Honor x264 tag in filename if mediainfo does not conclusively indicate h264.

Closes #2500

src/NzbDrone.Core.Test/MediaFiles/MediaInfo/MediaInfoFormatterTests/FormatVideoCodecFixture.cs

@@ -58,6 +58,26 @@ namespace NzbDrone.Core.Test.MediaFiles.MediaInfo.MediaInfoFormatterTests
             MediaInfoFormatter.FormatVideoCodec(mediaInfoModel, sceneName).Should().Be(expectedFormat);
         }
 
+        [TestCase("AVC, AVC, , x264", "Some.Video.S01E01.h264", "x264")] // Force mediainfo tag
+        [TestCase("HEVC, HEVC, , x265", "Some.Video.S01E01.h265", "x265")] // Force mediainfo tag
+        [TestCase("AVC, AVC, , ", "Some.Video.S01E01.x264", "x264")] // Not seen in practice, but honor tag if otherwise unknown
+        [TestCase("HEVC, HEVC, , ", "Some.Video.S01E01.x265", "x265")] // Not seen in practice, but honor tag if otherwise unknown
+        [TestCase("AVC, AVC, , ", "Some.Video.S01E01", "h264")] // Default value
+        [TestCase("HEVC, HEVC, , ", "Some.Video.S01E01", "h265")] // Default value
+        public void should_format_video_format_fallbacks(string videoFormatPack, string sceneName, string expectedFormat)
+        {
+            var split = videoFormatPack.Split(new string[] { ", " }, System.StringSplitOptions.None);
+            var mediaInfoModel = new MediaInfoModel
+            {
+                VideoFormat = split[0],
+                VideoCodecID = split[1],
+                VideoProfile = split[2],
+                VideoCodecLibrary = split[3]
+            };
+
+            MediaInfoFormatter.FormatVideoCodec(mediaInfoModel, sceneName).Should().Be(expectedFormat);
+        }
+
         [TestCase("MPEG-4 Visual, 20, , Intel(R) MPEG-4 encoder based on Intel(R) IPP 6.1 build 137.20[6.1.137.763]", "", "")]
         public void should_warn_on_unknown_video_format(string videoFormatPack, string sceneName, string expectedFormat)
         {

src/NzbDrone.Core/MediaFiles/MediaInfo/MediaInfoFormatter.cs

@@ -218,7 +218,7 @@ namespace NzbDrone.Core.MediaFiles.MediaInfo
                     return "x264";
                 }
 
-                return GetSceneNameMatch(sceneName, "AVC", "h264");
+                return GetSceneNameMatch(sceneName, "AVC", "x264", "h264");
             }
 
             if (videoFormat == "HEVC" || videoFormat == "V_MPEGH/ISO/HEVC")
@@ -228,7 +228,7 @@ namespace NzbDrone.Core.MediaFiles.MediaInfo
                     return "x265";
                 }
 
-                return GetSceneNameMatch(sceneName, "HEVC", "h265");
+                return GetSceneNameMatch(sceneName, "HEVC", "x265", "h265");
             }
 
             if (videoFormat == "MPEG Video")