gistfile1.txt

const char * filename = url.c_str();
	if(int errnum = avformat_open_input(&avFormatPtr, filename, NULL, NULL) != 0) {
		size_t errsz = 256;
		char * errbuf = new char[errsz];
		errnum = AVERROR(errnum);

		av_strerror(errnum, errbuf, errsz);
		const char * str = url.c_str();
		printf("Failed to open file: %s with error: %d %s", str, errnum, errbuf);
		delete [] errbuf;
		
		return;
	}