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2ba45a60 DM |
1 | /* |
2 | * AC-3 encoder float/fixed template | |
3 | * Copyright (c) 2000 Fabrice Bellard | |
4 | * Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com> | |
5 | * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> | |
6 | * | |
7 | * This file is part of FFmpeg. | |
8 | * | |
9 | * FFmpeg is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * FFmpeg is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with FFmpeg; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | /** | |
25 | * @file | |
26 | * AC-3 encoder float/fixed template | |
27 | */ | |
28 | ||
29 | #include <stdint.h> | |
30 | ||
31 | #include "libavutil/attributes.h" | |
32 | #include "libavutil/internal.h" | |
33 | ||
34 | #include "audiodsp.h" | |
35 | #include "internal.h" | |
36 | #include "ac3enc.h" | |
37 | #include "eac3enc.h" | |
38 | ||
39 | /* prototypes for static functions in ac3enc_fixed.c and ac3enc_float.c */ | |
40 | ||
41 | static void scale_coefficients(AC3EncodeContext *s); | |
42 | ||
43 | static int normalize_samples(AC3EncodeContext *s); | |
44 | ||
45 | static void clip_coefficients(AudioDSPContext *adsp, CoefType *coef, | |
46 | unsigned int len); | |
47 | ||
48 | static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl); | |
49 | ||
50 | static void sum_square_butterfly(AC3EncodeContext *s, CoefSumType sum[4], | |
51 | const CoefType *coef0, const CoefType *coef1, | |
52 | int len); | |
53 | ||
54 | int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s) | |
55 | { | |
56 | int ch; | |
57 | ||
58 | FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE * | |
59 | sizeof(*s->windowed_samples), alloc_fail); | |
60 | FF_ALLOC_ARRAY_OR_GOTO(s->avctx, s->planar_samples, s->channels, sizeof(*s->planar_samples), | |
61 | alloc_fail); | |
62 | for (ch = 0; ch < s->channels; ch++) { | |
63 | FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch], | |
64 | (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples), | |
65 | alloc_fail); | |
66 | } | |
67 | ||
68 | return 0; | |
69 | alloc_fail: | |
70 | return AVERROR(ENOMEM); | |
71 | } | |
72 | ||
73 | ||
74 | /* | |
75 | * Copy input samples. | |
76 | * Channels are reordered from FFmpeg's default order to AC-3 order. | |
77 | */ | |
78 | static void copy_input_samples(AC3EncodeContext *s, SampleType **samples) | |
79 | { | |
80 | int ch; | |
81 | ||
82 | /* copy and remap input samples */ | |
83 | for (ch = 0; ch < s->channels; ch++) { | |
84 | /* copy last 256 samples of previous frame to the start of the current frame */ | |
85 | memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_BLOCK_SIZE * s->num_blocks], | |
86 | AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); | |
87 | ||
88 | /* copy new samples for current frame */ | |
89 | memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE], | |
90 | samples[s->channel_map[ch]], | |
91 | AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0])); | |
92 | } | |
93 | } | |
94 | ||
95 | ||
96 | /* | |
97 | * Apply the MDCT to input samples to generate frequency coefficients. | |
98 | * This applies the KBD window and normalizes the input to reduce precision | |
99 | * loss due to fixed-point calculations. | |
100 | */ | |
101 | static void apply_mdct(AC3EncodeContext *s) | |
102 | { | |
103 | int blk, ch; | |
104 | ||
105 | for (ch = 0; ch < s->channels; ch++) { | |
106 | for (blk = 0; blk < s->num_blocks; blk++) { | |
107 | AC3Block *block = &s->blocks[blk]; | |
108 | const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE]; | |
109 | ||
110 | #if CONFIG_AC3ENC_FLOAT | |
f6fa7814 | 111 | s->fdsp->vector_fmul(s->windowed_samples, input_samples, |
2ba45a60 DM |
112 | s->mdct_window, AC3_WINDOW_SIZE); |
113 | #else | |
114 | s->ac3dsp.apply_window_int16(s->windowed_samples, input_samples, | |
115 | s->mdct_window, AC3_WINDOW_SIZE); | |
116 | #endif | |
117 | ||
118 | if (s->fixed_point) | |
119 | block->coeff_shift[ch+1] = normalize_samples(s); | |
120 | ||
121 | s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1], | |
122 | s->windowed_samples); | |
123 | } | |
124 | } | |
125 | } | |
126 | ||
127 | ||
128 | /* | |
129 | * Calculate coupling channel and coupling coordinates. | |
130 | */ | |
131 | static void apply_channel_coupling(AC3EncodeContext *s) | |
132 | { | |
133 | LOCAL_ALIGNED_16(CoefType, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); | |
134 | #if CONFIG_AC3ENC_FLOAT | |
135 | LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); | |
136 | #else | |
137 | int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords; | |
138 | #endif | |
139 | int av_uninit(blk), ch, bnd, i, j; | |
140 | CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}}; | |
141 | int cpl_start, num_cpl_coefs; | |
142 | ||
143 | memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); | |
144 | #if CONFIG_AC3ENC_FLOAT | |
145 | memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); | |
146 | #endif | |
147 | ||
148 | /* align start to 16-byte boundary. align length to multiple of 32. | |
149 | note: coupling start bin % 4 will always be 1 */ | |
150 | cpl_start = s->start_freq[CPL_CH] - 1; | |
151 | num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32); | |
152 | cpl_start = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs; | |
153 | ||
154 | /* calculate coupling channel from fbw channels */ | |
155 | for (blk = 0; blk < s->num_blocks; blk++) { | |
156 | AC3Block *block = &s->blocks[blk]; | |
157 | CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start]; | |
158 | if (!block->cpl_in_use) | |
159 | continue; | |
160 | memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef)); | |
161 | for (ch = 1; ch <= s->fbw_channels; ch++) { | |
162 | CoefType *ch_coef = &block->mdct_coef[ch][cpl_start]; | |
163 | if (!block->channel_in_cpl[ch]) | |
164 | continue; | |
165 | for (i = 0; i < num_cpl_coefs; i++) | |
166 | cpl_coef[i] += ch_coef[i]; | |
167 | } | |
168 | ||
169 | /* coefficients must be clipped in order to be encoded */ | |
170 | clip_coefficients(&s->adsp, cpl_coef, num_cpl_coefs); | |
171 | } | |
172 | ||
173 | /* calculate energy in each band in coupling channel and each fbw channel */ | |
174 | /* TODO: possibly use SIMD to speed up energy calculation */ | |
175 | bnd = 0; | |
176 | i = s->start_freq[CPL_CH]; | |
177 | while (i < s->cpl_end_freq) { | |
178 | int band_size = s->cpl_band_sizes[bnd]; | |
179 | for (ch = CPL_CH; ch <= s->fbw_channels; ch++) { | |
180 | for (blk = 0; blk < s->num_blocks; blk++) { | |
181 | AC3Block *block = &s->blocks[blk]; | |
182 | if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch])) | |
183 | continue; | |
184 | for (j = 0; j < band_size; j++) { | |
185 | CoefType v = block->mdct_coef[ch][i+j]; | |
186 | MAC_COEF(energy[blk][ch][bnd], v, v); | |
187 | } | |
188 | } | |
189 | } | |
190 | i += band_size; | |
191 | bnd++; | |
192 | } | |
193 | ||
194 | /* calculate coupling coordinates for all blocks for all channels */ | |
195 | for (blk = 0; blk < s->num_blocks; blk++) { | |
196 | AC3Block *block = &s->blocks[blk]; | |
197 | if (!block->cpl_in_use) | |
198 | continue; | |
199 | for (ch = 1; ch <= s->fbw_channels; ch++) { | |
200 | if (!block->channel_in_cpl[ch]) | |
201 | continue; | |
202 | for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { | |
203 | cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd], | |
204 | energy[blk][CPL_CH][bnd]); | |
205 | } | |
206 | } | |
207 | } | |
208 | ||
209 | /* determine which blocks to send new coupling coordinates for */ | |
210 | for (blk = 0; blk < s->num_blocks; blk++) { | |
211 | AC3Block *block = &s->blocks[blk]; | |
212 | AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL; | |
213 | ||
214 | memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords)); | |
215 | ||
216 | if (block->cpl_in_use) { | |
217 | /* send new coordinates if this is the first block, if previous | |
218 | * block did not use coupling but this block does, the channels | |
219 | * using coupling has changed from the previous block, or the | |
220 | * coordinate difference from the last block for any channel is | |
221 | * greater than a threshold value. */ | |
222 | if (blk == 0 || !block0->cpl_in_use) { | |
223 | for (ch = 1; ch <= s->fbw_channels; ch++) | |
224 | block->new_cpl_coords[ch] = 1; | |
225 | } else { | |
226 | for (ch = 1; ch <= s->fbw_channels; ch++) { | |
227 | if (!block->channel_in_cpl[ch]) | |
228 | continue; | |
229 | if (!block0->channel_in_cpl[ch]) { | |
230 | block->new_cpl_coords[ch] = 1; | |
231 | } else { | |
232 | CoefSumType coord_diff = 0; | |
233 | for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { | |
234 | coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] - | |
235 | cpl_coords[blk ][ch][bnd]); | |
236 | } | |
237 | coord_diff /= s->num_cpl_bands; | |
238 | if (coord_diff > NEW_CPL_COORD_THRESHOLD) | |
239 | block->new_cpl_coords[ch] = 1; | |
240 | } | |
241 | } | |
242 | } | |
243 | } | |
244 | } | |
245 | ||
246 | /* calculate final coupling coordinates, taking into account reusing of | |
247 | coordinates in successive blocks */ | |
248 | for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { | |
249 | blk = 0; | |
250 | while (blk < s->num_blocks) { | |
251 | int av_uninit(blk1); | |
252 | AC3Block *block = &s->blocks[blk]; | |
253 | ||
254 | if (!block->cpl_in_use) { | |
255 | blk++; | |
256 | continue; | |
257 | } | |
258 | ||
259 | for (ch = 1; ch <= s->fbw_channels; ch++) { | |
260 | CoefSumType energy_ch, energy_cpl; | |
261 | if (!block->channel_in_cpl[ch]) | |
262 | continue; | |
263 | energy_cpl = energy[blk][CPL_CH][bnd]; | |
264 | energy_ch = energy[blk][ch][bnd]; | |
265 | blk1 = blk+1; | |
266 | while (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) { | |
267 | if (s->blocks[blk1].cpl_in_use) { | |
268 | energy_cpl += energy[blk1][CPL_CH][bnd]; | |
269 | energy_ch += energy[blk1][ch][bnd]; | |
270 | } | |
271 | blk1++; | |
272 | } | |
273 | cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl); | |
274 | } | |
275 | blk = blk1; | |
276 | } | |
277 | } | |
278 | ||
279 | /* calculate exponents/mantissas for coupling coordinates */ | |
280 | for (blk = 0; blk < s->num_blocks; blk++) { | |
281 | AC3Block *block = &s->blocks[blk]; | |
282 | if (!block->cpl_in_use) | |
283 | continue; | |
284 | ||
285 | #if CONFIG_AC3ENC_FLOAT | |
286 | s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1], | |
287 | cpl_coords[blk][1], | |
288 | s->fbw_channels * 16); | |
289 | #endif | |
290 | s->ac3dsp.extract_exponents(block->cpl_coord_exp[1], | |
291 | fixed_cpl_coords[blk][1], | |
292 | s->fbw_channels * 16); | |
293 | ||
294 | for (ch = 1; ch <= s->fbw_channels; ch++) { | |
295 | int bnd, min_exp, max_exp, master_exp; | |
296 | ||
297 | if (!block->new_cpl_coords[ch]) | |
298 | continue; | |
299 | ||
300 | /* determine master exponent */ | |
301 | min_exp = max_exp = block->cpl_coord_exp[ch][0]; | |
302 | for (bnd = 1; bnd < s->num_cpl_bands; bnd++) { | |
303 | int exp = block->cpl_coord_exp[ch][bnd]; | |
304 | min_exp = FFMIN(exp, min_exp); | |
305 | max_exp = FFMAX(exp, max_exp); | |
306 | } | |
307 | master_exp = ((max_exp - 15) + 2) / 3; | |
308 | master_exp = FFMAX(master_exp, 0); | |
309 | while (min_exp < master_exp * 3) | |
310 | master_exp--; | |
311 | for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { | |
312 | block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] - | |
313 | master_exp * 3, 0, 15); | |
314 | } | |
315 | block->cpl_master_exp[ch] = master_exp; | |
316 | ||
317 | /* quantize mantissas */ | |
318 | for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { | |
319 | int cpl_exp = block->cpl_coord_exp[ch][bnd]; | |
320 | int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24; | |
321 | if (cpl_exp == 15) | |
322 | cpl_mant >>= 1; | |
323 | else | |
324 | cpl_mant -= 16; | |
325 | ||
326 | block->cpl_coord_mant[ch][bnd] = cpl_mant; | |
327 | } | |
328 | } | |
329 | } | |
330 | ||
331 | if (CONFIG_EAC3_ENCODER && s->eac3) | |
332 | ff_eac3_set_cpl_states(s); | |
333 | } | |
334 | ||
335 | ||
336 | /* | |
337 | * Determine rematrixing flags for each block and band. | |
338 | */ | |
339 | static void compute_rematrixing_strategy(AC3EncodeContext *s) | |
340 | { | |
341 | int nb_coefs; | |
342 | int blk, bnd; | |
343 | AC3Block *block, *block0 = NULL; | |
344 | ||
345 | if (s->channel_mode != AC3_CHMODE_STEREO) | |
346 | return; | |
347 | ||
348 | for (blk = 0; blk < s->num_blocks; blk++) { | |
349 | block = &s->blocks[blk]; | |
350 | block->new_rematrixing_strategy = !blk; | |
351 | ||
352 | block->num_rematrixing_bands = 4; | |
353 | if (block->cpl_in_use) { | |
354 | block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61); | |
355 | block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37); | |
356 | if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands) | |
357 | block->new_rematrixing_strategy = 1; | |
358 | } | |
359 | nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]); | |
360 | ||
361 | if (!s->rematrixing_enabled) { | |
362 | block0 = block; | |
363 | continue; | |
364 | } | |
365 | ||
366 | for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { | |
367 | /* calculate sum of squared coeffs for one band in one block */ | |
368 | int start = ff_ac3_rematrix_band_tab[bnd]; | |
369 | int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]); | |
370 | CoefSumType sum[4]; | |
371 | sum_square_butterfly(s, sum, block->mdct_coef[1] + start, | |
372 | block->mdct_coef[2] + start, end - start); | |
373 | ||
374 | /* compare sums to determine if rematrixing will be used for this band */ | |
375 | if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1])) | |
376 | block->rematrixing_flags[bnd] = 1; | |
377 | else | |
378 | block->rematrixing_flags[bnd] = 0; | |
379 | ||
380 | /* determine if new rematrixing flags will be sent */ | |
381 | if (blk && | |
382 | block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) { | |
383 | block->new_rematrixing_strategy = 1; | |
384 | } | |
385 | } | |
386 | block0 = block; | |
387 | } | |
388 | } | |
389 | ||
390 | ||
391 | int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt, | |
392 | const AVFrame *frame, int *got_packet_ptr) | |
393 | { | |
394 | AC3EncodeContext *s = avctx->priv_data; | |
395 | int ret; | |
396 | ||
397 | if (s->options.allow_per_frame_metadata) { | |
398 | ret = ff_ac3_validate_metadata(s); | |
399 | if (ret) | |
400 | return ret; | |
401 | } | |
402 | ||
403 | if (s->bit_alloc.sr_code == 1 || s->eac3) | |
404 | ff_ac3_adjust_frame_size(s); | |
405 | ||
406 | copy_input_samples(s, (SampleType **)frame->extended_data); | |
407 | ||
408 | apply_mdct(s); | |
409 | ||
410 | if (s->fixed_point) | |
411 | scale_coefficients(s); | |
412 | ||
413 | clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1], | |
414 | AC3_MAX_COEFS * s->num_blocks * s->channels); | |
415 | ||
416 | s->cpl_on = s->cpl_enabled; | |
417 | ff_ac3_compute_coupling_strategy(s); | |
418 | ||
419 | if (s->cpl_on) | |
420 | apply_channel_coupling(s); | |
421 | ||
422 | compute_rematrixing_strategy(s); | |
423 | ||
424 | if (!s->fixed_point) | |
425 | scale_coefficients(s); | |
426 | ||
427 | ff_ac3_apply_rematrixing(s); | |
428 | ||
429 | ff_ac3_process_exponents(s); | |
430 | ||
431 | ret = ff_ac3_compute_bit_allocation(s); | |
432 | if (ret) { | |
433 | av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n"); | |
434 | return ret; | |
435 | } | |
436 | ||
437 | ff_ac3_group_exponents(s); | |
438 | ||
439 | ff_ac3_quantize_mantissas(s); | |
440 | ||
441 | if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size)) < 0) | |
442 | return ret; | |
443 | ff_ac3_output_frame(s, avpkt->data); | |
444 | ||
445 | if (frame->pts != AV_NOPTS_VALUE) | |
f6fa7814 | 446 | avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding); |
2ba45a60 DM |
447 | |
448 | *got_packet_ptr = 1; | |
449 | return 0; | |
450 | } |