ErsatzTV/ErsatzTV.FFmpeg/InputOption/ReadrateInputOption.cs

using System.Globalization;
using ErsatzTV.FFmpeg.Environment;

namespace ErsatzTV.FFmpeg.InputOption;

public class ReadrateInputOption : IInputOption
{
    private readonly int _initialBurstSeconds;

    public ReadrateInputOption(int initialBurstSeconds = 0)
    {
        _initialBurstSeconds = initialBurstSeconds;
    }
    
    public IList<EnvironmentVariable> EnvironmentVariables => Array.Empty<EnvironmentVariable>();

    public IList<string> GlobalOptions => Array.Empty<string>();

    public IList<string> InputOptions(InputFile inputFile)
    {
        var result = new List<string> { "-readrate", "1.0" };

        if (_initialBurstSeconds > 0)
        {
            result.AddRange(
                new[]
                {
                    "-readrate_initial_burst",
                    _initialBurstSeconds.ToString(CultureInfo.InvariantCulture)
                });
        }

        return result;
    }

    public IList<string> FilterOptions => Array.Empty<string>();
    public IList<string> OutputOptions => Array.Empty<string>();
    public FrameState NextState(FrameState currentState) => currentState with { Realtime = true };

    public bool AppliesTo(AudioInputFile audioInputFile) => true;

    // don't use realtime input for a still image
    public bool AppliesTo(VideoInputFile videoInputFile) => videoInputFile.VideoStreams.All(s => !s.StillImage);

    public bool AppliesTo(ConcatInputFile concatInputFile) => true;
}