mxf: add cli option in mxfenc to replace GOP timecode parsing.

This is based on the original work by Baptiste Coudurier.

libavformat/mxfenc.c

@@ -35,6 +35,7 @@
 #include <math.h>
 #include <time.h>
 
+#include "libavutil/opt.h"
 #include "libavutil/random_seed.h"
 #include "libavcodec/bytestream.h"
 #include "libavcodec/timecode.h"
@@ -172,6 +173,7 @@ static const MXFContainerEssenceEntry mxf_essence_container_uls[] = {
 };
 
 typedef struct MXFContext {
+    AVClass *av_class;
     int64_t footer_partition_offset;
     int essence_container_count;
     AVRational time_base;
@@ -185,10 +187,9 @@ typedef struct MXFContext {
     unsigned body_partitions_count;
     int last_key_index;  ///< index of last key frame
     uint64_t duration;
+    struct ff_timecode tc;
     AVStream *timecode_track;
     int timecode_base;       ///< rounded time code base (25 or 30)
-    int timecode_start;      ///< frame number computed from mpeg-2 gop header timecode
-    int timecode_drop_frame; ///< time code use drop frame method frop mpeg-2 essence gop header
     int edit_unit_byte_count; ///< fixed edit unit byte count
     uint64_t body_offset;
     uint32_t instance_number;
@@ -666,7 +667,7 @@ static void mxf_write_timecode_component(AVFormatContext *s, AVStream *st, enum
 
     // Start Time Code
     mxf_write_local_tag(pb, 8, 0x1501);
-    avio_wb64(pb, mxf->timecode_start);
+    avio_wb64(pb, mxf->tc.start);
 
     // Rounded Time Code Base
     mxf_write_local_tag(pb, 2, 0x1502);
@@ -674,7 +675,7 @@ static void mxf_write_timecode_component(AVFormatContext *s, AVStream *st, enum
 
     // Drop Frame
     mxf_write_local_tag(pb, 1, 0x1503);
-    avio_w8(pb, mxf->timecode_drop_frame);
+    avio_w8(pb, mxf->tc.drop);
 }
 
 static void mxf_write_structural_component(AVFormatContext *s, AVStream *st, enum MXFMetadataSetType type)
@@ -1310,7 +1311,6 @@ static int mxf_parse_mpeg2_frame(AVFormatContext *s, AVStream *st,
                                  AVPacket *pkt, MXFIndexEntry *e)
 {
     MXFStreamContext *sc = st->priv_data;
-    MXFContext *mxf = s->priv_data;
     uint32_t c = -1;
     int i;
 
@@ -1330,21 +1330,6 @@ static int mxf_parse_mpeg2_frame(AVFormatContext *s, AVStream *st,
                 if (e->flags & 0x40) // sequence header present
                     e->flags |= 0x80; // random access
             }
-            if (!mxf->header_written) {
-                unsigned hours   =  (pkt->data[i+1]>>2) & 0x1f;
-                unsigned minutes = ((pkt->data[i+1] & 0x03) << 4) | (pkt->data[i+2]>>4);
-                unsigned seconds = ((pkt->data[i+2] & 0x07) << 3) | (pkt->data[i+3]>>5);
-                unsigned frames  = ((pkt->data[i+3] & 0x1f) << 1) | (pkt->data[i+4]>>7);
-                mxf->timecode_drop_frame = !!(pkt->data[i+1] & 0x80);
-                mxf->timecode_start = (hours*3600 + minutes*60 + seconds) *
-                    mxf->timecode_base + frames;
-                if (mxf->timecode_drop_frame) {
-                    unsigned tminutes = 60 * hours + minutes;
-                    mxf->timecode_start -= 2 * (tminutes - tminutes / 10);
-                }
-                av_log(s, AV_LOG_DEBUG, "frame %d %d:%d:%d%c%d\n", mxf->timecode_start,
-                       hours, minutes, seconds, mxf->timecode_drop_frame ? ';':':', frames);
-            }
         } else if (c == 0x1b3) { // seq
             e->flags |= 0x40;
             switch ((pkt->data[i+4]>>4) & 0xf) {
@@ -1440,6 +1425,12 @@ static int mxf_write_header(AVFormatContext *s)
                 return -1;
             }
             av_set_pts_info(st, 64, mxf->time_base.num, mxf->time_base.den);
+            if (mxf->tc.str) {
+                mxf->tc.rate.num = mxf->time_base.den;
+                mxf->tc.rate.den = mxf->time_base.num;
+                if (ff_init_smtpe_timecode(s, &mxf->tc) < 0)
+                    return -1;
+            }
             if (s->oformat == &ff_mxf_d10_muxer) {
                 if (st->codec->bit_rate == 50000000)
                     if (mxf->time_base.den == 25) sc->index = 3;
@@ -1554,7 +1545,7 @@ static void mxf_write_system_item(AVFormatContext *s)
     unsigned frame;
     uint32_t time_code;
 
-    frame = mxf->timecode_start + mxf->last_indexed_edit_unit + mxf->edit_units_count;
+    frame = mxf->tc.start + mxf->last_indexed_edit_unit + mxf->edit_units_count;
 
     // write system metadata pack
     avio_write(pb, system_metadata_pack_key, 16);
@@ -1576,7 +1567,7 @@ static void mxf_write_system_item(AVFormatContext *s)
 
     avio_w8(pb, 0x81); // SMPTE 12M time code
     time_code = ff_framenum_to_smtpe_timecode(frame, mxf->timecode_base,
-                                              mxf->timecode_drop_frame);
+                                              mxf->tc.drop);
     avio_wb32(pb, time_code);
     avio_wb32(pb, 0); // binary group data
     avio_wb64(pb, 0);
@@ -1873,6 +1864,16 @@ static int mxf_interleave(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int
                                mxf_interleave_get_packet, mxf_compare_timestamps);
 }
 
+static const AVClass class = {
+    .class_name = "mxf",
+    .item_name  = av_default_item_name,
+    .version    = LIBAVUTIL_VERSION_INT,
+    .option     = (const AVOption[]){
+        {TIMECODE_OPT(MXFContext, AV_OPT_FLAG_ENCODING_PARAM)},
+        {NULL}
+    },
+};
+
 AVOutputFormat ff_mxf_muxer = {
     .name              = "mxf",
     .long_name         = NULL_IF_CONFIG_SMALL("Material eXchange Format"),
@@ -1886,6 +1887,7 @@ AVOutputFormat ff_mxf_muxer = {
     .write_trailer     = mxf_write_footer,
     .flags             = AVFMT_NOTIMESTAMPS,
     .interleave_packet = mxf_interleave,
+    .priv_class        = &class,
 };
 
 AVOutputFormat ff_mxf_d10_muxer = {
@@ -1900,4 +1902,5 @@ AVOutputFormat ff_mxf_d10_muxer = {
     .write_trailer     = mxf_write_footer,
     .flags             = AVFMT_NOTIMESTAMPS,
     .interleave_packet = mxf_interleave,
+    .priv_class        = &class,
 };

tests/lavf-regression.sh

@@ -63,7 +63,7 @@ do_lavf mpg
 fi
 
 if [ -n "$do_mxf" ] ; then
-do_lavf mxf "-ar 48000 -bf 2 -timecode_frame_start 264363"
+do_lavf mxf "-ar 48000 -bf 2 -timecode 02:56:14:13"
 fi
 
 if [ -n "$do_mxf_d10" ]; then