[FFmpeg-cvslog] avcodec/g729dec: Avoid computing invalid temporary pointers for ff_acelp_weighted_vector_sum()

[Michael Niedermayer]

ffmpeg | branch: release/3.2 | Michael Niedermayer <michael at niedermayer.cc> | Thu Oct 17 11:54:12 2019 +0200| [abf9627f70ed8467b1646d56205e61f965f11468] | committer: Michael Niedermayer

avcodec/g729dec: Avoid computing invalid temporary pointers for ff_acelp_weighted_vector_sum()

Fixes: Ticket8176

Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 2c78a76cb0443f8a12a5eadc3b58373aa2f4ab22)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=abf9627f70ed8467b1646d56205e61f965f11468
---

 libavcodec/g729dec.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/libavcodec/g729dec.c b/libavcodec/g729dec.c
index 908c12a73a..943ddf5297 100644
--- a/libavcodec/g729dec.c
+++ b/libavcodec/g729dec.c
@@ -536,12 +536,13 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
           fc_v[i] = <
                      \ fc_v[i] + gain_pitch * fc_v[i-pitch_delay], i >= pitch_delay
         */
-        ff_acelp_weighted_vector_sum(fc + pitch_delay_int[i],
-                                     fc + pitch_delay_int[i],
-                                     fc, 1 << 14,
-                                     av_clip(ctx->past_gain_pitch[0], SHARP_MIN, SHARP_MAX),
-                                     0, 14,
-                                     SUBFRAME_SIZE - pitch_delay_int[i]);
+        if (SUBFRAME_SIZE > pitch_delay_int[i])
+            ff_acelp_weighted_vector_sum(fc + pitch_delay_int[i],
+                                         fc + pitch_delay_int[i],
+                                         fc, 1 << 14,
+                                         av_clip(ctx->past_gain_pitch[0], SHARP_MIN, SHARP_MAX),
+                                         0, 14,
+                                         SUBFRAME_SIZE - pitch_delay_int[i]);
 
         memmove(ctx->past_gain_pitch+1, ctx->past_gain_pitch, 5 * sizeof(int16_t));
         ctx->past_gain_code[1] = ctx->past_gain_code[0];