jellyfin/Emby.Server.Implementations/Library/MediaStreamSelector.cs
2022-02-14 16:31:07 +01:00

190 lines
7.7 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);
if (preferDefaultTrack)
{
var defaultStream = streams.FirstOrDefault(i => i.IsDefault);
if (defaultStream != 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)
.ToList();
MediaStream? stream = null;
if (mode == SubtitlePlaybackMode.Default)
{
// Prefer embedded metadata over smart logic
stream = sortedStreams.FirstOrDefault(s => s.IsExternal || s.IsForced || s.IsDefault);
// if the audio language is not understood by the user, load their preferred subs, if there are any
if (stream == null && !preferredLanguages.Contains(audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
{
stream = sortedStreams.FirstOrDefault(s => !s.IsForced && preferredLanguages.Contains(s.Language, StringComparison.OrdinalIgnoreCase));
}
}
else if (mode == SubtitlePlaybackMode.Smart)
{
// if the audio language is not understood by the user, load their preferred subs, if there are any
if (!preferredLanguages.Contains(audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
{
stream = streams.FirstOrDefault(s => !s.IsForced && preferredLanguages.Contains(s.Language, StringComparison.OrdinalIgnoreCase)) ??
streams.FirstOrDefault(s => preferredLanguages.Contains(s.Language, StringComparison.OrdinalIgnoreCase));
}
}
else if (mode == SubtitlePlaybackMode.Always)
{
// always load the most suitable full subtitles
stream = sortedStreams.FirstOrDefault(s => !s.IsForced);
}
else if (mode == SubtitlePlaybackMode.OnlyForced)
{
// always load the most suitable full subtitles
stream = sortedStreams.FirstOrDefault(x => x.IsForced);
}
// load forced subs if we have found no suitable full subtitles
stream ??= sortedStreams.FirstOrDefault(s => s.IsForced && string.Equals(s.Language, audioTrackLanguage, StringComparison.OrdinalIgnoreCase));
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)
.OrderBy(i =>
{
var index = languagePreferences.FindIndex(x => string.Equals(x, i.Language, StringComparison.OrdinalIgnoreCase));
return index == -1 ? 100 : index;
})
.ThenBy(i => GetBooleanOrderBy(i.IsDefault))
.ThenBy(i => GetBooleanOrderBy(i.SupportsExternalStream))
.ThenBy(i => GetBooleanOrderBy(i.IsTextSubtitleStream))
.ThenBy(i => GetBooleanOrderBy(i.IsExternal))
.ThenBy(i => i.Index);
}
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);
var filteredStreams = new List<MediaStream>();
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.Count == 0
? sortedStreams.Where(s => s.IsForced && string.Equals(s.Language, audioTrackLanguage, StringComparison.OrdinalIgnoreCase))
: filteredStreams;
foreach (var stream in iterStreams)
{
stream.Score = GetSubtitleScore(stream, preferredLanguages);
}
}
private static int GetSubtitleScore(MediaStream stream, IReadOnlyList<string> languagePreferences)
{
var values = new List<int>();
var index = languagePreferences.FindIndex(x => string.Equals(x, stream.Language, StringComparison.OrdinalIgnoreCase));
values.Add(index == -1 ? 0 : 100 - index);
values.Add(stream.IsForced ? 1 : 0);
values.Add(stream.IsDefault ? 1 : 0);
values.Add(stream.SupportsExternalStream ? 1 : 0);
values.Add(stream.IsTextSubtitleStream ? 1 : 0);
values.Add(stream.IsExternal ? 1 : 0);
values.Reverse();
var scale = 1;
var score = 0;
foreach (var value in values)
{
score += scale * (value + 1);
scale *= 10;
}
return score;
}
private static int GetBooleanOrderBy(bool value)
{
return value ? 0 : 1;
}
}
}