diff --git a/libavcodec/aaccoder.c b/libavcodec/aaccoder.c
index 2f99924821..cd996b2430 100644
--- a/libavcodec/aaccoder.c
+++ b/libavcodec/aaccoder.c
@@ -595,6 +595,43 @@ typedef struct TrellisPath {
 #define TRELLIS_STAGES 121
 #define TRELLIS_STATES (SCALE_MAX_DIFF+1)
 
+static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)
+{
+    int w, g, start = 0;
+    int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];
+    int bands = 0;
+
+    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
+        start = 0;
+        for (g = 0;  g < sce->ics.num_swb; g++) {
+            if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
+                sce->sf_idx[w*16+g] = av_clip(ceilf(log2f(sce->is_ener[w*16+g])*2), -155, 100);
+                minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);
+                bands++;
+            } else if (sce->band_type[w*16+g] == NOISE_BT) {
+                sce->sf_idx[w*16+g] = av_clip(4+log2f(sce->pns_ener[w*16+g])*2, -100, 155);
+                minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);
+                bands++;
+            }
+            start += sce->ics.swb_sizes[g];
+        }
+    }
+
+    if (!bands)
+        return;
+
+    /* Clip the scalefactor indices */
+    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
+        for (g = 0;  g < sce->ics.num_swb; g++) {
+            if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {
+                sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);
+            } else if (sce->band_type[w*16+g] == NOISE_BT) {
+                sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);
+            }
+        }
+    }
+}
+
 static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
                                        SingleChannelElement *sce,
                                        const float lambda)
diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index 897c3a10df..3a512ffeee 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -389,7 +389,7 @@ static void encode_scale_factors(AVCodecContext *avctx, AACEncContext *s,
                                  SingleChannelElement *sce)
 {
     int diff, off_sf = sce->sf_idx[0], off_pns = sce->sf_idx[0] - NOISE_OFFSET;
-    int noise_flag = 1;
+    int off_is = 0, noise_flag = 1;
     int i, w;
 
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
@@ -402,6 +402,10 @@ static void encode_scale_factors(AVCodecContext *avctx, AACEncContext *s,
                         put_bits(&s->pb, NOISE_PRE_BITS, diff + NOISE_PRE);
                         continue;
                     }
+                } else if (sce->band_type[w*16 + i] == INTENSITY_BT  ||
+                           sce->band_type[w*16 + i] == INTENSITY_BT2) {
+                    diff = sce->sf_idx[w*16 + i] - off_is;
+                    off_is = sce->sf_idx[w*16 + i];
                 } else {
                     diff = sce->sf_idx[w*16 + i] - off_sf;
                     off_sf = sce->sf_idx[w*16 + i];