I am trying to run the sample simple_transcode_opaque_async_ffmpeg.cpp with the ffmpeg integration. No problems build it. Running the code, I get in FFmpeg_Writer_Init() as far as
avio_open(&g_pFormatCtxMux->pb, g_pFormatCtxMux->filename, AVIO_FLAG_WRITE)
Here, avio_open always retunrs -13. I have tried to find out what -13 means, printing out the error with av_strerror(). I get no other information than -13, and I would like to know why this call fails? Any ideas?