libmp3lame.c
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1 /*
2  * Interface to libmp3lame for mp3 encoding
3  * Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
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 
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/log.h"
29 #include "libavutil/opt.h"
30 #include "avcodec.h"
31 #include "mpegaudio.h"
32 #include <lame/lame.h>
33 
34 #define BUFFER_SIZE (7200 + 2 * MPA_FRAME_SIZE + MPA_FRAME_SIZE / 4)
35 typedef struct Mp3AudioContext {
36  AVClass *class;
37  lame_global_flags *gfp;
38  int stereo;
39  uint8_t buffer[BUFFER_SIZE];
41  int reservoir;
43 
45 {
46  Mp3AudioContext *s = avctx->priv_data;
47 
48  if (avctx->channels > 2)
49  return -1;
50 
51  s->stereo = avctx->channels > 1 ? 1 : 0;
52 
53  if ((s->gfp = lame_init()) == NULL)
54  goto err;
55  lame_set_in_samplerate(s->gfp, avctx->sample_rate);
56  lame_set_out_samplerate(s->gfp, avctx->sample_rate);
57  lame_set_num_channels(s->gfp, avctx->channels);
59  lame_set_quality(s->gfp, 5);
60  } else {
61  lame_set_quality(s->gfp, avctx->compression_level);
62  }
63  lame_set_mode(s->gfp, s->stereo ? JOINT_STEREO : MONO);
64  lame_set_brate(s->gfp, avctx->bit_rate / 1000);
65  if (avctx->flags & CODEC_FLAG_QSCALE) {
66  lame_set_brate(s->gfp, 0);
67  lame_set_VBR(s->gfp, vbr_default);
68  lame_set_VBR_quality(s->gfp, avctx->global_quality / (float)FF_QP2LAMBDA);
69  }
70  lame_set_bWriteVbrTag(s->gfp,0);
71 #if FF_API_LAME_GLOBAL_OPTS
72  s->reservoir = avctx->flags2 & CODEC_FLAG2_BIT_RESERVOIR;
73 #endif
74  lame_set_disable_reservoir(s->gfp, !s->reservoir);
75  if (lame_init_params(s->gfp) < 0)
76  goto err_close;
77 
78  avctx->frame_size = lame_get_framesize(s->gfp);
80  avctx->coded_frame->key_frame = 1;
81 
82  return 0;
83 
84 err_close:
85  lame_close(s->gfp);
86 err:
87  return -1;
88 }
89 
90 static const int sSampleRates[] = {
91  44100, 48000, 32000, 22050, 24000, 16000, 11025, 12000, 8000, 0
92 };
93 
94 static const int sBitRates[2][3][15] = {
95  {
96  { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448 },
97  { 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384 },
98  { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 }
99  },
100  {
101  { 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256 },
102  { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 },
103  { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 }
104  },
105 };
106 
107 static const int sSamplesPerFrame[2][3] = {
108  { 384, 1152, 1152 },
109  { 384, 1152, 576 }
110 };
111 
112 static const int sBitsPerSlot[3] = { 32, 8, 8 };
113 
114 static int mp3len(void *data, int *samplesPerFrame, int *sampleRate)
115 {
116  uint32_t header = AV_RB32(data);
117  int layerID = 3 - ((header >> 17) & 0x03);
118  int bitRateID = ((header >> 12) & 0x0f);
119  int sampleRateID = ((header >> 10) & 0x03);
120  int bitsPerSlot = sBitsPerSlot[layerID];
121  int isPadded = ((header >> 9) & 0x01);
122  static int const mode_tab[4] = { 2, 3, 1, 0 };
123  int mode = mode_tab[(header >> 19) & 0x03];
124  int mpeg_id = mode > 0;
125  int temp0, temp1, bitRate;
126 
127  if (((header >> 21) & 0x7ff) != 0x7ff || mode == 3 || layerID == 3 ||
128  sampleRateID == 3) {
129  return -1;
130  }
131 
132  if (!samplesPerFrame)
133  samplesPerFrame = &temp0;
134  if (!sampleRate)
135  sampleRate = &temp1;
136 
137  //*isMono = ((header >> 6) & 0x03) == 0x03;
138 
139  *sampleRate = sSampleRates[sampleRateID] >> mode;
140  bitRate = sBitRates[mpeg_id][layerID][bitRateID] * 1000;
141  *samplesPerFrame = sSamplesPerFrame[mpeg_id][layerID];
142  //av_log(NULL, AV_LOG_DEBUG,
143  // "sr:%d br:%d spf:%d l:%d m:%d\n",
144  // *sampleRate, bitRate, *samplesPerFrame, layerID, mode);
145 
146  return *samplesPerFrame * bitRate / (bitsPerSlot * *sampleRate) + isPadded;
147 }
148 
149 static int MP3lame_encode_frame(AVCodecContext *avctx, unsigned char *frame,
150  int buf_size, void *data)
151 {
152  Mp3AudioContext *s = avctx->priv_data;
153  int len;
154  int lame_result;
155 
156  /* lame 3.91 dies on '1-channel interleaved' data */
157 
158  if (data) {
159  if (s->stereo) {
160  lame_result = lame_encode_buffer_interleaved(s->gfp, data,
161  avctx->frame_size,
162  s->buffer + s->buffer_index,
164  } else {
165  lame_result = lame_encode_buffer(s->gfp, data, data,
166  avctx->frame_size, s->buffer +
168  s->buffer_index);
169  }
170  } else {
171  lame_result = lame_encode_flush(s->gfp, s->buffer + s->buffer_index,
173  }
174 
175  if (lame_result < 0) {
176  if (lame_result == -1) {
177  /* output buffer too small */
178  av_log(avctx, AV_LOG_ERROR,
179  "lame: output buffer too small (buffer index: %d, free bytes: %d)\n",
181  }
182  return -1;
183  }
184 
185  s->buffer_index += lame_result;
186 
187  if (s->buffer_index < 4)
188  return 0;
189 
190  len = mp3len(s->buffer, NULL, NULL);
191  //av_log(avctx, AV_LOG_DEBUG, "in:%d packet-len:%d index:%d\n",
192  // avctx->frame_size, len, s->buffer_index);
193  if (len <= s->buffer_index) {
194  memcpy(frame, s->buffer, len);
195  s->buffer_index -= len;
196 
197  memmove(s->buffer, s->buffer + len, s->buffer_index);
198  // FIXME fix the audio codec API, so we do not need the memcpy()
199  /*for(i=0; i<len; i++) {
200  av_log(avctx, AV_LOG_DEBUG, "%2X ", frame[i]);
201  }*/
202  return len;
203  } else
204  return 0;
205 }
206 
208 {
209  Mp3AudioContext *s = avctx->priv_data;
210 
211  av_freep(&avctx->coded_frame);
212 
213  lame_close(s->gfp);
214  return 0;
215 }
216 
217 #define OFFSET(x) offsetof(Mp3AudioContext, x)
218 #define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
219 static const AVOption options[] = {
220  { "reservoir", "Use bit reservoir.", OFFSET(reservoir), AV_OPT_TYPE_INT, { 1 }, 0, 1, AE },
221  { NULL },
222 };
223 
224 static const AVClass libmp3lame_class = {
225  .class_name = "libmp3lame encoder",
226  .item_name = av_default_item_name,
227  .option = options,
228  .version = LIBAVUTIL_VERSION_INT,
229 };
230 
232  .name = "libmp3lame",
233  .type = AVMEDIA_TYPE_AUDIO,
234  .id = CODEC_ID_MP3,
235  .priv_data_size = sizeof(Mp3AudioContext),
237  .encode = MP3lame_encode_frame,
239  .capabilities = CODEC_CAP_DELAY,
240  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
242  .supported_samplerates = sSampleRates,
243  .long_name = NULL_IF_CONFIG_SMALL("libmp3lame MP3 (MPEG audio layer 3)"),
244  .priv_class = &libmp3lame_class,
245 };