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• Using ffmpeg in Powershell

  27 avril 2016, par Matthew Goode

  Can’t find much information on this, as I believe it’s a pretty noobish problem and there aren’t really any tutorials on it. Can anyone explain how I can use ffmpeg in a powershell script ? I downloaded ffmpeg and I have the path to ffmpeg.exe. Shouldn’t I be able to do something like this ?

  "C:\path\ffmpeg.exe" -i stuff.mp3 stuff.wav

  It returns an error message along the lines of -i not being a recognized parameter. Am I missing something pretty basic here ? Thanks for any help. I’m trying to convert some audio files between .wav, .mp3. and .flac, and if anyone has any better suggestions than ffmpeg then please let me know.

• Issue with Asynchronous Video Processing and New Window Creation in Windows Forms Application

  2 août 2023, par sadra hoseini

  I have a Windows Forms application that uses FFmpeg for video processing tasks. In this application, I have a textBox2_TextChanged event handler that performs some video processing tasks based on user input.

  


  However, I noticed that when textBox2_TextChanged is called, the UI becomes unresponsive, and it seems like another window is being created but doesn't show up. I suspect that this issue is related to threading.

  


  Here's a simplified version of the problematic code :

  


  // Relevant code snippet:
private async void textBox2_TextChanged(object sender, EventArgs e)
{
    if (listBox1.Items.Count > 0 && int.TryParse(textBox2.Text, out int itemvalue) && int.TryParse(textBox1.Text, out int ratio))
    {
        await Task.Run(() =>
        {
            // Video processing code using FFmpeg (e.g., creating thumbnails).
            // This code seems to cause the UI to freeze and prevent new windows from showing up.
        });
    }
}


  


  Expected Behavior :

  


  When a user enters a valid input in textBox2, the video processing tasks should be executed in the background without freezing the UI. The application should remain responsive, and any new windows, including message boxes or progress dialogs, should show up as expected.

  


  Actual Behavior :

  


  When a user enters a valid input in textBox2, the video processing tasks appear to be running, but the UI becomes unresponsive, and new windows, such as message boxes, do not show up as expected. This makes it challenging to display any progress or error messages to the user during video processing.

  


  Steps to Reproduce :

  


  Open the Windows Forms application.
Add some video files to the list (listBox1) and provide valid input in textBox2.
Observe the UI behavior and any new windows that should be displayed, such as progress dialogs or message boxes.
Additional Notes :

  


  I am using Visual Studio [version] for development.
The application uses FFmpeg for video processing tasks, and I've verified that FFmpeg is functioning correctly.
I've also tried using proper error handling to catch any exceptions, but no exceptions are thrown during the video processing tasks.
Any help or suggestions on how to resolve this issue and enable new window creation during video processing would be greatly appreciated. Thank you !

  


• Saving Raw Uncompressed Video Files using OpenCv, Gstreamer, and/or FFMPEG ?

  20 septembre 2022, par adav0033

  I have been trying to implement the cv::VideoWriter function from OpenCV to generate a an uncompressed (raw) video file. I started this because of a statement within the OpenCV Documentation which I will link here along with the statement.

  


  cv::VideoWriter::VideoWriter    (   const String &  filename,
int     fourcc,
double  fps,
Size    frameSize,
bool    isColor = true 
)       


  


  "If FFMPEG is enabled, using codec=0 ; fps=0 ; you can create an uncompressed (raw) video file."

  


  Ref. https://docs.opencv.org/3.4/dd/d9e/classcv_1_1VideoWriter.html

  


  However whilst troubleshooting the function I came across the refuting statement,

  


  " VideoCapture and VideoWriter do not provide interface to access raw compressed video stream, except maybe MJPEG in some cases.
Make sure you actually use FFmpeg backend by setting apiPreference parameter : VideoWriter("outfile.avi", cv2.CAP_FFMPEG, ...)"

  


  Ref. https://github.com/opencv/opencv/issues/14573

  


  I am now confused about how I go about writing the cv::VideoWriter function to satisfy the requirements to create a raw uncompressed video file (.avi) and if it is even possible. If it is not possible how do I achieve the outcome of saving an raw uncompressed video file, as I assume it would use some combination of FFMPEG, OpenCV,or Gstreamer.

  


  Note : My code is implemented in c++