common/JackAC3Encoder.cpp

   1 /*
   2 Copyright (C) 2006 Jesse Chappell <jesse@essej.net> (AC3Jack)
   3 Copyright (C) 2012 Grame
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19 */
  20
  21 #include "JackAC3Encoder.h"
  22 #include "JackError.h"
  23 #include <unistd.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26
  27 #define max(x,y) (((x)>(y)) ? (x) : (y))
  28 #define min(x,y) (((x)<(y)) ? (x) : (y))
  29
  30 namespace Jack
  31 {
  32
  33 JackAC3Encoder::JackAC3Encoder(const JackAC3EncoderParams& params)
  34 {
  35     aften_set_defaults(&fAftenContext);
  36
  37     fAftenContext.channels = params.channels;
  38         fAftenContext.samplerate = params.sample_rate;
  39         fAftenContext.params.bitrate = params.bitrate;
  40
  41         int acmod = A52_ACMOD_MONO;
  42         int lfe = params.lfe;
  43
  44         switch (params.channels) {
  45
  46         case 1: acmod = A52_ACMOD_MONO; break;
  47         case 2: acmod = A52_ACMOD_STEREO; break;
  48         case 3: acmod = A52_ACMOD_3_0; break;
  49         case 4: acmod = A52_ACMOD_2_2; break;
  50         case 5: acmod = A52_ACMOD_3_2; break;
  51             break;
  52
  53         default:
  54             break;
  55         }
  56
  57         if (lfe) {
  58                 fAftenContext.channels += 1;
  59         }
  60
  61         fAftenContext.acmod = acmod;
  62         fAftenContext.lfe = lfe;
  63         fAftenContext.sample_format = A52_SAMPLE_FMT_FLT;
  64         fAftenContext.verbose = 1;
  65
  66         fAftenContext.system.n_threads = 1;
  67
  68     // create interleaved framebuffer for MAX_AC3_CHANNELS
  69         fSampleBuffer = new float[MAX_AC3_CHANNELS * A52_SAMPLES_PER_FRAME];
  70
  71     // create AC3 buffer
  72         fAC3Buffer = new unsigned char[A52_MAX_CODED_FRAME_SIZE];
  73         memset(fAC3Buffer, 0, A52_MAX_CODED_FRAME_SIZE);
  74
  75     fZeroBuffer = new unsigned char[SPDIF_FRAME_SIZE];
  76         memset(fZeroBuffer, 0, SPDIF_FRAME_SIZE);
  77
  78     fRingBuffer = jack_ringbuffer_create(32768);
  79
  80     fOutSizeByte = 0;
  81     fFramePos = 0;
  82
  83     fSampleRate = 0;
  84     fByteRate = 0;
  85 }
  86
  87 bool JackAC3Encoder::Init(jack_nframes_t sample_rate)
  88 {
  89     fSampleRate = sample_rate;
  90         fByteRate = fSampleRate * sizeof(short) * 2;
  91     return (aften_encode_init(&fAftenContext) == 0);
  92 }
  93
  94 JackAC3Encoder::~JackAC3Encoder()
  95 {
  96     aften_encode_close(&fAftenContext);
  97
  98     delete [] fSampleBuffer;
  99     delete [] fAC3Buffer;
 100     delete [] fZeroBuffer;
 101
 102     if (fRingBuffer) {
 103         jack_ringbuffer_free(fRingBuffer);
 104     }
 105 }
 106
 107 void JackAC3Encoder::Process(float** inputs_buffer, float** outputs_buffer, int nframes)
 108 {
 109     // fill and process frame buffers as appropriate
 110         jack_nframes_t frames_left = A52_SAMPLES_PER_FRAME - fFramePos;
 111         jack_nframes_t offset = 0;
 112
 113         while (offset < nframes)
 114         {
 115                 if ((nframes - offset) >= frames_left) {
 116
 117                         // copy only frames_left more data
 118                         jack_nframes_t pos = fFramePos * fAftenContext.channels;
 119                         for (jack_nframes_t spos = offset; spos < offset + frames_left; ++spos) {
 120                                 for (size_t i = 0; i < fAftenContext.channels; ++i) {
 121                                         fSampleBuffer[pos + i] = inputs_buffer[i][spos];
 122                                 }
 123                                 pos += fAftenContext.channels;
 124                         }
 125
 126                         // use interleaved version
 127             int res = aften_encode_frame(&fAftenContext, fAC3Buffer + SPDIF_HEADER_SIZE, fSampleBuffer);
 128             if (res < 0) {
 129                 jack_error("aften_encode_frame error !!");
 130                 return;
 131             }
 132
 133             fOutSizeByte = res;
 134
 135                         FillSpdifHeader(fAC3Buffer, fOutSizeByte + SPDIF_HEADER_SIZE);
 136
 137                         // push AC3 output to SPDIF ring buffer
 138                         float calc_ac3byterate = (fOutSizeByte * fSampleRate / (float) A52_SAMPLES_PER_FRAME);
 139                         jack_nframes_t silencebytes = (jack_nframes_t) (fOutSizeByte * (fByteRate / calc_ac3byterate)) - fOutSizeByte - SPDIF_HEADER_SIZE;
 140
 141             jack_ringbuffer_write(fRingBuffer, (const char *)fAC3Buffer, fOutSizeByte + SPDIF_HEADER_SIZE);
 142
 143             // write the proper remainder of zero padding (inefficient, should be memsetting)
 144             jack_ringbuffer_write(fRingBuffer, (const char *)fZeroBuffer, silencebytes);
 145
 146                         offset += frames_left;
 147                         frames_left = A52_SAMPLES_PER_FRAME;
 148                         fFramePos = 0;
 149
 150                 } else {
 151
 152                         // copy incoming data into frame buffers without processing
 153                         jack_nframes_t pos = fFramePos * fAftenContext.channels;
 154                         for (jack_nframes_t spos = offset; spos < nframes; ++spos) {
 155                                 for (size_t i = 0; i < fAftenContext.channels; ++i) {
 156                                         fSampleBuffer[pos + i] = inputs_buffer[i][spos];
 157                                 }
 158                                 pos += fAftenContext.channels;
 159                         }
 160
 161                         fFramePos += (nframes - offset);
 162                         offset += (nframes-offset);
 163                 }
 164         }
 165
 166         Output2Driver(outputs_buffer, nframes);
 167 }
 168
 169 void JackAC3Encoder::FillSpdifHeader(unsigned char* buf, int outsize)
 170 {
 171         // todo, use outsize and not assume the fixed frame size?
 172         int ac3outsize = outsize - SPDIF_HEADER_SIZE;
 173
 174         buf[0] = 0x72; buf[1] = 0xf8;   /* spdif syncword */
 175         buf[2] = 0x1f; buf[3] = 0x4e;   /* .............. */
 176         buf[4] = 0x01;                  /* AC3 data */
 177         buf[5] = buf[13] & 7;           /* bsmod, stream = 0 */
 178         buf[6] = (ac3outsize << 3) & 0xff;
 179         buf[7] = (ac3outsize >> 5) & 0xff;
 180
 181 #if !IS_BIGENDIAN
 182         swab(buf+SPDIF_HEADER_SIZE, buf + SPDIF_HEADER_SIZE, ac3outsize);
 183 #endif
 184 }
 185
 186 int JackAC3Encoder::Output2Driver(float** outputs, jack_nframes_t nframes)
 187 {
 188         int wrotebytes = 0;
 189         jack_nframes_t nframes_left = nframes;
 190
 191         if (jack_ringbuffer_read_space(fRingBuffer) == 0) {
 192
 193                 // just write silence
 194                 memset(outputs[0], 0, nframes * sizeof(jack_default_audio_sample_t));
 195                 memset(outputs[1], 0, nframes * sizeof(jack_default_audio_sample_t));
 196
 197         } else {
 198
 199           jack_ringbuffer_data_t rb_data[2];
 200
 201                 jack_ringbuffer_get_read_vector(fRingBuffer, rb_data);
 202
 203                 while (nframes_left > 0 && rb_data[0].len > 4) {
 204
 205                         jack_nframes_t towrite_frames = (rb_data[0].len) / (sizeof(short) * 2);
 206                         towrite_frames = min(towrite_frames, nframes_left);
 207
 208                         // write and deinterleave into the two channels
 209 #if 1
 210                         sample_move_dS_s16(outputs[0] + (nframes - nframes_left), (char *) rb_data[0].buf, towrite_frames, sizeof(short) * 2);
 211                         sample_move_dS_s16(outputs[1] + (nframes - nframes_left), (char *) rb_data[0].buf + sizeof(short), towrite_frames, sizeof(short) * 2);
 212 #else
 213                         sample_move_dS_s16_24ph(outputs[0] + (nframes - nframes_left), (char *) rb_data[0].buf, towrite_frames, sizeof(short) * 2);
 214                         sample_move_dS_s16_24ph(outputs[1] + (nframes - nframes_left), (char *) rb_data[0].buf + sizeof(short), towrite_frames, sizeof(short) * 2);
 215 #endif
 216                         wrotebytes = towrite_frames * sizeof(short) * 2;
 217                         nframes_left -= towrite_frames;
 218
 219                         jack_ringbuffer_read_advance(fRingBuffer, wrotebytes);
 220                         jack_ringbuffer_get_read_vector(fRingBuffer, rb_data);
 221                 }
 222
 223                 if (nframes_left > 0) {
 224                         // write silence
 225                         memset(outputs[0] + (nframes - nframes_left), 0, (nframes_left) * sizeof(jack_default_audio_sample_t));
 226                         memset(outputs[1] + (nframes - nframes_left), 0, (nframes_left) * sizeof(jack_default_audio_sample_t));
 227                 }
 228         }
 229
 230         return wrotebytes;
 231 }
 232
 233 void JackAC3Encoder::sample_move_dS_s16(jack_default_audio_sample_t* dst, char *src, jack_nframes_t nsamples, unsigned long src_skip)
 234 {
 235         /* ALERT: signed sign-extension portability !!! */
 236         while (nsamples--) {
 237                 *dst = (*((short *) src)) / SAMPLE_MAX_16BIT;
 238                 dst++;
 239                 src += src_skip;
 240         }
 241 }
 242
 243 void JackAC3Encoder::sample_move_dS_s16_24ph(jack_default_audio_sample_t* dst, char *src, jack_nframes_t nsamples, unsigned long src_skip)
 244 {
 245         /* ALERT: signed sign-extension portability !!! */
 246         while (nsamples--) {
 247                 *dst = (((int)(*((short *) src))) << 8) / SAMPLE_MAX_24BIT;
 248                 dst++;
 249                 src += src_skip;
 250         }
 251 }
 252
 253 void JackAC3Encoder::GetChannelName(const char* name, const char* alias, char* portname, int channel)
 254 {
 255     /*
 256          * 2 channels = L, R
 257          * 3 channels = L, C, R
 258          * 4 channels = L, R, LS, RS
 259          * 5 ch       = L, C, R,  LS, RS
 260          * 6 ch       = L, C, R,  LS, RS, LFE
 261          */
 262
 263      const char* AC3_name = "";
 264
 265      switch (channel) {
 266
 267         case 0:
 268             AC3_name = "AC3_1_Left";
 269             break;
 270
 271         case 1:
 272             if (fAftenContext.channels == 2 || fAftenContext.channels == 4) {
 273                 AC3_name = "AC3_2_Right";
 274             } else {
 275                 AC3_name = "AC3_2_Center";
 276             }
 277             break;
 278
 279         case 2:
 280             if (fAftenContext.channels == 4) {
 281                 AC3_name = "AC3_3_LeftSurround";
 282             } else {
 283                 AC3_name = "AC3_3_Right";
 284             }
 285             break;
 286
 287         case 3:
 288             if (fAftenContext.channels == 4) {
 289                 AC3_name = "AC3_4_RightSurround";
 290             } else {
 291                 AC3_name = "AC3_4_LeftSurround";
 292             }
 293             break;
 294
 295         case 4:
 296             if (fAftenContext.channels > 4) {
 297                AC3_name = "AC3_5_RightSurround";
 298                         }
 299             break;
 300
 301         default:
 302             break;
 303      }
 304
 305      // Last channel
 306      if (fAftenContext.lfe && (channel == fAftenContext.channels - 1)) {
 307         sprintf(portname, "%s:%s:AC3_%d_LFE", name, alias, fAftenContext.channels);
 308      } else {
 309         sprintf(portname, "%s:%s:%s", name, alias, AC3_name);
 310      }
 311 }
 312
 313 } // end of namespace