jellyfin/MediaBrowser.Model/Dlna/ResolutionNormalizer.cs
2020-11-18 13:46:14 +00:00

104 lines
3.3 KiB
C#

#nullable disable
#pragma warning disable CS1591
using System;
namespace MediaBrowser.Model.Dlna
{
public class ResolutionNormalizer
{
private static readonly ResolutionConfiguration[] Configurations =
new[]
{
new ResolutionConfiguration(426, 320000),
new ResolutionConfiguration(640, 400000),
new ResolutionConfiguration(720, 950000),
new ResolutionConfiguration(1280, 2500000),
new ResolutionConfiguration(1920, 4000000),
new ResolutionConfiguration(2560, 8000000),
new ResolutionConfiguration(3840, 35000000)
};
public static ResolutionOptions Normalize(
int? inputBitrate,
int? unused1,
int? unused2,
int outputBitrate,
string inputCodec,
string outputCodec,
int? maxWidth,
int? maxHeight)
{
// If the bitrate isn't changing, then don't downscale the resolution
if (inputBitrate.HasValue && outputBitrate >= inputBitrate.Value)
{
if (maxWidth.HasValue || maxHeight.HasValue)
{
return new ResolutionOptions
{
MaxWidth = maxWidth,
MaxHeight = maxHeight
};
}
}
var resolutionConfig = GetResolutionConfiguration(outputBitrate);
if (resolutionConfig != null)
{
var originvalValue = maxWidth;
maxWidth = Math.Min(resolutionConfig.MaxWidth, maxWidth ?? resolutionConfig.MaxWidth);
if (!originvalValue.HasValue || originvalValue.Value != maxWidth.Value)
{
maxHeight = null;
}
}
return new ResolutionOptions
{
MaxWidth = maxWidth,
MaxHeight = maxHeight
};
}
private static ResolutionConfiguration GetResolutionConfiguration(int outputBitrate)
{
ResolutionConfiguration previousOption = null;
foreach (var config in Configurations)
{
if (outputBitrate <= config.MaxBitrate)
{
return previousOption ?? config;
}
previousOption = config;
}
return null;
}
private static double GetVideoBitrateScaleFactor(string codec)
{
if (string.Equals(codec, "h265", StringComparison.OrdinalIgnoreCase) ||
string.Equals(codec, "hevc", StringComparison.OrdinalIgnoreCase) ||
string.Equals(codec, "vp9", StringComparison.OrdinalIgnoreCase))
{
return .5;
}
return 1;
}
public static int ScaleBitrate(int bitrate, string inputVideoCodec, string outputVideoCodec)
{
var inputScaleFactor = GetVideoBitrateScaleFactor(inputVideoCodec);
var outputScaleFactor = GetVideoBitrateScaleFactor(outputVideoCodec);
var scaleFactor = outputScaleFactor / inputScaleFactor;
var newBitrate = scaleFactor * bitrate;
return Convert.ToInt32(newBitrate);
}
}
}