avformat/movenc: Factor check_pkt() out

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit deabcd2c05)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/movenc.c

@@ -4296,15 +4296,10 @@ static int mov_auto_flush_fragment(AVFormatContext *s)
     return ret;
 }
 
-int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
+static int check_pkt(AVFormatContext *s, AVPacket *pkt)
 {
     MOVMuxContext *mov = s->priv_data;
-    AVIOContext *pb = s->pb;
     MOVTrack *trk = &mov->tracks[pkt->stream_index];
-    AVCodecContext *enc = trk->enc;
-    unsigned int samples_in_chunk = 0;
-    int size = pkt->size, ret = 0;
-    uint8_t *reformatted_data = NULL;
 
     if (trk->entry) {
         int64_t duration = pkt->dts - trk->cluster[trk->entry - 1].dts;
@@ -4321,6 +4316,23 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
             return AVERROR(EINVAL);
         }
     }
+    return 0;
+}
+
+int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    MOVMuxContext *mov = s->priv_data;
+    AVIOContext *pb = s->pb;
+    MOVTrack *trk = &mov->tracks[pkt->stream_index];
+    AVCodecContext *enc = trk->enc;
+    unsigned int samples_in_chunk = 0;
+    int size = pkt->size, ret = 0;
+    uint8_t *reformatted_data = NULL;
+
+    ret = check_pkt(s, pkt);
+    if (ret < 0)
+        return ret;
+
     if (mov->flags & FF_MOV_FLAG_FRAGMENT) {
         int ret;
         if (mov->moov_written || mov->flags & FF_MOV_FLAG_EMPTY_MOOV) {