aacenc: coding style changes

This commit only changes the coding style to a saner way
of accessing coefficients (makes more sense to get the
memory address of a coefficients and start from there
rather than adding arbitrary numbers to offset a pointer).
Some compilers might detect an out of bounds access easier.

Also the way M/S and IS coefficients are calculated has been
changed, but should still have the same result (with the exception
that IS now applies from the normal coefficients rather than the
pristine ones, this is needed for upcoming commits).

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

2 files changed, 23 insertions, 21 deletions

diff --git a/libavcodec/aaccoder.c b/libavcodec/aaccoder.c
index f5ad5eacdf..24ea48e6d3 100644
--- a/libavcodec/aaccoder.c
+++ b/libavcodec/aaccoder.c
@@ -330,8 +330,8 @@ static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce
                 }
                 for (w = 0; w < group_len; w++) {
                     FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb];
-                    rd += quantize_band_cost(s, sce->coeffs + start + w*128,
-                                             s->scoefs + start + w*128, size,
+                    rd += quantize_band_cost(s, &sce->coeffs[start + w*128],
+                                             &s->scoefs[start + w*128], size,
                                              sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb],
                                              lambda / band->threshold, INFINITY, NULL, 0);
                 }
@@ -461,8 +461,8 @@ static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
                     continue;
                 }
                 for (w = 0; w < group_len; w++) {
-                    bits += quantize_band_cost(s, sce->coeffs + start + w*128,
-                                               s->scoefs + start + w*128, size,
+                    bits += quantize_band_cost(s, &sce->coeffs[start + w*128],
+                                               &s->scoefs[start + w*128], size,
                                                sce->sf_idx[win*16+swb],
                                                aac_cb_out_map[cb],
                                                0, INFINITY, NULL, 0);
@@ -636,7 +636,7 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
         start = w*128;
         for (g = 0; g < sce->ics.num_swb; g++) {
-            const float *coefs = sce->coeffs + start;
+            const float *coefs = &sce->coeffs[start];
             float qmin, qmax;
             int nz = 0;
 
@@ -800,8 +800,8 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
                 start = w*128;
                 for (g = 0;  g < sce->ics.num_swb; g++) {
-                    const float *coefs = sce->coeffs + start;
-                    const float *scaled = s->scoefs + start;
+                    const float *coefs = &sce->coeffs[start];
+                    const float *scaled = &s->scoefs[start];
                     int bits = 0;
                     int cb;
                     float dist = 0.0f;
@@ -896,7 +896,7 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
         }
     } else {
         for (w = 0; w < 8; w++) {
-            const float *coeffs = sce->coeffs + w*128;
+            const float *coeffs = &sce->coeffs[w*128];
             curband = start = 0;
             for (i = 0; i < 128; i++) {
                 if (i - start >= sce->ics.swb_sizes[curband]) {
@@ -921,7 +921,7 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
         start = w*128;
         for (g = 0; g < sce->ics.num_swb; g++) {
-            float *coefs   = sce->coeffs + start;
+            float *coefs   = &sce->coeffs[start];
             const int size = sce->ics.swb_sizes[g];
             int start2 = start, end2 = start + size, peakpos = start;
             float maxval = -1, thr = 0.0f, t;
@@ -962,8 +962,8 @@ static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
         start = w*128;
         for (g = 0;  g < sce->ics.num_swb; g++) {
-            const float *coefs  = sce->coeffs + start;
-            const float *scaled = s->scoefs   + start;
+            const float *coefs  = &sce->coeffs[start];
+            const float *scaled = &s->scoefs[start];
             const int size      = sce->ics.swb_sizes[g];
             int scf, prev_scf, step;
             int min_scf = -1, max_scf = 256;
@@ -1229,22 +1229,22 @@ static void search_for_ms(AACEncContext *s, ChannelElement *cpe)
                     float minthr = FFMIN(band0->threshold, band1->threshold);
                     float maxthr = FFMAX(band0->threshold, band1->threshold);
                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
-                        M[i] = (sce0->pcoeffs[start+(w+w2)*128+i]
-                              + sce1->pcoeffs[start+(w+w2)*128+i]) * 0.5;
+                        M[i] = (sce0->coeffs[start+(w+w2)*128+i]
+                              + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
                         S[i] =  M[i]
-                              - sce1->pcoeffs[start+(w+w2)*128+i];
+                              - sce1->coeffs[start+(w+w2)*128+i];
                     }
                     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(M34, M,                         sce0->ics.swb_sizes[g]);
                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
-                    dist1 += quantize_band_cost(s, sce0->coeffs + start + (w+w2)*128,
+                    dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128],
                                                 L34,
                                                 sce0->ics.swb_sizes[g],
                                                 sce0->sf_idx[(w+w2)*16+g],
                                                 sce0->band_type[(w+w2)*16+g],
                                                 lambda / band0->threshold, INFINITY, NULL, 0);
-                    dist1 += quantize_band_cost(s, sce1->coeffs + start + (w+w2)*128,
+                    dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128],
                                                 R34,
                                                 sce1->ics.swb_sizes[g],
                                                 sce1->sf_idx[(w+w2)*16+g],
diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index d87a90c7a0..8d48790745 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -149,7 +149,7 @@ static void apply_window_and_mdct(AACEncContext *s, SingleChannelElement *sce,
         s->mdct1024.mdct_calc(&s->mdct1024, sce->coeffs, output);
     else
         for (i = 0; i < 1024; i += 128)
-            s->mdct128.mdct_calc(&s->mdct128, sce->coeffs + i, output + i*2);
+            s->mdct128.mdct_calc(&s->mdct128, &sce->coeffs[i], output + i*2);
     memcpy(audio, audio + 1024, sizeof(audio[0]) * 1024);
     memcpy(sce->pcoeffs, sce->coeffs, sizeof(sce->pcoeffs));
 }
@@ -210,15 +210,17 @@ static void adjust_frame_information(ChannelElement *cpe, int chans)
                         int p = -1 + 2 * (cpe->ch[1].band_type[w*16+g] - 14);
                         float scale = cpe->ch[0].is_ener[w*16+g];
                         for (i = 0; i < ics->swb_sizes[g]; i++) {
-                            cpe->ch[0].coeffs[start+i] = (cpe->ch[0].pcoeffs[start+i] + p*cpe->ch[1].pcoeffs[start+i]) * scale;
+                            cpe->ch[0].coeffs[start+i] = (cpe->ch[0].coeffs[start+i] + p*cpe->ch[1].coeffs[start+i]) * scale;
                             cpe->ch[1].coeffs[start+i] = 0.0f;
                         }
                     } else if (cpe->ms_mask[w*16 + g] &&
                                cpe->ch[0].band_type[w*16 + g] < NOISE_BT &&
                                cpe->ch[1].band_type[w*16 + g] < NOISE_BT) {
                         for (i = 0; i < ics->swb_sizes[g]; i++) {
-                            cpe->ch[0].coeffs[start+i] = (cpe->ch[0].pcoeffs[start+i] + cpe->ch[1].pcoeffs[start+i]) * 0.5f;
-                            cpe->ch[1].coeffs[start+i] = cpe->ch[0].coeffs[start+i] - cpe->ch[1].pcoeffs[start+i];
+                            float L = (cpe->ch[0].coeffs[start+i] + cpe->ch[1].coeffs[start+i]) * 0.5f;
+                            float R = L - cpe->ch[1].coeffs[start+i];
+                            cpe->ch[0].coeffs[start+i] = L;
+                            cpe->ch[1].coeffs[start+i] = R;
                         }
                     }
                     start += ics->swb_sizes[g];
@@ -374,7 +376,7 @@ static void avoid_clipping(AACEncContext *s, SingleChannelElement *sce)
         for (w = 0; w < sce->ics.num_windows; w++) {
             start = 0;
             for (i = 0; i < sce->ics.max_sfb; i++) {
-                float *swb_coeffs = sce->coeffs + start + w*128;
+                float *swb_coeffs = &sce->coeffs[start + w*128];
                 for (j = 0; j < sce->ics.swb_sizes[i]; j++)
                     swb_coeffs[j] *= sce->ics.clip_avoidance_factor;
                 start += sce->ics.swb_sizes[i];