shithub: mp3dec

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ref: 7d78962e3677314c1f030ffbc8746650d059fd82
parent: 5f0132665740984a728a32d80bef8866578d1d2b
author: lieff <[email protected]>
date: Fri May 11 14:36:31 EDT 2018 

reduce tables size by 103 bytes with few instructions in code


--- a/minimp3.h
+++ b/minimp3.h
@@ -71,7 +71,7 @@
 #define HDR_GET_LAYER(h)            (((h[1]) >> 1) & 3)
 #define HDR_GET_BITRATE(h)          ((h[2]) >> 4)
 #define HDR_GET_SAMPLE_RATE(h)      (((h[2]) >> 2) & 3)
-#define HDR_GET_MY_SAMPLE_RATE(h)   (HDR_GET_SAMPLE_RATE(h) + (((h[1] >> 3) & 1) +  ((h[1] >> 4) & 1))*3)
+#define HDR_GET_MY_SAMPLE_RATE(h)   (HDR_GET_SAMPLE_RATE(h) + (((h[1] >> 3) & 1) + ((h[1] >> 4) & 1))*3)
 #define HDR_IS_FRAME_576(h)         ((h[1] & 14) == 2)
 #define HDR_IS_LAYER_1(h)           ((h[1] & 6) == 6)
 
@@ -492,9 +492,8 @@
 
 static int L3_read_side_info(bs_t *bs, L3_gr_info_t *gr, const uint8_t *hdr)
 {
-    static const uint8_t g_scf_long[9][23] = {
+    static const uint8_t g_scf_long[8][23] = {
         { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
-        { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
         { 12,12,12,12,12,12,16,20,24,28,32,40,48,56,64,76,90,2,2,2,2,2,0 },
         { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
         { 6,6,6,6,6,6,8,10,12,14,16,18,22,26,32,38,46,54,62,70,76,36,0 },
@@ -503,9 +502,8 @@
         { 4,4,4,4,4,4,6,6,6,8,10,12,16,18,22,28,34,40,46,54,54,192,0 },
         { 4,4,4,4,4,4,6,6,8,10,12,16,20,24,30,38,46,56,68,84,102,26,0 }
     };
-    static const uint8_t g_scf_short[9][40] = {
+    static const uint8_t g_scf_short[8][40] = {
         { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
-        { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
         { 8,8,8,8,8,8,8,8,8,12,12,12,16,16,16,20,20,20,24,24,24,28,28,28,36,36,36,2,2,2,2,2,2,2,2,2,26,26,26,0 },
         { 4,4,4,4,4,4,4,4,4,6,6,6,6,6,6,8,8,8,10,10,10,14,14,14,18,18,18,26,26,26,32,32,32,42,42,42,18,18,18,0 },
         { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,32,32,32,44,44,44,12,12,12,0 },
@@ -514,9 +512,8 @@
         { 4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,6,6,6,10,10,10,12,12,12,14,14,14,16,16,16,20,20,20,26,26,26,66,66,66,0 },
         { 4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,12,12,12,16,16,16,20,20,20,26,26,26,34,34,34,42,42,42,12,12,12,0 }
     };
-    static const uint8_t g_scf_mixed[9][40] = {
+    static const uint8_t g_scf_mixed[8][40] = {
         { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
-        { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
         { 12,12,12,4,4,4,8,8,8,12,12,12,16,16,16,20,20,20,24,24,24,28,28,28,36,36,36,2,2,2,2,2,2,2,2,2,26,26,26,0 },
         { 6,6,6,6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,14,14,14,18,18,18,26,26,26,32,32,32,42,42,42,18,18,18,0 },
         { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,32,32,32,44,44,44,12,12,12,0 },
@@ -528,7 +525,7 @@
 
     unsigned tables, scfsi = 0;
     int main_data_begin, part_23_sum = 0;
-    int sr_idx = HDR_GET_MY_SAMPLE_RATE(hdr);
+    int sr_idx = HDR_GET_MY_SAMPLE_RATE(hdr); sr_idx -= (sr_idx != 0);
     int gr_count = HDR_IS_MONO(hdr) ? 1 : 2;
 
     if (HDR_TEST_MPEG1(hdr))
@@ -959,7 +956,7 @@
         int prev = itop - max_blocks;
         ist_pos[itop] = max_band[i] >= prev ? default_pos : ist_pos[prev];
     }
-    L3_stereo_process(left, ist_pos, gr->sfbtab, hdr, max_band, gr[1].scalefac_compress&1);
+    L3_stereo_process(left, ist_pos, gr->sfbtab, hdr, max_band, gr[1].scalefac_compress & 1);
 }
 
 static void L3_reorder(float *grbuf, float *scratch, const uint8_t *sfb)