JD2022-TU1/main/tools/apps/JDSongConverter/Tasks/ChangeWaveSamplerateTask.cs

using System;
using System.IO;
using JD.LogService;
using NAudio.Wave;
using TeaBox.Macros;

namespace JDSongConverter.Tasks
{
    /// <summary>
    /// Checks the samplerate of a wave file and change it if necessary
    /// </summary>
    class ChangeWaveSamplerateTask : Task
    {
        public string InputFile { get; set; }
        public string OutputFile { get; set; }

        private const int RequestedSamplerate = 48000;

        public void Init(string inputFile, string outputFile)
        {
            InputFile = inputFile;
            OutputFile = outputFile;
        }

        public override string Name
        {
            get { return String.Format("Ensure wave samplerate is {0}", RequestedSamplerate); }
            set { }
        }

        public override string ProgressText
        {
            get { return String.Format("Checking samplerate of wave file '{0}'", InputFile); }
        }

        public override TaskResult Process(IExecutionContext executionContext)
        {
            if (string.IsNullOrEmpty(InputFile) || !File.Exists(InputFile))
                return TaskResult.ParametersError;

            string tempFile = System.IO.Path.ChangeExtension(InputFile, ".tmp");
            
            using (var reader = new CueWaveFileReader(InputFile))
            {
                if (reader.WaveFormat.SampleRate == RequestedSamplerate)
                {
                    executionContext.LogMessage("No need to change wave samplerate.");
                    return TaskResult.Ok;
                }

                var targetFormat = new WaveFormat(RequestedSamplerate, reader.WaveFormat.Channels);

                using (var waveFormatConversionStream = new WaveFormatConversionStream(targetFormat, reader))
                {
                    using (var writer = new CueWaveFileWriter(tempFile, targetFormat))
                    {
                        int bufferSize = waveFormatConversionStream.BlockAlign * 1024 * 4;
                        waveFormatConversionStream.CopyTo(writer, bufferSize);
                        double sampleRateFactor = targetFormat.SampleRate/(double)reader.WaveFormat.SampleRate;
                        foreach (Cue cue in reader.Cues)
                        {
                            writer.AddCue((int)(cue.Position * sampleRateFactor), cue.Label);
                        }
                    }
                }
            }
            File.Move(tempFile, OutputFile);

            return TaskResult.Ok;
        }

    }
}