jellyfin/Emby.Server.Implementations/Library/MediaStreamSelector.cs
2024-04-03 14:56:56 +02:00

160 lines
6.9 KiB
C#

#pragma warning disable CS1591
using System;
using System.Collections.Generic;
using System.Linq;
using Jellyfin.Data.Enums;
using Jellyfin.Extensions;
using MediaBrowser.Model.Entities;
namespace Emby.Server.Implementations.Library
{
public static class MediaStreamSelector
{
public static int? GetDefaultAudioStreamIndex(IReadOnlyList<MediaStream> streams, IReadOnlyList<string> preferredLanguages, bool preferDefaultTrack)
{
var sortedStreams = GetSortedStreams(streams, MediaStreamType.Audio, preferredLanguages).ToList();
if (preferDefaultTrack)
{
var defaultStream = sortedStreams.FirstOrDefault(i => i.IsDefault);
if (defaultStream is not null)
{
return defaultStream.Index;
}
}
return sortedStreams.FirstOrDefault()?.Index;
}
public static int? GetDefaultSubtitleStreamIndex(
IEnumerable<MediaStream> streams,
IReadOnlyList<string> preferredLanguages,
SubtitlePlaybackMode mode,
string audioTrackLanguage)
{
if (mode == SubtitlePlaybackMode.None)
{
return null;
}
var sortedStreams = streams
.Where(i => i.Type == MediaStreamType.Subtitle)
.OrderByDescending(x => x.IsExternal)
.ThenByDescending(x => x.IsForced && string.Equals(x.Language, audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
.ThenByDescending(x => x.IsForced)
.ThenByDescending(x => x.IsDefault)
.ThenByDescending(x => preferredLanguages.Contains(x.Language, StringComparison.OrdinalIgnoreCase))
.ToList();
MediaStream? stream = null;
if (mode == SubtitlePlaybackMode.Default)
{
// Load subtitles according to external, forced and default flags.
stream = sortedStreams.FirstOrDefault(x => x.IsExternal || x.IsForced || x.IsDefault);
}
else if (mode == SubtitlePlaybackMode.Smart)
{
// Only attempt to load subtitles if the audio language is not one of the user's preferred subtitle languages.
// If no subtitles of preferred language available, use default behaviour.
if (!preferredLanguages.Contains(audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
{
stream = sortedStreams.FirstOrDefault(x => preferredLanguages.Contains(x.Language, StringComparison.OrdinalIgnoreCase)) ??
sortedStreams.FirstOrDefault(x => x.IsExternal || x.IsForced || x.IsDefault);
}
else
{
// Respect forced flag.
stream = sortedStreams.FirstOrDefault(x => x.IsForced);
}
}
else if (mode == SubtitlePlaybackMode.Always)
{
// Always load (full/non-forced) subtitles of the user's preferred subtitle language if possible, otherwise default behaviour.
stream = sortedStreams.FirstOrDefault(x => !x.IsForced && preferredLanguages.Contains(x.Language, StringComparison.OrdinalIgnoreCase)) ??
sortedStreams.FirstOrDefault(x => x.IsExternal || x.IsForced || x.IsDefault);
}
else if (mode == SubtitlePlaybackMode.OnlyForced)
{
// Only load subtitles that are flagged forced.
stream = sortedStreams.FirstOrDefault(x => x.IsForced);
}
return stream?.Index;
}
private static IEnumerable<MediaStream> GetSortedStreams(IEnumerable<MediaStream> streams, MediaStreamType type, IReadOnlyList<string> languagePreferences)
{
// Give some preference to external text subs for better performance
return streams
.Where(i => i.Type == type)
.OrderByDescending(i => GetStreamScore(i, languagePreferences));
}
public static void SetSubtitleStreamScores(
IReadOnlyList<MediaStream> streams,
IReadOnlyList<string> preferredLanguages,
SubtitlePlaybackMode mode,
string audioTrackLanguage)
{
if (mode == SubtitlePlaybackMode.None)
{
return;
}
var sortedStreams = GetSortedStreams(streams, MediaStreamType.Subtitle, preferredLanguages).ToList();
List<MediaStream>? filteredStreams = null;
if (mode == SubtitlePlaybackMode.Default)
{
// Prefer embedded metadata over smart logic
filteredStreams = sortedStreams.Where(s => s.IsForced || s.IsDefault)
.ToList();
}
else if (mode == SubtitlePlaybackMode.Smart)
{
// Prefer smart logic over embedded metadata
if (!preferredLanguages.Contains(audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
{
filteredStreams = sortedStreams.Where(s => !s.IsForced && preferredLanguages.Contains(s.Language, StringComparison.OrdinalIgnoreCase))
.ToList();
}
}
else if (mode == SubtitlePlaybackMode.Always)
{
// Always load the most suitable full subtitles
filteredStreams = sortedStreams.Where(s => !s.IsForced).ToList();
}
else if (mode == SubtitlePlaybackMode.OnlyForced)
{
// Always load the most suitable full subtitles
filteredStreams = sortedStreams.Where(s => s.IsForced).ToList();
}
// Load forced subs if we have found no suitable full subtitles
var iterStreams = filteredStreams is null || filteredStreams.Count == 0
? sortedStreams.Where(s => s.IsForced && string.Equals(s.Language, audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
: filteredStreams;
foreach (var stream in iterStreams)
{
stream.Score = GetStreamScore(stream, preferredLanguages);
}
}
internal static int GetStreamScore(MediaStream stream, IReadOnlyList<string> languagePreferences)
{
var index = languagePreferences.FindIndex(x => string.Equals(x, stream.Language, StringComparison.OrdinalIgnoreCase));
var score = index == -1 ? 1 : 101 - index;
score = (score * 10) + (stream.IsForced ? 2 : 1);
score = (score * 10) + (stream.IsDefault ? 2 : 1);
score = (score * 10) + (stream.SupportsExternalStream ? 2 : 1);
score = (score * 10) + (stream.IsTextSubtitleStream ? 2 : 1);
score = (score * 10) + (stream.IsExternal ? 2 : 1);
return score;
}
}
}