From 9cd139cb404af807a056a442bd910f9bfac2e6ba Mon Sep 17 00:00:00 2001
From: trueChazza <chaz.goodare@gmail.com>
Date: Fri, 9 Feb 2024 16:01:27 +1300
Subject: [PATCH] fix: fix keyframes

---
 lib/hls_playlist.ex        | 24 +++++++------
 test/hls_playlist_test.exs | 69 ++++++++++++--------------------------
 2 files changed, 35 insertions(+), 58 deletions(-)

diff --git a/lib/hls_playlist.ex b/lib/hls_playlist.ex
index 5d94cc5..f0bc460 100644
--- a/lib/hls_playlist.ex
+++ b/lib/hls_playlist.ex
@@ -34,7 +34,13 @@ defmodule HlsPlaylist do
       |> Enum.filter(fn x -> String.contains?(x, "K__") end)
     end)
     |> Enum.reject(fn x -> Enum.empty?(x) end)
-    |> Enum.map(fn x -> String.trim_leading(Enum.at(x, 0), "packet,") end)
+    |> Enum.map(fn x ->
+      String.trim_leading(Enum.at(x, 0), "packet,")
+      |> String.trim_trailing(",K__")
+      |> String.split(",")
+      |> Kernel.hd()
+      |> String.to_float
+    end)
   end
 
   def get_segments(keyframes, duration, segment_length) do
@@ -54,12 +60,12 @@ defmodule HlsPlaylist do
           end
 
         kf_distance = kf - last_segment
-        kf_distance_from_desire = abs(desired_segment_length - kf_distance)
+        kf_distance_from_desire = Kernel.abs(desired_segment_length - kf_distance)
 
         kf_next_distance_from_desire =
           case {kf_next, kf_next_distance} do
             {nil, _} -> nil
-            {_next_kf, next_distance} -> abs(desired_segment_length - next_distance)
+            {_next_kf, next_distance} -> Kernel.abs(desired_segment_length - next_distance)
           end
 
         cond do
@@ -84,26 +90,24 @@ defmodule HlsPlaylist do
   end
 
   def get_playlist(segment_lengths, segment_name) do
-    {playlist_segments, largest_segment} =
+    {segments, largest_segment} =
       Enum.reduce(segment_lengths, {[], 0.0}, fn segl, {acc, current_largest} ->
         largest_segment = max(segl, current_largest)
 
-        playlist_segment =
+        extinf_segment =
           "#EXTINF:#{String.Chars.to_string(segl)},\n#{segment_name}#{length(acc)}.ts"
 
-        {[playlist_segment | acc], largest_segment}
+        {[extinf_segment | acc], largest_segment}
       end)
 
-    largest_segment_rounded = trunc(Float.floor(largest_segment))
-
     """
     #EXTM3U
     #EXT-X-VERSION:3
     #EXT-X-ALLOW-CACHE:NO
-    #EXT-X-TARGETDURATION:#{largest_segment_rounded}
+    #EXT-X-TARGETDURATION:#{Kernel.trunc(Float.floor(largest_segment))}
     #EXT-X-MEDIA-SEQUENCE:0
     #EXT-X-PLAYLIST-TYPE:VOD
-    #{Enum.join(Enum.reverse(playlist_segments), "\n")}
+    #{Enum.join(Enum.reverse(segments), "\n")}
     #EXT-X-ENDLIST\
     """
   end
diff --git a/test/hls_playlist_test.exs b/test/hls_playlist_test.exs
index 03de8a4..e6f04a7 100644
--- a/test/hls_playlist_test.exs
+++ b/test/hls_playlist_test.exs
@@ -2,39 +2,27 @@ defmodule HlsPlaylistTest do
   use ExUnit.Case
   doctest HlsPlaylist
 
+  @media_path "dev/sample__1080__libx264__ac3__30s__video.mp4"
+
   test "get_duration" do
-    assert HlsPlaylist.get_duration("dev/sample__1080__libx264__ac3__30s__video.mp4") == 30.0
+    assert HlsPlaylist.get_duration(@media_path) == 30.0
   end
 
   test "get_keyframes" do
-    assert HlsPlaylist.get_keyframes("dev/sample__1080__libx264__ac3__30s__video.mp4") == [
-             "0.000000,-0.033333,K__",
-             "4.166667,4.133333,K__",
-             "8.333333,8.300000,K__",
-             "12.500000,12.466667,K__",
-             "16.266667,16.233333,K__",
-             "20.133333,20.100000,K__",
-             "24.300000,24.266667,K__",
-             "27.433333,27.400000,K__"
+    assert HlsPlaylist.get_keyframes(@media_path) == [
+             0.0,
+             4.166667,
+             8.333333,
+             12.5,
+             16.266667,
+             20.133333,
+             24.3,
+             27.433333
            ]
   end
 
   test "get_segments" do
-    keyframes = [
-      0.000000,
-      4.166667,
-      8.333333,
-      12.500000,
-      16.266667,
-      20.133333,
-      24.300000,
-      27.433333
-    ]
-
-    duration = 30.0
-    segment_length = 3
-
-    assert HlsPlaylist.get_segments(keyframes, duration, segment_length) ==
+    assert HlsPlaylist.get_segments(HlsPlaylist.get_keyframes(@media_path), HlsPlaylist.get_duration(@media_path), 3) ==
              [
                4.166667,
                4.166666,
@@ -48,28 +36,15 @@ defmodule HlsPlaylistTest do
   end
 
   test "get_playlist" do
-    segment_lengths =
-      [
-        4.166667,
-        4.166666,
-        4.166667,
-        3.766667,
-        3.866666,
-        4.166667,
-        3.133333,
-        2.566667
-      ]
+    assert HlsPlaylist.get_playlist(HlsPlaylist.get_segments(HlsPlaylist.get_keyframes(@media_path), HlsPlaylist.get_duration(@media_path), 3), "segment") ==
 
-    segment_name = "segment"
-
-    # a little off from ffmpeg-generated.m3u8
-    #
-    # #EXTINF:4.166666, should be #EXTINF:4.166667
-    # segment1.ts
-    #
-    # #EXTINF:3.866666, should be #EXTINF:3.866667
-    # segment4.ts
-    expected_playlist =
+     # a little off from generated-ffmpeg.m3u8
+     #
+     # #EXTINF:4.166666, should be #EXTINF:4.166667
+     # segment1.ts
+     #
+     # #EXTINF:3.866666, should be #EXTINF:3.866667
+     # segment4.ts
       """
       #EXTM3U
       #EXT-X-VERSION:3
@@ -95,7 +70,5 @@ defmodule HlsPlaylistTest do
       segment7.ts
       #EXT-X-ENDLIST\
       """
-
-    assert HlsPlaylist.get_playlist(segment_lengths, segment_name) == expected_playlist
   end
 end