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ttaenc.c
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1 /*
2  * TTA (The Lossless True Audio) encoder
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #define BITSTREAM_WRITER_LE
22 #include "ttadata.h"
23 #include "avcodec.h"
24 #include "put_bits.h"
25 #include "internal.h"
26 #include "libavutil/crc.h"
27 
28 typedef struct TTAEncContext {
29  const AVCRC *crc_table;
30  int bps;
33 
35 {
36  TTAEncContext *s = avctx->priv_data;
37 
39 
40  switch (avctx->sample_fmt) {
41  case AV_SAMPLE_FMT_U8:
42  avctx->bits_per_raw_sample = 8;
43  break;
44  case AV_SAMPLE_FMT_S16:
45  avctx->bits_per_raw_sample = 16;
46  break;
47  case AV_SAMPLE_FMT_S32:
48  if (avctx->bits_per_raw_sample > 24)
49  av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
50  avctx->bits_per_raw_sample = 24;
51  }
52 
53  s->bps = avctx->bits_per_raw_sample >> 3;
54  avctx->frame_size = 256 * avctx->sample_rate / 245;
55 
56  s->ch_ctx = av_malloc_array(avctx->channels, sizeof(*s->ch_ctx));
57  if (!s->ch_ctx)
58  return AVERROR(ENOMEM);
59 
60  return 0;
61 }
62 
63 static inline void ttafilter_process(TTAFilter *c, int32_t *in)
64 {
65  register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;
66 
67  if (c->error < 0) {
68  qm[0] -= dx[0]; qm[1] -= dx[1]; qm[2] -= dx[2]; qm[3] -= dx[3];
69  qm[4] -= dx[4]; qm[5] -= dx[5]; qm[6] -= dx[6]; qm[7] -= dx[7];
70  } else if (c->error > 0) {
71  qm[0] += dx[0]; qm[1] += dx[1]; qm[2] += dx[2]; qm[3] += dx[3];
72  qm[4] += dx[4]; qm[5] += dx[5]; qm[6] += dx[6]; qm[7] += dx[7];
73  }
74 
75  sum += dl[0] * qm[0] + dl[1] * qm[1] + dl[2] * qm[2] + dl[3] * qm[3] +
76  dl[4] * qm[4] + dl[5] * qm[5] + dl[6] * qm[6] + dl[7] * qm[7];
77 
78  dx[0] = dx[1]; dx[1] = dx[2]; dx[2] = dx[3]; dx[3] = dx[4];
79  dl[0] = dl[1]; dl[1] = dl[2]; dl[2] = dl[3]; dl[3] = dl[4];
80 
81  dx[4] = ((dl[4] >> 30) | 1);
82  dx[5] = ((dl[5] >> 30) | 2) & ~1;
83  dx[6] = ((dl[6] >> 30) | 2) & ~1;
84  dx[7] = ((dl[7] >> 30) | 4) & ~3;
85 
86  dl[4] = -dl[5]; dl[5] = -dl[6];
87  dl[6] = *in - dl[7]; dl[7] = *in;
88  dl[5] += dl[6]; dl[4] += dl[5];
89 
90  *in -= (sum >> c->shift);
91  c->error = *in;
92 }
93 
94 static int32_t get_sample(const AVFrame *frame, int sample,
95  enum AVSampleFormat format)
96 {
97  int32_t ret;
98 
99  if (format == AV_SAMPLE_FMT_U8) {
100  ret = frame->data[0][sample] - 0x80;
101  } else if (format == AV_SAMPLE_FMT_S16) {
102  const int16_t *ptr = (const int16_t *)frame->data[0];
103  ret = ptr[sample];
104  } else {
105  const int32_t *ptr = (const int32_t *)frame->data[0];
106  ret = ptr[sample] >> 8;
107  }
108 
109  return ret;
110 }
111 
112 static int tta_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
113  const AVFrame *frame, int *got_packet_ptr)
114 {
115  TTAEncContext *s = avctx->priv_data;
116  PutBitContext pb;
117  int ret, i, out_bytes, cur_chan, res, samples;
118  int64_t pkt_size = frame->nb_samples * 2LL * avctx->channels * s->bps;
119 
120 pkt_alloc:
121  cur_chan = 0, res = 0, samples = 0;
122  if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size)) < 0)
123  return ret;
124  init_put_bits(&pb, avpkt->data, avpkt->size);
125 
126  // init per channel states
127  for (i = 0; i < avctx->channels; i++) {
128  s->ch_ctx[i].predictor = 0;
130  ff_tta_rice_init(&s->ch_ctx[i].rice, 10, 10);
131  }
132 
133  for (i = 0; i < frame->nb_samples * avctx->channels; i++) {
134  TTAChannel *c = &s->ch_ctx[cur_chan];
135  TTAFilter *filter = &c->filter;
136  TTARice *rice = &c->rice;
137  uint32_t k, unary, outval;
138  int32_t value, temp;
139 
140  value = get_sample(frame, samples++, avctx->sample_fmt);
141 
142  if (avctx->channels > 1) {
143  if (cur_chan < avctx->channels - 1)
144  value = res = get_sample(frame, samples, avctx->sample_fmt) - value;
145  else
146  value -= res / 2;
147  }
148 
149  temp = value;
150 #define PRED(x, k) (int32_t)((((uint64_t)(x) << (k)) - (x)) >> (k))
151  switch (s->bps) {
152  case 1: value -= PRED(c->predictor, 4); break;
153  case 2:
154  case 3: value -= PRED(c->predictor, 5); break;
155  }
156  c->predictor = temp;
157 
158  ttafilter_process(filter, &value);
159  outval = (value > 0) ? (value << 1) - 1: -value << 1;
160 
161  k = rice->k0;
162 
163  rice->sum0 += outval - (rice->sum0 >> 4);
164  if (rice->k0 > 0 && rice->sum0 < ff_tta_shift_16[rice->k0])
165  rice->k0--;
166  else if (rice->sum0 > ff_tta_shift_16[rice->k0 + 1])
167  rice->k0++;
168 
169  if (outval >= ff_tta_shift_1[k]) {
170  outval -= ff_tta_shift_1[k];
171  k = rice->k1;
172 
173  rice->sum1 += outval - (rice->sum1 >> 4);
174  if (rice->k1 > 0 && rice->sum1 < ff_tta_shift_16[rice->k1])
175  rice->k1--;
176  else if (rice->sum1 > ff_tta_shift_16[rice->k1 + 1])
177  rice->k1++;
178 
179  unary = 1 + (outval >> k);
180  if (unary + 100LL > put_bits_left(&pb)) {
181  if (pkt_size < INT_MAX/2) {
182  pkt_size *= 2;
183  av_packet_unref(avpkt);
184  goto pkt_alloc;
185  } else
186  return AVERROR(ENOMEM);
187  }
188  do {
189  if (unary > 31) {
190  put_bits(&pb, 31, 0x7FFFFFFF);
191  unary -= 31;
192  } else {
193  put_bits(&pb, unary, (1 << unary) - 1);
194  unary = 0;
195  }
196  } while (unary);
197  }
198 
199  put_bits(&pb, 1, 0);
200 
201  if (k)
202  put_bits(&pb, k, outval & (ff_tta_shift_1[k] - 1));
203 
204  if (cur_chan < avctx->channels - 1)
205  cur_chan++;
206  else
207  cur_chan = 0;
208  }
209 
210  flush_put_bits(&pb);
211  out_bytes = put_bits_count(&pb) >> 3;
212  put_bits32(&pb, av_crc(s->crc_table, UINT32_MAX, avpkt->data, out_bytes) ^ UINT32_MAX);
213  flush_put_bits(&pb);
214 
215  avpkt->pts = frame->pts;
216  avpkt->size = out_bytes + 4;
217  avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
218  *got_packet_ptr = 1;
219  return 0;
220 }
221 
223 {
224  TTAEncContext *s = avctx->priv_data;
225  av_freep(&s->ch_ctx);
226  return 0;
227 }
228 
230  .name = "tta",
231  .long_name = NULL_IF_CONFIG_SMALL("TTA (True Audio)"),
232  .type = AVMEDIA_TYPE_AUDIO,
233  .id = AV_CODEC_ID_TTA,
234  .priv_data_size = sizeof(TTAEncContext),
236  .close = tta_encode_close,
237  .encode2 = tta_encode_frame,
239  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_U8,
243 };