Newest 'ffmpeg' Questions - Stack Overflow

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• FFmpeg : Images to video, repeat x times

  25 novembre 2016, par user2190035

  I convert a list of images to a video with ffmpeg.

  But I want a video which repeat all the images x times without storing copies of the images on the harddrive.

  Is there a way to tell ffmpeg to repeat the input images in a video x times?

• How to get a list of audio devices in dshow and save

  25 novembre 2016, par H S T

  I use avformat_open_input in ffmpeg to open the audio device, but the second argument to this function is the audio device name, and may not be the full name. So how do I get avformat_open_input (& pFmtCtx, "video = dummy", iformat, & options); List of audio device names listed?Or directly use ffmpeg to open the default audio device?Thanks.

• opencv_ffmpeg module crash (IP Camera)

  25 novembre 2016, par Suraksha Ajith

  I'm using IP webcam android app(It converts mobile camera into IP web camera).
  I'm running below code in Visual Studio 2015 with OpenCV 3.1.

  VideoCapture cap; Mat img;
  cap.open("http://192.168.0.101:8080/video?x.mjpeg");
  while(waitKey(33)!=27)
  {
      try{
          cap>>img;  //code crashes here
          if(img.empty())
          {
           cout<<"camera Closed"<code>

  Getting below error.cIf the internet connection is slow or if the Wi-Fi is disconnected in my android device the program crashes
  Error:

  Exception thrown at 0x0BF2F6F0 (opencv_ffmpeg310.dll) in test.exe: 0xC0000005: Access violation reading location 0x00000020.

  If there is a handler for this exception, the program may be safely continued.

  even if the code is wrapped within try catch block, it crashes!
  
  Should I use try {} catch (...) block in source file, if yes, then where should I use this?
  I referred this link but did not find the right answer.

• How to generating waveform from video & show it with video

  25 novembre 2016, par Salil

  We are using Rails as a backend & AngularJS on Front End side in my App where we need to show Video & audio waveform of that video.

  We are using 'wavesurfer.js' to show the waveform on Front End side & 'node-pcm' to generate pcm from video file on BackEnd side.

  This is working as expected but in some of the videos while creating waveform from pcm data instead of showing small sine waves we get flat line. Also it takes too much time to show the waveform for every page reload.

  To overcome this issue we are planning to create waveform image using ffmpeg

  ffmpeg -i 'https://s3.amazonaws.com/aadasdsadsadasdas/xyz.mp4' -filter_complex showwavespic -frames:v 1 output.png
  

  This is working fine but it also takes too much time (Ofcourse only once ) to generate the image for remote video (i.e. We are saving videos on S3)

  Problem with this i don't get any library to integrate the waveform image with the Video.

  Can someone suggest any better approach related to this.

• Is there any way to stream video while encoding except using ffmpeg ?

  25 novembre 2016, par Ruslan Doronichev

  I am developing a cloud service, that allow users to upload video files from torrents and watch them online. In order to view the media, while transcoding - I convert the source file into hls format. I don't really like this approach, as every user has a storage limit and he has to use his space for storing both hls and source files, even if he is not going to watch the video while encoding. What would be the best solution in this case?