[FFmpeg-cvslog] r15033 - trunk/libavcodec/dca.c

[Benjamin Larsson]

michael wrote:
> Author: michael
> Date: Fri Aug 29 20:37:40 2008
> New Revision: 15033
> 
> Log:
> Half the size of subband_fir_noidea and get rid of memmove & memset of it.
> 
> 
> Modified:
>    trunk/libavcodec/dca.c
> 
> Modified: trunk/libavcodec/dca.c
> ==============================================================================
> --- trunk/libavcodec/dca.c	(original)
> +++ trunk/libavcodec/dca.c	Fri Aug 29 20:37:40 2008
> @@ -158,7 +158,7 @@ typedef struct {
>      /* Subband samples history (for ADPCM) */
>      float subband_samples_hist[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS][4];
>      float subband_fir_hist[DCA_PRIM_CHANNELS_MAX][512];
> -    float subband_fir_noidea[DCA_PRIM_CHANNELS_MAX][64];
> +    float subband_fir_noidea[DCA_PRIM_CHANNELS_MAX][32];
>  
>      int output;                 ///< type of output
>      int bias;                   ///< output bias
> @@ -693,20 +693,19 @@ static void qmf_32_subbands(DCAContext *
>          }
>  
>          /* Multiply by filter coefficients */
> -        for (k = 31, i = 0; i < 32; i++, k--)
> +        for (k = 31, i = 0; i < 32; i++, k--){
> +            float a= subband_fir_hist2[i];
> +            float b= 0;
>              for (j = 0; j < 512; j += 64){
> -                subband_fir_hist2[i]    += prCoeff[i+j]  * ( subband_fir_hist[i+j] - subband_fir_hist[j+k]);
> -                subband_fir_hist2[i+32] += prCoeff[i+j+32]*(-subband_fir_hist[i+j] - subband_fir_hist[j+k]);
> +                a += prCoeff[i+j   ]*( subband_fir_hist[i+j] - subband_fir_hist[j+k]);
> +                b += prCoeff[i+j+32]*(-subband_fir_hist[i+j] - subband_fir_hist[j+k]);
>              }
> -
> -        /* Create 32 PCM output samples */
> -        for (i = 0; i < 32; i++)
> -            samples_out[chindex++] = subband_fir_hist2[i] * scale + bias;
> +            samples_out[chindex++] = a * scale + bias;
> +            subband_fir_hist2[i] = b;
> +        }
>  
>          /* Update working arrays */
>          memmove(&subband_fir_hist[32], &subband_fir_hist[0], (512 - 32) * sizeof(float));
> -        memmove(&subband_fir_hist2[0], &subband_fir_hist2[32], 32 * sizeof(float));
> -        memset(&subband_fir_hist2[32], 0, 32 * sizeof(float));
>      }
>  }
>  

Patch ok.

MvH
Benjamin Larsson