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• lavc/version.h : remove empty line

  3 novembre 2013, par Stefano Sabatini

  lavc/version.h : remove empty line
  

  • [DH] libavcodec/version.h

• Find the library calls from FFMPEG command line

  6 octobre 2013, par Budius

  I'm trying to create an Android app that will use video edition, thou, using FFMPEG for the task. I already successfully compiled FFMPEG as a library (libavcodec, libavformat, etc) and included them in the Android project.

  Note that it does not contain the ffmpeg.c that can be called as a command line and the problem is that I only know the command lines to be used for all different things I want to accomplish.

  So the question is :

  from my Linux machine, how would I call ffmpeg main() in a "debug mode" to follow line-by-line what is being calling on those libraries, so I can write methods to mimic what I need to get done ? (currently I only have Android Studio installed, but I'm open to install whatever IDE ppl might suggest)

• ffmpeg command line for capturing audio and video in 720p from decklink card using Windows 7

  29 octobre 2013, par Huron

  I am trying to capture audio and video from a blackmagic decklink capture card using Windows 7 @ 720p, but I cant seem to get the ffmpeg command line settings right.

  ffmpeg -list_devices true -f dshow -i dummy

  [dshow @ 02457a60] DirectShow video devices
  
  [dshow @ 02457a60]  "Blackmagic WDM Capture"
  
  [dshow @ 02457a60]  "Decklink Video Capture"
  
  [dshow @ 02457a60] DirectShow audio devices
  
  [dshow @ 02457a60]  "Decklink Audio Capture"

  ffmpeg -list_options true -f dshow -i video="Decklink Video Capture"

  [dshow @ 03c2ea20] DirectShow video device options
  
  [dshow @ 03c2ea20]  Pin "Capture"
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=29.97 max s=720x486 fps=29.97
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=23.976 max s=720x486 fps=23.976
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x576 fps=25 max s=720x576 fps=25
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x486 fps=59.9402 max s=720x486 fps=59.9402
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=720x576 fps=50 max s=720x576 fps=50
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=23.976 max s=1920x1080 fps=23.976
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=24 max s=1920x1080 fps=24
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=25 max s=1920x1080 fps=25
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=29.97 max s=1920x1080 fps=29.97
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1920x1080 fps=30 max s=1920x1080 fps=30
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=50 max s=1280x720fps=50
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=59.9402 max s=1280x720 fps=59.9402
  
  [dshow @ 03c2ea20]   pixel_format=uyvy422  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002

  ffmpeg -list_options true -f dshow -i audio="Decklink Audio Capture"

  [dshow @ 047fea20] DirectShow audio device options
  
  [dshow @ 047fea20]  Pin "Capture"
  
  [dshow @ 047fea20]   min ch=1 bits=16 rate= 48000 max ch=1 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=2 bits=16 rate= 48000 max ch=2 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=4 bits=16 rate= 48000 max ch=4 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=6 bits=16 rate= 48000 max ch=6 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=8 bits=16 rate= 48000 max ch=8 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=10 bits=16 rate= 48000 max ch=10 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=12 bits=16 rate= 48000 max ch=12 bits=16 rate= 48000
  
  [dshow @ 047fea20]   min ch=16 bits=16 rate= 48000 max ch=16 bits=16 rate= 48000

  This is the stream information for my current video/audio source, connected to the decklink card's hdmi port

  Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422(tv), 1280x720, 59.94 tbr, 10000k tbn, 59.94 tbc
  
  Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s

  Ultimately I will need to display this video on screen. And simultaneously be able to start and stop recording, while the preview keeps playing.

  My idea was to use ffmpeg to capture the video and audio signal and transmit this to a network stream (eg 127.0.0.1:6666). Then use VLC player to display the stream (the preview). And ultimately start and/or stop another ffmpeg to save that same stream to disk.

  In my mind this works, but I am no audio/video expert so if anyone with more experience could help out, I would appreciate it.

  Update :

  I have been able to display the video using ffplay, with the following command :

  ffplay -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2

  Next step is streaming it so I can view the stream (preview) with VLC.

  Tried to use this command :

  ffmpeg -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2 -f mpegts rtp://127.0.0.1:6666?pkt_size=188?buffer_size=65535

  Which does not give any errors, so appears to work. But when I try to open the stream in VLC I get the following error :

  SDP required :
  A description in SDP format is required to receive the RTP stream. Note that rtp :// URIs cannot work with dynamic RTP payload format (65).

  After a bit of reading it seems I should not be streaming to rtp :// but rather to udp ://

  Command became :

  ffmpeg -f dshow -video_size 1280x720 -rtbufsize 702000k -framerate 60 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -threads 2 -f mpegts udp://127.0.0.1:6666?pkt_size=188?buffer_size=65535

  And when I try to open it now in VLC I get no error, no warning, but also no video.

  Time for some more reading.