public async Task ExecuteInstructionAsync()
{
var instruction = GetInstruction();
var ffmpeg = new FFmpeg();
ffmpeg.Progress += e => { Debug.WriteLine(e); };
await ffmpeg.ExecuteAsync(instruction);
}
public async Task ConvertFromAacToMp3Async()
{
var ffmpeg = new FFmpeg();
ffmpeg.Progress += e => { Debug.WriteLine(e); };
var files = Directory.EnumerateFiles(@"", "*.aac").Select(x => new FileInfo(x));
foreach (var file in files)
{
var instruction = new InstructionRoot()
.AddInput(new Input(file.FullName))
.AddOutput(new Output(file.FullName.Replace(".aac", ".mp3")))
.GetInstruction();
await ffmpeg.ExecuteAsync(instruction);
}
}
private async ValueTask ProcessAsync(
string filePath,
Container container,
IReadOnlyList <StreamInput> streamInputs,
IReadOnlyList <SubtitleInput> subtitleInputs,
IProgress <double>?progress = null,
CancellationToken cancellationToken = default)
{
var arguments = new ArgumentsBuilder();
// Stream inputs
foreach (var streamInput in streamInputs)
{
arguments.Add("-i").Add(streamInput.FilePath);
}
// Subtitle inputs
foreach (var subtitleInput in subtitleInputs)
{
arguments.Add("-i").Add(subtitleInput.FilePath);
}
// Format
arguments.Add("-f").Add(container.Name);
// Preset
arguments.Add("-preset").Add(_preset);
// Mapping
for (var i = 0; i < streamInputs.Count + subtitleInputs.Count; i++)
{
arguments.Add("-map").Add(i);
}
// Avoid transcoding if possible
if (streamInputs.All(s => s.Info.Container == container))
{
arguments
.Add("-c:a").Add("copy")
.Add("-c:v").Add("copy");
}
// MP4: specify subtitle codec manually, otherwise they're not injected
if (container == Container.Mp4 && subtitleInputs.Any())
{
arguments.Add("-c:s").Add("mov_text");
}
// MP3: specify bitrate manually, otherwise the metadata will contain wrong duration
// https://superuser.com/questions/892996/ffmpeg-is-doubling-audio-length-when-extracting-from-video
if (container == Container.Mp3)
{
arguments.Add("-b:a").Add("165k");
}
// Inject language metadata for subtitles
for (var i = 0; i < subtitleInputs.Count; i++)
{
arguments
.Add($"-metadata:s:s:{i}")
.Add($"language={subtitleInputs[i].Info.Language.Code}")
.Add($"-metadata:s:s:{i}")
.Add($"title={subtitleInputs[i].Info.Language.Name}");
}
// Misc settings
arguments
.Add("-threads").Add(Environment.ProcessorCount)
.Add("-nostdin")
.Add("-y");
// Output
arguments.Add(filePath);
// Run FFmpeg
await _ffmpeg.ExecuteAsync(arguments.Build(), progress, cancellationToken);
}