Stop a deprecated warning.
// initialize all muxers, demuxers and protocols for libavformat
// (does nothing if called twice during the course of one program execution)
// not needed in ffmpeg 4.0 and later... but still needed in ffmpeg 3.6 / ubuntu 18
+
+ #pragma GCC diagnostic push
+ #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
avcodec_register_all();
+ #pragma GCC diagnostic pop
AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_AAC);
if (codec == NULL) {