[FFmpeg-cvslog] celp_math: cleanup ff_dot_product()

[Vitor Sessak]

On Thu, Sep 29, 2011 at 10:09 PM, Michael Niedermayer <git at videolan.org> wrote:
> ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu Sep 29 21:21:26 2011 +0200| [11512367d3c6f67b093b54c532328763c9b815e2] | committer: Michael Niedermayer
>
> celp_math: cleanup ff_dot_product()
> based on code & idea by vitor
>
> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
>
>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=11512367d3c6f67b093b54c532328763c9b815e2
> ---
>
>  libavcodec/celp_math.c |   12 ++++++------
>  libavcodec/celp_math.h |    3 +--
>  libavcodec/g723_1.c    |   18 +++++++++---------
>  3 files changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/libavcodec/celp_math.c b/libavcodec/celp_math.c
> index b78edd1..a00bb39 100644
> --- a/libavcodec/celp_math.c
> +++ b/libavcodec/celp_math.c
> @@ -197,14 +197,14 @@ int ff_log2(uint32_t value)
>     return (power_int << 15) + value;
>  }
>
> -int ff_dot_product(const int16_t *a, const int16_t *b, int length, int shift)
> +int ff_dot_product(const int16_t *a, const int16_t *b, int length)
>  {
> -    int i, sum = 0;
> +    int i;
> +    int64_t sum = 0;
> +
> +    for (i = 0; i < length; i++)
> +        sum += MUL16(a[i], b[i]);
>
> -    for (i = 0; i < length; i++) {
> -        int64_t prod = av_clipl_int32(MUL64(a[i], b[i]) << shift);
> -        sum = av_clipl_int32(sum + prod);
> -    }
>     return sum;
>  }

Hmmm, are you sure you didn't meant to return a int64_t?

Also, I'm afraid that after this change (and a few other cleanup) the
decoder is not bit-identical anymore to the reference decoder. Have
you tested?

-Vitor