ersatztv/ErsatzTV.FFmpeg/Decoder/Cuvid/DecoderMpeg2Cuvid.cs

namespace ErsatzTV.FFmpeg.Decoder.Cuvid;

public class DecoderMpeg2Cuvid : DecoderBase
{
    private readonly FrameState _desiredState;

    public DecoderMpeg2Cuvid(FrameState desiredState)
    {
        _desiredState = desiredState;
    }

    public override string Name => "mpeg2_cuvid";
    public override IList<string> InputOptions
    {
        get
        {
            IList<string> result =  base.InputOptions;
            
            if (_desiredState.Deinterlaced)
            {
                result.Add("-deint");
                result.Add("2");

                // make sure we decode into software
                result.Add("-hwaccel_output_format");
                result.Add("nv12");
            }
            else
            {
                // make sure we decode into hardware
                result.Add("-hwaccel_output_format");
                result.Add("cuda");
            }

            return result;
        }
    }
    
    public override FrameDataLocation OutputFrameDataLocation => FrameDataLocation.Hardware;

    public override FrameState NextState(FrameState currentState)
    {
        FrameState result = base.NextState(currentState);
        return _desiredState.Deinterlaced
            // when -deint is used, a hwupload_cuda is required to use more hw filters
            ? result with { Deinterlaced = true, FrameDataLocation = FrameDataLocation.Software }
            : result;
    }
}