jellyfin/MediaBrowser.Api/Playback/Hls/HlsCodecStringFactory.cs

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3.7 KiB
C#
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using System;
using System.Text;
namespace MediaBrowser.Api.Playback
{
/// <summary>
/// Get various codec strings for use in HLS playlists.
/// </summary>
static class HlsCodecStringFactory
{
/// <summary>
/// Gets a MP3 codec string.
/// </summary>
/// <returns>MP3 codec string.</returns>
public static string GetMP3String()
{
return "mp4a.40.34";
}
/// <summary>
/// Gets an AAC codec string.
/// </summary>
/// <param name="profile">AAC profile.</param>
/// <returns>AAC codec string.</returns>
public static string GetAACString(string profile)
{
StringBuilder result = new StringBuilder("mp4a", 9);
if (string.Equals(profile, "HE", StringComparison.OrdinalIgnoreCase))
{
result.Append(".40.5");
}
else
{
// Default to LC if profile is invalid
result.Append(".40.2");
}
return result.ToString();
}
/// <summary>
/// Gets a H.264 codec string.
/// </summary>
/// <param name="profile">H.264 profile.</param>
/// <param name="level">H.264 level.</param>
/// <returns>H.264 string.</returns>
public static string GetH264String(string profile, int level)
{
StringBuilder result = new StringBuilder("avc1", 11);
if (string.Equals(profile, "high", StringComparison.OrdinalIgnoreCase))
{
result.Append(".6400");
}
else if (string.Equals(profile, "main", StringComparison.OrdinalIgnoreCase))
{
result.Append(".4D40");
}
else if (string.Equals(profile, "baseline", StringComparison.OrdinalIgnoreCase))
{
result.Append(".42E0");
}
else
{
// Default to constrained baseline if profile is invalid
result.Append(".4240");
}
string levelHex = level.ToString("X2");
result.Append(levelHex);
return result.ToString();
}
/// <summary>
/// Gets a H.265 codec string.
/// </summary>
/// <param name="profile">H.265 profile.</param>
/// <param name="level">H.265 level.</param>
/// <returns>H.265 string.</returns>
public static string GetH265String(string profile, int level)
{
// The h265 syntax is a bit of a mystery at the time this comment was written.
// This is what I've found through various sources:
// FORMAT: [codecTag].[profile].[constraint?].L[level * 30].[UNKNOWN]
StringBuilder result = new StringBuilder("hev1", 16);
if (string.Equals(profile, "main10", StringComparison.OrdinalIgnoreCase))
{
result.Append(".2.6");
}
else
{
// Default to main if profile is invalid
result.Append(".1.6");
}
result.Append(".L")
.Append(level * 3)
.Append(".B0");
return result.ToString();
}
/// <summary>
/// Gets an AC-3 codec string.
/// </summary>
/// <returns>AC-3 codec string.</returns>
public static string GetAC3String()
{
return "mp4a.a5";
}
/// <summary>
/// Gets an E-AC-3 codec string.
/// </summary>
/// <returns>E-AC-3 codec string.</returns>
public static string GetEAC3String()
{
return "mp4a.a6";
}
}
}