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• Capturing frames from an h264 stream with gst/ffmpeg

  17 août 2016, par Yuval.Sightec

  I want to save (as jpegs) or reach the data of the frames streaming from my usb camera.
  Meaning that I want to use the h.264 hardware encoding (I running it on nvdia jetson) in order to get a sequence of compressed files (I prefer not save it on the disc and get an array, if possible).
  Can I do that ?

  So far I tried this :

  gst-launch-1.0 -v v4l2src device=/dev/video0 ! video/x-h264,framerate=30/1,stream-format=byte-stream ! decodebin ! videorate ! video/x-raw,framerate=30/1 ! videoconvert ! jpegenc ! multifilesink location=img_%04d.jpg

  but I get an internal data flow error from v4l2src0 element, and an error from gst_base_src_loop() after the pipeline was set to PLAYING.

  Can anybody please help me ?

  b.t.w- It doesnt have to be neccecerly h.264 encoding, it also can be mpeg encoding or something else : I want to use the fact that it is pictures of a video, frames, in order to get smaller size frames.

  Thank you so much !

• Building FFMPEG for Visual Studio development

  28 juillet 2016, par gboy

  I’m trying to use ffmpeg in Visual Studio 2013 C++ software (ultimately as part of an OpenCV project) - but right now I’m just trying to get basic FFMPEG functionality. In general, when building in Visual Studio, I build 64—bit software with Multi-threaded DLL runtime libraries. I have built ffmpeg using the general instructions for ’Native Windows compilation using ... MinGW-w64’ at http://ffmpeg.org/platform.html#Windows (I provide a more detailed set of steps I followed below...).

  After building the ffmpeg software on my system, I tried to create a simple ’hello world’ project in Visual Studio 2013. Specifically, I tried to implement the initial tutorial file presented at http://dranger.com/ffmpeg/tutorial01.html. Upon building the project, I get the error :

  c :\msys64\usr\local\ffmpeg\libavutil\common.h(45) : fatal error C1083 : Cannot
  open include file : ’libavutil/avconfig.h’ : No such file or directory

  The following are the detailed steps I took to build ffmpeg and create my basic Visual Studio project :

  ============ Building ffmpeg ===============

  1. Downloaded and intalled msys2-x86_64-20160205.exe from http://msys2.github.io
  2. Ran update-core to update the Msys2 install
  3. Ran pacman -Suu (twice) to complete the update (following the instructions about updating shortcuts, etc.)
  4. Then I quit out of the MSys2 shell and opened the MinGW-w64 Win64 Shell. In this new shell :
  5. Installed the following packages using pacman -S The list of packages I installed is : make, pkg-config, diffutils, mingw-w64-x86_64-yasm, mingw-w64-x86_64-gcc, mingw-w64-x86_64-SDL, git
  6. Then I cd’d into cd /usr/local
  7. Ran git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
  8. I wanted to build the ffmpeg library ’out-of-tree’ of this MSys64 folder. So, in the regular file system of my Windows machine I created a folder at C :\ffmpeg
  9. Back in the Win64 Shell, I cd’d to this new folder : cd /c/ffmpeg
  10. Then ran /usr/loca/ffmpeg/configure --enable-shared
  11. Then make -r
  12. And, finally make install

  Now, if I had to guess, my ’flaw’ was in the options I used when calling the ’configure’ script of ffmpeg. Do I need to use particular options so that I can take the ffmpeg libraries built here and use them as dynamic (DLL) libraries in Visual Studio ?

  ========== Configuring my Visual Studio Project ============

  Here’s how I created a simple hello world project in Visual Studio to see if ffmpeg is working.

  1. I created a new Visual C++ ’Empty Project’ in Visual Studio 2013

  2. I then configured the project properties as follows :

     a. In C/C++ => General => Additional Include Directories, I put

     C :\msys64\usr\local\ffmpeg

     b. In Linker=>General => Additional Library Directories, I pointed to each of the built library folders (basically I pointed at all of the libraries that were built to ensure I was not inadvertently missing the critical one). The list is as follows :

     • C :\ffmpeg\libavcodec
     • C :\ffmpeg\libavdevice
     • C :\ffmpeg\libavfilter
     • C :\ffmpeg\libavformat
     • C :\ffmpeg\libavutil
     • C :\ffmpeg\libswresample
     • C :\ffmpeg\libswscale
     • C :\ffmpeg

     c. In Linker=> Input => Additional Dependencies, I pointed to the particular libraries (again - I pointed to all of the ones present). The list is :

     • avcodec.lib
     • avdevice.lib
     • avfilter.lib
     • avformat.lib
     • avutil.lib
     • swresample.lib
     • swscale.lib

  3. I then created a new source file called ’tut01.c’ and copied/pasted the code from http://dranger.com/ffmpeg/tutorial01.c

  4. Then hit F7 and got the error specified above about not finding avconfig.h

  The above is my best guess as to the steps I need to follow to get this working in Windows (btw, it’s Windows 10, 64-bit) & Microsoft Visual Studio 2013. What should I change to get this basic program to build and run ?

• how to use ffmpeg in eclipse c++(win7 64)？ [duplicate]

  22 août 2016, par Coco

  This question already has an answer here :

  • What is an undefined reference/unresolved external symbol error and how do I fix it ?
    
    25 answers
    

  How to use ffmpeg, such as config include,lib,dll. It’s always build error.
  Who can tell me, thanks...

  #define __STDC_CONSTANT_MACROS
  
  
  
  #include <iostream>
  
  using namespace std;
  
  
  
  extern "C" {
  
  #include "libavformat/avformat.h"
  
  }
  
  
  
  int main() {
  
      av_register_all();
  
      cout &lt;&lt; "!!!Hello World!!!" &lt;&lt; endl; // prints !!!Hello World!!!
  
      return 0;
  
  }
  
  </iostream>

  error : /../src/ffmpeg_test.cpp:18 : undefined reference to `av_register_all’