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• avformat/hlsenc : Improve checks for invalid stream mappings

  5 mai 2020, par Andreas Rheinhardt

  avformat/hlsenc : Improve checks for invalid stream mappings
  The mapping of streams to the various variant streams to be created by
  
  the HLS muxer is roughly as follows : Space and tab separate variant
  
  stream group maps while the entries in each variant stream group map are
  
  separated by ','.
  The parsing process of each variant stream group proceeded as follows :
  
  At first the number of occurences of "a :", "v :" and "s :" in each variant
  
  stream group is calculated so that one can can allocate an array of
  
  streams with this number of entries. Then each entry is checked and the
  
  check for stream numbers was deficient : It did check that there is a
  
  number beginning after the " :", but it did not check that the number
  
  extends until the next "," (or until the end).
  This means that an invalid variant stream group like v:0_v:1 will not be
  
  rejected ; the problem is that the variant stream in this example is
  
  supposed to have two streams associated with it (because it contains two
  
  "v :"), yet only one stream is actually associated with it (because there
  
  is no ',' to start a second stream specifier). This discrepancy led to
  
  segfaults (null pointer dereferencing) in the rest of the code (when the
  
  nonexistent second stream associated to the variant stream was inspected).
  Furthermore, this commit also removes an instance of using atoi() whose
  
  behaviour on a range error is undefined.
  Fixes ticket #8652.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/hlsenc.c

• Enable QSV for FFmpeg with directshow input and JPEG image sequence output

  10 mars 2020, par clic

  I’m using FFmpeg with Directshow input. The output is a series of single JPEG images. FFmpeg itself maps the stream to mjpeg and uses image2 for the output.

  Is it possible to increase performance by using the Intel QuickSync Video (QSV) hardware acceleration for this process ? The FFmpeg QuickSync Wiki actually lists JPEG encoding since Braswell.

  This is what I tried so far :

  ffmpeg -init_hw_device qsv=hw -filter_hw_device hw -f dshow -video_size 3840x2160 -framerate 25 -i "video=My Webcam" -vf hwupload=extra_hw_frames=64,format=qsv -vcodec mjpeg_qsv "C:\out\%d.jpg"

  The command works, images are generated - but the GPU load seems to be the same as without any qsv options..?

  Thanks !

• JavaFX MediaPlayer unable to play local m3u8 file

  22 février 2020, par Lennart

  I want to show a live stream of a web cam in my JavaFX application using the MediaPlayer/MediaView. My attempt was to use ffmpeg to record a HLS and to play the resulting m3u8 file, but that throws the following exception (VLC plays the video without problems) :

  MediaException: UNKNOWN : com.sun.media.jfxmedia.MediaException: Could not create player! : com.sun.media.jfxmedia.MediaException: Could not create player!
  
      at javafx.scene.media.MediaException.exceptionToMediaException(MediaException.java:146)
  
      at javafx.scene.media.MediaPlayer.init(MediaPlayer.java:511)
  
      at javafx.scene.media.MediaPlayer.<init>(MediaPlayer.java:414)
  
      at de.fraunhofer.iosb.ias.flow.assessment.management.monitor.MonitorViewController.testStream(MonitorViewController.java:203)
  
      ... 58 more
  
  Caused by: com.sun.media.jfxmedia.MediaException: Could not create player!
  
      at com.sun.media.jfxmediaimpl.NativeMediaManager.getPlayer(NativeMediaManager.java:274)
  
      at com.sun.media.jfxmedia.MediaManager.getPlayer(MediaManager.java:118)
  
      at javafx.scene.media.MediaPlayer.init(MediaPlayer.java:467)
  
      ... 60 more
  
  </init>

  I debugged the player creation and the error occurs inside the constructor of GSTMediaPlayer when GSTMediaPlayer.gstInitPlayer() is called. This native method returns the error code 257, which javafx maps to MediaError.ERROR_MEDIA_NULL.

  I used the following ffmpeg command to record the video :

  ffmpeg -hide_banner -y -rtbufsize 250MB -f dshow -pixel_format yuv420p -video_size 960x720 -i video="Logitech HD Pro Webcam C920" -c:v libx264 -crf 20 -pix_fmt yuv420p out.m3u8

  I’m pretty sure that the encoding matches the requirements of javafx, because if I change the output container from m3u8 to mp4, the video is played without problems using the exact same ffmpeg command.

  This is the output of ffprobe for the m3u8 file :

  Input #0, hls,applehttp, from 'out.m3u8':
  
    Duration: 00:00:24.23, start: 1.466667, bitrate: 0 kb/s
  
    Program 0
  
      Metadata:
  
        variant_bitrate : 0
  
      Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 960x720, 30 fps, 30 tbr, 90k tbn, 60 tbc

  And for the mp4 file :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.41.100
  
    Duration: 00:01:04.93, start: 0.000000, bitrate: 1676 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 960x720, 1673 kb/s, 30 fps, 30 tbr, 10000k tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  The resulting m3u8 file looks like this :

  #EXTM3U
  
  #EXT-X-VERSION:3
  
  #EXT-X-TARGETDURATION:9
  
  #EXT-X-MEDIA-SEQUENCE:0
  
  #EXTINF:8.333322,
  
  out0.ts
  
  #EXTINF:8.333333,
  
  out1.ts
  
  #EXTINF:7.133322,
  
  out2.ts
  
  #EXTINF:0.433333,
  
  out3.ts
  
  #EXT-X-ENDLIST

  Update : After I found this reference m3u file, I think that the problem is that the file is stored locally and isn’t delivered via HTTP. The video plays fine with this :

  Media media = new Media("http://download.oracle.com/otndocs/products/javafx/JavaRap/prog_index.m3u8");
  
  MediaPlayer player = new MediaPlayer(media);
  
  player.setAutoPlay(true);
  
  mediaView.setMediaPlayer(player);

  But after I downloaded the reference m3u and all of its segments and tried to open the local file like this, the error occurred again :

  File video = new File("H://Projects//Tools//ref//prog_index.m3u8");
  
  Media media = new Media(video.toURI().toString());
  
  MediaPlayer player = new MediaPlayer(media);
  
  player.setAutoPlay(true);
  
  mediaView.setMediaPlayer(player);

  I tried to change my m3u file so that the segements are referenced with absolute paths. I tried different notations (H:\f\out0.ts, H:/f/out0.ts, H://f//out0.ts, file:/H:/f/out0.ts, file:///H:/f/out0.ts), but I couldn’t get it to work.