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• avcodec/bsf : Beautify log messages from bitstream filters

  17 mars 2020, par Andreas Rheinhardt

  avcodec/bsf : Beautify log messages from bitstream filters
  Up until now, the name of every AVBSFContext for logging purposes was
  
  "AVBSFContext", so that the default logging callback produced output
  
  like "[AVBSFContext @ 0x55813bae92c0] Extradata". This has been changed
  
  to "[trace_headers @ 0x60a000000700] Extradata" by adding an item_name-
  
  function to the AVClass for bitstream filters.
  Furthermore, the correct category has been set so that the introductory
  
  part before the actual message (everything before "Extradata" in the
  
  above examples) are displayed in a different colour than the rest.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Reviewed-by : Anton Khirnov <anton@khirnov.net>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavcodec/bsf.c

• Problem with ffmpeg rtp stream to janus webrtc

  13 juin 2020, par XPModder

  I am trying to use ffmpeg and janus-gateway to stream video in the local network. I am piping the h264 video directly in to ffmpeg and from there it gets transferred to janus as an rtp stream. Janus then does the rest.

  



  The problem is, that when I try to open the stream using the streamingtest html page included in janus, I can select the stream, but I never get to see anything. On the console where I started janus, it throws multiple errors starting with : "SDP missing mandatory information"

  



  After starting ffmpeg it shows the SDP in console :

  



  v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 127.0.0.1
t=0 0
a=tool:libavformat 58.20.100
m=video 8004 RTP/AVP 96
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1; sprop-parameter-sets=J2QAKKwrQDwBE/LAPEiagA==,KO4BNywA; profile-level-id=640028


  



  The command I use to start ffmpeg is the following :

  



  ffmpeg -loglevel quiet -y -i - -c:v copy -preset veryfast -f rtp rtp://127.0.0.1:8004


  



  I assume that I am missing something in the ffmpeg command and therefore there is some kind of problem with the SDP.

  



  Edit : I looked a little further into this and actually looked at the code for janus at the lines that throw the error. Then I traced that to the origin of the error.

  



  Apparently the SDP is supposed to contain some authorization in for of this :

  



  a=... ice-ufrag=?; ice-pwd=?


  



  So how do I find out what this username and password are and how do I get it in to the SDP from ffmpeg ?

  



  Or how do I disable this entirely ?

  


• ffprobe reading wrong frame rate, any workarounds besides MediaInfo ?

  20 mai 2023, par Minty

  I want to check the frame rate of many videos. I decided to employ ffprobe :

  


  ffprobe -v error -select_streams v -of default=noprint_wrappers=1:nokey=1 -show_entries stream=r_frame_rate faulty.mkv =

  


  500/21


  


  That can't be right, what kind of fps is 500/21 ?

  


  ffprobe faulty.mkv (version 4.3.5-0+deb11u1+rpt3)

  


  Stream #0:0: Video: (...), 23.81 fps, 23.81 tbr, 1k tbn, 23.98 tbc (default)


  


  At least ffprobe 4 read the correct codec timescale i.e. 23.98 tbc (default), but in later versions tbc has been deprecated :

  


  Stream #0:0: Video: (...), 23.81 fps, 23.81 tbr, 1k tbn (default)


  


  However, MediaInfo gets it right :

  


  mediainfo faulty.mkv =

  


  (...)
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
(...)


  


  I tried using -count_packets to then divide nb_read_packets of the stream by the duration of the file, I'm getting 1 second per hour error. This is much better compared to 23,8095, but packets are not frames, and only the prohibitively, unusably slow -count_frames gets me the exact value.

  


  The rest of my workflow uses ffprobe, so I'm reluctant to switch to MediaInfo completely. I get that the file is, well, faulty, but if mediainfo can do it, is there a way to make sure the correct frame rate is read with ffprobe without decoding the entire file as -count_frames seems to do ?