lavc: fix mixing CODEC_ID/AV_CODEC_ID in C++ code.

C++ does not allow to mix different enums, so e.g. code comparing
ACodecID with CodecID would fail to compile with gcc.

This very evil hack should fix this problem.

doc/APIchanges

@@ -18,6 +18,10 @@ API changes, most recent first:
 
 2012-08-xx - xxxxxxx - lavc 54.25 - avcodec.h
   Rename CodecID to AVCodecID and all CODEC_ID_* to AV_CODEC_ID_*.
+  To provide backwards compatibility, CodecID is now #defined as AVCodecID.
+  Note that this can break user code that includes avcodec.h and uses the
+  'CodecID' identifier. Such code should either #undef CodecID or stop using the
+  CodecID name.
 
 2012-08-03 - xxxxxxx - lavu 51.37.1 - cpu.h
                        lsws 2.1.1   - swscale.h

libavcodec/Makefile

@@ -705,6 +705,7 @@ SKIPHEADERS                            += %_tablegen.h                  \
                                           %_tables.h                    \
                                           aac_tablegen_decl.h           \
                                           fft-internal.h                \
+                                          old_codec_ids.h               \
                                           tableprint.h                  \
                                           $(ARCH)/vp56_arith.h          \
 

libavcodec/avcodec.h

@@ -76,9 +76,6 @@
  * @{
  */
 
-#if FF_API_CODEC_ID
-#include "old_codec_ids.h"
-#endif
 
 /**
  * Identify the syntax and semantics of the bitstream.
@@ -428,8 +425,16 @@ enum AVCodecID {
     AV_CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
                                 * stream (only used by libavformat) */
     AV_CODEC_ID_FFMETADATA = 0x21000,   ///< Dummy codec for streams containing only metadata information.
+
+#if FF_API_CODEC_ID
+#include "old_codec_ids.h"
+#endif
 };
 
+#if FF_API_CODEC_ID
+#define CodecID AVCodecID
+#endif
+
 #if FF_API_OLD_DECODE_AUDIO
 /* in bytes */
 #define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio

libavcodec/old_codec_ids.h

@@ -19,8 +19,6 @@
 #ifndef AVCODEC_OLD_CODEC_IDS_H
 #define AVCODEC_OLD_CODEC_IDS_H
 
-#include "libavutil/attributes.h"
-
 /*
  * This header exists to prevent new codec IDs from being accidentally added to
  * the deprecated list.
@@ -29,8 +27,7 @@
  * Do not add new items to this list. Use the AVCodecID enum instead.
  */
 
-enum CodecID {
-    CODEC_ID_NONE,
+    CODEC_ID_NONE = AV_CODEC_ID_NONE,
 
     /* video codecs */
     CODEC_ID_MPEG1VIDEO,
@@ -365,6 +362,5 @@ enum CodecID {
     CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
                                 * stream (only used by libavformat) */
     CODEC_ID_FFMETADATA = 0x21000,   ///< Dummy codec for streams containing only metadata information.
-} attribute_deprecated;
 
 #endif /* AVCODEC_OLD_CODEC_IDS_H */