[coreMuxerFfmpeg] Set codec_tag in AVCodecParameters, needed when mul…

…tiple FourCCs match the same codec ID

avidemux_core/ADM_coreMuxer/src/ADM_coreMuxerFfmpeg.cpp

@@ -289,6 +289,7 @@ bool muxerFFmpeg::initVideo(ADM_videoStream *stream)
                                                     return false;
                                                 }
                                                 par->codec_id=cid;
+                                                par->codec_tag=id;
                                             }
                                         }
                         }