avcodec/aacsbr_fixed: Fix multiple runtime error: shift exponent 150 is too...

avcodec/aacsbr_fixed: Fix multiple runtime error: shift exponent 150 is too large for 32-bit type 'int'

Fixes: 1681/clusterfuzz-testcase-minimized-5970545365483520

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/aacsbr_fixed.c

@@ -288,6 +288,8 @@ static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
         shift = a00.exp;
         if (shift >= 3)
             alpha0[k][0] = 0x7fffffff;
+        else if (shift <= -30)
+            alpha0[k][0] = 0;
         else {
             a00.mant *= 2;
             shift = 2-shift;
@@ -302,6 +304,8 @@ static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
         shift = a01.exp;
         if (shift >= 3)
             alpha0[k][1] = 0x7fffffff;
+        else if (shift <= -30)
+            alpha0[k][1] = 0;
         else {
             a01.mant *= 2;
             shift = 2-shift;
@@ -315,6 +319,8 @@ static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
         shift = a10.exp;
         if (shift >= 3)
             alpha1[k][0] = 0x7fffffff;
+        else if (shift <= -30)
+            alpha1[k][0] = 0;
         else {
             a10.mant *= 2;
             shift = 2-shift;
@@ -329,6 +335,8 @@ static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
         shift = a11.exp;
         if (shift >= 3)
             alpha1[k][1] = 0x7fffffff;
+        else if (shift <= -30)
+            alpha1[k][1] = 0;
         else {
             a11.mant *= 2;
             shift = 2-shift;