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• How use FFMPEG to merege multiple audios and videos with delay and offset for any streams

  9 juillet 2020, par Morak

  I want to use FFMPEG to merge multiple audios and videos.

  


  Materials are :

  


  

  1. three short audio clips (S1.mp4, S2.mp4, S3.mp4) without video(files
only have audio stream),

  


  2. three video clips (V1.mp4, V2.mp4, V3.mp4) without sound(files only have video stream).

  


  


  I have start-time of all materials(i.e :

  


  start-time of "S1.mp4" is 0 sec...
start-time of "S2.mp4" is 1220.5 sec...
start-time of "S3.mp4" is 2500.12 sec...


  


  and

  


  start-time of "V1.mp4" is 15.22 sec...
start-time of "V2.mp4" is 853.99 sec...
start-time of "V3.mp4" is 2901.37 sec...)


  


  My goal is :

  


  Merge all videos and audios to single file with entering in their start time.

  


  The requirement is depicted like below(D=delay).

  


  D <—V1.mp4—> D <----------V2.mp4-------------> D <-V3.mp4->blank

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  <------------S1.mp4-----> D <-------S2.mp4—> D <-------S3.mp4------->

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  The command I use is as below, but it does not work as expected.

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  1st:prepare V.mp4(merging all videos) :

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  ffmpeg -itsoffset {OFFSET.V1} -i V1.mp4  -itsoffset {OFFSET.V2} -i V2.mp4  -itsoffset {OFFSET.V3} -i V3.mp4 -map 0:v -map 1:v -map 2:v -c:v copy V.mp4

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  2nd:prepare S.mp4(merging all audios) :

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  ffmpeg -i S1.mp4 -i S2.mp4 -i S3.mp4 -filter_complex "[0]adelay=0[aud1];[1]adelay=1220.5[aud2];[2]adelay=2500.12[aud3];[aud1][aud2][aud3]amix=3[a]" -map "[a]" -c:a copy S.mp4

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  final:merging V.mp4 with S.mp4 :

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  ffmpeg -i V.mp4 -i S.mp4 -map 0:v -map 1:a -vcodec copy -acodec copy final.mp4

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  Any hint is appreciated !

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• Using JavaCV/FFMPEG to push byte buffer image via RTMP

  6 mai 2022, par ljnoah

  I have a USB camera that returns frames as a byte buffer type to which I would like to push/send via rtmp using JavaCV library to be viewed using VLC. According to this link : http://bytedeco.org/javacpp-presets/ffmpeg/apidocs/org/bytedeco/ffmpeg/ffmpeg.html. It should be possible, but I don't really have any experience with ffmpeg, but from what I've read in their github it should be possible, only, thus far I was not able to find an example on how to do it. Basically, I would like to store a byte buffer and send an image that is in variable instead of grabbing frames from a camera as my USB camera is not detected by android and needs external libraries to work.

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  private byte[] FrameData = new byte[384 * 288 * 4];
  //private final Bitmap bitmap = Bitmap.createBitmap(PREVIEW_WIDTH, PREVIEW_HEIGHT, // Bitmap.Config.ARGB_8888); // creates a bitmap with the proper format in-case its needed
  private final IFrameCallback mIFrameCallback = new IFrameCallback() {
      @Override
      public void onFrame(final ByteBuffer frameData) {
          frameData.clear();
          frameData.get(FrameData, 0, frameData.capacity());
          }
  };


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  This callback gives me the frames from my camera on the fly and writes it to FrameData, which I can compress to a bitmap if needed.

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  My camera preview where I call the callback above :

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    public void handleStartPreview(Object surface) {
      if ((mUVCCamera == null)) return;
      try {
          mUVCCamera.setPreviewSize(mWidth, mHeight, 1, 26, UVCCamera.DEFAULT_PREVIEW_MODE, UVCCamera.DEFAULT_BANDWIDTH, 0);
      } catch (IllegalArgumentException e) {
          try {
              mUVCCamera.setPreviewSize(mWidth, mHeight, 1, 26, UVCCamera.DEFAULT_PREVIEW_MODE, UVCCamera.DEFAULT_BANDWIDTH, 0);
              Log.e(TAG, "handleStartPreview4");
          } catch (IllegalArgumentException e1) {
              callOnError(e1);
              return;
          }
      }
      int result = mUVCCamera.startPreview();
      mUVCCamera.setFrameCallback(mIFrameCallback, UVCCamera.PIXEL_FORMAT_RGBX);
      mUVCCamera.startCapture();
      startRecording();
  }


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  My question is How can I use this example :

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   String ffmpeg = Loader.load(org.bytedeco.ffmpeg.ffmpeg.class);
 ProcessBuilder pb = new ProcessBuilder(ffmpeg, "-i", "/path/to/input.mp4", "-vcodec", "h264", "/path/to/output.mp4");
 pb.inheritIO().start().waitFor();


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  to push my frames from the camera that are stored FrameData byte buffer via RTMP/RTSP to my server IP, even If I need to compress it to a bitmap before...

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• From jpg to animated gif

  12 mai 2016, par lleoun

  I’m desperate, I need to convert some jpg images into an animated gif.

  I’ve tried ffmpeg, but the result has a terrible quality.

  Also tried imagemagick, and the result looks great but it weights 511 KB !!

  Anyone please can tell me what to use or how to use the before applications to get a final animated gif with a normal quality and a normal weight for a gif ??

  As I said I’m desperate, I need to finish this asap :(

  Thanks a lot