avformat/mxfenc: Discard audio until valid video has been received

Normally, video packets are muxed before audio packets for mxf (there is
a dedicated interleave function for this); furthermore the first (video)
packet triggers writing the actual header. Yet when the first video packet
fails the checks performed on it, it will be an audio packet that leads
to writing the header and codec_ul (a value set based upon
properties of the bitstream which necessitates actually inspecting
packets) may be wrong. Therefore this commit discards audio packets until
a valid video packet has been received.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 72edaa9e301074a5ac9974eb53717046b774196f..1c668998e2cf1f1591d12dc8ca186dbff6358359 100644 (file)
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -2887,6 +2887,13 @@ static int mxf_write_packet(AVFormatContext *s, AVPacket *pkt)
     MXFIndexEntry ie = {0};
     int err;
 
+    if (!mxf->header_written && pkt->stream_index != 0 &&
+        s->oformat != &ff_mxf_opatom_muxer) {
+        av_log(s, AV_LOG_ERROR, "Received non-video packet before "
+                                "header has been written\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     if (!mxf->cbr_index && !mxf->edit_unit_byte_count && !(mxf->edit_units_count % EDIT_UNITS_PER_BODY)) {
         if ((err = av_reallocp_array(&mxf->index_entries, mxf->edit_units_count
                                      + EDIT_UNITS_PER_BODY, sizeof(*mxf->index_entries))) < 0) {