From d9ced0d6399c82ddad9e983605bb0d828a608e63 Mon Sep 17 00:00:00 2001 From: nyanmisaka Date: Sat, 2 May 2026 20:14:51 +0800 Subject: [PATCH] Use strict QSV CPB size for less powerful H.264 decoder Signed-off-by: nyanmisaka --- .../MediaEncoding/EncodingHelper.cs | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs index 117f376724..a0e04eae63 100644 --- a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs +++ b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs @@ -1621,13 +1621,25 @@ namespace MediaBrowser.Controller.MediaEncoding mbbrcOpt = " -mbbrc 1"; } + // Some less powerful H.264 HW decoders require strict CPB size + // So bufsize optimizations should not be applied to them + int factor = 2; + var codec = state.ActualOutputVideoCodec; + var level = state.GetRequestedLevel(codec); + if (string.Equals(codec, "h264", StringComparison.OrdinalIgnoreCase) + && double.TryParse(level, CultureInfo.InvariantCulture, out double requestedLevel) + && requestedLevel < 51) + { + factor = 1; + } + // Set (maxrate == bitrate + 1) to trigger VBR for better bitrate allocation // Set (rc_init_occupancy == 2 * bitrate) and (bufsize == 4 * bitrate) to deal with drastic scene changes // Use long arithmetic and clamp to int.MaxValue to prevent int32 overflow // (e.g. bitrate * 4 wraps to a negative value for bitrates above ~537 million) int qsvMaxrate = (int)Math.Min((long)bitrate + 1, int.MaxValue); - int qsvInitOcc = (int)Math.Min((long)bitrate * 2, int.MaxValue); - int qsvBufsize = (int)Math.Min((long)bitrate * 4, int.MaxValue); + int qsvInitOcc = (int)Math.Min((long)bitrate * 1 * factor, int.MaxValue); + int qsvBufsize = (int)Math.Min((long)bitrate * 2 * factor, int.MaxValue); return FormattableString.Invariant($"{mbbrcOpt} -b:v {bitrate} -maxrate {qsvMaxrate} -rc_init_occupancy {qsvInitOcc} -bufsize {qsvBufsize}"); }