[FFmpeg-devel] [PATCH 2/2] avformat/mxfenc: fix DNxHD GC element_type

[Nicolas Gaullier]

The values for the essence element type were updated in the spec
from 0x05/0x06 (ST2019-4 2008) to 0x0C/0x0D (ST2019-4 2009).

Fixes ticket #6380.

Thanks-to: Philip de Nier <philip.denier at bbc.co.uk>
Thanks-to: Matthieu Bouron <matthieu.bouron at gmail.com>

Signed-off-by: Nicolas Gaullier <nicolas.gaullier at cji.paris>
---
 libavformat/mxfenc.c      | 9 ++++++++-
 tests/ref/lavf/mxf_opatom | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 512baa45d3..bae41a774d 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -32,6 +32,7 @@
  * SMPTE 379M MXF Generic Container
  * SMPTE 381M Mapping MPEG Streams into the MXF Generic Container
  * SMPTE 422M Mapping JPEG 2000 Codestreams into the MXF Generic Container
+ * SMPTE ST2019-4 (2009 or later) Mapping VC-3 Coding Units into the MXF Generic Container
  * SMPTE RP210: SMPTE Metadata Dictionary
  * SMPTE RP224: Registry of SMPTE Universal Labels
  */
@@ -182,7 +183,7 @@ static const MXFContainerEssenceEntry mxf_essence_container_uls[] = {
       mxf_write_cdci_desc },
     // DNxHD
     { { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x0A,0x0D,0x01,0x03,0x01,0x02,0x11,0x01,0x00 },
-      { 0x06,0x0E,0x2B,0x34,0x01,0x02,0x01,0x01,0x0D,0x01,0x03,0x01,0x15,0x01,0x05,0x00 },
+      { 0x06,0x0E,0x2B,0x34,0x01,0x02,0x01,0x01,0x0D,0x01,0x03,0x01,0x15,0x01,0x0C,0x00 },
       { 0x06,0x0E,0x2B,0x34,0x04,0x01,0x01,0x0A,0x04,0x01,0x02,0x02,0x71,0x01,0x00,0x00 },
       mxf_write_cdci_desc },
     // JPEG2000
@@ -2674,6 +2675,12 @@ static int mxf_init(AVFormatContext *s)
 
         memcpy(sc->track_essence_element_key, mxf_essence_container_uls[sc->index].element_ul, 15);
         sc->track_essence_element_key[15] = present[sc->index];
+        if (s->oformat == &ff_mxf_opatom_muxer && st->codecpar->codec_id == AV_CODEC_ID_DNXHD) {
+            // clip-wrapping requires 0x0D per ST2019-4:2009 or 0x06 per previous version ST2019-4:2008
+            // we choose to use 0x06 instead 0x0D to be compatible with AVID systems
+            // and produce mxf files with the most relevant flavour for opatom
+            sc->track_essence_element_key[14] = 0x06;
+        }
         PRINT_KEY(s, "track essence element key", sc->track_essence_element_key);
 
         if (!present[sc->index])
diff --git a/tests/ref/lavf/mxf_opatom b/tests/ref/lavf/mxf_opatom
index b818f26c36..e34cf2559e 100644
--- a/tests/ref/lavf/mxf_opatom
+++ b/tests/ref/lavf/mxf_opatom
@@ -1,3 +1,3 @@
-e558e50a94d88762e07ab8149aced7b9 *tests/data/lavf/lavf.mxf_opatom
+aab6397829bd90f0c77a3f9fde53bb9c *tests/data/lavf/lavf.mxf_opatom
 4717625 tests/data/lavf/lavf.mxf_opatom
 tests/data/lavf/lavf.mxf_opatom CRC=0xf55aa22a
-- 
2.34.0