avcodec/atrac3: Don't use too big VLC tables

The longest code of any of the VLC tables used is eight bits long, so
using nine bits long VLC tables is wasteful. Furthermore, there are only
seven VLC tables used, yet the code up until now made it look like there
should be eight. This has been corrected, too.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

diff --git a/libavcodec/atrac3.c b/libavcodec/atrac3.c
index dc68e507aab8c1268110c042a31b8bc339454914..01b7f06bffb0b6d974488261dcc852815b0a7d1b 100644 (file)
--- a/libavcodec/atrac3.c
+++ b/libavcodec/atrac3.c
@@ -58,6 +58,8 @@
 #define SAMPLES_PER_FRAME 1024
 #define MDCT_SIZE          512
 
+#define ATRAC3_VLC_BITS 8
+
 typedef struct GainBlock {
     AtracGainInfo g_block[4];
 } GainBlock;
@@ -116,7 +118,7 @@ typedef struct ATRAC3Context {
 } ATRAC3Context;
 
 static DECLARE_ALIGNED(32, float, mdct_window)[MDCT_SIZE];
-static VLC_TYPE atrac3_vlc_table[4096][2];
+static VLC_TYPE atrac3_vlc_table[7 * 1 << ATRAC3_VLC_BITS][2];
 static VLC   spectral_coeff_tab[7];
 
 /**
@@ -851,6 +853,7 @@ static int atrac3al_decode_frame(AVCodecContext *avctx, void *data,
 
 static av_cold void atrac3_init_static_data(void)
 {
+    VLC_TYPE (*table)[2] = atrac3_vlc_table;
     int i;
 
     init_imdct_window();
@@ -858,12 +861,12 @@ static av_cold void atrac3_init_static_data(void)
 
     /* Initialize the VLC tables. */
     for (i = 0; i < 7; i++) {
-        spectral_coeff_tab[i].table = &atrac3_vlc_table[atrac3_vlc_offs[i]];
-        spectral_coeff_tab[i].table_allocated = atrac3_vlc_offs[i + 1] -
-                                                atrac3_vlc_offs[i    ];
-        init_vlc(&spectral_coeff_tab[i], 9, huff_tab_sizes[i],
+        spectral_coeff_tab[i].table           = table;
+        spectral_coeff_tab[i].table_allocated = 256;
+        init_vlc(&spectral_coeff_tab[i], ATRAC3_VLC_BITS, huff_tab_sizes[i],
                  huff_bits[i],  1, 1,
                  huff_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
+        table += 256;
     }
 }
 

diff --git a/libavcodec/atrac3data.h b/libavcodec/atrac3data.h
index 5d91274f489316270b5437a96765cc2b70c04907..a731fb7c4acc3e564026c37948408abd65f9f1f6 100644 (file)
--- a/libavcodec/atrac3data.h
+++ b/libavcodec/atrac3data.h
@@ -103,10 +103,6 @@ static const uint8_t* const huff_bits[7] = {
     huffbits1, huffbits2, huffbits3, huffbits4, huffbits5, huffbits6, huffbits7,
 };
 
-static const uint16_t atrac3_vlc_offs[9] = {
-    0, 512, 1024, 1536, 2048, 2560, 3072, 3584, 4096
-};
-
 /* selector tables */
 
 static const uint8_t clc_length_tab[8] = { 0, 4, 3, 3, 4, 4, 5, 6 };