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• How do I convert a 3D SBS dual-fisheye image to 3D SBS dual-equirectangular with only open-source tools ? [closed]

  21 octobre 2024, par Ethan T

  Canon has released a new 3D VR lens for their RF mount and I recently rented it to see what it's like to work with. Unfortunately, they charge a subscription fee for their conversion software, which I've also found to be inconveniently limited in real-world use cases. Thus I'm interested in an open-source approach to converting the video captured by this lens using something like ffmpeg.

  


  The video is dual-fisheye and the Canon tool produces dual-equirectangular side-by-side video. I would like to perform this same conversion in ffmpeg or a similarly-powerful open-source tool.

  


  Related questions exist but aren't quite correct. Most dual-fisheye input seems to be used to create 360-degree 2D video, not 3D SBS.

  


• How to open anullsrc input ?

  5 mai 2022, par dgsgsdgsgdhddhg

  I'm trying :

  


      avformat_open_input(
        &input_context,
        "anullsrc",       
        NULL,
        NULL
    );


  


  That however does not work and input_context remains NULL.

  


  The 3rd argument, NULL, is an optional AVInputFormat.
https://ffmpeg.org/doxygen/trunk/group__lavf__decoding.html#gac05d61a2b492ae3985c658f34622c19d

  


  fmt    If non-NULL, this parameter forces a specific input format. Otherwise the format is autodetected.

  


  I wanted to supply it by first creating the AVInputFormat with av_find_input_format - that however fails to find the format (lavfi), because it seems not to be registered in file ./libavformat/allformats.c even though it exists in ./libavdevice/lavfi.c.

  


  Edit

  


  I might have found an issue. When I do :

  


  $ ffmpeg -v 0 -demuxers | grep lavfi


  


  The output is :

  


   D  lavfi           Libavfilter virtual input device



  


  However, when I do :

  


  main | grep lavfi


  


  Where main is my program which includes :

  


      while ((fmt = av_demuxer_iterate(&i)))                                      
        printf("%s\n", fmt->name);  


  


  I get no output (I confirm that some demuxers are listed if I don't grep for lavfi).

  


  So it seems then, that libavformat.h does not know about lavfi demuxer, whereas ffmpeg does. So it seems I need to fix this issue now.

  


• Unable to open FFmpegFrameRecorder stream on a UDP port on Windows

  4 juin 2022, par DeoBelbert

  I am trying to stream a webcam video with FFmpegFrameRecorder and play it with "ffplay" command, but the ffplay command fails with the following message 'udp ://127.0.0.1:25777 : Invalid data found when processing input/0'.

  


  The code I am using for streaming the video,

  


   public void startStreaming() throws Exception {
    OpenCVFrameGrabber grabber = new OpenCVFrameGrabber(0);
    grabber.setVideoCodec(27);
    grabber.setImageMode(FrameGrabber.ImageMode.COLOR);
    grabber.setBitsPerPixel(10);
    grabber.setFormat("yuvj420p");
    grabber.start();
    FFmpegFrameRecorder  recorder = new FFmpegFrameRecorder("udp://127.0.0.1:25777", grabber.getImageWidth(), grabber.getImageHeight());
    recorder.setFrameRate(grabber.getFrameRate());
    recorder.setVideoBitrate(grabber.getVideoBitrate());
    recorder.setOption("listen", "1");
    recorder.setFormat("h264");
    recorder.setPixelFormat(AV_PIX_FMT_YUV420P);
    recorder.setVideoCodecName("h264_videotoolbox");
    recorder.setVideoCodec(27);
    recorder.setOption("keyint", "10");
    recorder.start();}


  


  And I am calling the recorder.record in a thread as follows,

  


  frame = grabber.grabFrame();                      
recorder.record(frame);


  


  After starting the stream, I opened the command line and tried to play the stream with the following command,

  


  ffplay udp://127.0.0.1:25777


  


  And it is failing with the following message,

  


  udp://127.0.0.1:25777: Invalid data found when processing input/0


  


  To get the stream information, I used the following command,

  


  ffmpeg -i udp://127.0.0.1:25777


  


  And it showed the following output,

  


  [h264 @ 0000014dd1424880] non-existing PPS 0 referenced
[h264 @ 0000014dd1424880] decode_slice_header error
[h264 @ 0000014dd1424880] non-existing PPS 0 referenced
[h264 @ 0000014dd1424880] decode_slice_header error
[h264 @ 0000014dd1424880] non-existing PPS 0 referenced
[h264 @ 0000014dd1424880] decode_slice_header error
[h264 @ 0000014dd1424880] non-existing PPS 0 referenced
[h264 @ 0000014dd1424880] decode_slice_header error
[h264 @ 0000014dd1424880] no frame!


  


  But when I tried with TCP protocol it is working fine and I am able to play the video.
How can I fix this issue ? this is the first time I am using the FFmpeg and JavaCV.