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| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-01-20 20:20:42 +0100 |
|---|---|---|
| committer | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-05-20 04:05:39 +0200 |
| commit | dfe0d907c2258bb9c81b8c65e42cec2b3022d5e8 (patch) | |
| tree | 8f9e31a45247d6af0afedcc7fa132b8307244ed9 | |
| parent | 4f17205a510d2d54054f12541c4a209dc76cc197 (diff) | |
| download | ffmpeg-dfe0d907c2258bb9c81b8c65e42cec2b3022d5e8.tar.gz | |
avcodec/adxenc: Avoid undefined left shift of negative numbers
Replace "((a << shift) + b) >> shift" by "a + (b >> shift)". This avoids
a left shift which also happens to trigger undefined behaviour in case "a"
is negative. This affected the FATE-tests acodec-adpcm-adx and
acodec-adpcm-adx-trellis; it also fixes ticket #8008.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 59a9d65e0d790821f88527a82569f56eb2f8a9be)
| -rw-r--r-- | libavcodec/adxenc.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/libavcodec/adxenc.c b/libavcodec/adxenc.c index f1ba5911b3..77f6bf0487 100644 --- a/libavcodec/adxenc.c +++ b/libavcodec/adxenc.c @@ -48,7 +48,7 @@ static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav, s2 = prev->s2; for (i = 0, j = 0; j < 32; i += channels, j++) { s0 = wav[i]; - d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; + d = s0 + ((-c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS); if (max < d) max = d; if (min > d) @@ -79,13 +79,13 @@ static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav, s1 = prev->s1; s2 = prev->s2; for (i = 0, j = 0; j < 32; i += channels, j++) { - d = ((wav[i] << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; + d = wav[i] + ((-c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS); d = av_clip_intp2(ROUNDED_DIV(d, scale), 3); put_sbits(&pb, 4, d); - s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS; + s0 = d * scale + ((c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS); s2 = s1; s1 = s0; } |