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How to save Video (from webcam) and Audio (from directsound device) in avi file ?
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Issue description
Hello,
I'm trying to accomplish something easy as first sight: recording video and audio (from webcam) in an avi file. It appears more complex that it seems :)
So far, I handle video frames nicely (I think) with this frame handler:
void videoDevice_NewFrame(object sender, Accord.Video.NewFrameEventArgs eventArgs)
{
System.Drawing.Image imgforms = (Bitmap)eventArgs.Frame.Clone();
BitmapImage bi = new BitmapImage();
bi.BeginInit();
MemoryStream ms = new MemoryStream();
imgforms.Save(ms, ImageFormat.Bmp);
ms.Seek(0, SeekOrigin.Begin);
bi.StreamSource = ms;
bi.EndInit();
//Using the freeze function to avoid cross thread operations
bi.Freeze();
//Calling the UI thread using the Dispatcher to update the 'Image' WPF control
Dispatcher.BeginInvoke(new ThreadStart(delegate
{
pbox.Source = bi; /*pbox is the name of the 'Image' WPF control*/
}));
if (_recording)
{
long currentTick = DateTime.Now.Ticks;
StartTick = StartTick ?? currentTick;
var frameOffset = new TimeSpan(currentTick - StartTick.Value);
double elapsedTimeInSeconds = stopwatch.ElapsedTicks / (double)Stopwatch.Frequency;
double timeBetweenFramesInSeconds = 1.0 / 25;
if (elapsedTimeInSeconds >= timeBetweenFramesInSeconds)
{
stopwatch.Restart();
try
{
_writer.WriteVideoFrame(eventArgs.Frame, frameOffset);
}catch(Exception ex)
{
}
//Here come WriteAudioFrame(Signal signal) ?
}
}
}
and Audio data is stored in a memory stream / WaveEncoder in the audio new frame event handler:
audio_stream = new MemoryStream();
audio_encoder = new WaveEncoder(audio_stream);
void audioDevice_NewFrame(object sender, Accord.Audio.NewFrameEventArgs eventArgs)
{
audio_encoder.Encode(eventArgs.Signal);
}
So now, I don't understand how to transform audio memory stream (or WaveEncoder ?) into Signal object needed to new method writted by @cesarsouza :
_writer.WriteAudioFrame(Signal signal)
and how to synchronise video and audio. I suspect we need to get same amount of audio and video frames according to the samplerate.
Do you have any exemple how to do that ?
Many thanks
Hi hbtech-ai, Yes and No...I've finally record video and audio separatly, and then merge them at the end of recording with ffmpeg.exe (and eventually do some more compression with it).
Hi,yoannwyffels Thanks for your answer,you means video and audio should separatly recorded,then merge audio and video using ffmpeg.exe,I will test it soon.
Hi,yoannwyffels, I test ffmpeg merge video and audio,but video length is below the audio length,so merge result is video stop in a moment,audio is play.how you to reslove this problem.
You have to write video frames with frameOffset informations (how many times the frame is). You just have to use a timespan to do this in your c# code.
private long? StartTick;
void audioDevice_NewFrame(object sender, Accord.Audio.NewFrameEventArgs eventArgs)
{
if (_recording)
{
audio_encoder.Encode(eventArgs.Signal);
}
}
void videoDevice_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
if (_recording)
{
long currentTick = DateTime.Now.Ticks;
StartTick = StartTick ?? currentTick;
var frameOffset = new TimeSpan(currentTick - StartTick.Value);
try
{
_writer.WriteVideoFrame(eventArgs.Frame, frameOffset);
}catch(Exception ex)
{
App.logit(ex.Message);
}
}
}
For what I remember, some compression codecs aren't working well. Here is how I configured the videoFileWrite (I'm using Video and Audio "Default" Codec.
public void startRecording(string previewVideo_www)
{
previewVideo_whileRec = previewVideo_www;
if (_recording== false)
{
StartTick = null;
_writer = new VideoFileWriter()
{
Width = video_vc.FrameSize.Width,
Height = video_vc.FrameSize.Height,
FrameRate = video_vc.AverageFrameRate,
VideoCodec = VideoCodec.Default,
AudioCodec = AudioCodec.Default,
AudioBitRate = 44100,
BitRate = 3000 * 1000,
AudioLayout = AudioLayout.Mono,
};
_writer.Open(App.DataPath + "temp.avi");
audio_file_stream = new FileStream(App.DataPath + "temp.wav", FileMode.Create);
audio_encoder = new WaveEncoder(audio_file_stream);
final_videoFileName = "MyVideo-"+DateTime.Now.ToString("yyyyMMdd-HHmmss");
_recording = true;
}
}
and here is the ffmpeg command line I use to merge (using copy method, no compression):
private void mergeAudioAndVideo()
{
App.logit("Merging Audio & Video");
File.Delete(App.DataPath + "merge.avi");
Process pss = new Process();
ProcessStartInfo si = new ProcessStartInfo();
si.FileName = App.ExePath + "ffmpeg.exe";
si.UseShellExecute = false;
si.CreateNoWindow = true;
si.Arguments = "-i \""+App.DataPath+"temp.avi\" -i \""+App.DataPath+"temp.wav\" -c:v copy -c:a copy -map 0:v:0 -map 1:a:0 \""+App.DataPath+ final_videoFileName+".avi\"";
pss.StartInfo = si;
pss.Start();
pss.WaitForExit();
if (File.Exists(App.DataPath + final_videoFileName+".avi"))
{
File.Delete(App.DataPath + "temp.wav");
File.Delete(App.DataPath + "temp.avi");
App.logit("record succeed !");
File.Move(App.DataPath + final_videoFileName + ".avi", GetFolderSave() + "\\" + final_videoFileName + ".avi");
lastCapturedMedia = GetFolderSave() + "\\" + final_videoFileName + ".avi";
}
}
I hope it will help you well :)
@yoannwyffels Hello Yoan Would you please send me the full code please at : [email protected], i'm struggling with the audio part. Thanks.
hey can some one post the complete project. it will be helpful to see a complete sample of using it.
