 local function autostart_override(value)
-    if value and value ~= "no" and value ~= "yes" then
-        msg.warn("Invalid input '" .. value .. "'. Use yes or no.")
-        mp.osd_message("streamsave: invalid input; use yes or no")
-        return
-    end
     if not value or value == "no" then
         opts.autostart = false
         print("Autostart disabled")
@@ -437,6 +491,10 @@ local function autostart_override(value)
         opts.autostart = true
         print("Autostart enabled")
         mp.osd_message("streamsave: autostart enabled")
+    else
+        msg.error("Invalid input '" .. value .. "'. Use yes or no.")
+        mp.osd_message("streamsave: invalid input; use yes or no")
+        return
     end
     observe_cache()
 end
@@ -451,24 +509,31 @@ local function autoend_override(value)
 end
 
 local function hostchange_override(value)
+    local hostchange = opts.hostchange
     value = value == "cycle" and (not opts.hostchange and "yes" or "no") or value
-    if value and value ~= "no" and value ~= "yes" then
-        msg.warn("Invalid input '" .. value .. "'. Use yes or no.")
-        mp.osd_message("streamsave: invalid input; use yes or no")
-        return
-    end
     if not value or value == "no" then
         opts.hostchange = false
-        mp.unobserve_property(reload)
-        local timer = cache.restart and cache.restart:kill()
         print("Hostchange disabled")
         mp.osd_message("streamsave: hostchange disabled")
     elseif value == "yes" then
         opts.hostchange = true
         print("Hostchange enabled")
         mp.osd_message("streamsave: hostchange enabled")
+    elseif value == "on_demand" then
+        opts.on_demand = not opts.on_demand
+        opts.hostchange = opts.on_demand or opts.hostchange
+        local status = opts.on_demand and "enabled" or "disabled"
+        print("Hostchange: On Demand " .. status)
+        mp.osd_message("streamsave: hostchange on_demand " .. status)
+    else
+        local allowed = "yes, no, cycle, or on_demand"
+        msg.error("Invalid input '" .. value .. "'. Use " .. allowed .. ".")
+        mp.osd_message("streamsave: invalid input; use " .. allowed)
+        return
+    end
+    if opts.hostchange ~= hostchange then
+        observe_tracks(opts.hostchange)
     end
-    observe_cache()
 end
 
 local function quit_override(value)
@@ -491,11 +556,33 @@ local function piecewise_override(value)
         print("Piecewise dumping enabled")
         mp.osd_message("streamsave: piecewise dumping enabled")
     else
-        msg.warn("Invalid input '" .. value .. "'. Use yes or no.")
+        msg.error("Invalid input '" .. value .. "'. Use yes or no.")
         mp.osd_message("streamsave: invalid input; use yes or no")
     end
 end
 
+local function packet_override(value)
+    local track_packets = opts.track_packets
+    if value == "cycle" then
+        value = not track_packets and "yes" or "no"
+    end
+    if not value or value == "no" then
+        opts.track_packets = false
+        print("Track packets disabled")
+        mp.osd_message("streamsave: track packets disabled")
+    elseif value == "yes" then
+        opts.track_packets = true
+        print("Track packets enabled")
+        mp.osd_message("streamsave: track packets enabled")
+    else
+        msg.error("Invalid input '" .. value .. "'. Use yes or no.")
+        mp.osd_message("streamsave: invalid input; use yes or no")
+    end
+    if opts.track_packets ~= track_packets then
+        packet_events(opts.track_packets)
+    end
+end
+
 local function range_flip()
     loop.a = mp.get_property_number("ab-loop-a")
     loop.b = mp.get_property_number("ab-loop-b")
@@ -550,6 +637,47 @@ local function range_stamp(mode)
     end
 end
 
+local function write_chapter(chapter)
+    get_chapters()
+    if chapter_list[chapter] or chapter == 0 then
+        segments[1] = {
+            ["start"] = chapter == 0 and 0 or chapter_list[chapter]["time"],
+            ["end"] = chapter_list[chapter + 1]
+                      and chapter_list[chapter + 1]["time"]
+                      or mp.get_property_number("duration", "no"),
+            ["title"] = chapter .. ". " .. (chapter ~= 0
+                        and chapter_list[chapter]["title"] or file.title)
+        }
+        print("Writing chapter " .. chapter .. " ....")
+        return true
+    else
+        msg.error("Chapter not found.")
+    end
+end
+
+local function extract_segments(n)
+    for i = 1, n - 1 do
+        segments[i] = {
+            ["start"] = chapter_list[i]["time"],
+            ["end"] = chapter_list[i + 1]["time"],
+            ["title"] = i .. ". " .. (chapter_list[i]["title"] or file.title)
+        }
+    end
+    if chapter_list[1]["time"] ~= 0 then
+        table.insert(segments, 1, {
+            ["start"] = 0,
+            ["end"] = chapter_list[1]["time"],
+            ["title"] = "0. " .. file.title
+        })
+    end
+    table.insert(segments, {
+        ["start"] = chapter_list[n]["time"],
+        ["end"] = mp.get_property_number("duration", "no"),
+        ["title"] = n .. ". " .. (chapter_list[n]["title"] or file.title)
+    })
+    print("Writing out all " .. #segments .. " chapters to separate files ....")
+end
+
 local function write_set(mode, file_name, file_pos, quiet)
     local command = {
         _flags = {
@@ -559,6 +687,11 @@ local function write_set(mode, file_name, file_pos, quiet)
     }
     if mode == "ab" then
         command["name"] = "ab-loop-dump-cache"
+    elseif (mode == "chapter" or mode == "segments") and segments[1] then
+        command["name"] = "dump-cache"
+        command["start"] = segments[1]["start"]
+        command["end"] = segments[1]["end"]
+        table.remove(segments, 1)
     else
         command["name"] = "dump-cache"
         command["start"] = 0
@@ -567,18 +700,67 @@ local function write_set(mode, file_name, file_pos, quiet)
     return command
 end
 
-local function cache_write(mode, quiet)
+local function on_write_finish(cache_write, mode, file_name)
+    return function(success, _, command_error)
+        command_error = command_error and msg.error(command_error)
+        -- check if file is written
+        if utils.file_info(file_name) then
+            if success then
+                print("Finished writing cache to: " .. file_name)
+            else
+                msg.warn("Possibly broken file created at: " .. file_name)
+            end
+        else
+            msg.error("File not written.")
+        end
+        if loop.continuous and file.pending == 2 then
+            print("Dumping cache continuously to: " .. file.name)
+        end
+        file.pending = file.pending - 1
+        -- fulfil any write requests now that the pending queue has been serviced
+        if next(segments) then
+            cache_write("segments", true)
+        elseif mode == "segments" then
+            mp.osd_message("Cache dumping successfully ended.")
+        end
+        if file.queue and next(file.queue) and not segments[1] then
+            cache_write(unpack(file.queue[1]))
+            table.remove(file.queue, 1)
+        end
+    end
+end
+
+local function cache_write(mode, quiet, chapter)
     if not (file.title and file.ext) then
         return end
-    if file.pending == 2 then
+    if file.pending == 2
+       or segments[1] and file.pending > 0 and not loop.continuous
+    then
         file.queue = file.queue or {}
         -- honor extra write requests when pending queue is full
         -- but limit number of outstanding write requests to be fulfilled
         if #file.queue < 10 then
-            table.insert(file.queue, {mode, quiet})
+            table.insert(file.queue, {mode, quiet, chapter})
         end
         return end
     range_flip()
+    -- set the output list for the chapter modes
+    if mode == "segments" and not segments[1] then
+        get_chapters()
+        local n = #chapter_list
+        if n > 0 then
+            extract_segments(n)
+            quiet = true
+            mp.osd_message("Cache dumping started.")
+        else
+            mode = "continuous"
+        end
+    elseif mode == "chapter" and not segments[1] then
+        chapter = chapter or mp.get_property_number("chapter", -1) + 1
+        if not write_chapter(chapter) then
+            return
+        end
+    end
     -- evaluate tagging conditions and set file name
     if opts.output_label == "increment" then
         increment_filename()
@@ -588,42 +770,27 @@ local function cache_write(mode, quiet)
         file.name = set_name(-os.time())
     elseif opts.output_label == "overwrite" then
         file.name = set_name("")
+    elseif opts.output_label == "chapter" then
+        if segments[1] then
+            file.name = file.path .. "/" .. segments[1]["title"] .. file.ext
+        else
+            increment_filename()
+        end
     end
     -- dump cache according to mode
     local file_pos
-    local file_name = file.name -- scope reduction so callback verifies correct file
     file.pending = (file.pending or 0) + 1
-    continuous = mode == "continuous" or loop.a and not loop.b
+    loop.continuous = mode == "continuous"
+                      or mode == "ab" and loop.a and not loop.b
+                      or segments[1] and segments[1]["end"] == "no"
     if mode == "current" then
         file_pos = mp.get_property_number("playback-time", 0)
-    elseif continuous and file.pending == 1 then
+    elseif loop.continuous and file.pending == 1 then
-        print("Dumping cache continuously to:" .. file_name)
+        print("Dumping cache continuously to: " .. file.name)
     end
-    write_file = mp.command_native_async (
+    local commands = write_set(mode, file.name, file_pos, quiet)
-        write_set(mode, file_name, file_pos, quiet),
+    local callback = on_write_finish(cache_write, mode, file.name)
-        function(success, _, command_error)
+    file.writing = mp.command_native_async(commands, callback)
-            command_error = command_error and msg.error(command_error)
-            -- check if file is written
-            if utils.file_info(file_name) then
-                if success then
-                    print("Finished writing cache to:" .. file_name)
-                else
-                    msg.warn("Possibly broken file created at:" .. file_name)
-                end
-            else
-                msg.error("File not written.")
-            end
-            if continuous and file.pending == 2 then
-                print("Dumping cache continuously to:" .. file.name)
-            end
-            file.pending = file.pending - 1
-            -- fulfil any write requests now that the pending queue has been serviced
-            if file.queue and #file.queue > 0 then
-                cache_write(file.queue[1][1], file.queue[1][2])
-                table.remove(file.queue, 1)
-            end
-        end
-    )
     return true
 end
 
@@ -649,16 +816,15 @@ local function align_cache()
     end
 end
 
--- creates chapters at A-B loop points
+function get_chapters()
-function chapter_points()
-    if not opts.range_marks then
-        return end
     local current_chapters = mp.get_property_native("chapter-list", {})
+    local updated -- do the stored chapters reflect the current chapters ?
     -- make sure master list is up to date
-    if current_chapters[1] and
+    if not current_chapters[1] or
        not string.match(current_chapters[1]["title"], "^[AB] loop point$")
     then
         chapter_list = current_chapters
+        updated = true
     -- if a script has added chapters after A-B points are set then
     -- add those to the original chapter list
     elseif #current_chapters > #ab_chapters then
@@ -666,12 +832,22 @@ function chapter_points()
             table.insert(chapter_list, current_chapters[i])
         end
     end
+    return updated
+end
+
+-- creates chapters at A-B loop points
+function chapter_points()
+    if not opts.range_marks then
+        return end
+    local updated = get_chapters()
     ab_chapters = {}
     -- restore original chapter list if A-B points are cleared
     -- otherwise set chapters to A-B points
     range_flip()
     if not loop.a and not loop.b then
-        mp.set_property_native("chapter-list", chapter_list)
+        if not updated then
+            mp.set_property_native("chapter-list", chapter_list)
+        end
     else
         if loop.a then
             ab_chapters[1] = {
@@ -696,36 +872,53 @@ end
 
 -- stops writing the file
 local function stop()
-    mp.abort_async_command(write_file or {})
+    mp.abort_async_command(file.writing or {})
 end
 
 function reset()
     if cache.observed or cache.dumped then
         stop()
         mp.unobserve_property(automatic)
-        mp.unobserve_property(reload)
         mp.unobserve_property(get_seekable_cache)
         cache.endsec = convert_time(opts.autoend)
         cache.observed = false
     end
-    cache.prior = 0
     cache.part = 0
     cache.dumped = false
     cache.switch = true
 end
 reset()
 
-function get_seekable_cache(prop, range_check, underrun)
+-- reload on demand (hostchange)
+local function reload()
+    reset()
+    observe_tracks()
+    msg.warn("Reloading stream due to host change.")
+    mp.command("playlist-play-index current")
+end
+
+local function stabilize()
+    if mp.get_property_number("demuxer-cache-time", 0) > 1500 then
+        reload()
+    end
+end
+
+local function suspend()
+    if not track.suspend then
+        track.suspend = mp.add_timeout(25, stabilize)
+    else
+        track.suspend:resume()
+    end
+end
+
+function get_seekable_cache(prop, range_check)
     -- use the seekable part of the cache for more accurate timestamps
     local cache_state = mp.get_property_native("demuxer-cache-state", {})
-    if underrun then
-        return cache_state["underrun"]
-    end
     local seekable_ranges = cache_state["seekable-ranges"] or {}
     if prop then
         if range_check ~= false and
            (#seekable_ranges == 0
-            or not mp.get_property_number("demuxer-cache-time"))
+            or not cache_state["cache-end"])
         then
             reset()
             cache.use = opts.piecewise
@@ -737,45 +930,67 @@ function get_seekable_cache(prop, range_check, underrun)
     for i, range in ipairs(seekable_ranges) do
         seekable_ends[i] = range["end"] or 0
     end
-    cache.seekend = math.max(0, unpack(seekable_ends))
+    return math.max(0, unpack(seekable_ends))
-    return cache.seekend
 end
 
-function reload(_, play_time)
+-- seamlessly reload on inserts (hostchange)
-    local cache_duration = mp.get_property_number("demuxer-cache-duration")
+local function seamless(_, cache_state)
-    if play_time and play_time >= cache.seekend - 0.25
+    cache_state = cache_state or {}
-       or cache_duration and math.abs(cache.prior - cache_duration) > 4800
+    local reader = math.abs(cache_state["reader-pts"] or 0)
-       or get_seekable_cache(nil, false, true)
+    local cache_duration = math.abs(cache_state["cache-duration"] or cache.prior)
+    -- wait until playback of the loaded cache has practically ended
+    -- or there's a timestamp reset / position shift
+    if reader >= cache.seekend - 0.25
+       or cache.prior - cache_duration > 3000
+       or cache_state["underrun"]
     then
+        reload()
+        track.restart = track.restart or mp.add_timeout(300, function() end)
+        track.restart:resume()
+    end
+end
+
+-- detect stream switches (hostchange)
+local function detect()
+    local eq = true
+    local t = {
+        vid = mp.get_property_number("current-tracks/video/id", 0),
+        aid = mp.get_property_number("current-tracks/audio/id", 0),
+        sid = mp.get_property_number("current-tracks/sub/id", 0)
+    }
+    for k, v in pairs(t) do
+        eq = track[k] == v and eq
+        track[k] = v
+    end
+    -- do not initiate a reload process if the track ids do not match
+    -- or the track loading suspension interval is active
+    if not eq then
+        return
+    end
+    if track.suspend:is_enabled() then
+        stabilize()
+        return
+    end
+    -- bifurcate
+    if track.restart and track.restart:is_enabled() then
+        track.restart:kill()
+        reload()
+    elseif opts.on_demand then
+        reload()
+    else
+        -- watch the cache state outside of the interval
+        -- and use it to decide when to reload
         reset()
-        cache.restart = cache.restart or mp.add_timeout(300, function() end)
+        observe_tracks(false)
-        cache.restart:resume()
+        cache.observed = true
-        msg.warn("Reloading stream due to host change.")
+        cache.prior = math.abs(mp.get_property_number("demuxer-cache-duration", 4E3))
-        mp.command("playlist-play-index current")
+        cache.seekend = get_seekable_cache()
+        mp.observe_property("demuxer-cache-state", "native", seamless)
     end
 end
 
 function automatic(_, cache_time)
-    if opts.hostchange and cache.prior ~= 0
+    if not cache_time then
-       and (not cache_time or math.abs(cache_time - cache.prior) > 300
-            or mp.get_property_number("demuxer-cache-duration", 0) > 11000)
-       and not mp.get_property_bool("seeking")
-    then
-        if not cache.restart or not cache.restart:is_enabled() then
-            reset()
-            cache.observed = true
-            cache.prior = mp.get_property_number("demuxer-cache-duration", 0)
-            get_seekable_cache()
-            mp.observe_property("playback-time", "number", reload)
-        else
-            -- reload stream
-            cache.restart:kill()
-            reset()
-            msg.warn("Reloading stream due to host change.")
-            mp.command("playlist-play-index current")
-        end
-        return
-    elseif not cache_time then
         reset()
         cache.use = opts.piecewise
         observe_cache()
@@ -805,12 +1020,9 @@ function automatic(_, cache_time)
         mp.observe_property("seeking", "bool", get_seekable_cache)
     end
     -- unobserve cache time if not needed
-    if cache.dumped and not cache.switch
+    if cache.dumped and not cache.switch and not cache.endsec then
-       and not cache.endsec and not opts.hostchange
-    then
         mp.unobserve_property(automatic)
         cache.observed = false
-        cache.prior = 0
         return
     end
     -- stop cache dump
@@ -830,34 +1042,104 @@ function automatic(_, cache_time)
         end
         stop()
     end
-    cache.prior = cache_time
 end
 
 function autoquit()
     if opts.quit == "no" then
-        if quit_timer then
+        if file.quit_timer then
-            quit_timer:kill()
+            file.quit_timer:kill()
         end
-    elseif not quit_timer then
+    elseif not file.quit_timer then
-        quit_timer = mp.add_timeout(quitseconds,
+        file.quit_timer = mp.add_timeout(file.quitsec,
             function()
                 stop()
                 mp.command("quit")
                 print("Quit after " .. opts.quit)
             end)
     else
-        quit_timer["timeout"] = quitseconds
+        file.quit_timer["timeout"] = file.quitsec
-        quit_timer:kill()
+        file.quit_timer:kill()
-        quit_timer:resume()
+        file.quit_timer:resume()
     end
 end
 autoquit()
 
+local function fragment_chapters(packets, cache_time, stamp)
+    local no_loop_chapters = get_chapters()
+    local title = string.format("%s segment(s) dropped [%s]", packets, stamp)
+    for _, chapter in ipairs(chapter_list) do
+        if chapter["title"] == title then
+            cache.packets[stamp]:kill()
+            cache.packets[stamp] = nil
+            return
+        end
+    end
+    table.insert(chapter_list, {
+        title = title,
+        time = cache_time
+    })
+    if no_loop_chapters then
+        mp.set_property_native("chapter-list", chapter_list)
+    end
+end
+
+local function packet_handler(t)
+    if not opts.track_packets then -- second layer in case unregistering is async
+        return
+    end
+    if t.prefix == "ffmpeg/demuxer" then
+        local packets = t.text:match("^hls: skipping (%d+)")
+        if packets then
+            local cache_time = mp.get_property_number("demuxer-cache-time")
+            if cache_time then
+                -- ensure the chapters set
+                cache.id = cache.id + 1
+                local stamp = string.format("%#x", cache.id)
+                cache.packets[stamp] = mp.add_periodic_timer(3,
+                    function()
+                        fragment_chapters(packets, cache_time, stamp)
+                    end
+                )
+            end
+        end
+    end
+end
+
+function packet_events(state)
+    if not state then
+        mp.unregister_event(packet_handler)
+        for _, timer in pairs(cache.packets) do
+            timer:kill()
+        end
+        cache.id = nil
+        cache.packets = nil
+        local no_loop_chapters = get_chapters()
+        local n = #chapter_list
+        for i = n, 1, -1 do
+            if chapter_list[i]["title"]:match("%d+ segment%(s%) dropped") then
+                table.remove(chapter_list, i)
+            end
+        end
+        if no_loop_chapters and n > #chapter_list then
+            mp.set_property_native("chapter-list", chapter_list)
+        end
+    else
+        cache.id = 0
+        cache.packets = {}
+        mp.enable_messages("warn")
+        mp.register_event("log-message", packet_handler)
+    end
+end
+if opts.track_packets then
+    packet_events(true)
+end
+
 -- cache time observation switch for runtime changes
 function observe_cache()
     local network = mp.get_property_bool("demuxer-via-network")
-    local obs_xyz = opts.autostart or cache.endsec or opts.hostchange
+    local obs_xyz = opts.autostart or cache.endsec
     if not cache.observed and obs_xyz and network then
+        cache.dumped = (file.pending or 0) ~= 0
         mp.observe_property("demuxer-cache-time", "number", automatic)
         cache.observed = true
     elseif (cache.observed or cache.dumped) and (not obs_xyz or not network) then
@@ -865,7 +1147,30 @@ function observe_cache()
     end
 end
 
-mp.observe_property("media-uuid", "string", title_change)
+-- track-list observation switch for runtime changes
+function observe_tracks(state)
+    if state then
+        suspend()
+        mp.observe_property("track-list", "native", detect)
+    elseif state == false then
+        mp.unobserve_property(detect)
+        mp.unobserve_property(seamless)
+        cache.prior = nil
+        local timer = track.restart and track.restart:kill()
+    -- reset the state on manual reloads
+    elseif cache.prior then
+        observe_tracks(false)
+        observe_tracks(true)
+    elseif opts.hostchange then
+        suspend()
+    end
+end
+
+if opts.hostchange then
+    observe_tracks(true)
+end
+
+mp.observe_property("media-title", "string", title_change)
 
 --[[ video and audio formats observed in order to handle track changes
 useful if e.g. --script-opts=ytdl_hook-all_formats=yes
@@ -878,13 +1183,16 @@ mp.observe_property("file-format", "string", container)
 an external file, so make sure existing chapters are not overwritten
 by observing A-B loop changes only after the file is loaded. ]]
 local function on_file_load()
-    mp.observe_property("ab-loop-a", "native", chapter_points)
+    if file.loaded then
-    mp.observe_property("ab-loop-b", "native", chapter_points)
+        chapter_points()
+    else
+        mp.observe_property("ab-loop-a", "native", chapter_points)
+        mp.observe_property("ab-loop-b", "native", chapter_points)
+        file.loaded = true
+    end
 end
 mp.register_event("file-loaded", on_file_load)
 
-mp.register_script_message("streamsave-rec", function() cache_write(opts.dump_mode)
-                   end)
 mp.register_script_message("streamsave-mode", mode_switch)
 mp.register_script_message("streamsave-title", title_override)
 mp.register_script_message("streamsave-extension", format_override)
@@ -896,6 +1204,12 @@ mp.register_script_message("streamsave-autoend", autoend_override)
 mp.register_script_message("streamsave-hostchange", hostchange_override)
 mp.register_script_message("streamsave-quit", quit_override)
 mp.register_script_message("streamsave-piecewise", piecewise_override)
+mp.register_script_message("streamsave-packets", packet_override)
+mp.register_script_message("streamsave-chapter",
+    function(chapter)
+        cache_write("chapter", _, tonumber(chapter))
+    end
+)
 
 mp.add_key_binding("Alt+z", "mode-switch", function() mode_switch("cycle") end)
 mp.add_key_binding("Ctrl+x", "stop-cache-write", stop)