FFmpeg: libavcodec/eac3enc.c Source File

00001 /*
00002  * E-AC-3 encoder
00003  * Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #define CONFIG_AC3ENC_FLOAT 1
00028 #include "ac3enc.h"
00029 #include "eac3enc.h"
00030 #include "eac3_data.h"
00031 
00032 
00033 #define AC3ENC_TYPE AC3ENC_TYPE_EAC3
00034 #include "ac3enc_opts_template.c"
00035 
00036 static const AVClass eac3enc_class = {
00037     .class_name = "E-AC-3 Encoder",
00038     .item_name  = av_default_item_name,
00039     .option     = ac3_options,
00040     .version    = LIBAVUTIL_VERSION_INT,
00041 };
00042 
00047 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
00048 
00049 
00050 void ff_eac3_exponent_init(void)
00051 {
00052     int i;
00053 
00054     memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
00055     for (i = 0; i < 32; i++) {
00056         eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
00057                                    [ff_eac3_frm_expstr[i][1]]
00058                                    [ff_eac3_frm_expstr[i][2]]
00059                                    [ff_eac3_frm_expstr[i][3]]
00060                                    [ff_eac3_frm_expstr[i][4]]
00061                                    [ff_eac3_frm_expstr[i][5]] = i;
00062     }
00063 }
00064 
00065 
00066 void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
00067 {
00068     int ch;
00069 
00070     if (s->num_blocks < 6) {
00071         s->use_frame_exp_strategy = 0;
00072         return;
00073     }
00074 
00075     s->use_frame_exp_strategy = 1;
00076     for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
00077         int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
00078                                                 [s->exp_strategy[ch][1]]
00079                                                 [s->exp_strategy[ch][2]]
00080                                                 [s->exp_strategy[ch][3]]
00081                                                 [s->exp_strategy[ch][4]]
00082                                                 [s->exp_strategy[ch][5]];
00083         if (expstr < 0) {
00084             s->use_frame_exp_strategy = 0;
00085             break;
00086         }
00087         s->frame_exp_strategy[ch] = expstr;
00088     }
00089 }
00090 
00091 
00092 
00093 void ff_eac3_set_cpl_states(AC3EncodeContext *s)
00094 {
00095     int ch, blk;
00096     int first_cpl_coords[AC3_MAX_CHANNELS];
00097 
00098     /* set first cpl coords */
00099     for (ch = 1; ch <= s->fbw_channels; ch++)
00100         first_cpl_coords[ch] = 1;
00101     for (blk = 0; blk < s->num_blocks; blk++) {
00102         AC3Block *block = &s->blocks[blk];
00103         for (ch = 1; ch <= s->fbw_channels; ch++) {
00104             if (block->channel_in_cpl[ch]) {
00105                 if (first_cpl_coords[ch]) {
00106                     block->new_cpl_coords[ch] = 2;
00107                     first_cpl_coords[ch]  = 0;
00108                 }
00109             } else {
00110                 first_cpl_coords[ch] = 1;
00111             }
00112         }
00113     }
00114 
00115     /* set first cpl leak */
00116     for (blk = 0; blk < s->num_blocks; blk++) {
00117         AC3Block *block = &s->blocks[blk];
00118         if (block->cpl_in_use) {
00119             block->new_cpl_leak = 2;
00120             break;
00121         }
00122     }
00123 }
00124 
00125 
00126 void ff_eac3_output_frame_header(AC3EncodeContext *s)
00127 {
00128     int blk, ch;
00129     AC3EncOptions *opt = &s->options;
00130 
00131     put_bits(&s->pb, 16, 0x0b77);                   /* sync word */
00132 
00133     /* BSI header */
00134     put_bits(&s->pb,  2, 0);                        /* stream type = independent */
00135     put_bits(&s->pb,  3, 0);                        /* substream id = 0 */
00136     put_bits(&s->pb, 11, (s->frame_size / 2) - 1);  /* frame size */
00137     if (s->bit_alloc.sr_shift) {
00138         put_bits(&s->pb, 2, 0x3);                   /* fscod2 */
00139         put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
00140     } else {
00141         put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
00142         put_bits(&s->pb, 2, s->num_blks_code);      /* number of blocks */
00143     }
00144     put_bits(&s->pb, 3, s->channel_mode);           /* audio coding mode */
00145     put_bits(&s->pb, 1, s->lfe_on);                 /* LFE channel indicator */
00146     put_bits(&s->pb, 5, s->bitstream_id);           /* bitstream id (EAC3=16) */
00147     put_bits(&s->pb, 5, -opt->dialogue_level);      /* dialogue normalization level */
00148     put_bits(&s->pb, 1, 0);                         /* no compression gain */
00149     /* mixing metadata*/
00150     put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
00151     if (opt->eac3_mixing_metadata) {
00152         if (s->channel_mode > AC3_CHMODE_STEREO)
00153             put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
00154         if (s->has_center) {
00155             put_bits(&s->pb, 3, s->ltrt_center_mix_level);
00156             put_bits(&s->pb, 3, s->loro_center_mix_level);
00157         }
00158         if (s->has_surround) {
00159             put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
00160             put_bits(&s->pb, 3, s->loro_surround_mix_level);
00161         }
00162         if (s->lfe_on)
00163             put_bits(&s->pb, 1, 0);
00164         put_bits(&s->pb, 1, 0);                     /* no program scale */
00165         put_bits(&s->pb, 1, 0);                     /* no ext program scale */
00166         put_bits(&s->pb, 2, 0);                     /* no mixing parameters */
00167         if (s->channel_mode < AC3_CHMODE_STEREO)
00168             put_bits(&s->pb, 1, 0);                 /* no pan info */
00169         put_bits(&s->pb, 1, 0);                     /* no frame mix config info */
00170     }
00171     /* info metadata*/
00172     put_bits(&s->pb, 1, opt->eac3_info_metadata);
00173     if (opt->eac3_info_metadata) {
00174         put_bits(&s->pb, 3, s->bitstream_mode);
00175         put_bits(&s->pb, 1, opt->copyright);
00176         put_bits(&s->pb, 1, opt->original);
00177         if (s->channel_mode == AC3_CHMODE_STEREO) {
00178             put_bits(&s->pb, 2, opt->dolby_surround_mode);
00179             put_bits(&s->pb, 2, opt->dolby_headphone_mode);
00180         }
00181         if (s->channel_mode >= AC3_CHMODE_2F2R)
00182             put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
00183         put_bits(&s->pb, 1, opt->audio_production_info);
00184         if (opt->audio_production_info) {
00185             put_bits(&s->pb, 5, opt->mixing_level - 80);
00186             put_bits(&s->pb, 2, opt->room_type);
00187             put_bits(&s->pb, 1, opt->ad_converter_type);
00188         }
00189         put_bits(&s->pb, 1, 0);
00190     }
00191     if (s->num_blocks != 6)
00192         put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
00193     put_bits(&s->pb, 1, 0);                         /* no additional bit stream info */
00194 
00195     /* frame header */
00196     if (s->num_blocks == 6) {
00197     put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
00198     put_bits(&s->pb, 1, 0);                         /* aht enabled = no */
00199     }
00200     put_bits(&s->pb, 2, 0);                         /* snr offset strategy = 1 */
00201     put_bits(&s->pb, 1, 0);                         /* transient pre-noise processing enabled = no */
00202     put_bits(&s->pb, 1, 0);                         /* block switch syntax enabled = no */
00203     put_bits(&s->pb, 1, 0);                         /* dither flag syntax enabled = no */
00204     put_bits(&s->pb, 1, 0);                         /* bit allocation model syntax enabled = no */
00205     put_bits(&s->pb, 1, 0);                         /* fast gain codes enabled = no */
00206     put_bits(&s->pb, 1, 0);                         /* dba syntax enabled = no */
00207     put_bits(&s->pb, 1, 0);                         /* skip field syntax enabled = no */
00208     put_bits(&s->pb, 1, 0);                         /* spx enabled = no */
00209     /* coupling strategy use flags */
00210     if (s->channel_mode > AC3_CHMODE_MONO) {
00211         put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
00212         for (blk = 1; blk < s->num_blocks; blk++) {
00213             AC3Block *block = &s->blocks[blk];
00214             put_bits(&s->pb, 1, block->new_cpl_strategy);
00215             if (block->new_cpl_strategy)
00216                 put_bits(&s->pb, 1, block->cpl_in_use);
00217         }
00218     }
00219     /* exponent strategy */
00220     if (s->use_frame_exp_strategy) {
00221         for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
00222             put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
00223     } else {
00224         for (blk = 0; blk < s->num_blocks; blk++)
00225             for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
00226                 put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
00227     }
00228     if (s->lfe_on) {
00229         for (blk = 0; blk < s->num_blocks; blk++)
00230             put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
00231     }
00232     /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
00233     if (s->num_blocks != 6) {
00234         put_bits(&s->pb, 1, 0);
00235     } else {
00236     for (ch = 1; ch <= s->fbw_channels; ch++) {
00237         if (s->use_frame_exp_strategy)
00238             put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
00239         else
00240             put_bits(&s->pb, 5, 0);
00241     }
00242     }
00243     /* snr offsets */
00244     put_bits(&s->pb, 6, s->coarse_snr_offset);
00245     put_bits(&s->pb, 4, s->fine_snr_offset[1]);
00246     /* block start info */
00247     if (s->num_blocks > 1)
00248         put_bits(&s->pb, 1, 0);
00249 }
00250 
00251 
00252 #if CONFIG_EAC3_ENCODER
00253 AVCodec ff_eac3_encoder = {
00254     .name            = "eac3",
00255     .type            = AVMEDIA_TYPE_AUDIO,
00256     .id              = AV_CODEC_ID_EAC3,
00257     .priv_data_size  = sizeof(AC3EncodeContext),
00258     .init            = ff_ac3_encode_init,
00259     .encode2         = ff_ac3_float_encode_frame,
00260     .close           = ff_ac3_encode_close,
00261     .sample_fmts     = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLT,
00262                                                       AV_SAMPLE_FMT_NONE },
00263     .long_name       = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
00264     .priv_class      = &eac3enc_class,
00265     .channel_layouts = ff_ac3_channel_layouts,
00266     .defaults        = ac3_defaults,
00267 };
00268 #endif