[FFmpeg-devel] [PATCH] avformat/vpcc: fix vpcC generation for RTMP

[Alessandro Ros]

In order to send VP9 tracks with RTMP, the enhanced RTMP specification
tells that VPCodecConfigurationRecord, a.k.a. vpcC ISO-BMFF box, must
be inserted into a metadata message. However, the function responsible
for generating vpcCs currently returns invalid boxes, that are lacking
the Version and Flag fields, inherited from FullBox. For some reason,
both flags were being added manually in movenc. This patch fixes the
issue.

Signed-off-by: Alessandro Ros <aler9.dev at gmail.com>
---
  libavformat/movenc.c | 3 ---
  libavformat/vpcc.c   | 2 ++
  2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 7ef6cef46a..696ae5a6c9 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1441,10 +1441,7 @@ static int mov_write_vpcc_tag(AVFormatContext *s, 
AVIOContext *pb, MOVTrack *tra
       avio_wb32(pb, 0);
      ffio_wfourcc(pb, "vpcC");
-    avio_w8(pb, 1); /* version */
-    avio_wb24(pb, 0); /* flags */
      ff_isom_write_vpcc(s, pb, track->vos_data, track->vos_len, 
track->par);
-
      return update_size(pb, pos);
  }

diff --git a/libavformat/vpcc.c b/libavformat/vpcc.c
index ea66959abf..256407dd6d 100644
--- a/libavformat/vpcc.c
+++ b/libavformat/vpcc.c
@@ -208,6 +208,8 @@ int ff_isom_write_vpcc(AVFormatContext *s, 
AVIOContext *pb,
      if (ret < 0)
          return ret;

+    avio_w8(pb, 1); /* version */
+    avio_wb24(pb, 0); /* flags */
      avio_w8(pb, vpcc.profile);
      avio_w8(pb, vpcc.level);
      avio_w8(pb, (vpcc.bitdepth << 4) | (vpcc.chroma_subsampling << 1) 
| vpcc.full_range_flag);
-- 
2.34.1