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• Save frame as image during video stream using ffmpeg, in C

  30 avril 2017, par George T.

  I’m using the Parrot SDK3 to retrieve the video stream from a Bebop2 drone. From it I need to "extract" a frame and save it as an image.

  The whole code can be found here, but I shall try to include the (what I understand as) important parts here.

  Where the video is sent to mplayer. I assume from this that the video format is h624.

  if (videoOut != NULL)
  
  {
  
      if (codec.type == ARCONTROLLER_STREAM_CODEC_TYPE_H264)
  
      {
  
          if (DISPLAY_WITH_MPLAYER)
  
          {
  
              fwrite(codec.parameters.h264parameters.spsBuffer, codec.parameters.h264parameters.spsSize, 1, videoOut);
  
              fwrite(codec.parameters.h264parameters.ppsBuffer, codec.parameters.h264parameters.ppsSize, 1, videoOut);
  
  
  
              fflush (videoOut);
  
          }
  
      }
  
  }

  Where the frame is received and written to videoOut, to be displayed

  eARCONTROLLER_ERROR didReceiveFrameCallback (ARCONTROLLER_Frame_t *frame, void *customData)
  
  {
  
      if (videoOut != NULL)
  
      {
  
          if (frame != NULL)
  
          {
  
              if (DISPLAY_WITH_MPLAYER)
  
              {
  
                  fwrite(frame->data, frame->used, 1, videoOut);
  
  
  
                  fflush (videoOut);
  
              }
  
          }
  
      }
  
      return ARCONTROLLER_OK;
  
  }

  The idea I had in mind is to fwrite(frame->data, frame->used, 1, videoOut); to a different file but that just creates a corrupted file, probably because of encoding. In what way can I get this frame and store it to a separate image ? The preferable image filetype .png, .jpg or .gif

  Any help will be greatly appreciated ! Thanks in advance !

• Java FFMPEG AVFrame save as jpeg format

  23 juillet 2015, par Amarnath

  Trying to save image from Video using the below code

  https://github.com/bytedeco/javacpp-presets/tree/master/ffmpeg

  Wanted to save it in jpg format, but the image format is ppm.

  Any help is appreciated.

• How to set the length metadata property with fluent-ffmpeg ?

  8 avril 2024, par volume one

  I have transcoded a sample video using fluent-ffpmeg and want to set the length metadata property so that the <video></video> player knows how long the video is going to be.

  


  To get the duration of the video I did this :

  


  import ffmpeg from 'fluent-ffmpeg';

function ffprobePromise() {
            return new Promise((resolve, reject) => {
                ffmpeg.ffprobe('/path/to/file'), function (err, metadata) {
                    FileDuration = metadata.format.duration;
                    resolve()
                });
            })}

  await ffprobePromise();

  ffmpeg('path/to/output')
                    .videoCodec('libx264')
                    .audioCodec('libmp3lame')
                    .duration(FileDuration)   // !! not setting 'length' metadata property in file
                    .size(`960x400`)
                    // Stream output requires manually specifying output formats
                    .format('mp4')
                    .outputOptions(['-movflags dash', `-metadata length=${FileDuration}`]) // also not setting length in metadata


  


  Here is the sample file that was created : https://devxxx001.s3.amazonaws.com/sample_960x400_47sec.mp4

  


  If you download and view the properties of that file, there is no length property in the metadata. Hence when you play the file, the video player is not able to determine the total duration of the video. You'll notice it keeps jumping up as the video plays.

  


  The ffmpeg documentation states that you can use ffmpeg -i in.avi -metadata title="my title" out.flv to set the title for example. But how do you do this with fluent-ffmpeg ?