[FFmpeg-devel] [PATCH v2] mpegts: Add support for preserving SMPTE 2038 when transcoding MPEG-TS streams

[Devin Heitmueller]

Add the appropriate descriptors to the MPEG-TS demux and mux to
ensure that SMPTE 2038 VANC streams are properly preserved
when using codec copy (including adding the appropriate PMT
descriptors).

The focus of this patch is TS input to TS output.  A separate
patch adds support for output of 2038 VANC over decklink SDI.

Thanks to Marton Balint for feedback to preserve ABI compatibility.

Signed-off-by: Devin Heitmueller <dheitmueller at ltnglobal.com>
---
 libavcodec/codec_desc.c | 6 ++++++
 libavcodec/codec_id.h   | 1 +
 libavformat/mpegts.c    | 1 +
 libavformat/mpegtsenc.c | 5 +++++
 libavformat/mux.c       | 6 ++++--
 5 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index e80ac07700..d912704891 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -3627,6 +3627,12 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("binary data"),
         .mime_types= MT("application/octet-stream"),
     },
+    {
+        .id        = AV_CODEC_ID_SMPTE_2038,
+        .type      = AVMEDIA_TYPE_DATA,
+        .name      = "smpte_2038",
+        .long_name = NULL_IF_CONFIG_SMALL("SMPTE ST 2038 VANC in MPEG-2 TS"),
+    },
     {
         .id        = AV_CODEC_ID_MPEG2TS,
         .type      = AVMEDIA_TYPE_DATA,
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index 89a4a0cb89..64df9699f4 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -582,6 +582,7 @@ enum AVCodecID {
     AV_CODEC_ID_DVD_NAV,
     AV_CODEC_ID_TIMED_ID3,
     AV_CODEC_ID_BIN_DATA,
+    AV_CODEC_ID_SMPTE_2038,
 
 
     AV_CODEC_ID_PROBE = 0x19000, ///< codec_id is not known (like AV_CODEC_ID_NONE) but lavf should attempt to identify it
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index d97702fcd7..a8fa3c0b28 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -866,6 +866,7 @@ static const StreamType REGD_types[] = {
     { MKTAG('E', 'A', 'C', '3'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_EAC3  },
     { MKTAG('H', 'E', 'V', 'C'), AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_HEVC  },
     { MKTAG('K', 'L', 'V', 'A'), AVMEDIA_TYPE_DATA,  AV_CODEC_ID_SMPTE_KLV },
+    { MKTAG('V', 'A', 'N', 'C'), AVMEDIA_TYPE_DATA,  AV_CODEC_ID_SMPTE_2038 },
     { MKTAG('I', 'D', '3', ' '), AVMEDIA_TYPE_DATA,  AV_CODEC_ID_TIMED_ID3 },
     { MKTAG('V', 'C', '-', '1'), AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_VC1   },
     { MKTAG('O', 'p', 'u', 's'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_OPUS  },
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 3f201cce1d..0b38555362 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -422,6 +422,9 @@ static int get_dvb_stream_type(AVFormatContext *s, AVStream *st)
     case AV_CODEC_ID_TIMED_ID3:
         stream_type = STREAM_TYPE_METADATA;
         break;
+    case AV_CODEC_ID_SMPTE_2038:
+        stream_type = STREAM_TYPE_PRIVATE_DATA;
+        break;
     case AV_CODEC_ID_DVB_SUBTITLE:
     case AV_CODEC_ID_DVB_TELETEXT:
     case AV_CODEC_ID_ARIB_CAPTION:
@@ -804,6 +807,8 @@ static int mpegts_write_pmt(AVFormatContext *s, MpegTSService *service)
         case AVMEDIA_TYPE_DATA:
             if (codec_id == AV_CODEC_ID_SMPTE_KLV) {
                 put_registration_descriptor(&q, MKTAG('K', 'L', 'V', 'A'));
+            } else if (st->codecpar->codec_id == AV_CODEC_ID_SMPTE_2038) {
+                put_registration_descriptor(&q, MKTAG('V', 'A', 'N', 'C'));
             } else if (codec_id == AV_CODEC_ID_TIMED_ID3) {
                 const char *tag = "ID3 ";
                 *q++ = METADATA_DESCRIPTOR;
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 04de05ec17..0bc9b6b87d 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -304,7 +304,8 @@ FF_ENABLE_DEPRECATION_WARNINGS
                 par->codec_tag = av_codec_get_tag(of->p.codec_tag, par->codec_id);
         }
 
-        if (par->codec_type != AVMEDIA_TYPE_ATTACHMENT)
+        if (par->codec_type != AVMEDIA_TYPE_ATTACHMENT &&
+            par->codec_id != AV_CODEC_ID_SMPTE_2038)
             si->nb_interleaved_streams++;
     }
     si->interleave_packet = of->interleave_packet;
@@ -942,7 +943,8 @@ int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *pkt,
             ++stream_count;
         } else if (par->codec_type != AVMEDIA_TYPE_ATTACHMENT &&
                    par->codec_id != AV_CODEC_ID_VP8 &&
-                   par->codec_id != AV_CODEC_ID_VP9) {
+                   par->codec_id != AV_CODEC_ID_VP9 &&
+                   par->codec_id != AV_CODEC_ID_SMPTE_2038) {
             ++noninterleaved_count;
         }
     }
-- 
2.35.1.655.ga68dfadae5