@@ -210,6 +210,9 @@ int swr_rematrix_init(SwrContext *s){

         if(s->out_ch_layout & (1ULL<<i))

             out_i++;

     }

+    if(s->rematrix_volume  < 0)

+        maxcoef = -s->rematrix_volume;

+

     if((   s->out_sample_fmt < AV_SAMPLE_FMT_FLT

         || s->int_sample_fmt < AV_SAMPLE_FMT_FLT) && maxcoef > 1.0){

         for(i=0; i<SWR_CH_MAX; i++)

@@ -218,6 +221,15 @@ int swr_rematrix_init(SwrContext *s){

                 s->matrix32[i][j]= lrintf(s->matrix[i][j] * 32768);

             }

     }

+

+    if(s->rematrix_volume > 0){

+        for(i=0; i<SWR_CH_MAX; i++)

+            for(j=0; j<SWR_CH_MAX; j++){

+                s->matrix[i][j] *= s->rematrix_volume;

+                s->matrix32[i][j]= lrintf(s->matrix[i][j] * 32768);

+            }

+    }

+

     for(i=0; i<av_get_channel_layout_nb_channels(s->out_ch_layout); i++){

         for(j=0; j<av_get_channel_layout_nb_channels(s->in_ch_layout); j++){

             av_log(NULL, AV_LOG_DEBUG, "%f ", s->matrix[i][j]);

@@ -49,6 +49,7 @@ static const AVOption options[]={

 {"ocl",  "output channel layout", OFFSET(out_ch_layout), AV_OPT_TYPE_INT64, {.dbl=0}, 0, INT64_MAX, 0, "channel_layout"},

 {"clev", "center mix level"     , OFFSET(clev)         , AV_OPT_TYPE_FLOAT, {.dbl=C_30DB}, 0, 4, 0},

 {"slev", "sourround mix level"  , OFFSET(slev)         , AV_OPT_TYPE_FLOAT, {.dbl=C_30DB}, 0, 4, 0},

+{"rmvol", "rematrix volume"     , OFFSET(rematrix_volume), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, -1000, 1000, 0},

 {"flags", NULL                  , OFFSET(flags)        , AV_OPT_TYPE_FLAGS, {.dbl=0}, 0,  UINT_MAX, 0, "flags"},

 {"res", "force resampling", 0, AV_OPT_TYPE_CONST, {.dbl=SWR_FLAG_RESAMPLE}, INT_MIN, INT_MAX, 0, "flags"},

@@ -176,7 +177,7 @@ int swr_init(SwrContext *s){

     if(!s->out_ch_layout)

         s->out_ch_layout= av_get_default_channel_layout(s->out.ch_count);

-    s->rematrix= s->out_ch_layout  !=s->in_ch_layout;

+    s->rematrix= s->out_ch_layout  !=s->in_ch_layout || s->rematrix_volume!=1.0;

 #define RSC 1 //FIXME finetune

     if(!s-> in.ch_count)

@@ -44,7 +44,7 @@ typedef struct SwrContext {          //FIXME find unused fields

     int      in_sample_rate;

     int     out_sample_rate;

     int flags;

-    float slev, clev;

+    float slev, clev, rematrix_volume;

     //below are private

     int int_bps;