[deb_ffmpeg.git] / ffmpeg / libavcodec / ac3.c

/*
 * Common code between the AC-3 encoder and decoder
 * Copyright (c) 2000 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Common code between the AC-3 encoder and decoder.
 */

#include "avcodec.h"
#include "ac3.h"
#include "get_bits.h"

/**
 * Starting frequency coefficient bin for each critical band.
 */
const uint8_t ff_ac3_band_start_tab[AC3_CRITICAL_BANDS+1] = {
      0,  1,   2,   3,   4,   5,   6,   7,   8,   9,
     10,  11, 12,  13,  14,  15,  16,  17,  18,  19,
     20,  21, 22,  23,  24,  25,  26,  27,  28,  31,
     34,  37, 40,  43,  46,  49,  55,  61,  67,  73,
     79,  85, 97, 109, 121, 133, 157, 181, 205, 229, 253
};

#if CONFIG_HARDCODED_TABLES

/**
 * Map each frequency coefficient bin to the critical band that contains it.
 */
const uint8_t ff_ac3_bin_to_band_tab[253] = {
     0,
     1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12,
    13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
    25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30,
    31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34,
    35, 35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36,
    37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38,
    39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40,
    41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
    42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
    43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43,
    44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44,
    45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
    45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
    46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
    46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
    47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
    47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
    48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
    48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
    49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49,
    49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49
};

#else /* CONFIG_HARDCODED_TABLES */
uint8_t ff_ac3_bin_to_band_tab[253];
#endif

static inline int calc_lowcomp1(int a, int b0, int b1, int c)
{
    if ((b0 + 256) == b1) {
        a = c;
    } else if (b0 > b1) {
        a = FFMAX(a - 64, 0);
    }
    return a;
}

static inline int calc_lowcomp(int a, int b0, int b1, int bin)
{
    if (bin < 7) {
        return calc_lowcomp1(a, b0, b1, 384);
    } else if (bin < 20) {
        return calc_lowcomp1(a, b0, b1, 320);
    } else {
        return FFMAX(a - 128, 0);
    }
}

void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
                               int16_t *band_psd)
{
    int bin, band;

    /* exponent mapping to PSD */
    for (bin = start; bin < end; bin++) {
        psd[bin]=(3072 - (exp[bin] << 7));
    }

    /* PSD integration */
    bin  = start;
    band = ff_ac3_bin_to_band_tab[start];
    do {
        int v = psd[bin++];
        int band_end = FFMIN(ff_ac3_band_start_tab[band+1], end);
        for (; bin < band_end; bin++) {
            int max = FFMAX(v, psd[bin]);
            /* logadd */
            int adr = FFMIN(max - ((v + psd[bin] + 1) >> 1), 255);
            v = max + ff_ac3_log_add_tab[adr];
        }
        band_psd[band++] = v;
    } while (end > ff_ac3_band_start_tab[band]);
}

int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
                               int start, int end, int fast_gain, int is_lfe,
                               int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
                               uint8_t *dba_lengths, uint8_t *dba_values,
                               int16_t *mask)
{
    int16_t excite[AC3_CRITICAL_BANDS]; /* excitation */
    int band;
    int band_start, band_end, begin, end1;
    int lowcomp, fastleak, slowleak;

    /* excitation function */
    band_start = ff_ac3_bin_to_band_tab[start];
    band_end   = ff_ac3_bin_to_band_tab[end-1] + 1;

    if (band_start == 0) {
        lowcomp = 0;
        lowcomp = calc_lowcomp1(lowcomp, band_psd[0], band_psd[1], 384);
        excite[0] = band_psd[0] - fast_gain - lowcomp;
        lowcomp = calc_lowcomp1(lowcomp, band_psd[1], band_psd[2], 384);
        excite[1] = band_psd[1] - fast_gain - lowcomp;
        begin = 7;
        for (band = 2; band < 7; band++) {
            if (!(is_lfe && band == 6))
                lowcomp = calc_lowcomp1(lowcomp, band_psd[band], band_psd[band+1], 384);
            fastleak = band_psd[band] - fast_gain;
            slowleak = band_psd[band] - s->slow_gain;
            excite[band] = fastleak - lowcomp;
            if (!(is_lfe && band == 6)) {
                if (band_psd[band] <= band_psd[band+1]) {
                    begin = band + 1;
                    break;
                }
            }
        }

        end1 = FFMIN(band_end, 22);
        for (band = begin; band < end1; band++) {
            if (!(is_lfe && band == 6))
                lowcomp = calc_lowcomp(lowcomp, band_psd[band], band_psd[band+1], band);
            fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
            slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
            excite[band] = FFMAX(fastleak - lowcomp, slowleak);
        }
        begin = 22;
    } else {
        /* coupling channel */
        begin = band_start;
        fastleak = (s->cpl_fast_leak << 8) + 768;
        slowleak = (s->cpl_slow_leak << 8) + 768;
    }

    for (band = begin; band < band_end; band++) {
        fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
        slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
        excite[band] = FFMAX(fastleak, slowleak);
    }

    /* compute masking curve */

    for (band = band_start; band < band_end; band++) {
        int tmp = s->db_per_bit - band_psd[band];
        if (tmp > 0) {
            excite[band] += tmp >> 2;
        }
        mask[band] = FFMAX(ff_ac3_hearing_threshold_tab[band >> s->sr_shift][s->sr_code], excite[band]);
    }

    /* delta bit allocation */

    if (dba_mode == DBA_REUSE || dba_mode == DBA_NEW) {
        int i, seg, delta;
        if (dba_nsegs > 8)
            return -1;
        band = band_start;
        for (seg = 0; seg < dba_nsegs; seg++) {
            band += dba_offsets[seg];
            if (band >= AC3_CRITICAL_BANDS || dba_lengths[seg] > AC3_CRITICAL_BANDS-band)
                return -1;
            if (dba_values[seg] >= 4) {
                delta = (dba_values[seg] - 3) << 7;
            } else {
                delta = (dba_values[seg] - 4) << 7;
            }
            for (i = 0; i < dba_lengths[seg]; i++) {
                mask[band++] += delta;
            }
        }
    }
    return 0;
}

/**
 * Initialize some tables.
 * note: This function must remain thread safe because it is called by the
 *       AVParser init code.
 */
av_cold void ff_ac3_common_init(void)
{
#if !CONFIG_HARDCODED_TABLES
    /* compute ff_ac3_bin_to_band_tab from ff_ac3_band_start_tab */
    int bin = 0, band;
    for (band = 0; band < AC3_CRITICAL_BANDS; band++) {
        int band_end = ff_ac3_band_start_tab[band+1];
        while (bin < band_end)
            ff_ac3_bin_to_band_tab[bin++] = band;
    }
#endif /* !CONFIG_HARDCODED_TABLES */
}
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Common code between the AC-3 encoder and decoder
	3	* Copyright (c) 2000 Fabrice Bellard
	4	*
	5	* This file is part of FFmpeg.
	6	*
	7	* FFmpeg is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU Lesser General Public
	9	* License as published by the Free Software Foundation; either
	10	* version 2.1 of the License, or (at your option) any later version.
	11	*
	12	* FFmpeg is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* Lesser General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU Lesser General Public
	18	* License along with FFmpeg; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	20	*/
	21
	22	/**
	23	* @file
	24	* Common code between the AC-3 encoder and decoder.
	25	*/
	26
	27	#include "avcodec.h"
	28	#include "ac3.h"
	29	#include "get_bits.h"
	30
	31	/**
	32	* Starting frequency coefficient bin for each critical band.
	33	*/
	34	const uint8_t ff_ac3_band_start_tab[AC3_CRITICAL_BANDS+1] = {
	35	0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
	36	10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
	37	20, 21, 22, 23, 24, 25, 26, 27, 28, 31,
	38	34, 37, 40, 43, 46, 49, 55, 61, 67, 73,
	39	79, 85, 97, 109, 121, 133, 157, 181, 205, 229, 253
	40	};
	41
	42	#if CONFIG_HARDCODED_TABLES
	43
	44	/**
	45	* Map each frequency coefficient bin to the critical band that contains it.
	46	*/
	47	const uint8_t ff_ac3_bin_to_band_tab[253] = {
	48	0,
	49	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
	50	13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
	51	25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30,
	52	31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34,
	53	35, 35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36,
	54	37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38,
	55	39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40,
	56	41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
	57	42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
	58	43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43,
	59	44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44,
	60	45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
	61	45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
	62	46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
	63	46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
	64	47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
65	47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
66	48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
67	48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
68	49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49,
69	49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49
70	};
71
72	#else /* CONFIG_HARDCODED_TABLES */
73	uint8_t ff_ac3_bin_to_band_tab[253];
74	#endif
75
76	static inline int calc_lowcomp1(int a, int b0, int b1, int c)
77	{
78	if ((b0 + 256) == b1) {
79	a = c;
80	} else if (b0 > b1) {
81	a = FFMAX(a - 64, 0);
82	}
83	return a;
84	}
85
86	static inline int calc_lowcomp(int a, int b0, int b1, int bin)
87	{
88	if (bin < 7) {
89	return calc_lowcomp1(a, b0, b1, 384);
90	} else if (bin < 20) {
91	return calc_lowcomp1(a, b0, b1, 320);
92	} else {
93	return FFMAX(a - 128, 0);
94	}
95	}
96
97	void ff_ac3_bit_alloc_calc_psd(int8_t exp, int start, int end, int16_t psd,
98	int16_t *band_psd)
99	{
100	int bin, band;
101
102	/* exponent mapping to PSD */
103	for (bin = start; bin < end; bin++) {
104	psd[bin]=(3072 - (exp[bin] << 7));
105	}
106
107	/* PSD integration */
108	bin = start;
109	band = ff_ac3_bin_to_band_tab[start];
110	do {
111	int v = psd[bin++];
112	int band_end = FFMIN(ff_ac3_band_start_tab[band+1], end);
113	for (; bin < band_end; bin++) {
114	int max = FFMAX(v, psd[bin]);
115	/* logadd */
116	int adr = FFMIN(max - ((v + psd[bin] + 1) >> 1), 255);
117	v = max + ff_ac3_log_add_tab[adr];
118	}
119	band_psd[band++] = v;
120	} while (end > ff_ac3_band_start_tab[band]);
121	}
122
123	int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters s, int16_t band_psd,
124	int start, int end, int fast_gain, int is_lfe,
125	int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
126	uint8_t dba_lengths, uint8_t dba_values,
127	int16_t *mask)
128	{
129	int16_t excite[AC3_CRITICAL_BANDS]; /* excitation */
130	int band;
131	int band_start, band_end, begin, end1;
132	int lowcomp, fastleak, slowleak;
133
134	/* excitation function */
135	band_start = ff_ac3_bin_to_band_tab[start];
136	band_end = ff_ac3_bin_to_band_tab[end-1] + 1;
137
138	if (band_start == 0) {
139	lowcomp = 0;
140	lowcomp = calc_lowcomp1(lowcomp, band_psd[0], band_psd[1], 384);
141	excite[0] = band_psd[0] - fast_gain - lowcomp;
142	lowcomp = calc_lowcomp1(lowcomp, band_psd[1], band_psd[2], 384);
143	excite[1] = band_psd[1] - fast_gain - lowcomp;
144	begin = 7;
145	for (band = 2; band < 7; band++) {
146	if (!(is_lfe && band == 6))
147	lowcomp = calc_lowcomp1(lowcomp, band_psd[band], band_psd[band+1], 384);
148	fastleak = band_psd[band] - fast_gain;
149	slowleak = band_psd[band] - s->slow_gain;
150	excite[band] = fastleak - lowcomp;
151	if (!(is_lfe && band == 6)) {
152	if (band_psd[band] <= band_psd[band+1]) {
153	begin = band + 1;
154	break;
155	}
156	}
157	}
158
159	end1 = FFMIN(band_end, 22);
160	for (band = begin; band < end1; band++) {
161	if (!(is_lfe && band == 6))
162	lowcomp = calc_lowcomp(lowcomp, band_psd[band], band_psd[band+1], band);
163	fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
164	slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
165	excite[band] = FFMAX(fastleak - lowcomp, slowleak);
166	}
167	begin = 22;
168	} else {
169	/* coupling channel */
170	begin = band_start;
171	fastleak = (s->cpl_fast_leak << 8) + 768;
172	slowleak = (s->cpl_slow_leak << 8) + 768;
173	}
174
175	for (band = begin; band < band_end; band++) {
176	fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
177	slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
178	excite[band] = FFMAX(fastleak, slowleak);
179	}
180
181	/* compute masking curve */
182
183	for (band = band_start; band < band_end; band++) {
184	int tmp = s->db_per_bit - band_psd[band];
185	if (tmp > 0) {
186	excite[band] += tmp >> 2;
187	}
188	mask[band] = FFMAX(ff_ac3_hearing_threshold_tab[band >> s->sr_shift][s->sr_code], excite[band]);
189	}
190
191	/* delta bit allocation */
192
193	if (dba_mode == DBA_REUSE \|\| dba_mode == DBA_NEW) {
194	int i, seg, delta;
195	if (dba_nsegs > 8)
196	return -1;
197	band = band_start;
198	for (seg = 0; seg < dba_nsegs; seg++) {
199	band += dba_offsets[seg];
200	if (band >= AC3_CRITICAL_BANDS \|\| dba_lengths[seg] > AC3_CRITICAL_BANDS-band)
201	return -1;
202	if (dba_values[seg] >= 4) {
203	delta = (dba_values[seg] - 3) << 7;
204	} else {
205	delta = (dba_values[seg] - 4) << 7;
206	}
207	for (i = 0; i < dba_lengths[seg]; i++) {
208	mask[band++] += delta;
209	}
210	}
211	}
212	return 0;
213	}
214
215	/**
216	* Initialize some tables.
217	* note: This function must remain thread safe because it is called by the
218	* AVParser init code.
219	*/
220	av_cold void ff_ac3_common_init(void)
221	{
222	#if !CONFIG_HARDCODED_TABLES
223	/* compute ff_ac3_bin_to_band_tab from ff_ac3_band_start_tab */
224	int bin = 0, band;
225	for (band = 0; band < AC3_CRITICAL_BANDS; band++) {
226	int band_end = ff_ac3_band_start_tab[band+1];
227	while (bin < band_end)
228	ff_ac3_bin_to_band_tab[bin++] = band;
229	}
230	#endif /* !CONFIG_HARDCODED_TABLES */
231	}