c++ - How to use libavcodec in Qt4? -

how use libavcodec in qt4 access individual video frames?

after verifying video stream can decoded libavcodec compiling this example, moved source code c++ program. av_open_input_file() unable open video file (returning errorcode: -2).

the call looks right now:

... // register formats , codecs avcodec_register_all();  // open video file qstring videofilename("/absolute/path/to/video.avi"); // somewhere else in application const char* filename = videofilename.tostdstring().c_str(); int err = 0; if((err = av_open_input_file(&pformatctx, filename, null, 0, null)) != 0) {     doerrorhandling(err, filename); // err = -2 } 

when @ const char* filename inside debugger looks correct. making basic mistake in mixing c , c++ code (for first attempt dumped code example constructor of class)?

note: in order application compile include headers this:

extern "c" { #define __stdc_constant_macros // uint64_c #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswscale/swscale.h> } 

i have tried hard code path video file application without success:

av_open_input_file(&pformatctx, "/home/bjoernz/video.avi", null, 0, null); 

i able compile , execute example (avcodec_sample.0.5.0.c) using g++.

error -2 means no such file or directory. i'm pretty sure file you're attempting open isn't located in "current working directory" when running application.