Add IsVideoUpscaled property to IVideoStreamInfo to detect AI-upscaled streams

YoutubeExplode.Tests/StreamSpecs.cs

@@ -112,6 +112,21 @@ public async Task I_can_get_the_list_of_available_streams_of_a_video_with_multip
             );
     }
 
+    [Fact]
+    public async Task I_can_get_the_list_of_available_streams_of_a_video_with_upscaled_streams()
+    {
+        // Arrange
+        using var youtube = new YoutubeClient();
+
+        // Act
+        var manifest = await youtube.Videos.Streams.GetManifestAsync(VideoIds.WithUpscaledStreams);
+
+        // Assert
+        manifest.Streams.Should().NotBeEmpty();
+        manifest.GetVideoStreams().Should().Contain(s => s.IsUpscaled);
+        manifest.GetVideoStreams().Should().Contain(s => !s.IsUpscaled);
+    }
+
     [Theory]
     [InlineData(VideoIds.Normal)]
     [InlineData(VideoIds.Unlisted)]

YoutubeExplode.Tests/TestData/VideoIds.cs

@@ -22,4 +22,5 @@ internal static class VideoIds
     public const string WithClosedCaptions = "YltHGKX80Y8";
     public const string WithBrokenClosedCaptions = "1VKIIw05JnE";
     public const string WithMultipleAudioLanguages = "ngqcjXfggHQ";
+    public const string WithUpscaledStreams = "IFACrIx5SZ0";
 }

YoutubeExplode/Bridge/DashManifest.cs

@@ -82,6 +82,8 @@ public class StreamData(XElement content) : IStreamData
 
         public string? VideoQualityLabel => null;
 
+        public bool IsVideoUpscaled => false;
+
         [Lazy]
         public int? VideoWidth => (int?)content.Attribute("width");
 

YoutubeExplode/Bridge/IStreamData.cs

@@ -28,6 +28,8 @@ internal interface IStreamData
 
     string? VideoQualityLabel { get; }
 
+    bool IsVideoUpscaled { get; }
+
     int? VideoWidth { get; }
 
     int? VideoHeight { get; }

YoutubeExplode/Bridge/PlayerResponse.cs

@@ -299,6 +299,42 @@ public string? VideoCodec
         public string? VideoQualityLabel =>
             content.GetPropertyOrNull("qualityLabel")?.GetStringOrNull();
 
+        [Lazy]
+        public bool IsVideoUpscaled
+        {
+            get
+            {
+                var xtags = content.GetPropertyOrNull("xtags")?.GetStringOrNull();
+                if (string.IsNullOrEmpty(xtags))
+                    return false;
+
+                try
+                {
+                    // xtags is a base64-encoded protobuf map<string, string>.
+                    // Streams upscaled with YouTube's Super Resolution feature have
+                    // the map entry {"sr": "1"}, whose key is encoded in the binary as:
+                    // field 1 LEN (0x0a), length 2 (0x02), 's' (0x73), 'r' (0x72)
+                    var bytes = Convert.FromBase64String(xtags);
+                    for (var i = 0; i <= bytes.Length - 4; i++)
+                    {
+                        if (
+                            bytes[i] == 0x0a
+                            && bytes[i + 1] == 0x02
+                            && bytes[i + 2] == 0x73
+                            && bytes[i + 3] == 0x72
+                        )
+                            return true;
+                    }
+                }
+                catch (FormatException)
+                {
+                    // Ignore invalid base64 encoding
+                }
+
+                return false;
+            }
+        }
+
         [Lazy]
         public int? VideoWidth => content.GetPropertyOrNull("width")?.GetInt32OrNull();
 

YoutubeExplode/Videos/Streams/IVideoStreamInfo.cs

@@ -24,6 +24,11 @@ public interface IVideoStreamInfo : IStreamInfo
     /// Video resolution.
     /// </summary>
     Resolution VideoResolution { get; }
+
+    /// <summary>
+    /// Whether this stream was produced by YouTube's Super Resolution (AI upscaling) feature.
+    /// </summary>
+    bool IsUpscaled { get; }
 }
 
 /// <summary>

YoutubeExplode/Videos/Streams/MuxedStreamInfo.cs

@@ -17,7 +17,8 @@ public class MuxedStreamInfo(
     bool? isAudioLanguageDefault,
     string videoCodec,
     VideoQuality videoQuality,
-    Resolution videoResolution
+    Resolution videoResolution,
+    bool isUpscaled
 ) : IAudioStreamInfo, IVideoStreamInfo
 {
     /// <inheritdoc />
@@ -50,6 +51,9 @@ Resolution videoResolution
     /// <inheritdoc />
     public Resolution VideoResolution { get; } = videoResolution;
 
+    /// <inheritdoc />
+    public bool IsUpscaled { get; } = isUpscaled;
+
     /// <inheritdoc />
     [ExcludeFromCodeCoverage]
     public override string ToString() => $"Muxed ({VideoQuality} | {Container})";

YoutubeExplode/Videos/Streams/StreamClient.cs

@@ -158,7 +158,8 @@ streamData.VideoWidth is not null && streamData.VideoHeight is not null
                         streamData.IsAudioLanguageDefault,
                         streamData.VideoCodec,
                         videoQuality,
-                        videoResolution
+                        videoResolution,
+                        streamData.IsVideoUpscaled
                     );
 
                     yield return streamInfo;
@@ -173,7 +174,8 @@ streamData.VideoWidth is not null && streamData.VideoHeight is not null
                         bitrate,
                         streamData.VideoCodec,
                         videoQuality,
-                        videoResolution
+                        videoResolution,
+                        streamData.IsVideoUpscaled
                     );
 
                     yield return streamInfo;

YoutubeExplode/Videos/Streams/VideoOnlyStreamInfo.cs

@@ -13,7 +13,8 @@ public class VideoOnlyStreamInfo(
     Bitrate bitrate,
     string videoCodec,
     VideoQuality videoQuality,
-    Resolution videoResolution
+    Resolution videoResolution,
+    bool isUpscaled
 ) : IVideoStreamInfo
 {
     /// <inheritdoc />
@@ -37,6 +38,9 @@ Resolution videoResolution
     /// <inheritdoc />
     public Resolution VideoResolution { get; } = videoResolution;
 
+    /// <inheritdoc />
+    public bool IsUpscaled { get; } = isUpscaled;
+
     /// <inheritdoc />
     [ExcludeFromCodeCoverage]
     public override string ToString() => $"Video-only ({VideoQuality} | {Container})";

YoutubeExplode/Videos/Streams/VideoQuality.cs

@@ -196,7 +196,7 @@ internal static VideoQuality FromItag(int itag, int framerate)
             _ => throw new ArgumentException($"Unrecognized itag '{itag}'.", nameof(itag)),
         };
 
-        return new VideoQuality(maxHeight, framerate);
+        return new VideoQuality(FormatLabel(maxHeight, framerate), maxHeight, framerate);
     }
 }