[FFmpeg-cvslog] r18860 - in trunk/libavcodec: ac3dec.c ac3dec_data.c ac3dec_data.h eac3dec.c
jbr
subversion
Sun May 17 08:53:27 CEST 2009
Author: jbr
Date: Sun May 17 08:53:24 2009
New Revision: 18860
Log:
eac3dec: use 16-bit pre-mantissas instead of 24-bit in AHT decoding. it is
simpler and also fixes a bug in GAQ dequantization.
Modified:
trunk/libavcodec/ac3dec.c
trunk/libavcodec/ac3dec_data.c
trunk/libavcodec/ac3dec_data.h
trunk/libavcodec/eac3dec.c
Modified: trunk/libavcodec/ac3dec.c
==============================================================================
--- trunk/libavcodec/ac3dec.c Sun May 17 02:54:29 2009 (r18859)
+++ trunk/libavcodec/ac3dec.c Sun May 17 08:53:24 2009 (r18860)
@@ -568,7 +568,7 @@ static void decode_transform_coeffs_ch(A
if (!blk)
ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
- s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
+ s->fixed_coeffs[ch][bin] = (s->pre_mantissa[ch][bin][blk] << 8) >> s->dexps[ch][bin];
}
}
}
Modified: trunk/libavcodec/ac3dec_data.c
==============================================================================
--- trunk/libavcodec/ac3dec_data.c Sun May 17 02:54:29 2009 (r18859)
+++ trunk/libavcodec/ac3dec_data.c Sun May 17 08:53:24 2009 (r18860)
@@ -87,19 +87,18 @@ const int16_t ff_eac3_gaq_remap_2_4_a[9]
/**
* Table E3.6, Gk=2 & Gk=4, B
* Large mantissa inverse quantization, negative mantissa remapping offsets
- * Table values from the spec are right-shifted by 8 to simplify calculations.
* ff_eac3_gaq_remap_3_4_b[hebap-8][Gk=2,4]
*/
-const int8_t ff_eac3_gaq_remap_2_4_b[9][2] = {
- { -22, -5 },
- { -46, -20 },
- { -56, -26 },
- { -60, -29 },
- { -62, -31 },
- { -63, -32 },
- { -64, -32 },
- { -64, -32 },
- { -64, -32 },
+const int16_t ff_eac3_gaq_remap_2_4_b[9][2] = {
+ { -5461, -1170 },
+ { -11703, -4915 },
+ { -14199, -6606 },
+ { -15327, -7412 },
+ { -15864, -7805 },
+ { -16126, -7999 },
+ { -16255, -8096 },
+ { -16320, -8144 },
+ { -16352, -8168 }
};
static const int16_t vq_hebap1[4][6] = {
Modified: trunk/libavcodec/ac3dec_data.h
==============================================================================
--- trunk/libavcodec/ac3dec_data.h Sun May 17 02:54:29 2009 (r18859)
+++ trunk/libavcodec/ac3dec_data.h Sun May 17 08:53:24 2009 (r18860)
@@ -29,7 +29,7 @@ extern const uint8_t ff_eac3_hebap_tab[6
extern const uint8_t ff_eac3_bits_vs_hebap[20];
extern const int16_t ff_eac3_gaq_remap_1[12];
extern const int16_t ff_eac3_gaq_remap_2_4_a[9][2];
-extern const int8_t ff_eac3_gaq_remap_2_4_b[9][2];
+extern const int16_t ff_eac3_gaq_remap_2_4_b[9][2];
extern const int16_t (* const ff_eac3_mantissa_vq[8])[6];
extern const uint8_t ff_eac3_frm_expstr[32][6];
Modified: trunk/libavcodec/eac3dec.c
==============================================================================
--- trunk/libavcodec/eac3dec.c Sun May 17 02:54:29 2009 (r18859)
+++ trunk/libavcodec/eac3dec.c Sun May 17 08:53:24 2009 (r18860)
@@ -66,18 +66,18 @@ typedef enum {
#define EAC3_SR_CODE_REDUCED 3
-/** lrint(M_SQRT2*cos(2*M_PI/12)*(1<<23)) */
-#define COEFF_0 10273905LL
+/** lrint(M_SQRT2*cos(2*M_PI/12)*(1<<15)) */
+#define COEFF_0 40132
-/** lrint(M_SQRT2*cos(0*M_PI/12)*(1<<23)) = lrint(M_SQRT2*(1<<23)) */
-#define COEFF_1 11863283LL
+/** lrint(M_SQRT2*cos(0*M_PI/12)*(1<<15)) = lrint(M_SQRT2*(1<<15)) */
+#define COEFF_1 46341
-/** lrint(M_SQRT2*cos(5*M_PI/12)*(1<<23)) */
-#define COEFF_2 3070444LL
+/** lrint(M_SQRT2*cos(5*M_PI/12)*(1<<15)) */
+#define COEFF_2 11994
/**
* Calculate 6-point IDCT of the pre-mantissas.
- * All calculations are 24-bit fixed-point.
+ * All calculations are 16-bit fixed-point.
*/
static void idct6(int pre_mant[6])
{
@@ -86,9 +86,9 @@ static void idct6(int pre_mant[6])
odd1 = pre_mant[1] - pre_mant[3] - pre_mant[5];
- even2 = ( pre_mant[2] * COEFF_0) >> 23;
- tmp = ( pre_mant[4] * COEFF_1) >> 23;
- odd0 = ((pre_mant[1] + pre_mant[5]) * COEFF_2) >> 23;
+ even2 = ( pre_mant[2] * COEFF_0) >> 15;
+ tmp = ( pre_mant[4] * COEFF_1) >> 15;
+ odd0 = ((pre_mant[1] + pre_mant[5]) * COEFF_2) >> 15;
even0 = pre_mant[0] + (tmp >> 1);
even1 = pre_mant[0] - tmp;
@@ -155,13 +155,13 @@ void ff_eac3_decode_transform_coeffs_aht
if (!hebap) {
/* zero-mantissa dithering */
for (blk = 0; blk < 6; blk++) {
- s->pre_mantissa[ch][bin][blk] = (av_lfg_get(&s->dith_state) & 0x7FFFFF) - 0x400000;
+ s->pre_mantissa[ch][bin][blk] = (av_lfg_get(&s->dith_state) & 0x7FFF) - 0x4000;
}
} else if (hebap < 8) {
/* Vector Quantization */
int v = get_bits(gbc, bits);
for (blk = 0; blk < 6; blk++) {
- s->pre_mantissa[ch][bin][blk] = ff_eac3_mantissa_vq[hebap][v][blk] << 8;
+ s->pre_mantissa[ch][bin][blk] = ff_eac3_mantissa_vq[hebap][v][blk];
}
} else {
/* Gain Adaptive Quantization */
@@ -175,22 +175,24 @@ void ff_eac3_decode_transform_coeffs_aht
for (blk = 0; blk < 6; blk++) {
int mant = get_sbits(gbc, gbits);
- if (mant == -(1 << (gbits-1))) {
+ if (log_gain > 0 && mant == -(1 << (gbits-1))) {
/* large mantissa */
int b;
- mant = get_sbits(gbc, bits-2+log_gain) << (26-log_gain-bits);
+ int mbits = bits - (2 - log_gain);
+ mant = get_sbits(gbc, mbits);
+ mant <<= (15 - (mbits - 1));
/* remap mantissa value to correct for asymmetric quantization */
if (mant >= 0)
- b = 32768 >> (log_gain+8);
+ b = 32768 >> log_gain;
else
b = ff_eac3_gaq_remap_2_4_b[hebap-8][log_gain-1];
- mant += (ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] * (mant>>8) + b) >> 7;
+ mant += ((ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] * mant) >> 15) + b;
} else {
/* small mantissa, no GAQ, or Gk=1 */
- mant <<= 24 - bits;
+ mant <<= 15 - (bits-1);
if (!log_gain) {
/* remap mantissa value for no GAQ or Gk=1 */
- mant += (ff_eac3_gaq_remap_1[hebap-8] * (mant>>8)) >> 7;
+ mant += (ff_eac3_gaq_remap_1[hebap-8] * mant) >> 15;
}
}
s->pre_mantissa[ch][bin][blk] = mant;
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