avcodec/tscc2: Skip duplicate frames

This turns CFR duplicated frames into skiped frames

Fixes: Timeout
Fixes: 1719/clusterfuzz-testcase-minimized-6375090079924224

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

1 files changed, 5 insertions, 8 deletions

diff --git a/libavcodec/tscc2.c b/libavcodec/tscc2.c
index f64c76507e..a8c7ee7996 100644
--- a/libavcodec/tscc2.c
+++ b/libavcodec/tscc2.c
@@ -235,18 +235,15 @@ static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
         return AVERROR_INVALIDDATA;
     }
 
-    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) {
-        return ret;
-    }
-
     if (frame_type == 0) {
-        *got_frame      = 1;
-        if ((ret = av_frame_ref(data, c->pic)) < 0)
-            return ret;
-
+        // Skip duplicate frames
         return buf_size;
     }
 
+    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) {
+        return ret;
+    }
+
     if (bytestream2_get_bytes_left(&gb) < 4) {
         av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
         return AVERROR_INVALIDDATA;