@@ -35,6 +35,7 @@ version <next>:

 - sdl1 output device and sdl1 support removed

 - extended mov edit list support

 - libfaac encoder removed

+- Matroska muxer now writes CRC32 elements by default in all Level 1 elements

 version 3.1:

@@ -134,6 +134,7 @@ typedef struct MatroskaMuxContext {

     int is_dash;

     int dash_track_number;

     int is_live;

+    int write_crc;

     uint32_t chapter_id_offset;

     int wrote_chapters;

@@ -334,7 +335,7 @@ static void end_ebml_master_crc32(AVIOContext *pb, AVIOContext **dyn_cp, Matrosk

     if (pb->seekable) {

         size = avio_close_dyn_buf(*dyn_cp, &buf);

-        if (mkv->mode != MODE_WEBM) {

+        if (mkv->write_crc && mkv->mode != MODE_WEBM) {

             AV_WL32(crc, av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), UINT32_MAX, buf, size) ^ UINT32_MAX);

             put_ebml_binary(pb, EBML_ID_CRC32, crc, sizeof(crc));

         }

@@ -1485,7 +1486,7 @@ static int mkv_write_tags(AVFormatContext *s)

     if (mkv->tags.pos) {

         if (s->pb->seekable && !mkv->is_live)

-            put_ebml_void(s->pb, avio_tell(mkv->tags_bc) + ((mkv->mode != MODE_WEBM) ? 2 /* ebml id + data size */ + 4 /* CRC32 */ : 0));

+            put_ebml_void(s->pb, avio_tell(mkv->tags_bc) + ((mkv->write_crc && mkv->mode != MODE_WEBM) ? 2 /* ebml id + data size */ + 4 /* CRC32 */ : 0));

         else

             end_ebml_master_crc32(s->pb, &mkv->tags_bc, mkv, mkv->tags);

     }

@@ -1729,7 +1730,7 @@ static int mkv_write_header(AVFormatContext *s)

         }

     }

     if (s->pb->seekable)

-        put_ebml_void(s->pb, avio_tell(pb) + ((mkv->mode != MODE_WEBM) ? 2 /* ebml id + data size */ + 4 /* CRC32 */ : 0));

+        put_ebml_void(s->pb, avio_tell(pb) + ((mkv->write_crc && mkv->mode != MODE_WEBM) ? 2 /* ebml id + data size */ + 4 /* CRC32 */ : 0));

     else

         end_ebml_master_crc32(s->pb, &mkv->info_bc, mkv, mkv->info);

     pb = s->pb;

@@ -2390,6 +2391,7 @@ static const AVOption options[] = {

     { "dash_track_number", "Track number for the DASH stream", OFFSET(dash_track_number), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 127, FLAGS },

     { "live", "Write files assuming it is a live stream.", OFFSET(is_live), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },

     { "allow_raw_vfw", "allow RAW VFW mode", OFFSET(allow_raw_vfw), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },

+    { "write_crc32", "write a CRC32 element inside every Level 1 element", OFFSET(write_crc), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },

     { NULL },

 };

@@ -33,7 +33,7 @@

 // Also please add any ticket numbers that you believe might be affected here

 #define LIBAVFORMAT_VERSION_MAJOR  57

 #define LIBAVFORMAT_VERSION_MINOR  51

-#define LIBAVFORMAT_VERSION_MICRO 102

+#define LIBAVFORMAT_VERSION_MICRO 103

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

                                                LIBAVFORMAT_VERSION_MINOR, \