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• Add Win32 GDI-based screen grabbing

  2 avril 2014, par Calvin Walton

  Add Win32 GDI-based screen grabbing
  Based on original code by Christophe Gisquet in 2010, updated to work
  
  with current ffmpeg APIs.
  Supports grabbing a single window or an area of the screen, including
  
  support for multiple monitors (Windows does funky stuff with negative
  
  coordinates here).
  I’ve moved most of the configuration to AVOptions ; the input file name
  
  is now only the string "desktop", or "title=<windowname>" to select a
  
  single window. The AVOptions are the same as x11grab where possible.
  Code has been added to support a "show_region" mode, like x11grab, which
  
  will draw a rectangle on the screen around the area being captured.
  Instead of duplicating code for paletted image handling, I make use of
  
  the GDI API’s ability to output DIB (BMP) images, which can be run
  
  through ffmpeg’s existing BMP decoder.
  Signed-off-by : Calvin Walton <calvin.walton@kepstin.ca>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] Changelog
  • [DH] configure
  • [DH] doc/general.texi
  • [DH] doc/indevs.texi
  • [DH] libavdevice/Makefile
  • [DH] libavdevice/alldevices.c
  • [DH] libavdevice/gdigrab.c

• JavaCV FFmpegFrameRecorder properties explanation needed

  29 décembre 2014, par Leron

  I’m using FFmpegFrameRecorder to get the video input from my webcam and record it into a video file. The problem is that I’m building my application using a few different demo source codes that I found and I use properties some of which are not completely clear to me.

  First, here is my code snippet :

  FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(FILENAME,  grabber.getImageWidth(),grabber.getImageHeight());
  
  
  
          recorder.setVideoCodec(13);
  
          recorder.setFormat("mp4");
  
          recorder.setPixelFormat(avutil.PIX_FMT_YUV420P);
  
          recorder.setFrameRate(30);
  
          recorder.setVideoBitrate(10 * 1024 * 1024);
  
  
  
          recorder.start();

  • setVideoCodec(13) - What is the meaning of this (13) how can I understand what actual codec stands behind any number ?
  • setPixelFormat - Just get this, don’t know what it’s doing in general
  • setFrameRate(30) - I think this should be pretty clear but still what is the logic behind what frame rate we choose (isn’t the high the better ?)
  • setVideoBitrate(10*1024*1024) - again almost no idea what this does and what’s the logic behind the numbers ?

  At the end I just want to mention one last problem that I get recording video like this. If the actual length of the video is let’s say 20secs. When I play the video file created from the program it runs significantly faster. Can’t tell if it’s exactly 2 times faster than it should be but in general if I record a 20sec video then it’s played for about 10secs. What may cause this and how can I fix it ?

• Configure ffmpeg for wowza and wp8

  11 octobre 2013, par Anton Shakalo

  I have mp4 file from my windows phone.

  There is info :

  General
  
  Format                                   : MPEG-4
  
  Format profile                           : Base Media / Version 2
  
  Codec ID                                 : mp42
  
  
  
  Video
  
  Format                                    : AVC
  
  Codec ID                                 : avc1
  
  Codec ID/Info                           : Advanced Video Coding
  
  
  
  Audio
  
  Format                                    : AAC
  
  Format profile                           : LC
  
  Codec ID                                 : 40
  
  Bit rate                                   : 96.0 Kbps
  
  Sampling rate                           : 44.1 KHz

  When I stream it to wowza with next ffmpeg command ( I got it from documentation)

  ffmpeg -re -i "C:\sample2.mp4"  -vcodec libx264  -vb 150000 -g 60 -vprofile main -level 2.1 -acodec aac -ab 64000 -ar 48000 -ac 2 -vbsf h264_mp4toannexb  -f mpegts udp://127.0.0.1:10001?pkt_size=1316

  In client app I see corrupted video : http://i.imgur.com/fKEMlsB.png

  With sample file provided by wowza streamed video looks fine.

  There is info about sample file from wowza :

  General
  
  Format                                   : MPEG-4
  
  Format profile                           : QuickTime
  
  Codec ID                                 : qt  
  
  
  
  Video
  
  Format                                   : AVC
  
  Format profile                           : Baseline@L3.0
  
  Codec ID                                 : avc1
  
  
  
  Audio
  
  Format                                   : AAC
  
  Format profile                           : LC
  
  Codec ID                                 : 40

  Can you help me with ffmpeg configuring ?
  I read documentation, but understand nothing.