public async Task TranscodeVideo(Stream outputStream, TranscodeVideoFile options, CancellationToken token)
{
string cmd;
if (options.HwAccelDeviceType != HwAccelDeviceType.None)
{
cmd = BuildVideoTranscodeCmd(options, 0, 2);
_logger.LogInformation($"{nameof(TranscodeVideo)}: Checking if we can use the default cmd for hwAccelType = {options.HwAccelDeviceType}...");
_transcodeProcess.StartInfo.Arguments = cmd;
_transcodeProcess.Start();
await using var memStream = new MemoryStream();
var testStream = _transcodeProcess.StandardOutput.BaseStream as FileStream;
await testStream.CopyToAsync(memStream, token).ConfigureAwait(false);
if (_transcodeProcess.ExitCode != 0)
{
_logger.LogWarning(
$"{nameof(TranscodeVideo)}: We cant use the default cmd = {cmd} for hwAccelType = {options.HwAccelDeviceType}. " +
$"Creating a new one with hwAccelType = {HwAccelDeviceType.None}..");
options.HwAccelDeviceType = HwAccelDeviceType.None;
}
}
cmd = BuildVideoTranscodeCmd(options);
//https://forums.plex.tv/t/best-format-for-streaming-via-chromecast/49978/6
//ffmpeg - i[inputfile] - c:v libx264 -profile:v high -level 5 - crf 18 - maxrate 10M - bufsize 16M - pix_fmt yuv420p - vf "scale=iw*sar:ih, scale='if(gt(iw,ih),min(1920,iw),-1)':'if(gt(iw,ih),-1,min(1080,ih))'" - x264opts bframes = 3:cabac = 1 - movflags faststart - strict experimental - c:a aac -b:a 320k - y[outputfile]
//string cmd = $@"-v quiet -ss {seconds} -y -i ""{filePath}"" -preset superfast -c:v copy -acodec aac -b:a 128k -movflags frag_keyframe+faststart -f mp4 -";
_logger.LogInformation($"{nameof(TranscodeVideo)}: Trying to transcode file with CMD = {cmd}");
_transcodeProcess.StartInfo.Arguments = cmd;
_transcodeProcess.Start();
var stream = _transcodeProcess.StandardOutput.BaseStream as FileStream;
await stream.CopyToAsync(outputStream, token).ConfigureAwait(false);
_logger.LogInformation($"{nameof(TranscodeVideo)}: Transcode completed for file = {options.FilePath}");
}
private static string BuildVideoTranscodeCmd(
TranscodeVideoFile options,
double?from = null,
double?to = null)
{
var builder = new FFmpegArgsBuilder();
var inputArgs = builder.AddInputFile(options.FilePath)
.BeQuiet()
.SetVSync(0)
.SetAutoConfirmChanges()
.SetHwAccel(options.HwAccelDeviceType)
.SetVideoCodec(options.HwAccelDeviceType);
var outputArgs = builder.AddOutputPipe()
.SetPreset(options.HwAccelDeviceType)
.AddArg("map_metadata", -1)
.AddArg("map_chapters", -1); //for some reason the chromecast doesnt like chapters o.o
if (options.VideoStreamIndex >= 0)
{
outputArgs.SetMap(options.VideoStreamIndex);
}
if (options.AudioStreamIndex >= 0)
{
outputArgs.SetMap(options.AudioStreamIndex);
}
if (options.Seconds > 0 && !from.HasValue && !to.HasValue)
{
inputArgs.Seek(options.Seconds);
}
if (from.HasValue)
{
outputArgs.Seek(from.Value);
}
if (to.HasValue)
{
outputArgs.To(to.Value);
}
if (options.ForceVideoTranscode)
{
outputArgs.SetVideoCodec(options.HwAccelDeviceType).SetProfileVideo("main").SetLevel(4).SetPixelFormat(options.HwAccelDeviceType);
if (options.VideoScaleType != VideoScaleType.Original)
{
int videoScale = (int)options.VideoScaleType;
switch (options.HwAccelDeviceType)
{
case HwAccelDeviceType.Intel:
outputArgs.AddArg("global_quality", 25)
.AddArg("look_ahead", 1)
.SetFilters($"scale_qsv=trunc(oh*a/2)*2:{videoScale}");
break;
case HwAccelDeviceType.Nvidia:
string scale = options.VideoScaleType == VideoScaleType.Hd ? "1280x720" : "1920x1080";
if (scale != options.VideoWidthAndHeight && !string.IsNullOrWhiteSpace(options.VideoWidthAndHeight))
{
inputArgs.AddArg("resize", scale);
}
break;
case HwAccelDeviceType.None:
outputArgs.SetFilters($"scale=trunc(oh*a/2)*2:{videoScale}");
break;
case HwAccelDeviceType.AMD:
break;
default:
throw new ArgumentOutOfRangeException();
}
}
}
else
{
outputArgs.CopyVideoCodec();
}
if (options.ForceAudioTranscode)
{
outputArgs.SetAudioCodec("aac").SetAudioBitrate(128).SetAudioChannels(2);
}
else
{
outputArgs.CopyAudioCodec();
}
outputArgs.SetMovFlagToTheStart().SetFormat("mp4");
return(builder.GetArgs());
}
