stream-shorts/src/StreamShorts.Library/Media/FFMpegService.cs

using FFMpegCore;
using FFMpegCore.Enums;
using FFMpegCore.Pipes;

namespace StreamShorts.Library.Media;

/// <summary>
/// Represents a service for processing video files using FFMpeg.
/// </summary>
/// <inheritdoc/>
internal sealed class FFMpegService : IVideoService
{
  public async Task<bool> ExtractAudioFromVideoAsync(Stream video, Stream audio)
  {
    return await FFMpegArguments
      .FromPipeInput(new StreamPipeSource(video))
      .OutputToPipe(
        new StreamPipeSink(audio),
        static o => o.DisableChannel(Channel.Video).ForceFormat("mp3")
      )
      .ProcessAsynchronously()
      .ConfigureAwait(false);
  }

  public async Task CreateClipFromVideoAsync(
    string sourcePath, 
    string destinationPath, 
    TimeSpan startTime,
    TimeSpan endTime,
    TimeSpan? buffer = null
  )
  {
    var start = startTime - (buffer ?? TimeSpan.Zero);
    var end = endTime + (buffer ?? TimeSpan.Zero);
    
    await FFMpeg.SubVideoAsync(sourcePath, destinationPath, start, end)
      .ConfigureAwait(false);
  }
}