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• -12909 error decoding h264 stream with intra-refresh

  2 juillet 2024, par ciclopez

  I'm making an iOS app that decodes an h264 stream using video-toolbox. I create the stream with ffmpeg on a PC and send it to an iPhone using RTP. It's working nicely when I use this command to create it :

  



  ffmpeg -y -f:v rawvideo -c:v rawvideo -s 1280x720 -pix_fmt bgra -r 30 -an -i - -pix_fmt yuv420p -c:v libx264 -tune zerolatency -preset fast -b:v 5M -refs 1 -g 30 -profile:v high -level 4.1 -f rtp rtp://192.168.1.100:5678


  



  The iPhone receives and displays all the frames. However, when I enable intra-refresh

  



  -intra-refresh 1


  



  decoding fails with error code -12909 (-8969 on simulator) when VTDecompressionSessionDecodeFrame() is called.

  



  I take care of processing UDP packets to extract NAL Units, so I triple checked this process and discarded a problem with this part of the code.

  



  I didn't find any info about Video-toolbox not supporting intra-refresh, so the question is, does Video-toolbox support intra-refresh ? and if it does, am I missing something in the ffmpeg side that makes the stream not supported by Video-toolbox ?
Do I have to add something to the CMVideoFormatDescriptionRef apart from creating it with SPS and PPS data using CMVideoFormatDescriptionCreateFromH264ParameterSets() ?

  


• How To Concatenate Two MP4 Videos With Different Aspect Ratios and Resolutions

  11 novembre 2017, par PortableDiag

  I am using ffmpeg to concatenate multiple MP4 videos, two at a time. The problem I am having is that the videos are often different resolutions and aspect ratios. One might come from a 480p webcam with a 1:1 aspect ratio and the other a brand new iPhone with 4k video and rectangular aspect ratio. Currently I must choose and set the aspect ratio manually and this results in one of the two videos becoming distorted, depending on the selected aspect ratio.

  How can I merge two videos so that the overall viewing field has a square aspect ratio but videos with a rectangular aspect ratio will be scaled to fit inside.

  I am using this command to merge the videos :

  ffmpeg -threads 1 -i '/518.mp4' -i '/516.mp4' -y -filter_complex "[0:v]scale=1080x1920,setpts=PTS-STARTPTS,setdar=0/1[v0];[1:v]scale=1080x1920,setpts=PTS-STARTPTS,setdar=0/1[v1];[v0][0:a][v1][1:a]concat=n=2:v=1:a=1" '/partial1.mp4'

  This is the result : https://www.dropbox.com/s/x1un7z1ljwr6tty/merged_newsort.mp4?dl=0

  Is it possible to apply a border to the rectangular video to give them a square aspect ratio ?

  How can I keep prevent distortion from occurring during the merge process ?

  Thanks in advance.

• Video width is different in different devices

  8 novembre 2017, par David

  I have a special video when i want to get this video’s width code returns different value for Samsung galaxy s6 and Samsung note 3. I tested many different codes and libraries, but result is the same.
  in Samsung galaxy s6 : 640x480
  in Samsung note 3 : 853x480
  when I open this video with Gspot program it shows :

  Recommended Display Size : 853x480

  and this is the same value is returned by our IOS app tested in Iphone 7. aspect radio is not the same and this is big problem.

  here is some of codes I tested :

  (1)

      MediaMetadataRetriever metaRetriever = new MediaMetadataRetriever();
  
      metaRetriever.setDataSource(path);
  
      Bitmap bmp = metaRetriever.getFrameAtTime(-1);
  
  
  
      int height = bmp.getHeight();
  
      int width = bmp.getWidth();

  (2)

      MediaPlayer myMediaPlayer= MediaPlayer.create(ApplicationLoader.applicationContext, 
  
                                       Uri.fromFile(new File(path)));
  
  
  
      width = myMediaPlayer.getVideoWidth();
  
      height = myMediaPlayer.getVideoHeight();

  (3)

   MediaMetadataRetriever metaRetriever = new MediaMetadataRetriever();
  
          metaRetriever.setDataSource(path);
  
   String heights = metaRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT);
  
          String widths = metaRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH);
  
      int height = Integer.valueOf(heights);
  
          int width = Integer.valueOf(widths);

  (4)

    MediaPlayer myMediaPlayer= MediaPlayer.create(ApplicationLoader.applicationContext, Uri.fromFile(new File(path)));
  
              myMediaPlayer.setOnVideoSizeChangedListener((mp, width, height) -> {
  
          int videoWidth = width;
  
          int videoHeight = height;
  
      );
  
              myMediaPlayer.setDataSource(path);
  
              myMediaPlayer.prepare();

  FFmpegMediaMetadataRetriever, FFmpeg Java, ExoPlayer and some other libraries returns the same result.