From ef68cfcc8a1f0179bbdade48225907a881ba0abd Mon Sep 17 00:00:00 2001
From: Ben Boeckel <mathstuf@gmail.com>
Date: Fri, 18 Oct 2013 21:50:08 -0400
Subject: demux_lavf: get updated metadata from a packet if available

The side_data type is brand new in ffmpeg.
---
 demux/demux_lavf.c | 25 +++++++++++++++++++++++++
 old-configure      | 12 ++++++++++++
 wscript            |  6 ++++++
 3 files changed, 43 insertions(+)

diff --git a/demux/demux_lavf.c b/demux/demux_lavf.c
index 6c440bcb23..c92e4850b2 100644
--- a/demux/demux_lavf.c
+++ b/demux/demux_lavf.c
@@ -518,6 +518,23 @@ static void add_metadata(demuxer_t *demuxer, AVDictionary *metadata)
         demux_info_add(demuxer, t->key, t->value);
 }
 
+static void update_metadata(demuxer_t *demuxer, AVPacket *pkt)
+{
+#if HAVE_AVCODEC_METADATA_UPDATE_SIDE_DATA
+    int md_size;
+    const uint8_t *md;
+    md = av_packet_get_side_data(pkt, AV_PKT_DATA_METADATA_UPDATE, &md_size);
+    if (md) {
+        AVDictionary *dict = NULL;
+        av_packet_unpack_dictionary(md, md_size, &dict);
+        if (dict) {
+            add_metadata(demuxer, dict);
+            av_dict_free(&dict);
+        }
+    }
+#endif
+}
+
 static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
 {
     struct MPOpts *opts = demuxer->opts;
@@ -542,6 +559,12 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
         avfc->flags |= AVFMT_FLAG_GENPTS;
     if (opts->index_mode == 0)
         avfc->flags |= AVFMT_FLAG_IGNIDX;
+    /* Keep side data as side data instead of mashing it into the packet
+     * stream. */
+    if (av_opt_set(avfc, "fflags", "+keepside", 0) < 0) {
+        MP_WARN(demuxer, "demux_lavf, couldn't set option keepdata; "
+                "in-stream metadata updates will be ignored\n");
+    }
 
     if (lavfdopts->probesize) {
         if (av_opt_set_int(avfc, "probesize", lavfdopts->probesize, 0) < 0)
@@ -705,6 +728,8 @@ static int demux_lavf_fill_buffer(demuxer_t *demux)
     if (av_dup_packet(pkt) < 0)
         abort();
 
+    update_metadata(demux, pkt);
+
     dp = new_demux_packet_fromdata(pkt->data, pkt->size);
     dp->avpacket = talloc_steal(dp, pkt);
 
diff --git a/old-configure b/old-configure
index 8dffab00f7..c26c7742cf 100755
--- a/old-configure
+++ b/old-configure
@@ -2750,6 +2750,17 @@ fi
 echores "$_avcodec_has_chroma_pos_api"
 
 
+echocheck "libavcodec metadata update side data"
+_avcodec_has_metadata_update_side_data=no
+statement_check libavcodec/avcodec.h 'enum AVPacketSideDataType type = AV_PKT_DATA_METADATA_UPDATE' && _avcodec_has_metadata_update_side_data=yes
+if test "$_avcodec_has_metadata_update_side_data" = yes ; then
+  def_avcodec_has_metadata_update_side_data='#define HAVE_AVCODEC_METADATA_UPDATE_SIDE_DATA 1'
+else
+  def_avcodec_has_metadata_update_side_data='#define HAVE_AVCODEC_METADATA_UPDATE_SIDE_DATA 0'
+fi
+echores "$_avcodec_has_metadata_update_side_data"
+
+
 echocheck "libavutil QP API"
 _avutil_has_qp_api=no
 statement_check libavutil/frame.h 'av_frame_get_qp_table(NULL, NULL, NULL)' && _avutil_has_qp_api=yes
@@ -3454,6 +3465,7 @@ $def_avutil_has_refcounting
 $def_avutil_has_qp_api
 $def_avcodec_new_vdpau_api
 $def_avcodec_has_chroma_pos_api
+$def_avcodec_has_metadata_update_side_data
 $def_libpostproc
 $def_libavdevice
 $def_libavfilter
diff --git a/wscript b/wscript
index 479cc6ec73..3c9373e295 100644
--- a/wscript
+++ b/wscript
@@ -396,6 +396,12 @@ Libav libraries ({0}). Aborting.".format(" ".join(libav_pkg_config_checks))
         'name': '--libpostproc',
         'desc': 'libpostproc',
         'func': check_pkg_config('libpostproc', '>= 52.0.0'),
+    }, {
+        'name': 'avcodec-metadata-update-side-data',
+        'desc': 'libavcodec AV_PKT_DATA_METADATA_UPDATE side data type',
+        'func': check_statement('libavcodec/avcodec.h',
+                                'enum AVPacketSideDataType type = AV_PKT_DATA_METADATA_UPDATE',
+                                use='libav')
     }
 ]
 
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