This should fix the undefined behavior reported in: https://trac.ffmpeg.org/ticket/4727.
I can reproduce this at runtime: simply stick in an abort call in asym_quant to check if c < 0 and run FATE. I don't know ac3 so I can't confirm if negative coefficients are intentional, but at the moment they clearly are according to FATE. This resolves the undefined behavior. Tested with FATE. Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> --- libavcodec/ac3enc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c index 35e721a..c8a0caa 100644 --- a/libavcodec/ac3enc.c +++ b/libavcodec/ac3enc.c @@ -1183,7 +1183,7 @@ static inline int asym_quant(int c, int e, int qbits) { int m; - c = (((c << e) >> (24 - qbits)) + 1) >> 1; + c = (((c * (1<<e)) >> (24 - qbits)) + 1) >> 1; m = (1 << (qbits-1)); if (c >= m) c = m - 1; -- 2.6.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel