libavcenc: use number_t while computing number of bits in period

For large intra frame intervals or for a choice of bit rate that causes
large bits per frame, it possible that while computing number of bits
available in the gop overflow the datatype bounds. For these
calculations use number_t as this offers wider space

Bug: oss-fuzz-63044
Test: avc_enc_fuzzer

Change-Id: Ifee9130f0021f77905aea67832abc044537088e5

encoder/irc_bit_allocation.c

@@ -172,14 +172,11 @@ static void check_update_rbip(rem_bit_in_prd_t *ps_rbip,
 
 static void irc_ba_update_rbip(rem_bit_in_prd_t *ps_rbip,
                                pic_handling_handle ps_pic_handling,
-                               WORD32 i4_num_of_bits)
+                               number_t vq_num_bits)
 {
-    number_t vq_num_bits;
-
     check_update_rbip(ps_rbip, ps_pic_handling);
 
     /* rem_bits_in_period += num_of_bits */
-    SET_VAR_Q(vq_num_bits, i4_num_of_bits, 0);
     add32_var_q(vq_num_bits, ps_rbip->vq_rem_bits_in_period,
                 &ps_rbip->vq_rem_bits_in_period);
 }
@@ -359,7 +356,7 @@ WORD32 irc_ba_get_cur_frm_est_texture_bits(bit_allocation_t *ps_bit_allocation,
     number_t vq_max_consumable_bits;
     number_t vq_rem_frms_in_period[MAX_PIC_TYPE], vq_est_texture_bits_for_frm;
     number_t vq_prev_hdr_bits[MAX_PIC_TYPE];
-
+    number_t vq_num_bits;
     WORD32 complexity_est = 0;
 
     /* Get the rem_frms_in_gop & the frms_in_gop from the pic_type state struct */
@@ -376,7 +373,8 @@ WORD32 irc_ba_get_cur_frm_est_texture_bits(bit_allocation_t *ps_bit_allocation,
 
     /* Remove the header bits from the remaining bits to find how many bits you
      can transfer.*/
-    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, 0);
+    SET_VAR_Q(vq_num_bits, 0, 0);
+    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, vq_num_bits);
     for(i = 0; i < MAX_PIC_TYPE; i++)
     {
         SET_VAR_Q(vq_rem_frms_in_period[i], i4_rem_frms_in_period[i], 0);
@@ -559,7 +557,11 @@ WORD32 irc_ba_get_rem_bits_in_period(bit_allocation_t *ps_bit_allocation,
                                      pic_handling_handle ps_pic_handling)
 {
     WORD32 i4_rem_bits_in_gop = 0;
-    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, 0);
+
+    number_t vq_num_bits;
+    SET_VAR_Q(vq_num_bits, 0, 0);
+
+    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, vq_num_bits);
     number_t_to_word32(ps_bit_allocation->s_rbip.vq_rem_bits_in_period,
                        &i4_rem_bits_in_gop);
     return (i4_rem_bits_in_gop);
@@ -581,8 +583,10 @@ void irc_ba_update_cur_frm_consumed_bits(bit_allocation_t *ps_bit_allocation,
     WORD32 i4_error_bits = irc_get_error_bits(ps_bit_allocation->ps_error_bits);
 
     /* Update the remaining bits in period */
-    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling,
-                       (-i4_total_frame_bits + i4_error_bits));
+    number_t vq_num_bits;
+    SET_VAR_Q(vq_num_bits, (-i4_total_frame_bits + i4_error_bits), 0);
+
+    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, vq_num_bits);
 
     /*
      * Update the header bits so that it can be used as an estimate to the next
@@ -619,8 +623,15 @@ void irc_ba_update_cur_frm_consumed_bits(bit_allocation_t *ps_bit_allocation,
 
     if(i4_last_frm_in_gop)
     {
-        WORD32 i4_num_bits_in_a_gop = get_number_of_frms_in_a_gop(
-                        ps_pic_handling) * ps_bit_allocation->i4_bits_per_frm;
+        WORD32 i4_tot_frms_in_gop = get_number_of_frms_in_a_gop(
+                ps_pic_handling);
+        number_t vq_total_frms_in_gop, vq_bits_per_frm, vq_num_bits_in_gop;
+
+        SET_VAR_Q(vq_total_frms_in_gop, i4_tot_frms_in_gop, 0);
+        SET_VAR_Q(vq_bits_per_frm, ps_bit_allocation->i4_bits_per_frm, 0);
+
+        mult32_var_q(vq_bits_per_frm, vq_total_frms_in_gop,
+                     &vq_num_bits_in_gop);
         /*
          * If the number of gops in period has been increased due to scene
          * change, slowly bring in down across the gops
@@ -638,7 +649,7 @@ void irc_ba_update_cur_frm_consumed_bits(bit_allocation_t *ps_bit_allocation,
          * the next period else increase it
          */
         irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling,
-                           i4_num_bits_in_a_gop);
+                           vq_num_bits_in_gop);
     }
     /* Update the lower modules */
     irc_update_error_bits(ps_bit_allocation->ps_error_bits);
@@ -722,10 +733,16 @@ void irc_ba_change_rem_bits_in_prd_at_force_I_frame(bit_allocation_t *ps_bit_all
                                                     pic_handling_handle ps_pic_handling)
 {
     WORD32 i4_frms_in_period;
+    number_t vq_frms_in_period, vq_bits_per_frm, vq_num_bits_in_period;
+
     i4_frms_in_period = irc_pic_type_get_frms_in_gop_force_I_frm(
                     ps_pic_handling);
-    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling,
-                       ps_bit_allocation->i4_bits_per_frm * i4_frms_in_period);
+    SET_VAR_Q(vq_frms_in_period, i4_frms_in_period, 0);
+    SET_VAR_Q(vq_bits_per_frm, ps_bit_allocation->i4_bits_per_frm, 0);
+
+    mult32_var_q(vq_bits_per_frm, vq_frms_in_period, &vq_num_bits_in_period);
+
+    irc_ba_update_rbip(&ps_bit_allocation->s_rbip, ps_pic_handling, vq_num_bits_in_period);
 }
 
 void irc_ba_check_and_update_bit_allocation(bit_allocation_t *ps_bit_allocation,