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• flutter_ffmpeg concat demuxer | front camera videos are upside-down or corrupted

  27 février 2024, par Gicminos

  I am currently recording multiple mp4 clips (using Flutter's camera package) and then using ffmpeg concat demuxer to create a single video :

  


  await _flutterFFmpeg.execute('-f concat -safe 0 -i ${txtFile.path} -c copy ${outputClipPath.path}');


  


  This works correctly with any video from the rear camera. When I also concat videos from the front camera, these are upside-down as it seems that ffmpeg does not detect their metadata rotation.

  


  Currently, I have manged to detect if a video is front camera or rear camera in this way :

  


  final FlutterFFprobe flutterFFprobe = FlutterFFprobe();
MediaInformation mediaInformation = await flutterFFprobe.getMediaInformation(this.path);

Map mp = mediaInformation.getAllProperties();

int rotation = mp['streams'][0]['side_data_list'][0]['rotation'];
if (rotation == 90) {
  // Video is upside down and from front-camera
}


  


  The question is, do I need to rotate the video myself prior to concat it ? If yes, what is the best way to do that with flutter_ffmpeg ?

  


  I managed to rotate the video with the following command :

  


  await _flutterFFmpeg.execute('-noautorotate -i ${this.path} -metadata:s:v rotate="0" -vf "transpose=2" ${outputClipPath.path}');


  


  But if I do that then the concat result is corrupted. How do I preserve the encoding and stream after rotation ?

  


  Thank you.

  


• Use ffmpeg to move moov atom to front of mp4 file on Google Cloud Platform and Google Cloud Storage

  19 avril 2021, par BlueBoy

  I would like to use ffmpeg to move the moov atom of a .mp4 file to the front of the file so that it can then be streamed.

  


  The .mp4 file is in Google Cloud Storage. I want to take that file and apply the conversion on it (or copy it if needed).

  


  I have successfully run the following command in the terminal and it works. I want to essentially run this command server side on the Google Cloud in a Java environment :

  


  ffmpeg -i input_video_file.mp4 -vcodec copy -acodec copy -movflags faststart output_video_file.mp4

  


  I can get my file from Google Cloud Storage like this :

  


  GcsService gcsService = GcsServiceFactory.createGcsService();
GcsFilename file = new GcsFilename("bucket", "folder/filename;


  


  I was able to find a Java library wrapper for ffmpeg (https://github.com/bramp/ffmpeg-cli-wrapper) but it doesn't seem to allow to move the moov atom. Could anyone help me figure this out further ? Is there a

  


• flutter_ffmpeg concat demuxer | front camera videos are upside-down

  18 avril 2021, par Gicminos

  I am currently recording multiple mp4 clips (using Flutter's camera package) and then using ffmpeg concat demuxer to create a single video :

  


  await _flutterFFmpeg.execute('-f concat -safe 0 -i ${txtFile.path} -c copy ${outputClipPath.path}');


  


  This works correctly with any video from the rear camera. When I also concat videos from the front camera, these are upside-down as it seems that ffmpeg does not detect their metadata rotation.

  


  Currently, I have manged to detect if a video is front camera or rear camera in this way :

  


  final FlutterFFprobe flutterFFprobe = FlutterFFprobe();
MediaInformation mediaInformation = await flutterFFprobe.getMediaInformation(this.path);

Map mp = mediaInformation.getAllProperties();

int rotation = mp['streams'][0]['side_data_list'][0]['rotation'];
if (rotation == 90) {
  // Video is upside down and from front-camera
}


  


  The question is, do I need to rotate the video myself prior to concat it ? If yes, what is the best way to do that with flutter_ffmpeg ?

  


  I managed to rotate the video with the following command :

  


  await _flutterFFmpeg.execute('-noautorotate -i ${this.path} -metadata:s:v rotate="0" -vf "transpose=2" ${outputClipPath.path}');


  


  But if I do that then the concat result is corrupted. How do I preserve the encoding and stream after rotation ?

  


  Thank you.