avformat/tiertexseq: Cleanup on error

Fixes: memleak
Fixes: 15122/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5685964636160000

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/tiertexseq.c

@@ -202,16 +202,20 @@ static int seq_read_header(AVFormatContext *s)
 
     /* init internal buffers */
     rc = seq_init_frame_buffers(seq, pb);
-    if (rc)
+    if (rc) {
+        seq_read_close(s);
         return rc;
+    }
 
     seq->current_frame_offs = 0;
 
     /* preload (no audio data, just buffer operations related data) */
     for (i = 1; i <= 100; i++) {
         rc = seq_parse_frame_data(seq, pb);
-        if (rc)
+        if (rc) {
+            seq_read_close(s);
             return rc;
+        }
     }
 
     seq->current_frame_pts = 0;
@@ -220,8 +224,10 @@ static int seq_read_header(AVFormatContext *s)
 
     /* initialize the video decoder stream */
     st = avformat_new_stream(s, NULL);
-    if (!st)
+    if (!st) {
+        seq_read_close(s);
         return AVERROR(ENOMEM);
+    }
 
     avpriv_set_pts_info(st, 32, 1, SEQ_FRAME_RATE);
     seq->video_stream_index = st->index;
@@ -233,8 +239,10 @@ static int seq_read_header(AVFormatContext *s)
 
     /* initialize the audio decoder stream */
     st = avformat_new_stream(s, NULL);
-    if (!st)
+    if (!st) {
+        seq_read_close(s);
         return AVERROR(ENOMEM);
+    }
 
     st->start_time = 0;
     avpriv_set_pts_info(st, 32, 1, SEQ_SAMPLE_RATE);