ac3dec: actually use drc_scale private option

libavcodec/ac3dec.c

@@ -176,6 +176,11 @@ static av_cold int ac3_decode_init(AVCodecContext *avctx)
     AC3DecodeContext *s = avctx->priv_data;
     s->avctx = avctx;
 
+#if FF_API_DRC_SCALE
+    if (avctx->drc_scale)
+        s->drc_scale = avctx->drc_scale;
+#endif
+
     ff_ac3_common_init();
     ac3_tables_init();
     ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
@@ -788,7 +793,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
     do {
         if(get_bits1(gbc)) {
             s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) *
-                                  s->avctx->drc_scale)+1.0;
+                                  s->drc_scale)+1.0;
         } else if(blk == 0) {
             s->dynamic_range[i] = 1.0f;
         }

libavcodec/options.c

@@ -447,7 +447,7 @@ static const AVOption options[]={
 {"request_channels", "set desired number of audio channels", OFFSET(request_channels), FF_OPT_TYPE_INT, {.dbl = DEFAULT }, 0, INT_MAX, A|D},
 #endif
 #if FF_API_DRC_SCALE
-{"drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), FF_OPT_TYPE_FLOAT, {.dbl = 1.0 }, 0.0, 1.0, A|D},
+{"drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), FF_OPT_TYPE_FLOAT, {.dbl = 0.0 }, 0.0, 1.0, A|D},
 #endif
 #if FF_API_LAME_GLOBAL_OPTS
 {"reservoir", "use bit reservoir", 0, FF_OPT_TYPE_CONST, {.dbl = CODEC_FLAG2_BIT_RESERVOIR }, INT_MIN, INT_MAX, A|E, "flags2"},