lavc: schedule FF_BUG_AC_VLC for removal on the next major bump.

It has been deprecated/unused for about 10 years.

libavcodec/avcodec.h

@@ -2256,7 +2256,9 @@ typedef struct AVCodecContext {
 #define FF_BUG_UMP4             8
 #define FF_BUG_NO_PADDING       16
 #define FF_BUG_AMV              32
+#if FF_API_AC_VLC
 #define FF_BUG_AC_VLC           0  ///< Will be removed, libavcodec can now handle these non-compliant files by default.
+#endif
 #define FF_BUG_QPEL_CHROMA      64
 #define FF_BUG_STD_QPEL         128
 #define FF_BUG_QPEL_CHROMA2     256

libavcodec/options_table.h

@@ -123,7 +123,9 @@ static const AVOption avcodec_options[] = {
 {"ump4", "(autodetected if FOURCC == UMP4)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_UMP4 }, INT_MIN, INT_MAX, V|D, "bug"},
 {"no_padding", "padding bug (autodetected)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_NO_PADDING }, INT_MIN, INT_MAX, V|D, "bug"},
 {"amv", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_AMV }, INT_MIN, INT_MAX, V|D, "bug"},
+#if FF_API_AC_VLC
 {"ac_vlc", "illegal VLC bug (autodetected per FOURCC)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_AC_VLC }, INT_MIN, INT_MAX, V|D, "bug"},
+#endif
 {"qpel_chroma", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_QPEL_CHROMA }, INT_MIN, INT_MAX, V|D, "bug"},
 {"std_qpel", "old standard qpel (autodetected per FOURCC/version)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_STD_QPEL }, INT_MIN, INT_MAX, V|D, "bug"},
 {"qpel_chroma2", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_QPEL_CHROMA2 }, INT_MIN, INT_MAX, V|D, "bug"},

libavcodec/version.h

@@ -79,5 +79,8 @@
 #ifndef FF_API_DEBUG_MV
 #define FF_API_DEBUG_MV          (LIBAVCODEC_VERSION_MAJOR < 56)
 #endif
+#ifndef FF_API_AC_VLC
+#define FF_API_AC_VLC            (LIBAVCODEC_VERSION_MAJOR < 56)
+#endif
 
 #endif /* AVCODEC_VERSION_H */