avformat/avienc: Fix memleaks on errors

Fixes CID1361951

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/avienc.c

@@ -728,10 +728,10 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
         } else
             reshuffle_ret = 0;
         if (par->format == AV_PIX_FMT_PAL8) {
-            int ret2 = ff_get_packet_palette(s, opkt, reshuffle_ret, avist->palette);
-            if (ret2 < 0)
-                return ret2;
-            if (ret2) {
+            ret = ff_get_packet_palette(s, opkt, reshuffle_ret, avist->palette);
+            if (ret < 0)
+                goto fail;
+            if (ret) {
                 int pal_size = 1 << par->bits_per_coded_sample;
                 int pc_tag, i;
 
@@ -763,7 +763,7 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
                         ret = avi_add_ientry(s, stream_index, tag, AVIIF_NO_TIME,
                                        pal_size * 4 + 4);
                         if (ret < 0)
-                            return ret;
+                            goto fail;
                     }
                     pc_tag = ff_start_tag(pb, tag);
                     avio_w8(pb, 0);
@@ -780,7 +780,10 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
         }
         if (reshuffle_ret) {
             ret = avi_write_packet_internal(s, pkt);
-            av_packet_free(&pkt);
+
+fail:
+            if (reshuffle_ret)
+                av_packet_free(&pkt);
             return ret;
         }
     }