+static inline void bwf_write_bext_string(AVFormatContext *s, const char *key, int maxlen)
+{
+ AVDictionaryEntry *tag;
+ int len = 0;
+
+ if (tag = av_dict_get(s->metadata, key, NULL, 0)) {
+ len = strlen(tag->value);
+ len = FFMIN(len, maxlen);
+ avio_write(s->pb, tag->value, len);
+ }
+
+ ffio_fill(s->pb, 0, maxlen - len);
+}
+
+static void bwf_write_bext_chunk(AVFormatContext *s)
+{
+ AVDictionaryEntry *tmp_tag;
+ uint64_t time_reference = 0;
+ int64_t bext = ff_start_tag(s->pb, "bext");
+
+ bwf_write_bext_string(s, "description", 256);
+ bwf_write_bext_string(s, "originator", 32);
+ bwf_write_bext_string(s, "originator_reference", 32);
+ bwf_write_bext_string(s, "origination_date", 10);
+ bwf_write_bext_string(s, "origination_time", 8);
+
+ if (tmp_tag = av_dict_get(s->metadata, "time_reference", NULL, 0))
+ time_reference = strtoll(tmp_tag->value, NULL, 10);
+ avio_wl64(s->pb, time_reference);
+ avio_wl16(s->pb, 1); // set version to 1
+
+ if (tmp_tag = av_dict_get(s->metadata, "umid", NULL, 0)) {
+ unsigned char umidpart_str[17] = {0};
+ int i;
+ uint64_t umidpart;
+ int len = strlen(tmp_tag->value+2);
+
+ for (i = 0; i < len/16; i++) {
+ memcpy(umidpart_str, tmp_tag->value + 2 + (i*16), 16);
+ umidpart = strtoll(umidpart_str, NULL, 16);
+ avio_wb64(s->pb, umidpart);
+ }
+ ffio_fill(s->pb, 0, 64 - i*8);
+ } else
+ ffio_fill(s->pb, 0, 64); // zero UMID
+
+ ffio_fill(s->pb, 0, 190); // Reserved
+
+ if (tmp_tag = av_dict_get(s->metadata, "coding_history", NULL, 0))
+ avio_put_str(s->pb, tmp_tag->value);
+
+ ff_end_tag(s->pb, bext);
+}
+