[FFmpeg-cvslog] avcodec/wcmv: prevent frame copying when outputting duplicate frames

[James Almer]

ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Tue Sep  3 23:53:46 2019 -0300| [343f8d514e521ea52fc64aab0ddf1d497b0e4cec] | committer: James Almer

avcodec/wcmv: prevent frame copying when outputting duplicate frames

Signed-off-by: James Almer <jamrial at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=343f8d514e521ea52fc64aab0ddf1d497b0e4cec
---

 libavcodec/wcmv.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/libavcodec/wcmv.c b/libavcodec/wcmv.c
index 2f21c1430c..d7a3cbd1b7 100644
--- a/libavcodec/wcmv.c
+++ b/libavcodec/wcmv.c
@@ -45,7 +45,7 @@ static int decode_frame(AVCodecContext *avctx,
 {
     WCMVContext *s = avctx->priv_data;
     AVFrame *frame = data;
-    int skip, blocks, zret, ret, intra = 0, bpp = s->bpp;
+    int skip, blocks, zret, ret, intra = 0, flags = 0, bpp = s->bpp;
     GetByteContext gb;
     uint8_t *dst;
 
@@ -56,11 +56,13 @@ static int decode_frame(AVCodecContext *avctx,
     }
 
     bytestream2_init(&gb, avpkt->data, avpkt->size);
+    blocks = bytestream2_get_le16(&gb);
+    if (!blocks)
+        flags |= FF_REGET_BUFFER_FLAG_READONLY;
 
-    if ((ret = ff_reget_buffer(avctx, s->prev_frame, 0)) < 0)
+    if ((ret = ff_reget_buffer(avctx, s->prev_frame, flags)) < 0)
         return ret;
 
-    blocks = bytestream2_get_le16(&gb);
     if (blocks > 5) {
         GetByteContext bgb;
         int x = 0, size;