Message ID | 20190920182431.2906-1-michael@niedermayer.cc |
---|---|
State | Accepted |
Commit | c7c0229bebbb2ea6eec6eddb75774eca3e33d075 |
Headers | show |
Michael Niedermayer: > This avoids some invalid shifts > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/truespeech.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/libavcodec/truespeech.c b/libavcodec/truespeech.c > index d4ddfcbf9c..54352851b3 100644 > --- a/libavcodec/truespeech.c > +++ b/libavcodec/truespeech.c > @@ -132,8 +132,7 @@ static void truespeech_correlate_filter(TSContext *dec) > if(i > 0){ > memcpy(tmp, dec->cvector, i * sizeof(*tmp)); > for(j = 0; j < i; j++) > - dec->cvector[j] = ((tmp[i - j - 1] * dec->vector[i]) + > - (dec->cvector[j] << 15) + 0x4000) >> 15; > + dec->cvector[j] += (tmp[i - j - 1] * dec->vector[i] + 0x4000) >> 15; > } > dec->cvector[i] = (8 - dec->vector[i]) >> 3; > } > @@ -256,7 +255,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) > int sum = 0; > for(k = 0; k < 8; k++) > sum += ptr0[k] * ptr1[k]; > - sum = (sum + (out[i] << 12) + 0x800) >> 12; > + sum = out[i] + ((sum + 0x800) >> 12); > out[i] = av_clip(sum, -0x7FFE, 0x7FFE); > for(k = 7; k > 0; k--) > ptr0[k] = ptr0[k - 1]; > @@ -274,7 +273,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) > for(k = 7; k > 0; k--) > ptr0[k] = ptr0[k - 1]; > ptr0[0] = out[i]; > - out[i] = ((out[i] << 12) - sum) >> 12; > + out[i] += (- sum) >> 12; > } > > for(i = 0; i < 8; i++) > LGTM. - Andreas PS: My first patch for this (never sent to the ML) was exactly as yours until I dropped this approach because (x << shift) >> shift is not the identity, but may change the high bits. Then I switched to using multiplications and checked that they don't overflow, because one factor is always an int16_t. At this point I should have realized that my first approach was viable, but somehow didn't.
On Sun, Sep 22, 2019 at 09:02:00AM +0000, Andreas Rheinhardt wrote: > Michael Niedermayer: > > This avoids some invalid shifts > > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/truespeech.c | 7 +++---- > > 1 file changed, 3 insertions(+), 4 deletions(-) > > > > diff --git a/libavcodec/truespeech.c b/libavcodec/truespeech.c > > index d4ddfcbf9c..54352851b3 100644 > > --- a/libavcodec/truespeech.c > > +++ b/libavcodec/truespeech.c > > @@ -132,8 +132,7 @@ static void truespeech_correlate_filter(TSContext *dec) > > if(i > 0){ > > memcpy(tmp, dec->cvector, i * sizeof(*tmp)); > > for(j = 0; j < i; j++) > > - dec->cvector[j] = ((tmp[i - j - 1] * dec->vector[i]) + > > - (dec->cvector[j] << 15) + 0x4000) >> 15; > > + dec->cvector[j] += (tmp[i - j - 1] * dec->vector[i] + 0x4000) >> 15; > > } > > dec->cvector[i] = (8 - dec->vector[i]) >> 3; > > } > > @@ -256,7 +255,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) > > int sum = 0; > > for(k = 0; k < 8; k++) > > sum += ptr0[k] * ptr1[k]; > > - sum = (sum + (out[i] << 12) + 0x800) >> 12; > > + sum = out[i] + ((sum + 0x800) >> 12); > > out[i] = av_clip(sum, -0x7FFE, 0x7FFE); > > for(k = 7; k > 0; k--) > > ptr0[k] = ptr0[k - 1]; > > @@ -274,7 +273,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) > > for(k = 7; k > 0; k--) > > ptr0[k] = ptr0[k - 1]; > > ptr0[0] = out[i]; > > - out[i] = ((out[i] << 12) - sum) >> 12; > > + out[i] += (- sum) >> 12; > > } > > > > for(i = 0; i < 8; i++) > > > LGTM. will apply thx [...]
diff --git a/libavcodec/truespeech.c b/libavcodec/truespeech.c index d4ddfcbf9c..54352851b3 100644 --- a/libavcodec/truespeech.c +++ b/libavcodec/truespeech.c @@ -132,8 +132,7 @@ static void truespeech_correlate_filter(TSContext *dec) if(i > 0){ memcpy(tmp, dec->cvector, i * sizeof(*tmp)); for(j = 0; j < i; j++) - dec->cvector[j] = ((tmp[i - j - 1] * dec->vector[i]) + - (dec->cvector[j] << 15) + 0x4000) >> 15; + dec->cvector[j] += (tmp[i - j - 1] * dec->vector[i] + 0x4000) >> 15; } dec->cvector[i] = (8 - dec->vector[i]) >> 3; } @@ -256,7 +255,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) int sum = 0; for(k = 0; k < 8; k++) sum += ptr0[k] * ptr1[k]; - sum = (sum + (out[i] << 12) + 0x800) >> 12; + sum = out[i] + ((sum + 0x800) >> 12); out[i] = av_clip(sum, -0x7FFE, 0x7FFE); for(k = 7; k > 0; k--) ptr0[k] = ptr0[k - 1]; @@ -274,7 +273,7 @@ static void truespeech_synth(TSContext *dec, int16_t *out, int quart) for(k = 7; k > 0; k--) ptr0[k] = ptr0[k - 1]; ptr0[0] = out[i]; - out[i] = ((out[i] << 12) - sum) >> 12; + out[i] += (- sum) >> 12; } for(i = 0; i < 8; i++)
This avoids some invalid shifts Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/truespeech.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)