diff --git a/libavcodec/aacenc_is.c b/libavcodec/aacenc_is.c
index 88ba915d2a..bb201f628d 100644
--- a/libavcodec/aacenc_is.c
+++ b/libavcodec/aacenc_is.c
@@ -32,39 +32,39 @@
 
 struct AACISError ff_aac_is_encoding_err(AACEncContext *s, ChannelElement *cpe,
                                          int start, int w, int g, float ener0,
-                                         float ener1, float ener01, int phase)
+                                         float ener1, float ener01,
+                                         int use_pcoeffs, int phase)
 {
     int i, w2;
+    SingleChannelElement *sce0 = &cpe->ch[0];
+    SingleChannelElement *sce1 = &cpe->ch[1];
+    float *L = use_pcoeffs ? sce0->pcoeffs : sce0->coeffs;
+    float *R = use_pcoeffs ? sce1->pcoeffs : sce1->coeffs;
     float *L34 = &s->scoefs[256*0], *R34 = &s->scoefs[256*1];
     float *IS  = &s->scoefs[256*2], *I34 = &s->scoefs[256*3];
     float dist1 = 0.0f, dist2 = 0.0f;
     struct AACISError is_error = {0};
-    SingleChannelElement *sce0 = &cpe->ch[0];
-    SingleChannelElement *sce1 = &cpe->ch[1];
 
     for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
         FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
         FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
         int is_band_type, is_sf_idx = FFMAX(1, sce0->sf_idx[(w+w2)*16+g]-4);
-        float e01_34 = phase*pow(sqrt(ener1/ener0), 3.0/4.0);
+        float e01_34 = phase*pow(ener1/ener0, 3.0/4.0);
         float maxval, dist_spec_err = 0.0f;
         float minthr = FFMIN(band0->threshold, band1->threshold);
-        for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
-            IS[i] = (sce0->pcoeffs[start+(w+w2)*128+i]+
-                     phase*sce1->pcoeffs[start+(w+w2)*128+i])*
-                     sqrt(ener0/ener01);
-        }
-        abs_pow34_v(L34, &sce0->coeffs[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
-        abs_pow34_v(R34, &sce1->coeffs[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
-        abs_pow34_v(I34, IS,                            sce0->ics.swb_sizes[g]);
+        for (i = 0; i < sce0->ics.swb_sizes[g]; i++)
+            IS[i] = (L[start+(w+w2)*128+i] + phase*R[start+(w+w2)*128+i])*sqrt(ener0/ener01);
+        abs_pow34_v(L34, &L[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
+        abs_pow34_v(R34, &R[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
+        abs_pow34_v(I34, IS,                   sce0->ics.swb_sizes[g]);
         maxval = find_max_val(1, sce0->ics.swb_sizes[g], I34);
         is_band_type = find_min_book(maxval, is_sf_idx);
-        dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128], L34,
+        dist1 += quantize_band_cost(s, &L[start + (w+w2)*128], L34,
                                     sce0->ics.swb_sizes[g],
                                     sce0->sf_idx[(w+w2)*16+g],
                                     sce0->band_type[(w+w2)*16+g],
                                     s->lambda / band0->threshold, INFINITY, NULL, 0);
-        dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128], R34,
+        dist1 += quantize_band_cost(s, &R[start + (w+w2)*128], R34,
                                     sce1->ics.swb_sizes[g],
                                     sce1->sf_idx[(w+w2)*16+g],
                                     sce1->band_type[(w+w2)*16+g],
@@ -111,15 +111,15 @@ void ff_aac_search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElemen
                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
                         float coef0 = sce0->pcoeffs[start+(w+w2)*128+i];
                         float coef1 = sce1->pcoeffs[start+(w+w2)*128+i];
-                        ener0 += coef0*coef0;
-                        ener1 += coef1*coef1;
+                        ener0  += coef0*coef0;
+                        ener1  += coef1*coef1;
                         ener01 += (coef0 + coef1)*(coef0 + coef1);
                     }
                 }
                 ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g,
-                                                 ener0, ener1, ener01, -1);
+                                                 ener0, ener1, ener01, 0, -1);
                 ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g,
-                                                 ener0, ener1, ener01, +1);
+                                                 ener0, ener1, ener01, 0, +1);
                 erf = ph_err1.error < ph_err2.error ? &ph_err1 : &ph_err2;
                 if (erf->pass) {
                     cpe->is_mask[w*16+g] = 1;
diff --git a/libavcodec/aacenc_is.h b/libavcodec/aacenc_is.h
index e35f0aa695..31bbacac58 100644
--- a/libavcodec/aacenc_is.h
+++ b/libavcodec/aacenc_is.h
@@ -43,7 +43,8 @@ struct AACISError {
 
 struct AACISError ff_aac_is_encoding_err(AACEncContext *s, ChannelElement *cpe,
                                          int start, int w, int g, float ener0,
-                                         float ener1, float ener01, int phase);
+                                         float ener1, float ener01,
+                                         int use_pcoeffs, int phase);
 void ff_aac_search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElement *cpe);
 
 #endif /* AVCODEC_AACENC_IS_H */
diff --git a/libavcodec/aacenc_pred.c b/libavcodec/aacenc_pred.c
index fafe0029d4..eb8e7f7d27 100644
--- a/libavcodec/aacenc_pred.c
+++ b/libavcodec/aacenc_pred.c
@@ -179,15 +179,15 @@ void ff_aac_adjust_common_prediction(AACEncContext *s, ChannelElement *cpe)
                 for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
                     float coef0 = sce0->pcoeffs[start+(w+w2)*128+i];
                     float coef1 = sce1->pcoeffs[start+(w+w2)*128+i];
-                    ener0 += coef0*coef0;
-                    ener1 += coef1*coef1;
+                    ener0  += coef0*coef0;
+                    ener1  += coef1*coef1;
                     ener01 += (coef0 + coef1)*(coef0 + coef1);
                 }
             }
             ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g,
-                                             ener0, ener1, ener01, -1);
+                                             ener0, ener1, ener01, 1, -1);
             ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g,
-                                             ener0, ener1, ener01, +1);
+                                             ener0, ener1, ener01, 1, +1);
             erf = ph_err1.error < ph_err2.error ? &ph_err1 : &ph_err2;
             if (erf->pass) {
                 sce0->ics.prediction_used[sfb] = 1;