Tune x264/5 encoding params for realtime playback

Some options that are too performance-intensive are disabled, while
others are left enabled to trade-off between real-time playback and quality.

Signed-off-by: nyanmisaka <nst799610810@gmail.com>

Jellyfin.Api/Controllers/DynamicHlsController.cs

@@ -45,6 +45,7 @@ public class DynamicHlsController : BaseJellyfinApiController
     private const TranscodingJobType TranscodingJobType = MediaBrowser.Controller.MediaEncoding.TranscodingJobType.Hls;
 
     private readonly Version _minFFmpegFlacInMp4 = new Version(6, 0);
+    private readonly Version _minFFmpegX265BframeInFmp4 = new Version(7, 0, 1);
 
     private readonly ILibraryManager _libraryManager;
     private readonly IUserManager _userManager;
@@ -1851,13 +1852,12 @@ public class DynamicHlsController : BaseJellyfinApiController
             args += _encodingHelper.GetHlsVideoKeyFrameArguments(state, codec, state.SegmentLength, isEventPlaylist, startNumber);
 
             // Currently b-frames in libx265 breaks the FMP4-HLS playback on iOS, disable it for now.
-            if (string.Equals(codec, "libx265", StringComparison.OrdinalIgnoreCase))
+            if (string.Equals(codec, "libx265", StringComparison.OrdinalIgnoreCase)
+                && _mediaEncoder.EncoderVersion < _minFFmpegX265BframeInFmp4)
             {
                 args += " -bf 0";
             }
 
-            // args += " -mixed-refs 0 -refs 3 -x264opts b_pyramid=0:weightb=0:weightp=0";
-
             // video processing filters.
             var videoProcessParam = _encodingHelper.GetVideoProcessingFilterParam(state, _encodingOptions, codec);
 

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -1480,7 +1480,6 @@ namespace MediaBrowser.Controller.MediaEncoding
                     }
                 }
 
-                // TODO: Perhaps also use original_size=1920x800 ??
                 return string.Format(
                     CultureInfo.InvariantCulture,
                     "subtitles=f='{0}'{1}{2}{3}{4}{5}",
@@ -1502,7 +1501,6 @@ namespace MediaBrowser.Controller.MediaEncoding
                 alphaParam,
                 sub2videoParam,
                 fontParam,
-                // fallbackFontParam,
                 setPtsParam);
         }
 
@@ -1776,12 +1774,6 @@ namespace MediaBrowser.Controller.MediaEncoding
                 {
                     param += " -preset veryfast";
                 }
-
-                // Only h264_qsv has look_ahead option
-                if (string.Equals(videoEncoder, "h264_qsv", StringComparison.OrdinalIgnoreCase))
-                {
-                    param += " -look_ahead 0";
-                }
             }
             else if (string.Equals(videoEncoder, "h264_nvenc", StringComparison.OrdinalIgnoreCase) // h264 (h264_nvenc)
                      || string.Equals(videoEncoder, "hevc_nvenc", StringComparison.OrdinalIgnoreCase) // hevc (hevc_nvenc)
@@ -2068,7 +2060,7 @@ namespace MediaBrowser.Controller.MediaEncoding
 
             if (string.Equals(videoEncoder, "libx264", StringComparison.OrdinalIgnoreCase))
             {
-                param += " -x264opts:0 subme=0:me_range=4:rc_lookahead=10:me=dia:no_chroma_me:8x8dct=0:partitions=none";
+                param += " -x264opts:0 subme=0:me_range=16:rc_lookahead=10:me=hex:open_gop=0";
             }
 
             if (string.Equals(videoEncoder, "libx265", StringComparison.OrdinalIgnoreCase))
@@ -2076,8 +2068,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                 // libx265 only accept level option in -x265-params.
                 // level option may cause libx265 to fail.
                 // libx265 cannot adjust the given level, just throw an error.
-                // TODO: set fine tuned params.
-                param += " -x265-params:0 no-info=1";
+                param += " -x265-params:0 subme=3:merange=25:rc-lookahead=10:me=star:ctu=32:max-tu-size=32:min-cu-size=16:rskip=2:rskip-edge-threshold=2:no-sao=1:no-strong-intra-smoothing=1:no-scenecut=1:no-open-gop=1:no-info=1";
             }
 
             if (string.Equals(videoEncoder, "libsvtav1", StringComparison.OrdinalIgnoreCase)