[Opus] Update to v1.2.1

third_party/opus/src/silk/gain_quant.c

 /***********************************************************************
 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 - Redistributions of source code must retain the above copyright notice,
 this list of conditions and the following disclaimer.
 - Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
@@ skipping 58 matching lines @@
             double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
             if( ind[ k ] > double_step_size_threshold ) {
                 ind[ k ] = double_step_size_threshold + silk_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
             }
 
             ind[ k ] = silk_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
 
             /* Accumulate deltas */
             if( ind[ k ] > double_step_size_threshold ) {
                 *prev_ind += silk_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
+                *prev_ind = silk_min_int( *prev_ind, N_LEVELS_QGAIN - 1 );
             } else {
                 *prev_ind += ind[ k ];
             }
 
             /* Shift to make non-negative */
             ind[ k ] -= MIN_DELTA_GAIN_QUANT;
         }
 
         /* Scale and convert to linear scale */
         gain_Q16[ k ] = silk_log2lin( silk_min_32( silk_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
@@ skipping 43 matching lines @@
     opus_int   k;
     opus_int32 gainsID;
 
     gainsID = 0;
     for( k = 0; k < nb_subfr; k++ ) {
         gainsID = silk_ADD_LSHIFT32( ind[ k ], gainsID, 8 );
     }
 
     return gainsID;
 }