avformat/movenc: Make the packet check more tolerant

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/movenc.c

@@ -4666,25 +4666,26 @@ static int check_pkt(AVFormatContext *s, AVPacket *pkt)
 {
     MOVMuxContext *mov = s->priv_data;
     MOVTrack *trk = &mov->tracks[pkt->stream_index];
+    int64_t ref;
+    uint64_t duration;
 
     if (trk->entry) {
-        int64_t duration = pkt->dts - trk->cluster[trk->entry - 1].dts;
-        if (duration < 0 || duration > INT_MAX) {
-            av_log(s, AV_LOG_ERROR, "Application provided duration: %"PRId64" / timestamp: %"PRId64" is out of range for mov/mp4 format\n",
-                duration, pkt->dts
-            );
-
-            pkt->dts = trk->cluster[trk->entry - 1].dts + 1;
-            pkt->pts = AV_NOPTS_VALUE;
-        }
-    } else if (pkt->dts <= INT_MIN || pkt->dts >= INT_MAX) {
-            av_log(s, AV_LOG_ERROR, "Application provided initial timestamp: %"PRId64" is out of range for mov/mp4 format\n",
-                pkt->dts
-            );
+        ref = trk->cluster[trk->entry - 1].dts;
+    } else if (trk->start_dts != AV_NOPTS_VALUE) {
+        ref = trk->start_dts + trk->track_duration;
+    } else
+        ref = pkt->dts; // Skip tests for the first packet
 
-            pkt->dts = 0;
-            pkt->pts = AV_NOPTS_VALUE;
+    duration = pkt->dts - ref;
+    if (pkt->dts < ref || duration >= INT_MAX) {
+        av_log(s, AV_LOG_ERROR, "Application provided duration: %"PRId64" / timestamp: %"PRId64" is out of range for mov/mp4 format\n",
+            duration, pkt->dts
+        );
+
+        pkt->dts = ref + 1;
+        pkt->pts = AV_NOPTS_VALUE;
     }
+
     if (pkt->duration < 0 || pkt->duration > INT_MAX) {
         av_log(s, AV_LOG_ERROR, "Application provided duration: %"PRId64" is invalid\n", pkt->duration);
         return AVERROR(EINVAL);