[FFmpeg-devel] [PATCH 1/2] avcodec/g729postfilter: Fix left shift of negative value

[Paul B Mahol]

lgtm

On 10/17/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> Fixes: Ticket8176
>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/g729postfilter.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/g729postfilter.c b/libavcodec/g729postfilter.c
> index ef4fec4c95..fc9a8d54cc 100644
> --- a/libavcodec/g729postfilter.c
> +++ b/libavcodec/g729postfilter.c
> @@ -346,7 +346,7 @@ static int16_t long_term_filter(AudioDSPContext *adsp,
> int pitch_delay_int,
>          L_temp1 = gain_long_num * gain_long_num;
>          L_temp1 = MULL(L_temp1, gain_den, FRAC_BITS);
>
> -        tmp = ((sh_gain_long_num - sh_gain_num) << 1) - (sh_gain_long_den -
> sh_gain_den);
> +        tmp = ((sh_gain_long_num - sh_gain_num) * 2) - (sh_gain_long_den -
> sh_gain_den);
>          if (tmp > 0)
>              L_temp0 >>= tmp;
>          else
> @@ -367,7 +367,7 @@ static int16_t long_term_filter(AudioDSPContext *adsp,
> int pitch_delay_int,
>          /* Rescale selected signal to original value. */
>          if (shift > 0)
>              for (i = 0; i < subframe_size; i++)
> -                selected_signal[i] <<= shift;
> +                selected_signal[i] *= 1 << shift;
>          else
>              for (i = 0; i < subframe_size; i++)
>                  selected_signal[i] >>= -shift;
> @@ -464,7 +464,7 @@ static int16_t get_tilt_comp(AudioDSPContext *adsp,
> int16_t *lp_gn,
>              speech[i] = (speech[i] * temp + 0x4000) >> 15;
>      }
>
> -    return -(rh1 << 15) / rh0;
> +    return -(rh1 * (1 << 15)) / rh0;
>  }
>
>  /**
> --
> 2.23.0
>
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