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• FFMPEG : Remove packets based on PTS/DTS

  9 mai 2018, par stevendesu

  I have a video which contains some audio packets beyond the end of the video data :

  $> ffprobe -show_packets video.mp4
  
  ...
  
  ...
  
  ...
  
  [PACKET]
  
  codec_type=video
  
  stream_index=0
  
  pts=5653648
  
  pts_time=235.568667
  
  dts=5653648
  
  dts_time=235.568667
  
  duration=1001
  
  duration_time=0.041708
  
  convergence_duration=N/A
  
  convergence_duration_time=N/A
  
  size=1030
  
  pos=25233684
  
  flags=__
  
  [/PACKET]
  
  [PACKET]
  
  codec_type=audio
  
  stream_index=1
  
  pts=11310080
  
  pts_time=235.626667
  
  dts=11310080
  
  dts_time=235.626667
  
  duration=1024
  
  duration_time=0.021333
  
  convergence_duration=N/A
  
  convergence_duration_time=N/A
  
  size=284
  
  pos=25234714
  
  flags=K_
  
  [/PACKET]
  
  [PACKET]
  
  codec_type=audio
  
  stream_index=1
  
  pts=11311104
  
  pts_time=235.648000
  
  dts=11311104
  
  dts_time=235.648000
  
  duration=1024
  
  duration_time=0.021333
  
  convergence_duration=N/A
  
  convergence_duration_time=N/A
  
  size=285
  
  pos=25234998
  
  flags=K_
  
  [/PACKET]
  
  [PACKET]
  
  codec_type=audio
  
  stream_index=1
  
  pts=11312128
  
  pts_time=235.669333
  
  dts=11312128
  
  dts_time=235.669333
  
  duration=992
  
  duration_time=0.020667
  
  convergence_duration=N/A
  
  convergence_duration_time=N/A
  
  size=290
  
  pos=25235283
  
  flags=K_
  
  [/PACKET]
  
  $>

  The last video packet in the video has a PTS time of 235.568667 and a duration of 0.041708 - meaning all video data ends at 235.610375. However there are audio packets beginning at 235.626667 and later.

  Is there an easy way to strip these audio packets from the file so that the audio and video end simultaneously ?

• How to read raw audio data using FFmpeg ?

  6 juin 2020, par Yousef Alaqra

  I'm trying to use this command to get the audio stream using UDP :

  



  ffmpeg -i udp://192.168.1.1:6980 -acodec copy


  



  I got an error when I execute it, which says :

  



  [udp @ 00000157a76b9a40] bind failed: Error number -10048 occurred
udp://192.168.1.1:6980: I/O error


  



  What's the meaning of this error ?

  



  Update :

  



  I was able to read raw audio data using FFmpeg and output into a wave file, using the following command :

  



  ffmpeg -f u16be -ar 44100 -ac 2 -i 'udp://127.0.0.1:1223' output.wav


  



  The problem now, Sine there is surrounding metadata in the network packets being received, it needs to be stripped out or it will result in noise.

  



  In C# I used Skip() to trim the first 28 bytes of the received packet, how would I achieve this using FFmpeg ?

  



  Update :

  



  I was able to read the raw bytes from UDP packets using by executing child process in node js :

  



  var http = require("http");
var port = 8888;
var host = "localhost";
var children = require("child_process");

http
  .createServer(function (req, res) {
    //ffmpeg -f s16le -ar 48000 -ac 2 -i 'udp://192.168.1.230:65535' -b:a 128k -f webm -
    var ffm = children.spawn(
      "ffmpeg",
      "-f s16le -ar 48000 -ac 2 -i udp://192.168.1.230:65535 -b:a 128k -f webm -".split(
        " "
      )
    );

    res.writeHead(200, { "Content-Type": "audio/webm" });
    ffm.stdout.on("data", (data) => {
      console.log(data);
      res.write(data);
    });
  })
  .listen(port, host);

console.log("Server running at http://" + host + ":" + port + "/");


  



  As you can see in the code sample above, I'm trying to pipe the output of the child process into the response, so I would be able to hear the audio in the browser.

  



  I'm receiving the data, after executing the child process, but the browser unable to play audio for some reason that I need to figure it out.

  



  Do you have an idea of what am I missing ?

  


• lavc : Use hardware config information in ff_get_format()

  26 octobre 2017, par Mark Thompson

  lavc : Use hardware config information in ff_get_format()
  This removes the dependency that hardware pixel formats previously had on
  
  AVHWAccel instances, meaning only those which actually do something need
  
  exist after this patch.
  Also updates avcodec_default_get_format() to be able to choose hardware
  
  formats if either a matching device has been supplied or no additional
  
  external configuration is required, and avcodec_get_hw_frames_parameters()
  
  to use the hardware config rather than searching the old hwaccel list.
  The FF_CODEC_CAP_HWACCEL_REQUIRE_CLASS mechanism is deleted because it
  
  no longer does anything (the codec already contains the pointers to the
  
  matching hwaccels).
  

  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/cuviddec.c
  • [DH] libavcodec/decode.c
  • [DH] libavcodec/internal.h