mov: support timecode extraction.

Changelog

@@ -6,7 +6,7 @@ version next:
 - v410 Quicktime Uncompressed 4:4:4 10-bit encoder and decoder
 - SBaGen (SBG) binaural beats script demuxer
 - OpenMG Audio muxer
-- dv: add timecode to metadata
+- Timecode extraction in DV and MOV
 - thumbnail video filter
 - XML output in ffprobe
 - asplit audio filter

libavformat/mov.c

@@ -36,6 +36,7 @@
 #include "riff.h"
 #include "isom.h"
 #include "libavcodec/get_bits.h"
+#include "libavcodec/timecode.h"
 #include "id3v1.h"
 #include "mov_chan.h"
 
@@ -2615,6 +2616,46 @@ finish:
     avio_seek(sc->pb, cur_pos, SEEK_SET);
 }
 
+static int parse_timecode_in_framenum_format(AVFormatContext *s, AVStream *st,
+                                             uint32_t value)
+{
+    char buf[16];
+    struct ff_timecode tc = {
+        .drop  = st->codec->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE,
+        .rate  = (AVRational){st->codec->time_base.den,
+                              st->codec->time_base.num},
+    };
+
+    if (avpriv_check_timecode_rate(s, tc.rate, tc.drop) < 0)
+        return AVERROR(EINVAL);
+    av_dict_set(&st->metadata, "timecode",
+                avpriv_timecode_to_string(buf, &tc, value), 0);
+    return 0;
+}
+
+static int mov_read_timecode_track(AVFormatContext *s, AVStream *st)
+{
+    MOVStreamContext *sc = st->priv_data;
+    int64_t cur_pos = avio_tell(sc->pb);
+    uint32_t value;
+
+    if (!st->nb_index_entries)
+        return -1;
+
+    avio_seek(sc->pb, st->index_entries->pos, SEEK_SET);
+    value = avio_rb32(s->pb);
+
+    /* Assume Counter flag is set to 1 in tmcd track (even though it is likely
+     * not the case) and thus assume "frame number format" instead of QT one.
+     * No sample with tmcd track can be found with a QT timecode at the moment,
+     * despite what the tmcd track "suggests" (Counter flag set to 0 means QT
+     * format). */
+    parse_timecode_in_framenum_format(s, st, value);
+
+    avio_seek(sc->pb, cur_pos, SEEK_SET);
+    return 0;
+}
+
 static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
 {
     MOVContext *mov = s->priv_data;
@@ -2640,8 +2681,14 @@ static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
     }
     av_dlog(mov->fc, "on_parse_exit_offset=%"PRId64"\n", avio_tell(pb));
 
-    if (pb->seekable && mov->chapter_track > 0)
-        mov_read_chapters(s);
+    if (pb->seekable) {
+        int i;
+        if (mov->chapter_track > 0)
+            mov_read_chapters(s);
+        for (i = 0; i < s->nb_streams; i++)
+            if (s->streams[i]->codec->codec_tag == AV_RL32("tmcd"))
+                mov_read_timecode_track(s, s->streams[i]);
+    }
 
     return 0;
 }