diff --git a/CHANGELOG.md b/CHANGELOG.md
index e12c6bf..355653a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## Unreleased
+
+* Use max part target duration of all renditions to calculate part hold back.
+* Add ci GitHub action 
+
 ## v0.5.0 - 2025-12-24
 
 * Add server control option to writer.
diff --git a/lib/hlx/muxer/cmaf.ex b/lib/hlx/muxer/cmaf.ex
index 83ea1f3..5b4fc61 100644
--- a/lib/hlx/muxer/cmaf.ex
+++ b/lib/hlx/muxer/cmaf.ex
@@ -77,13 +77,13 @@ defmodule HLX.Muxer.CMAF do
         part_duration_s = traf_dur / state.tracks[track_id].timescale
         parts_duration = Map.update!(parts_duration, track_id, &(&1 + traf_dur))
 
-        moof = %Box.Moof{moof | traf: [traf | moof.traf]}
-        mdat = %Box.Mdat{mdat | content: [Enum.map(samples, & &1.payload) | mdat.content]}
+        moof = %{moof | traf: [traf | moof.traf]}
+        mdat = %{mdat | content: [Enum.map(samples, & &1.payload) | mdat.content]}
         {moof, mdat, parts_duration, max(part_duration, part_duration_s)}
       end)
 
-    moof = %Box.Moof{moof | traf: Enum.reverse(moof.traf)}
-    mdat = %Box.Mdat{mdat | content: Enum.reverse(mdat.content)}
+    moof = %{moof | traf: Enum.reverse(moof.traf)}
+    mdat = %{mdat | content: Enum.reverse(mdat.content)}
 
     moof = Box.Moof.update_base_offsets(moof, Box.size(moof) + @mdat_header_size, true)
 
@@ -175,14 +175,14 @@ defmodule HLX.Muxer.CMAF do
         traf = Box.Traf.finalize(traf, true)
         data = Enum.reverse(data)
 
-        moof = %Box.Moof{moof | traf: [traf | moof.traf]}
-        mdat = %Box.Mdat{mdat | content: [data | mdat.content]}
+        moof = %{moof | traf: [traf | moof.traf]}
+        mdat = %{mdat | content: [data | mdat.content]}
 
         {moof, mdat}
       end)
 
-    moof = %Box.Moof{moof | traf: Enum.reverse(moof.traf)}
-    mdat = %Box.Mdat{mdat | content: Enum.reverse(mdat.content)}
+    moof = %{moof | traf: Enum.reverse(moof.traf)}
+    mdat = %{mdat | content: Enum.reverse(mdat.content)}
 
     {moof, mdat}
   end
@@ -190,7 +190,7 @@ defmodule HLX.Muxer.CMAF do
   defp finalize_segments(segments, moof, mdat) do
     {segments, _size} =
       Enum.map_reduce(moof.traf, 0, fn traf, acc ->
-        segment = segments[traf.tfhd.track_id]
+        %Box.Sidx{} = segment = segments[traf.tfhd.track_id]
 
         segment = %Box.Sidx{
           segment
diff --git a/mix.exs b/mix.exs
index 9849ef9..b6f7ed6 100644
--- a/mix.exs
+++ b/mix.exs
@@ -33,7 +33,7 @@ defmodule HLX.MixProject do
     [
       {:media_codecs, "~> 0.10.0"},
       {:ex_mp4, "~> 0.14.0"},
-      {:ex_m3u8, "~> 0.15.0"},
+      {:ex_m3u8, "~> 0.16.0"},
       {:mpeg_ts, "~> 3.3.5"},
       {:qex, "~> 0.5.1"},
       {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
diff --git a/mix.lock b/mix.lock
index 558c70d..85bbc01 100644
--- a/mix.lock
+++ b/mix.lock
@@ -5,7 +5,7 @@
   "credo": {:hex, :credo, "1.7.15", "283da72eeb2fd3ccf7248f4941a0527efb97afa224bcdef30b4b580bc8258e1c", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "291e8645ea3fea7481829f1e1eb0881b8395db212821338e577a90bf225c5607"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.44", "f20830dd6b5c77afe2b063777ddbbff09f9759396500cdbe7523efd58d7a339c", [:mix], [], "hexpm", "4778ac752b4701a5599215f7030989c989ffdc4f6df457c5f36938cc2d2a2750"},
   "ex_doc": {:hex, :ex_doc, "0.39.3", "519c6bc7e84a2918b737aec7ef48b96aa4698342927d080437f61395d361dcee", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "0590955cf7ad3b625780ee1c1ea627c28a78948c6c0a9b0322bd976a079996e1"},
-  "ex_m3u8": {:hex, :ex_m3u8, "0.15.4", "66f6ec7e4fb7372c48032db1c2d4a3e6c2bbbde2d1d9a1098986e3caa0ab7a55", [:mix], [{:nimble_parsec, "~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}, {:typed_struct, "~> 0.3.0", [hex: :typed_struct, repo: "hexpm", optional: false]}], "hexpm", "ec03aa516919e0c8ec202da55f609b763bd7960195a3388900090fcad270c873"},
+  "ex_m3u8": {:hex, :ex_m3u8, "0.16.0", "29fc405a790d95bb320cbbbbaa1d6c2608f043bce02ad8d35e6489497ca4b2a0", [:mix], [{:nimble_parsec, "~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}, {:typed_struct, "~> 0.3.0", [hex: :typed_struct, repo: "hexpm", optional: false]}], "hexpm", "a98a149c14b3929cfe163fd9d23edfa86ab0bc72bee5c1945e9dab058aa051d7"},
   "ex_mp4": {:hex, :ex_mp4, "0.14.1", "6152b9b981d5d6d5069d8dccd3d60f4f4be135f758f9b4bae039018119fdf089", [:mix], [{:media_codecs, "~> 0.10.0", [hex: :media_codecs, repo: "hexpm", optional: true]}, {:ratio, "~> 4.0", [hex: :ratio, repo: "hexpm", optional: false]}, {:table_rex, "~> 4.0", [hex: :table_rex, repo: "hexpm", optional: true]}], "hexpm", "f9f9630406371d19691673acea83f378b96e5c1961eb28436aa5d8ded148188c"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
   "jason": {:hex, :jason, "1.4.4", "b9226785a9aa77b6857ca22832cffa5d5011a667207eb2a0ad56adb5db443b8a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "c5eb0cab91f094599f94d55bc63409236a8ec69a21a67814529e8d5f6cc90b3b"},