From 88635e929e57c052a3cdd0f8c65467c80d6a77ca Mon Sep 17 00:00:00 2001
From: Scrub <72096833+ScrubN@users.noreply.github.com>
Date: Sat, 20 Jan 2024 20:21:58 -0500
Subject: [PATCH] Improve handling of some source quality related edge cases
 (#953)

* Always sort source quality to the top of the list regardless of video metadata

* Return best quality when quality string contains "source" or "chunked"

* Always include "Source" in the source stream's quality string because of Twitch API weirdness.
Distinguishes between 720p60 (source) and 720p30 (transcoded) when framerates are not included in the M3U8 response.

* Cleanup
---
 .../Extensions/M3U8Extensions.cs              | 36 +++++++++++++++----
 .../Tools/M3U8StreamQualityComparer.cs        |  4 +++
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/TwitchDownloaderCore/Extensions/M3U8Extensions.cs b/TwitchDownloaderCore/Extensions/M3U8Extensions.cs
index 29571e15..a6fbcdd4 100644
--- a/TwitchDownloaderCore/Extensions/M3U8Extensions.cs
+++ b/TwitchDownloaderCore/Extensions/M3U8Extensions.cs
@@ -37,6 +37,11 @@ public static M3U8.Stream GetStreamOfQuality(this M3U8 m3u8, string qualityStrin
                 return m3u8.BestQualityStream();
             }
 
+            if (qualityString.Contains("source", StringComparison.OrdinalIgnoreCase) || qualityString.Contains("chunked", StringComparison.OrdinalIgnoreCase))
+            {
+                return m3u8.BestQualityStream();
+            }
+
             if (qualityString.Contains("audio", StringComparison.OrdinalIgnoreCase) &&
                 streams.FirstOrDefault(x => x.MediaInfo.Name.Contains("audio", StringComparison.OrdinalIgnoreCase)) is { } audioStream)
             {
@@ -84,25 +89,32 @@ public static M3U8.Stream GetStreamOfQuality(this M3U8 m3u8, string qualityStrin
         /// </returns>
         public static string GetResolutionFramerateString(this M3U8.Stream stream)
         {
+            const string RESOLUTION_FRAMERATE_PATTERN = /*lang=regex*/@"\d{3,4}p\d{2,3}";
+
             var mediaInfo = stream.MediaInfo;
-            if (mediaInfo.Name.Contains("audio", StringComparison.OrdinalIgnoreCase) || Regex.IsMatch(mediaInfo.Name, @"\d{3,4}p\d{2,3}"))
+            if (mediaInfo.Name.Contains("audio", StringComparison.OrdinalIgnoreCase) || Regex.IsMatch(mediaInfo.Name, RESOLUTION_FRAMERATE_PATTERN))
             {
                 return mediaInfo.Name;
             }
 
             var streamInfo = stream.StreamInfo;
-            if (Regex.IsMatch(streamInfo.Video, @"\d{3,4}p\d{2,3}"))
+            if (Regex.IsMatch(streamInfo.Video, RESOLUTION_FRAMERATE_PATTERN))
             {
                 return streamInfo.Video;
             }
 
-            if (Regex.IsMatch(mediaInfo.GroupId, @"\d{3,4}p\d{2,3}"))
+            if (Regex.IsMatch(mediaInfo.GroupId, RESOLUTION_FRAMERATE_PATTERN))
             {
                 return mediaInfo.GroupId;
             }
 
             if (streamInfo.Resolution == default)
             {
+                if (stream.IsSource())
+                {
+                    return "Source";
+                }
+
                 return "";
             }
 
@@ -110,12 +122,22 @@ public static string GetResolutionFramerateString(this M3U8.Stream stream)
 
             if (streamInfo.Framerate == default)
             {
+                if (stream.IsSource())
+                {
+                    return $"{frameHeight}p (Source)";
+                }
+
                 return $"{frameHeight}p";
             }
 
             // Some M3U8 responses have framerate values up to 2fps more/less than the typical framerate.
             var frameRate = (uint)(Math.Round(streamInfo.Framerate / 10) * 10);
 
+            if (stream.IsSource())
+            {
+                return $"{frameHeight}p{frameRate} (Source)";
+            }
+
             return $"{frameHeight}p{frameRate}";
         }
 
@@ -124,10 +146,12 @@ public static string GetResolutionFramerateString(this M3U8.Stream stream)
         /// </summary>
         public static M3U8.Stream BestQualityStream(this M3U8 m3u8)
         {
-            var source = Array.Find(
-                m3u8.Streams, x => x.MediaInfo.Name.Contains("source", StringComparison.OrdinalIgnoreCase) ||
-                    x.MediaInfo.GroupId.Equals("chunked", StringComparison.OrdinalIgnoreCase));
+            var source = Array.Find(m3u8.Streams, x => x.IsSource());
             return source ?? m3u8.Streams.MaxBy(x => x.StreamInfo.Resolution.Width * x.StreamInfo.Resolution.Height * x.StreamInfo.Framerate);
         }
+
+        internal static bool IsSource(this M3U8.Stream stream)
+            => stream.MediaInfo.Name.Contains("source", StringComparison.OrdinalIgnoreCase) ||
+               stream.MediaInfo.GroupId.Equals("chunked", StringComparison.OrdinalIgnoreCase);
     }
 }
\ No newline at end of file
diff --git a/TwitchDownloaderCore/Tools/M3U8StreamQualityComparer.cs b/TwitchDownloaderCore/Tools/M3U8StreamQualityComparer.cs
index a9ec0a6a..af6cd062 100644
--- a/TwitchDownloaderCore/Tools/M3U8StreamQualityComparer.cs
+++ b/TwitchDownloaderCore/Tools/M3U8StreamQualityComparer.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using TwitchDownloaderCore.Extensions;
 
 namespace TwitchDownloaderCore.Tools
 {
@@ -14,6 +15,9 @@ public int Compare(M3U8.Stream x, M3U8.Stream y)
 
             if (y?.StreamInfo is null) return 1;
 
+            if (x.IsSource()) return -1;
+            if (y.IsSource()) return 1;
+
             var xResolution = x.StreamInfo.Resolution;
             var yResolution = y.StreamInfo.Resolution;
             var xTotalPixels = xResolution.Width * xResolution.Height;