using MediaBrowser.Common.Logging;
using MediaBrowser.Common.Serialization;
using MediaBrowser.Controller.Entities;
using System;
using System.Diagnostics;
using System.IO;
using System.Threading.Tasks;
namespace MediaBrowser.Controller.FFMpeg
{
///
/// Runs FFProbe against a media file and returns metadata.
///
public static class FFProbe
{
///
/// Runs FFProbe against an Audio file, caches the result and returns the output
///
public static FFProbeResult Run(BaseItem item, string cacheDirectory)
{
string cachePath = GetFfProbeCachePath(item, cacheDirectory);
// Use try catch to avoid having to use File.Exists
try
{
return GetCachedResult(cachePath);
}
catch (FileNotFoundException)
{
}
catch (Exception ex)
{
Logger.LogException(ex);
}
FFProbeResult result = Run(item.Path);
if (result != null)
{
// Fire and forget
CacheResult(result, cachePath);
}
return result;
}
///
/// Gets the cached result of an FFProbe operation
///
private static FFProbeResult GetCachedResult(string path)
{
return ProtobufSerializer.DeserializeFromFile(path);
}
///
/// Caches the result of an FFProbe operation
///
private static async void CacheResult(FFProbeResult result, string outputCachePath)
{
await Task.Run(() =>
{
try
{
ProtobufSerializer.SerializeToFile(result, outputCachePath);
}
catch (Exception ex)
{
Logger.LogException(ex);
}
}).ConfigureAwait(false);
}
private static FFProbeResult Run(string input)
{
var startInfo = new ProcessStartInfo { };
startInfo.CreateNoWindow = true;
startInfo.UseShellExecute = false;
// Must consume both or ffmpeg may hang due to deadlocks. See comments below.
startInfo.RedirectStandardOutput = true;
startInfo.RedirectStandardError = true;
startInfo.FileName = Kernel.Instance.ApplicationPaths.FFProbePath;
startInfo.WorkingDirectory = Kernel.Instance.ApplicationPaths.FFMpegDirectory;
startInfo.Arguments = string.Format("\"{0}\" -v quiet -print_format json -show_streams -show_format", input);
//Logger.LogInfo(startInfo.FileName + " " + startInfo.Arguments);
var process = new Process { };
process.StartInfo = startInfo;
process.EnableRaisingEvents = true;
process.Exited += ProcessExited;
try
{
process.Start();
// MUST read both stdout and stderr asynchronously or a deadlock may occurr
// If we ever decide to disable the ffmpeg log then you must uncomment the below line.
process.BeginErrorReadLine();
return JsonSerializer.DeserializeFromStream(process.StandardOutput.BaseStream);
}
catch (Exception ex)
{
Logger.LogException(ex);
// Hate having to do this
try
{
process.Kill();
}
catch
{
}
return null;
}
}
static void ProcessExited(object sender, EventArgs e)
{
(sender as Process).Dispose();
}
private static string GetFfProbeCachePath(BaseItem item, string cacheDirectory)
{
string outputDirectory = Path.Combine(cacheDirectory, item.Id.ToString().Substring(0, 1));
return Path.Combine(outputDirectory, item.Id + "-" + item.DateModified.Ticks + ".pb");
}
}
}