Develop Reference

How to record two audio inputs and one video input?

I am trying to record two audio input (webcam + microphone) and one video input (webcam) via MediaCapture from C#. Just 1 audio and 1 video input works like a charm but the class itself does not allow to specify two audio input device ids.
An example:
var captureDeviceSettings = new MediaCaptureInitializationSettings
{
VideoDeviceId = videoDeviceId, #Webcam video input
AudioDeviceId = audioDeviceId, #Webcam audio input
StreamingCaptureMode = StreamingCaptureMode.AudioAndVideo,
}
I thought about using audio graph and using a submix node but, I need to specify a device ID for the media capture, the submix node does not give that. Further on, using the output device of audio graph seems not like the solution, I do not want to play microphone to default output device. Tried that but sounds horrible. I thought about creating a virtual audio device but I don't know how.
Any suggestions on that?

MediaCapture won't be able to do this, WASAPI maybe possibile, but it is not trivial to do.
Best option may be to utilize https://learn.microsoft.com/en-us/windows/win32/coreaudio/loopback-recording.
You will still have to mux in video stream though if you get loopback recording to work.

WPF Select Input Audio and set Output device Audio

I'm trying to create a WPF application that allows me to select an audio source, which comes from a video, microphone, input audio, or other device connected to the PC and send it to an audio device that is connected to the PC.
To test, I used MediaElement but it only lets me select a video, I can't select another source, and I can't select the output device.
I tried to see NAudio and also Unosquare.FFME but I couldn't figure out how to solve the problem.
Thank you so much for your help

With NAudio you can do that easily.
You can get all available devices on computer by using the class MMDeviceEnumerator. Call the static function named EnumerateAudioEndPoints.
Example:
using NAudio.CoreAudioApi;
using (var devices = new MMDeviceEnumerator())
{
foreach (var device in devices.EnumerateAudioEndPoints(DataFlow.All, DeviceState.Active))
{
// do something with device
}
}
The DataFlow enum you can choise between input or output devices.

mix microphone with mp3 file and output that to specific device

I'd like to be able to mix the microphone output with a mp3-File, and output that to a specific device.
I got playing the mp3-File to a specific device working:
Mp3FileReader reader = new Mp3FileReader("C:\\Users\\Victor\\Music\\Musik\\Attack.mp3");
var waveOut = new WaveOut();// or WaveOutEvent()
waveOut.DeviceNumber = deviceId; //deviceId, like 0 or 1
waveOut.Init(reader);
waveOut.Play();
So would I would like to be able to do is basically send the microphone output always to specific output and overlay that output to that specific device with the sound of a mp3-file when for example a button is pressed.
Now is what I'm trying to do possible with naudio and if so how would I go about it?
Thanks!

The basic strategy is to put the audio rececived from the microphone into a BufferedWaveProvider. Then turn that into an ISampleProvider with the ToSampleProvider extension method. Now you can pass that into a MixingSampleProvider. Then play from the MixingSampleProvider. Now at any time you can mix in other audio by adding an input into the MixingSampleProvider

How to capture screen to be video using C# .Net?

I know there are lots of question like this.
But I don't want to use the Windows media encoder 9 because it's a problem to get one, and then it is no longer supported.
I know that, one possibility is to capture lots of screenshots and create a video with ffmpeg but I don't want use third party executables.
Is there are a .net only solution?

the answer is the Microsoft Expression Encoder. It is according to my opinion the easiest way to record something on vista and windows 7
private void CaptureMoni()
{
try
{
Rectangle _screenRectangle = Screen.PrimaryScreen.Bounds;
_screenCaptureJob = new ScreenCaptureJob();
_screenCaptureJob.CaptureRectangle = _screenRectangle;
_screenCaptureJob.ShowFlashingBoundary = true;
_screenCaptureJob.ScreenCaptureVideoProfile.FrameRate = 20;
_screenCaptureJob.CaptureMouseCursor = true;
_screenCaptureJob.OutputScreenCaptureFileName = string.Format(#"C:\test.wmv");
if (File.Exists(_screenCaptureJob.OutputScreenCaptureFileName))
{
File.Delete(_screenCaptureJob.OutputScreenCaptureFileName);
}
_screenCaptureJob.Start();
}
catch(Exception e) { }
}

Edit Based on Comment Feedback:
A developer by the name baSSiLL has graciously shared a repository that has a screen recording c# library as well as a sample project in c# that shows how it can be used to capture the screen and mic.
Starting a screen capture using the sample code is as straight forward as:
recorder = new Recorder(_filePath,
KnownFourCCs.Codecs.X264, quality,
0, SupportedWaveFormat.WAVE_FORMAT_44S16, true, 160);
_filePath is the path of the file I'd like to save the video to.
You can pass in a variety of codecs including AVI, MotionJPEG, X264, etc. In the case of x264 I had to install the codec on my machine first but AVI works out of the box.
Quality only comes into play when using AVI or MotionJPEG. The x264 codec manages its own quality settings.
The 0 above is the audio device I'd like to use. The Default is zero.
It currently supports 2 wave formats. 44100 at 16bit either stereo or mono.
The true parameter indicates that I want the audio encoded into mp3 format. I believe this is required when choosing x264 as the uncompressed audio combined in a .mp4 file would not play back for me.
The 160 is the bitrate at which to encode the audio.
~~~~~
To stop the recording you just
recorder.Dispose();
recorder = null;
Everything is open source so you can edit the recorder class and change dimensions, frames per second, etc.
~~~~
To get up and running with this library you will need to either download or pull from the github / codeplex libraries below. You can also use NuGet:
Install-Package SharpAvi
Original Post:
Sharp AVI:
https://sharpavi.codeplex.com/
or
https://github.com/baSSiLL/SharpAvi
There is a sample project within that library that has a great screen recorder in it along with a menu for settings/etc.
I found Screna first from another answer on this StackoverFlow question but I ran into a couple issues involving getting Mp3 Lame encoder to work correctly. Screna is a wrapper for SharpAVI. I found by removing Screna and going off of SharpAvi's sample I had better luck.

c# DirectShow example shows black screen, but sound is OK

DirectShowLib.DVB-T example "DTVViewer" plays audio, but doesn't play video, I think it's because of H.264 video compressor, which is used in our Digital television and "DTVViewer" is trying to decompress MPEG2.
I want to ask how to form Graph and what filters to use to make "DTVViewer" support H.264?
CurrentGraph.
"MPEG2 DEMULTIPLEXER" pins:
(1)->BDA MPEG2 TRANSPORT INFORMATION FILTER
(2)->DScaler Mpeg2 Video Decoder->Video Renderer
(3)->AUDIO PART...
(5)->MPEG-2 SECTIONS AND TABLES
(ViPin) = AMMediaType(formatType?majorType?subType?)->Filter?->Video Renderer
Thinking, that now i only need help to configure new VideoPin correctly and add some H.264 decoder to it. Can anyone suggest something?
Thank you.

Try using Geraint Davies' free mpeg4 demux available at http://www.gdcl.co.uk/mpeg4/ instead of mpeg2 demultiplexer

If you are using Windows 7, you could look at using the Microsoft decoders. Take a look at the graph at this question: best way to build graph for MPEG2 transport stream.
As for what to specify for the video type, I use major type = video, subtype = H264, format type = video info.