avformat/mxf: Establish register of local tags

Tags can be marked "not used" upfront, saving some space in the primer.
av_asserts0() is used to enforce that only tags that are in the primer can actually be written.
Sharing of MasteringDisplay ULs is now done via macros.

libavformat/mxf.c

@@ -22,19 +22,8 @@
 #include "libavutil/common.h"
 #include "mxf.h"
 
-const uint8_t ff_mxf_mastering_display_prefix[13]           = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01 };
-
 const uint8_t ff_mxf_random_index_pack_key[16] = { 0x06,0x0e,0x2b,0x34,0x02,0x05,0x01,0x01,0x0d,0x01,0x02,0x01,0x01,0x11,0x01,0x00 };
 
-/* be careful to update references to this array if reordering */
-/* local tags are dynamic and must not clash with others in mxfenc.c */
-const MXFLocalTagPair ff_mxf_mastering_display_local_tags[4] = {
-    { 0x8301, { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01,0x01,0x00,0x00 }}, /* Mastering Display Primaries */
-    { 0x8302, { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01,0x02,0x00,0x00 }}, /* Mastering Display White Point Chromaticity */
-    { 0x8303, { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01,0x03,0x00,0x00 }}, /* Mastering Display Maximum Luminance */
-    { 0x8304, { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01,0x04,0x00,0x00 }}  /* Mastering Display Minimum Luminance */
-};
-
 /**
  * SMPTE RP224 http://www.smpte-ra.org/mdd/index.html
  */

libavformat/mxf.h

@@ -83,9 +83,13 @@ typedef struct MXFLocalTagPair {
     UID uid;
 } MXFLocalTagPair;
 
-extern const uint8_t ff_mxf_mastering_display_prefix[13];
 extern const uint8_t ff_mxf_random_index_pack_key[16];
-extern const MXFLocalTagPair ff_mxf_mastering_display_local_tags[4];
+
+#define FF_MXF_MasteringDisplay_PREFIX                  0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x20,0x04,0x01,0x01
+#define FF_MXF_MasteringDisplayPrimaries                { FF_MXF_MasteringDisplay_PREFIX,0x01,0x00,0x00 }
+#define FF_MXF_MasteringDisplayWhitePointChromaticity   { FF_MXF_MasteringDisplay_PREFIX,0x02,0x00,0x00 }
+#define FF_MXF_MasteringDisplayMaximumLuminance         { FF_MXF_MasteringDisplay_PREFIX,0x03,0x00,0x00 }
+#define FF_MXF_MasteringDisplayMinimumLuminance         { FF_MXF_MasteringDisplay_PREFIX,0x04,0x00,0x00 }
 
 #define FF_MXF_MASTERING_CHROMA_DEN 50000
 #define FF_MXF_MASTERING_LUMA_DEN   10000

libavformat/mxfdec.c

@@ -336,6 +336,14 @@ static const uint8_t mxf_indirect_value_utf16be[]          = { 0x42,0x01,0x10,0x
 static const uint8_t mxf_apple_coll_max_cll[]              = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x0e,0x20,0x04,0x01,0x05,0x03,0x01,0x01 };
 static const uint8_t mxf_apple_coll_max_fall[]             = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x0e,0x20,0x04,0x01,0x05,0x03,0x01,0x02 };
 
+static uint8_t mxf_mastering_display_prefix[13]            = { FF_MXF_MasteringDisplay_PREFIX };
+static uint8_t mxf_mastering_display_uls[4][16] = {
+    FF_MXF_MasteringDisplayPrimaries,
+    FF_MXF_MasteringDisplayWhitePointChromaticity,
+    FF_MXF_MasteringDisplayMaximumLuminance,
+    FF_MXF_MasteringDisplayMinimumLuminance,
+};
+
 #define IS_KLV_KEY(x, y) (!memcmp(x, y, sizeof(y)))
 
 static void mxf_free_metadataset(MXFMetadataSet **ctx, int freectx)
@@ -1280,13 +1288,13 @@ static int mxf_read_generic_descriptor(void *arg, AVIOContext *pb, int tag, int
                 rsiz == FF_PROFILE_JPEG2000_DCINEMA_4K)
                 descriptor->pix_fmt = AV_PIX_FMT_XYZ12;
         }
-        if (IS_KLV_KEY(uid, ff_mxf_mastering_display_prefix)) {
+        if (IS_KLV_KEY(uid, mxf_mastering_display_prefix)) {
             if (!descriptor->mastering) {
                 descriptor->mastering = av_mastering_display_metadata_alloc();
                 if (!descriptor->mastering)
                     return AVERROR(ENOMEM);
             }
-            if (IS_KLV_KEY(uid, ff_mxf_mastering_display_local_tags[0].uid)) {
+            if (IS_KLV_KEY(uid, mxf_mastering_display_uls[0])) {
                 for (int i = 0; i < 3; i++) {
                     /* Order: large x, large y, other (i.e. RGB) */
                     descriptor->mastering->display_primaries[i][0] = av_make_q(avio_rb16(pb), FF_MXF_MASTERING_CHROMA_DEN);
@@ -1296,20 +1304,20 @@ static int mxf_read_generic_descriptor(void *arg, AVIOContext *pb, int tag, int
                 if (descriptor->mastering->white_point[0].den != 0)
                     descriptor->mastering->has_primaries = 1;
             }
-            if (IS_KLV_KEY(uid, ff_mxf_mastering_display_local_tags[1].uid)) {
+            if (IS_KLV_KEY(uid, mxf_mastering_display_uls[1])) {
                 descriptor->mastering->white_point[0] = av_make_q(avio_rb16(pb), FF_MXF_MASTERING_CHROMA_DEN);
                 descriptor->mastering->white_point[1] = av_make_q(avio_rb16(pb), FF_MXF_MASTERING_CHROMA_DEN);
                 /* Check we have seen mxf_mastering_display_primaries */
                 if (descriptor->mastering->display_primaries[0][0].den != 0)
                     descriptor->mastering->has_primaries = 1;
             }
-            if (IS_KLV_KEY(uid, ff_mxf_mastering_display_local_tags[2].uid)) {
+            if (IS_KLV_KEY(uid, mxf_mastering_display_uls[2])) {
                 descriptor->mastering->max_luminance = av_make_q(avio_rb32(pb), FF_MXF_MASTERING_LUMA_DEN);
                 /* Check we have seen mxf_mastering_display_minimum_luminance */
                 if (descriptor->mastering->min_luminance.den != 0)
                     descriptor->mastering->has_luminance = 1;
             }
-            if (IS_KLV_KEY(uid, ff_mxf_mastering_display_local_tags[3].uid)) {
+            if (IS_KLV_KEY(uid, mxf_mastering_display_uls[3])) {
                 descriptor->mastering->min_luminance = av_make_q(avio_rb32(pb), FF_MXF_MASTERING_LUMA_DEN);
                 /* Check we have seen mxf_mastering_display_maximum_luminance */
                 if (descriptor->mastering->max_luminance.den != 0)