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• getting AVFrame pts value

  25 février 2014, par Whoami
  1. I have a AVStream of Video from FormatContext. [ avstream ]
  2. Read Packet
  3. Decode packet if it is from video.

  4. Now Display the following.

     Packet DTS ->  7200.00    [ from packet ]
     
     Frame PTS   -> -9223372036854775808.000000
     
     stream time_base ->  0.000011
     
     Offset                    ->  0.080000    [ pts * time_base ]

  code :

  double pts = (double) packet.dts;
  
  printf (" dts of packet %f , Frame pts:  %f, timeBase %f Offset: %f ",
  
      pts,
  
      (double)pFrame->pts, 
  
      av_q2d (avstream->time_base) , 
  
      pts
  
  *av_q2d(avstream->time_base));

  1. Why is Frame pts negative ? Is it expected behavior ?
  2. Do I need to consider Frame pts from packet DTS [ ie : frame pts = packet
     dts ]

• How to format the output of ffmpeg

  1er mars 2023, par Default

  I am trying to use ffmpeg to get the list of audio input devices for my machine(windows 11).

  


  This is the command that I use to achieve this :

  


  ffmpeg -list_devices true -f dshow -i dummy -hide_banner


  


  This is the output :

  


  [dshow @ 00000282627590c0] "OBS Virtual Camera" (video)
[dshow @ 00000282627590c0]   Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B- 
00A0C911CE86}\{A3FCE0F5-3493-419F-958A-ABA1250EC20B}"
[dshow @ 00000282627590c0] "Microphone (Realtek(R) Audio)" (audio)
[dshow @ 00000282627590c0]   Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43- 
00A0C911CE86}\wave_{2409F2C8-F2CB-4A6D-AEA7-DAD79C4EE9DF}"


  


  I want to modify the output so it only shows this :

  


  "OBS Virtual Camera" (video)
"Microphone (Realtek(R) Audio)" (audio)


  


  How can I remove the brackets at the beginning as well as the alternative names to achieve this ? What command do I use ?

  


• Getting error while streaming with ffmpeg

  30 novembre 2019, par Tirtha

  I am trying to stream with ffmpeg. Video source is vmix. While streaming ffmpeg throws i/o error and stops.
  Available Devices :

  [dshow @ 0000028c44498ec0] DirectShow video devices (some may be both video and audio devices)
  
  [dshow @ 0000028c44498ec0]  "e2eSoft VCam"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_pnp_\\?\root#image#0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
  
  [dshow @ 0000028c44498ec0]  "HP Truevision HD"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_pnp_\\?\usb#vid_04f2&pid_b50d&mi_00#6&2557162&1&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
  
  [dshow @ 0000028c44498ec0]  "vMix Video"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{8E14549A-DB61-4309-AFA1-3578E927E938}"
  
  [dshow @ 0000028c44498ec0]  "vMix Video External 2"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{8E14549A-DB61-4309-AFA1-3578E927F974}"
  
  [dshow @ 0000028c44498ec0]  "vMix Video YV12"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{8E14549A-DB61-4309-AFA1-3578E927FF92}"
  
  [dshow @ 0000028c44498ec0] DirectShow audio devices
  
  [dshow @ 0000028c44498ec0]  "Microphone (Realtek High Definition Audio)"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{3522D665-FB21-41E0-AF83-CC3432431D30}"
  
  [dshow @ 0000028c44498ec0]  "vMix Audio"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{008E145B-DB61-4309-AEA1-3578E927E940}"
  
  [dshow @ 0000028c44498ec0]  "vMix Audio - Bus A"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{008E145B-DB61-4309-AEA1-3578E927E944}"
  
  [dshow @ 0000028c44498ec0]  "vMix Audio - Bus B"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{008E145B-DB61-4309-AEA1-3578E927E948}"
  
  [dshow @ 0000028c44498ec0]  "vMix Audio - M A B"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{008E145B-DB61-4309-AEA1-3578E927E952}"
  
  [dshow @ 0000028c44498ec0]  "vMix Audio - M A"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{008E145B-DB61-4309-AEA1-3578E927E956}"
  
  [dshow @ 0000028c44498ec0]  "CABLE Output (VB-Audio Virtual Cable)"
  
  [dshow @ 0000028c44498ec0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{D27F382E-4EA5-49D0-8F87-2B5F144BC155}"

  I tried to stream using the command as :

  ffmpeg -re -rtbufsize 1024M -framerate 25 -f dshow -video_size 1280x720 -channels 2 -i video="vMix Video":audio="vMix Audio" -c:v libx264 -pix_fmt yuv420p -g 50 -crf 20 -profile:v high -preset:v veryfast -tune film -c:a libfaac -b:a 256k -f mp4 "D:\recordedfile.mp4"

  Getting error as :

  [dshow @ 0000028144d4c7c0] Could not set video options
  
  video=vMix Video:audio=vMix Audio: I/O error

  Video interface works fine if i use other tools like gstreamer but its not working with ffmpeg. Please suggest where I am wrong or what I am missing ? I am using windows OS. Thank you for reading.