--- ffms-2.17-src.orig/configure.in
+++ ffms-2.17-src/configure.in
@@ -135,7 +135,7 @@ AC_DEFUN([TEST_LIBAV],
             #include <libavcodec/avcodec.h>
             #include <libswscale/swscale.h>
             ]],[[
-                avcodec_init();
+                av_register_all();
                 swscale_version();
                 #ifdef FFMS_USE_FFMPEG_COMPAT
                 int bogus = CODEC_ID_G2M;
--- ffms-2.17-src.orig/include/ffmscompat.h
+++ ffms-2.17-src/include/ffmscompat.h
@@ -84,6 +84,14 @@
 #	else
 #		define FFMS_CALCULATE_DELAY (CodecContext->has_b_frames + (CodecContext->thread_count - 1))
 #	endif
+#       if VERSION_CHECK(LIBAVCODEC_VERSION_INT, <, 54, 25, 0, 54, 51, 100)
+#               define FFMS_ID(x) (CODEC_ID_##x)
+#               define FFMS_CodecID CodecID
+#       else
+#               define FFMS_ID(x) (AV_CODEC_ID_##x)
+#               define FFMS_CodecID AVCodecID
+#               undef CodecID
+#       endif
 #endif
 
 #ifdef LIBAVUTIL_VERSION_INT
--- ffms-2.17-src.orig/src/core/codectype.cpp
+++ ffms-2.17-src/src/core/codectype.cpp
@@ -25,7 +25,7 @@
 
 typedef struct CodecTags {
 	char str[20];
-	CodecID id;
+	FFMS_CodecID id;
 } CodecTags;
 
 static const CodecTags mkv_codec_tags[] = {
@@ -92,7 +92,7 @@ static const CodecTags mkv_codec_tags[]
 };
 
 typedef struct AVCodecTag {
-	enum CodecID id;
+	enum FFMS_CodecID id;
 	unsigned int tag;
 } AVCodecTag;
 
@@ -400,7 +400,7 @@ const char *GetLAVCSampleFormatName(AVSa
 	}
 }
 
-CodecID MatroskaToFFCodecID(char *Codec, void *CodecPrivate, unsigned int FourCC, unsigned int BitsPerSample) {
+FFMS_CodecID MatroskaToFFCodecID(char *Codec, void *CodecPrivate, unsigned int FourCC, unsigned int BitsPerSample) {
 	/* Look up native codecs */
 	for(int i = 0; mkv_codec_tags[i].id != CODEC_ID_NONE; i++){
 		if(!strncmp(mkv_codec_tags[i].str, Codec,
@@ -408,7 +408,7 @@ CodecID MatroskaToFFCodecID(char *Codec,
 
 				// Uncompressed and exotic format fixup
 				// This list is incomplete
-				CodecID CID = mkv_codec_tags[i].id;
+				FFMS_CodecID CID = mkv_codec_tags[i].id;
 				switch (CID) {
 					case CODEC_ID_PCM_S16LE:
 						switch (BitsPerSample) {
--- ffms-2.17-src.orig/src/core/codectype.h
+++ ffms-2.17-src/src/core/codectype.h
@@ -27,5 +27,5 @@ extern "C" {
 #include "ffmscompat.h"
 
 FFMS_TrackType HaaliTrackTypeToFFTrackType(int TT);
-CodecID MatroskaToFFCodecID(char *Codec, void *CodecPrivate, unsigned int FourCC = 0, unsigned int BitsPerSample = 0);
+FFMS_CodecID MatroskaToFFCodecID(char *Codec, void *CodecPrivate, unsigned int FourCC = 0, unsigned int BitsPerSample = 0);
 const char *GetLAVCSampleFormatName(AVSampleFormat s);
--- ffms-2.17-src.orig/src/core/matroskaparser.h
+++ ffms-2.17-src/src/core/matroskaparser.h
@@ -32,6 +32,11 @@
 #ifndef MATROSKA_PARSER_H
 #define	MATROSKA_PARSER_H
 
+/* Make sure we undefine CodecID, since libavcodec defines it as AVCodec ID */
+#ifdef CodecID
+#undef CodecID
+#endif
+
 /* Random notes:
  *
  * The parser does not process frame data in any way and does not read it into