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Merge pull request #12354 from gnattu/ac-4-downmix

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Add AC-4 downmix algorithm
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Bond-009 2024-08-01 20:05:18 +02:00 committed by GitHub
commit f2e749548c
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2 changed files with 19 additions and 3 deletions
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9
MediaBrowser.Controller/MediaEncoding/DownMixAlgorithmsHelper.cs
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@ -15,13 +15,22 @@ public static class DownMixAlgorithmsHelper
public static readonly Dictionary<(DownMixStereoAlgorithms, string), string> AlgorithmFilterStrings = new()
{
{ (DownMixStereoAlgorithms.Dave750, "5.1"), "pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" },
// Use AC-4 algorithm to downmix 7.1 inputs to 5.1 first
{ (DownMixStereoAlgorithms.Dave750, "7.1"), "pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=0.707*c4+0.707*c6|c5=0.707*c5+0.707*c7,pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" },
{ (DownMixStereoAlgorithms.NightmodeDialogue, "5.1"), "pan=stereo|c0=c2+0.30*c0+0.30*c4|c1=c2+0.30*c1+0.30*c5" },
// Use AC-4 algorithm to downmix 7.1 inputs to 5.1 first
{ (DownMixStereoAlgorithms.NightmodeDialogue, "7.1"), "pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=0.707*c4+0.707*c6|c5=0.707*c5+0.707*c7,pan=stereo|c0=c2+0.30*c0+0.30*c4|c1=c2+0.30*c1+0.30*c5" },
{ (DownMixStereoAlgorithms.Rfc7845, "3.0"), "pan=stereo|c0=0.414214*c2+0.585786*c0|c1=0.414214*c2+0.585786*c1" },
{ (DownMixStereoAlgorithms.Rfc7845, "quad"), "pan=stereo|c0=0.422650*c0+0.366025*c2+0.211325*c3|c1=0.422650*c1+0.366025*c3+0.211325*c2" },
{ (DownMixStereoAlgorithms.Rfc7845, "5.0"), "pan=stereo|c0=0.460186*c2+0.650802*c0+0.563611*c3+0.325401*c4|c1=0.460186*c2+0.650802*c1+0.563611*c4+0.325401*c3" },
{ (DownMixStereoAlgorithms.Rfc7845, "5.1"), "pan=stereo|c0=0.374107*c2+0.529067*c0+0.458186*c4+0.264534*c5+0.374107*c3|c1=0.374107*c2+0.529067*c1+0.458186*c5+0.264534*c4+0.374107*c3" },
{ (DownMixStereoAlgorithms.Rfc7845, "6.1"), "pan=stereo|c0=0.321953*c2+0.455310*c0+0.394310*c5+0.227655*c6+0.278819*c4+0.321953*c3|c1=0.321953*c2+0.455310*c1+0.394310*c6+0.227655*c5+0.278819*c4+0.321953*c3" },
{ (DownMixStereoAlgorithms.Rfc7845, "7.1"), "pan=stereo|c0=0.274804*c2+0.388631*c0+0.336565*c6+0.194316*c7+0.336565*c4+0.194316*c5+0.274804*c3|c1=0.274804*c2+0.388631*c1+0.336565*c7+0.194316*c6+0.336565*c5+0.194316*c4+0.274804*c3" },
{ (DownMixStereoAlgorithms.Ac4, "3.0"), "pan=stereo|c0=c0+0.707*c2|c1=c1+0.707*c2" },
{ (DownMixStereoAlgorithms.Ac4, "5.0"), "pan=stereo|c0=c0+0.707*c2+0.707*c3|c1=c1+0.707*c2+0.707*c4" },
{ (DownMixStereoAlgorithms.Ac4, "5.1"), "pan=stereo|c0=c0+0.707*c2+0.707*c4|c1=c1+0.707*c2+0.707*c5" },
{ (DownMixStereoAlgorithms.Ac4, "7.0"), "pan=5.0(side)|c0=c0|c1=c1|c2=c2|c3=0.707*c3+0.707*c5|c4=0.707*c4+0.707*c6,pan=stereo|c0=c0+0.707*c2+0.707*c3|c1=c1+0.707*c2+0.707*c4" },
{ (DownMixStereoAlgorithms.Ac4, "7.1"), "pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=0.707*c4+0.707*c6|c5=0.707*c5+0.707*c7,pan=stereo|c0=c0+0.707*c2+0.707*c4|c1=c1+0.707*c2+0.707*c5" },
};
/// <summary>

13
MediaBrowser.Model/Entities/DownMixStereoAlgorithms.cs
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@ -1,8 +1,7 @@
namespace MediaBrowser.Model.Entities;
/// <summary>
/// An enum representing an algorithm to downmix 6ch+ to stereo.
/// Algorithms sourced from https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg/1410620#1410620.
/// An enum representing an algorithm to downmix surround sound to stereo.
/// </summary>
public enum DownMixStereoAlgorithms
{
@ -13,16 +12,24 @@ public enum DownMixStereoAlgorithms
/// <summary>
/// Algorithm by Dave_750.
/// Sourced from https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg/1410620#1410620.
/// </summary>
Dave750 = 1,
/// <summary>
/// Nightmode Dialogue algorithm.
/// Sourced from https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg/1410620#1410620.
/// </summary>
NightmodeDialogue = 2,
/// <summary>
/// RFC7845 Section 5.1.1.5 defined algorithm.
/// </summary>
Rfc7845 = 3
Rfc7845 = 3,
/// <summary>
/// AC-4 standard algorithm with its default gain values.
/// Defined in ETSI TS 103 190 Section 6.2.17.
/// </summary>
Ac4 = 4
}