1/*
2 * DSP Group TrueSpeech compatible decoder
3 * Copyright (c) 2005 Konstantin Shishkov
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/intreadwrite.h"
23#include "avcodec.h"
24#include "dsputil.h"
25#include "get_bits.h"
26
27#include "truespeech_data.h"
28/**
29 * @file
30 * TrueSpeech decoder.
31 */
32
33/**
34 * TrueSpeech decoder context
35 */
36typedef struct {
37    AVFrame frame;
38    DSPContext dsp;
39    /* input data */
40    uint8_t buffer[32];
41    int16_t vector[8];  ///< input vector: 5/5/4/4/4/3/3/3
42    int offset1[2];     ///< 8-bit value, used in one copying offset
43    int offset2[4];     ///< 7-bit value, encodes offsets for copying and for two-point filter
44    int pulseoff[4];    ///< 4-bit offset of pulse values block
45    int pulsepos[4];    ///< 27-bit variable, encodes 7 pulse positions
46    int pulseval[4];    ///< 7x2-bit pulse values
47    int flag;           ///< 1-bit flag, shows how to choose filters
48    /* temporary data */
49    int filtbuf[146];   // some big vector used for storing filters
50    int prevfilt[8];    // filter from previous frame
51    int16_t tmp1[8];    // coefficients for adding to out
52    int16_t tmp2[8];    // coefficients for adding to out
53    int16_t tmp3[8];    // coefficients for adding to out
54    int16_t cvector[8]; // correlated input vector
55    int filtval;        // gain value for one function
56    int16_t newvec[60]; // tmp vector
57    int16_t filters[32]; // filters for every subframe
58} TSContext;
59
60static av_cold int truespeech_decode_init(AVCodecContext * avctx)
61{
62    TSContext *c = avctx->priv_data;
63
64    if (avctx->channels != 1) {
65        av_log_ask_for_sample(avctx, "Unsupported channel count: %d\n", avctx->channels);
66        return AVERROR(EINVAL);
67    }
68
69    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
70
71    dsputil_init(&c->dsp, avctx);
72
73    avcodec_get_frame_defaults(&c->frame);
74    avctx->coded_frame = &c->frame;
75
76    return 0;
77}
78
79static void truespeech_read_frame(TSContext *dec, const uint8_t *input)
80{
81    GetBitContext gb;
82
83    dec->dsp.bswap_buf((uint32_t *)dec->buffer, (const uint32_t *)input, 8);
84    init_get_bits(&gb, dec->buffer, 32 * 8);
85
86    dec->vector[7] = ts_codebook[7][get_bits(&gb, 3)];
87    dec->vector[6] = ts_codebook[6][get_bits(&gb, 3)];
88    dec->vector[5] = ts_codebook[5][get_bits(&gb, 3)];
89    dec->vector[4] = ts_codebook[4][get_bits(&gb, 4)];
90    dec->vector[3] = ts_codebook[3][get_bits(&gb, 4)];
91    dec->vector[2] = ts_codebook[2][get_bits(&gb, 4)];
92    dec->vector[1] = ts_codebook[1][get_bits(&gb, 5)];
93    dec->vector[0] = ts_codebook[0][get_bits(&gb, 5)];
94    dec->flag      = get_bits1(&gb);
95
96    dec->offset1[0] = get_bits(&gb, 4) << 4;
97    dec->offset2[3] = get_bits(&gb, 7);
98    dec->offset2[2] = get_bits(&gb, 7);
99    dec->offset2[1] = get_bits(&gb, 7);
100    dec->offset2[0] = get_bits(&gb, 7);
101
102    dec->offset1[1]  = get_bits(&gb, 4);
103    dec->pulseval[1] = get_bits(&gb, 14);
104    dec->pulseval[0] = get_bits(&gb, 14);
105
106    dec->offset1[1] |= get_bits(&gb, 4) << 4;
107    dec->pulseval[3] = get_bits(&gb, 14);
108    dec->pulseval[2] = get_bits(&gb, 14);
109
110    dec->offset1[0] |= get_bits1(&gb);
111    dec->pulsepos[0] = get_bits_long(&gb, 27);
112    dec->pulseoff[0] = get_bits(&gb, 4);
113
114    dec->offset1[0] |= get_bits1(&gb) << 1;
115    dec->pulsepos[1] = get_bits_long(&gb, 27);
116    dec->pulseoff[1] = get_bits(&gb, 4);
117
118    dec->offset1[0] |= get_bits1(&gb) << 2;
119    dec->pulsepos[2] = get_bits_long(&gb, 27);
120    dec->pulseoff[2] = get_bits(&gb, 4);
121
122    dec->offset1[0] |= get_bits1(&gb) << 3;
123    dec->pulsepos[3] = get_bits_long(&gb, 27);
124    dec->pulseoff[3] = get_bits(&gb, 4);
125}
126
127static void truespeech_correlate_filter(TSContext *dec)
128{
129    int16_t tmp[8];
130    int i, j;
131
132    for(i = 0; i < 8; i++){
133        if(i > 0){
134            memcpy(tmp, dec->cvector, i * sizeof(*tmp));
135            for(j = 0; j < i; j++)
136                dec->cvector[j] = ((tmp[i - j - 1] * dec->vector[i]) +
137                                   (dec->cvector[j] << 15) + 0x4000) >> 15;
138        }
139        dec->cvector[i] = (8 - dec->vector[i]) >> 3;
140    }
141    for(i = 0; i < 8; i++)
142        dec->cvector[i] = (dec->cvector[i] * ts_decay_994_1000[i]) >> 15;
143
144    dec->filtval = dec->vector[0];
145}
146
147static void truespeech_filters_merge(TSContext *dec)
148{
149    int i;
150
151    if(!dec->flag){
152        for(i = 0; i < 8; i++){
153            dec->filters[i + 0] = dec->prevfilt[i];
154            dec->filters[i + 8] = dec->prevfilt[i];
155        }
156    }else{
157        for(i = 0; i < 8; i++){
158            dec->filters[i + 0]=(dec->cvector[i] * 21846 + dec->prevfilt[i] * 10923 + 16384) >> 15;
159            dec->filters[i + 8]=(dec->cvector[i] * 10923 + dec->prevfilt[i] * 21846 + 16384) >> 15;
160        }
161    }
162    for(i = 0; i < 8; i++){
163        dec->filters[i + 16] = dec->cvector[i];
164        dec->filters[i + 24] = dec->cvector[i];
165    }
166}
167
168static void truespeech_apply_twopoint_filter(TSContext *dec, int quart)
169{
170    int16_t tmp[146 + 60], *ptr0, *ptr1;
171    const int16_t *filter;
172    int i, t, off;
173
174    t = dec->offset2[quart];
175    if(t == 127){
176        memset(dec->newvec, 0, 60 * sizeof(*dec->newvec));
177        return;
178    }
179    for(i = 0; i < 146; i++)
180        tmp[i] = dec->filtbuf[i];
181    off = (t / 25) + dec->offset1[quart >> 1] + 18;
182    off = av_clip(off, 0, 145);
183    ptr0 = tmp + 145 - off;
184    ptr1 = tmp + 146;
185    filter = (const int16_t*)ts_order2_coeffs + (t % 25) * 2;
186    for(i = 0; i < 60; i++){
187        t = (ptr0[0] * filter[0] + ptr0[1] * filter[1] + 0x2000) >> 14;
188        ptr0++;
189        dec->newvec[i] = t;
190        ptr1[i] = t;
191    }
192}
193
194static void truespeech_place_pulses(TSContext *dec, int16_t *out, int quart)
195{
196    int16_t tmp[7];
197    int i, j, t;
198    const int16_t *ptr1;
199    int16_t *ptr2;
200    int coef;
201
202    memset(out, 0, 60 * sizeof(*out));
203    for(i = 0; i < 7; i++) {
204        t = dec->pulseval[quart] & 3;
205        dec->pulseval[quart] >>= 2;
206        tmp[6 - i] = ts_pulse_scales[dec->pulseoff[quart] * 4 + t];
207    }
208
209    coef = dec->pulsepos[quart] >> 15;
210    ptr1 = (const int16_t*)ts_pulse_values + 30;
211    ptr2 = tmp;
212    for(i = 0, j = 3; (i < 30) && (j > 0); i++){
213        t = *ptr1++;
214        if(coef >= t)
215            coef -= t;
216        else{
217            out[i] = *ptr2++;
218            ptr1 += 30;
219            j--;
220        }
221    }
222    coef = dec->pulsepos[quart] & 0x7FFF;
223    ptr1 = (const int16_t*)ts_pulse_values;
224    for(i = 30, j = 4; (i < 60) && (j > 0); i++){
225        t = *ptr1++;
226        if(coef >= t)
227            coef -= t;
228        else{
229            out[i] = *ptr2++;
230            ptr1 += 30;
231            j--;
232        }
233    }
234
235}
236
237static void truespeech_update_filters(TSContext *dec, int16_t *out, int quart)
238{
239    int i;
240
241    memmove(dec->filtbuf, &dec->filtbuf[60], 86 * sizeof(*dec->filtbuf));
242    for(i = 0; i < 60; i++){
243        dec->filtbuf[i + 86] = out[i] + dec->newvec[i] - (dec->newvec[i] >> 3);
244        out[i] += dec->newvec[i];
245    }
246}
247
248static void truespeech_synth(TSContext *dec, int16_t *out, int quart)
249{
250    int i,k;
251    int t[8];
252    int16_t *ptr0, *ptr1;
253
254    ptr0 = dec->tmp1;
255    ptr1 = dec->filters + quart * 8;
256    for(i = 0; i < 60; i++){
257        int sum = 0;
258        for(k = 0; k < 8; k++)
259            sum += ptr0[k] * ptr1[k];
260        sum = (sum + (out[i] << 12) + 0x800) >> 12;
261        out[i] = av_clip(sum, -0x7FFE, 0x7FFE);
262        for(k = 7; k > 0; k--)
263            ptr0[k] = ptr0[k - 1];
264        ptr0[0] = out[i];
265    }
266
267    for(i = 0; i < 8; i++)
268        t[i] = (ts_decay_35_64[i] * ptr1[i]) >> 15;
269
270    ptr0 = dec->tmp2;
271    for(i = 0; i < 60; i++){
272        int sum = 0;
273        for(k = 0; k < 8; k++)
274            sum += ptr0[k] * t[k];
275        for(k = 7; k > 0; k--)
276            ptr0[k] = ptr0[k - 1];
277        ptr0[0] = out[i];
278        out[i] = ((out[i] << 12) - sum) >> 12;
279    }
280
281    for(i = 0; i < 8; i++)
282        t[i] = (ts_decay_3_4[i] * ptr1[i]) >> 15;
283
284    ptr0 = dec->tmp3;
285    for(i = 0; i < 60; i++){
286        int sum = out[i] << 12;
287        for(k = 0; k < 8; k++)
288            sum += ptr0[k] * t[k];
289        for(k = 7; k > 0; k--)
290            ptr0[k] = ptr0[k - 1];
291        ptr0[0] = av_clip((sum + 0x800) >> 12, -0x7FFE, 0x7FFE);
292
293        sum = ((ptr0[1] * (dec->filtval - (dec->filtval >> 2))) >> 4) + sum;
294        sum = sum - (sum >> 3);
295        out[i] = av_clip((sum + 0x800) >> 12, -0x7FFE, 0x7FFE);
296    }
297}
298
299static void truespeech_save_prevvec(TSContext *c)
300{
301    int i;
302
303    for(i = 0; i < 8; i++)
304        c->prevfilt[i] = c->cvector[i];
305}
306
307static int truespeech_decode_frame(AVCodecContext *avctx, void *data,
308                                   int *got_frame_ptr, AVPacket *avpkt)
309{
310    const uint8_t *buf = avpkt->data;
311    int buf_size = avpkt->size;
312    TSContext *c = avctx->priv_data;
313
314    int i, j;
315    int16_t *samples;
316    int iterations, ret;
317
318    iterations = buf_size / 32;
319
320    if (!iterations) {
321        av_log(avctx, AV_LOG_ERROR,
322               "Too small input buffer (%d bytes), need at least 32 bytes\n", buf_size);
323        return -1;
324    }
325
326    /* get output buffer */
327    c->frame.nb_samples = iterations * 240;
328    if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) {
329        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
330        return ret;
331    }
332    samples = (int16_t *)c->frame.data[0];
333
334    memset(samples, 0, iterations * 240 * sizeof(*samples));
335
336    for(j = 0; j < iterations; j++) {
337        truespeech_read_frame(c, buf);
338        buf += 32;
339
340        truespeech_correlate_filter(c);
341        truespeech_filters_merge(c);
342
343        for(i = 0; i < 4; i++) {
344            truespeech_apply_twopoint_filter(c, i);
345            truespeech_place_pulses  (c, samples, i);
346            truespeech_update_filters(c, samples, i);
347            truespeech_synth         (c, samples, i);
348            samples += 60;
349        }
350
351        truespeech_save_prevvec(c);
352    }
353
354    *got_frame_ptr   = 1;
355    *(AVFrame *)data = c->frame;
356
357    return buf_size;
358}
359
360AVCodec ff_truespeech_decoder = {
361    .name           = "truespeech",
362    .type           = AVMEDIA_TYPE_AUDIO,
363    .id             = CODEC_ID_TRUESPEECH,
364    .priv_data_size = sizeof(TSContext),
365    .init           = truespeech_decode_init,
366    .decode         = truespeech_decode_frame,
367    .capabilities   = CODEC_CAP_DR1,
368    .long_name = NULL_IF_CONFIG_SMALL("DSP Group TrueSpeech"),
369};
370