Develop Reference

Problem / Error with converting M4A Audio File to MP3 using NAudio in C#

I'm in a process of creating a demo for an audio conversion software that I create as a hobby. I wanted converting an M4A (MPEG-4) audio file to an MP3 using a simple GUI for the user to interact. I also implemented a feature that allows the user to play the selected audio file (M4A) before conversion, which I have learned from watching NAudio video tutorials. However, I was stuck with a specific issue that stops me from progressing this demo project.
I have received an error right after the SaveFileDialogue selection to place the converted file (MP3) which prevents me from continuing the process. (I have put the error message in the comments for all of you to see in the method of btnConvertToMp3_Click()).
I have tried using MediaFoundationEncoder.EncodeToMp3() to solve this case. Unfortunately, I get an error, stating that there are "No available MP3 encoders" which I have researched that it is not fully supported enough to be used functionally for every audio format.
I have tried searching for more solutions, close to this problem but sadly could not find what I was hoping for, so I decided to ask if you have any input about this problem.
Here is my current code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NAudio.Wave;
using NAudio;
using NAudio.Lame;
using NAudio.Dmo;
using System.Windows.Forms;
namespace M4AtoMP3ConversionDEMO
{
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private NAudio.Wave.BlockAlignReductionStream stream = null;
private NAudio.Wave.DirectSoundOut output = null;
public void btnOpenM4AFile_Click(object sender, EventArgs e)
{
OpenFileDialog open = new OpenFileDialog();
open.Filter = "M4A Audio File (*.m4a)|*.m4a;";
if (open.ShowDialog() != DialogResult.OK)
{
return;
}
MediaFoundationReader mfM4A = new MediaFoundationReader(open.FileName);
stream = new NAudio.Wave.BlockAlignReductionStream(mfM4A);
btnPlayPauseButton.Enabled = true;
btnConvertToMP3.Visible = true;
output = new NAudio.Wave.DirectSoundOut();
output.Init(mfM4A);
output.Play();
MessageBox.Show(".M4A Format has been accepted", ".M4A Audio Format", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
private void btnConvertToMP3_Click(object sender, EventArgs e)
{
DialogResult mb1 = MessageBox.Show("Are you sure you want to convert this M4A File?", "Converting to MP3", MessageBoxButtons.YesNo, MessageBoxIcon.Information);
switch (mb1)
{
case DialogResult.Yes:
SaveFileDialog save = new SaveFileDialog();
save.Filter = "MP3 File (*.mp3)|*.mp3";
if (save.ShowDialog() != DialogResult.OK) return;
// Unable to cast COM object of type 'System.__ComObject' to interface type 'NAudio.MediaFoundation.IMFSourceReader'.
// This operation failed because the QueryInterface call on the COM component for the interface with IID '{70AE66F2-C809-4E4F-8915-BDCB406B7993}' failed due to the following error:
// No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE))
using (var mp3FileReader = new LameMP3FileWriter(save.FileName, stream.WaveFormat, LAMEPreset.ABR_320))
{
stream.CopyTo(mp3FileReader);
}
break;
case DialogResult.No:
break;
}
}
private void btnPlayPauseButton_Click(object sender, EventArgs e)
{
if (output != null)
{
if (output.PlaybackState == NAudio.Wave.PlaybackState.Playing)
{
output.Pause();
Image playButton = new Bitmap(#"C:\Users\CeX\source\repos\AudioConverterUI-WorkInProgress\AudioConverterUI-WorkInProgress\Resources\play-button-size.png");
btnPlayPauseButton.Image = playButton;
}
else if (output.PlaybackState == NAudio.Wave.PlaybackState.Paused)
{
output.Play();
Image pauseButton = new Bitmap(#"C:\Users\CeX\source\repos\AudioConverterUI-WorkInProgress\AudioConverterUI-WorkInProgress\Resources\pause-button-size.png");
btnPlayPauseButton.Image = pauseButton;
}
}
}
private void DisposeWave()
{
if (output != null)
{
if (output.PlaybackState == NAudio.Wave.PlaybackState.Playing)
{
output.Stop();
output.Dispose();
output = null;
}
if (stream != null)
{
stream.Dispose();
stream = null;
}
}
}
}
}
If there isn't a suitable solution to this error, is there a possible alternative or simple solution that would allow me to convert M4A to MP3 without using NAudio, even with GUI?

A simple approach without using NAudio (which relies on Windows codecs) is to use FFMPEG, and do a command line conversion.

Downoald multiple files on same time

I have Listbox full with links like this: http://example.com/sorted/Avicii/Avicii+-+Wake+Me+Up.mp3 and I wanna download them all on same time any suggestions?
this code I use to download a single file
private void txtUrl_TextChanged(object sender, EventArgs e)
{
try
{
// function that enter the file name automatically in the savefiledialog.
Uri uri = new Uri(txtUrl.Text);
// Save the file name to the string.
filename = Path.GetFileName(uri.LocalPath);
}
catch
{
// no need need an exception message.
}
}
private void DownloadFile(string url, string save)
{
using (var client = new WebClient())
{
// Run code every time the download changes.
client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(Changed);
// Run codes when file download has been completed.
client.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
client.DownloadFileAsync(new Uri(url), save);

The solution could look like this:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
namespace SillyCSharpNameSpace
{
public class VerboseDownloaderClassName
{
private string downloadFile(string url, string localDir)
{
try
{
var localPath = Path.Combine(localDir, Path.GetFileName(url));
using (var wc = new WebClient())
{
wc.DownloadFile(url, localPath);
return localPath;
}
}
catch (Exception e)
{
Console.WriteLine(e);
return null;
}
}
public void DownloadAll(List<string> urls)
{
urls.AsParallel()
.Where(url => !string.IsNullOrWhiteSpace(url))
.WithDegreeOfParallelism(20)
.Select(url => downloadFile(url, "."));
}
}
}
I'm sure if you work with WinForms or ASP.NET you can figure out how to take an url string from a list box item. And note, that Path.GetFileName() works only for the form you have provided - with the file name at the end of URL, without any URL parameters. AsParallel method parallelizes the downloading work into 20 "threads". I think it should be enough for your purpose.
Bonus. This is the same in F#, just because I can ;o)
open System.IO
open System.Net
open FSharp.Collections.ParallelSeq // from NuGet FSharp.Collections.ParallelSeq
let downloadFile dir url =
let localPath = Path.Combine(dir, Path.GetFileName url)
try
use wc = new WebClient()
wc.DownloadFile(url, localPath)
Some localPath
with ex ->
printfn "Can't download file from %s: %A" url ex
None
let downloadAll (urls: string list) =
urls
|> PSeq.withDegreeOfParallelism 20 // 20 threads
|> PSeq.choose (downloadFile ".")

Xamarin/Android - Issue reading locally stored photo from camera - no read access

I'm trying to create a simple test app to take photos in Android, using Xamarin. When I get this app working (or so I hope), i'll use the code in a real app that I'm working on. I'm using the following recipe from Xamarin as my basis:
http://docs.xamarin.com/recipes/android/other_ux/camera_intent/take_a_picture_and_save_using_camera_app/
The major difference is that I need to store images locally, and not on the SD card. I'm able to successfully take a picture (with the Android simulator). I can see the file in the file structure using ADB and can successfully copy and open the file on my PC. However, I'm unsuccessfull in accessing the file in the app, probably due to user rights.
Please note that I was successfull in creating my own .txt files, and reading them back using either System.IO and Java.IO.
Please review the following code. My app crashes when using "System.IO.File.ReadAllText" and gives me "Access to the path "/data/data/CameraAppDemo.CameraAppDemo/files/photo.jpg" is denied.". And whatever I try (absolute, relative paths, uri's), objBitmap is always null.
ADB says that "photo.jpg" has -rwxrwx--- rights, and though I'm not entirely sure, I think that should be more than sufficient
On the other hand, maybe the intent still has a lock on "photo.jpg"? Or something else is going on...
And one final note, I'm using System.IO.File.ReadAllText just for testing purposes. I experimented with stream readers as well, but with the same result. Also, though I believe this step is unnecessary, I enabled "WriteExternalStore" in the Manifest
namespace CameraAppDemo
{
using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.Graphics;
using Android.OS;
using Android.Provider;
using Android.Widget;
using Java.IO;
using Environment = Android.OS.Environment;
using Uri = Android.Net.Uri;
[Activity(Label = "Camera App Demo", MainLauncher = true)]
public class MainActivity : Activity
{
private File _file;
private string _basePath;
private ImageView _imageView;
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
var objBitmap = BitmapFactory.DecodeFile(_file.AbsolutePath) ;
Console.WriteLine ("objBitmap = null : " + (objBitmap == null).ToString ());
var strOutput = System.IO.File.ReadAllText (FileManager.BasePath + "/photo.jpg");
Console.WriteLine (strOutput);
}
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
FileManager.SetupFolderStructure();
if (IsThereAnAppToTakePictures())
{
Button button = FindViewById<Button>(Resource.Id.myButton);
_imageView = FindViewById<ImageView>(Resource.Id.imageView1);
button.Click += TakeAPicture;
}
}
private bool IsThereAnAppToTakePictures()
{
Intent intent = new Intent(MediaStore.ActionImageCapture);
IList<ResolveInfo> availableActivities = PackageManager.QueryIntentActivities(intent, PackageInfoFlags.MatchDefaultOnly);
return availableActivities != null && availableActivities.Count > 0;
}
private void TakeAPicture(object sender, EventArgs eventArgs)
{
System.IO.Directory.Delete (FileManager.BasePath, true);
_basePath = FileManager.BasePath;
_file = new Java.IO.File (_basePath, "photo.jpg");
Intent intent = new Intent(MediaStore.ActionImageCapture);
intent.PutExtra(MediaStore.ExtraOutput, Uri.FromFile(_file));
StartActivityForResult(intent, 0);
}
}
}
//Part of the FileManager class:
using System;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using Android.Graphics;
namespace CameraAppDemo
{
public class FileManager
{
public static string BasePath {
get {
var libraryPath = Environment.GetFolderPath (Environment.SpecialFolder.Personal);
if (Directory.Exists (libraryPath) == false) {
Directory.CreateDirectory (libraryPath);
}
return libraryPath;
}
}
}
}
==== Edit ====
It seems that I'm simply not able to read the file. As an ex-webdeveloper, I'm fairly new to programming for mobile, let alone the combo of C# and Java and I'm still learning a lot.
Anyway, I added the following lines:
Console.WriteLine("Setting file :" + _file.SetReadable (true));
Console.WriteLine("Can read :" + _file.CanRead());
Both cases return False. I can't read the file, and I am unable to give read access.
So, any ideas? Is this by design? Can I tell the Intent for taking images to give me read access, or is there another workaround?
If everything fails, I'm hoping to workaround the problem by saving to the SD card first and then copying the file to the local filesystem. But that's something I rather would not do; I can't guarantee that the end users have an SD card, and the pictures should not be deleted by accident.

C# IF Else loop

I want to create a c# program that will look in a folder for files. If the files are found then I want to start a program. If the file is not there then I want to program to sleep for 30 minutes and look in the folder again. I want to keep doing it maybe 10 times and if it still doesn’t find the file then exit the program. I wrote the if part but I need help on the else part. This is what I have so far.
using System;
using System.IO;
using System.Net;
using System.Net.Mail;
using System.Diagnostics;
class Program
{
static void Main()
{
// See if this file exists in the SAME DIRECTORY.
if (File.Exists(#"C:\name.txt"))
{
Process.Start(#"C:\bulkload.bat");
}
else
{
}
}
}

Untested, for guidance purpose only.
for (int i = 0; i < 10; i++)
{
if (File.Exists(#"C:\name.txt"))
{
Process.Start(#"C:\bulkload.bat");
return;
}
else //no need of else block really.
{
Thread.Sleep(30 * 60 * 1000);
}
}

How to get Monotorrents DHT to work?

Iam trying to get the dht implementation of monotorrent to work but i just cant seem to find any peers.
ive tried most of the examplecode code availeble on the net like the testclient and dhttest.
I have tried with several diffrent infohashes.
Anyone here got it working? or do you know where i can find the devs?
This is how my code looks atm:
using System;
using System.Collections.Generic;
using System.Text;
using MonoTorrent.Dht;
using MonoTorrent.Dht.Listeners;
using System.Net;
using System.IO;
using MonoTorrent.Common;
using MonoTorrent.Tracker.Listeners;
namespace SampleClient
{
class Program
{
static void Main(string[] args)
{
string basePath = Environment.CurrentDirectory;
string torrentsPath = Path.Combine(basePath, "Torrents");
Torrent torrent = null;
// If the torrentsPath does not exist, we want to create it
if (!Directory.Exists(torrentsPath))
Directory.CreateDirectory(torrentsPath);
// For each file in the torrents path that is a .torrent file, load it into the engine.
foreach (string file in Directory.GetFiles(torrentsPath))
{
if (file.EndsWith(".torrent"))
{
try
{
// Load the .torrent from the file into a Torrent instance
// You can use this to do preprocessing should you need to
torrent = Torrent.Load(file);
Console.WriteLine(torrent.InfoHash.ToString());
}
catch (Exception e)
{
Console.Write("Couldn't decode {0}: ", file);
Console.WriteLine(e.Message);
continue;
}
}
}
DhtListener listener = new DhtListener(new IPEndPoint(IPAddress.Parse("192.168.2.3"), 10000));
DhtEngine engine = new DhtEngine(listener);
//engine.RegisterDht(dht);
byte[] nodes = null;
if (File.Exists("mynodes"))
nodes = File.ReadAllBytes("mynodes");
listener.Start();
int i = 0;
bool running = true;
StringBuilder sb = new StringBuilder(1024);
while (running)
{
engine.Start(nodes);
while (Console.ReadLine() != "q")
{
engine.GetPeers(torrent.InfoHash);
}
File.WriteAllBytes("mynodes", engine.SaveNodes());
}
}
}
}

I know it's very old question, I'm not sure why it's still noone has answer it, anyway. The problem seem to be this line:
DhtListener listener = new DhtListener(new IPEndPoint(IPAddress.Parse("192.168.2.3"), 10000));
This ip is not the real ip, so you actually asl peers to send the respone to unkonw adress.
What to do? register your own adress.