Libav 0.7.1
libavcodec/wmaenc.c
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00001 /*
00002  * WMA compatible encoder
00003  * Copyright (c) 2007 Michael Niedermayer
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 
00022 #include "avcodec.h"
00023 #include "wma.h"
00024 
00025 #undef NDEBUG
00026 #include <assert.h>
00027 
00028 
00029 static int encode_init(AVCodecContext * avctx){
00030     WMACodecContext *s = avctx->priv_data;
00031     int i, flags1, flags2;
00032     uint8_t *extradata;
00033 
00034     s->avctx = avctx;
00035 
00036     if(avctx->channels > MAX_CHANNELS) {
00037         av_log(avctx, AV_LOG_ERROR, "too many channels: got %i, need %i or fewer",
00038                avctx->channels, MAX_CHANNELS);
00039         return AVERROR(EINVAL);
00040     }
00041 
00042     if(avctx->bit_rate < 24*1000) {
00043         av_log(avctx, AV_LOG_ERROR, "bitrate too low: got %i, need 24000 or higher\n",
00044                avctx->bit_rate);
00045         return AVERROR(EINVAL);
00046     }
00047 
00048     /* extract flag infos */
00049     flags1 = 0;
00050     flags2 = 1;
00051     if (avctx->codec->id == CODEC_ID_WMAV1) {
00052         extradata= av_malloc(4);
00053         avctx->extradata_size= 4;
00054         AV_WL16(extradata, flags1);
00055         AV_WL16(extradata+2, flags2);
00056     } else if (avctx->codec->id == CODEC_ID_WMAV2) {
00057         extradata= av_mallocz(10);
00058         avctx->extradata_size= 10;
00059         AV_WL32(extradata, flags1);
00060         AV_WL16(extradata+4, flags2);
00061     }else
00062         assert(0);
00063     avctx->extradata= extradata;
00064     s->use_exp_vlc = flags2 & 0x0001;
00065     s->use_bit_reservoir = flags2 & 0x0002;
00066     s->use_variable_block_len = flags2 & 0x0004;
00067 
00068     ff_wma_init(avctx, flags2);
00069 
00070     /* init MDCT */
00071     for(i = 0; i < s->nb_block_sizes; i++)
00072         ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 0, 1.0);
00073 
00074     avctx->block_align=
00075     s->block_align= avctx->bit_rate*(int64_t)s->frame_len / (avctx->sample_rate*8);
00076 //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d\n", s->block_align, avctx->bit_rate, s->frame_len, avctx->sample_rate);
00077     avctx->frame_size= s->frame_len;
00078 
00079     return 0;
00080 }
00081 
00082 
00083 static void apply_window_and_mdct(AVCodecContext * avctx, const signed short * audio, int len) {
00084     WMACodecContext *s = avctx->priv_data;
00085     int window_index= s->frame_len_bits - s->block_len_bits;
00086     FFTContext *mdct = &s->mdct_ctx[window_index];
00087     int i, j, channel;
00088     const float * win = s->windows[window_index];
00089     int window_len = 1 << s->block_len_bits;
00090     float n = window_len/2;
00091 
00092     for (channel = 0; channel < avctx->channels; channel++) {
00093         memcpy(s->output, s->frame_out[channel], sizeof(float)*window_len);
00094         j = channel;
00095         for (i = 0; i < len; i++, j += avctx->channels){
00096             s->output[i+window_len]  = audio[j] / n * win[window_len - i - 1];
00097             s->frame_out[channel][i] = audio[j] / n * win[i];
00098         }
00099         mdct->mdct_calc(mdct, s->coefs[channel], s->output);
00100     }
00101 }
00102 
00103 //FIXME use for decoding too
00104 static void init_exp(WMACodecContext *s, int ch, const int *exp_param){
00105     int n;
00106     const uint16_t *ptr;
00107     float v, *q, max_scale, *q_end;
00108 
00109     ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];
00110     q = s->exponents[ch];
00111     q_end = q + s->block_len;
00112     max_scale = 0;
00113     while (q < q_end) {
00114         /* XXX: use a table */
00115         v = pow(10, *exp_param++ * (1.0 / 16.0));
00116         max_scale= FFMAX(max_scale, v);
00117         n = *ptr++;
00118         do {
00119             *q++ = v;
00120         } while (--n);
00121     }
00122     s->max_exponent[ch] = max_scale;
00123 }
00124 
00125 static void encode_exp_vlc(WMACodecContext *s, int ch, const int *exp_param){
00126     int last_exp;
00127     const uint16_t *ptr;
00128     float *q, *q_end;
00129 
00130     ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];
00131     q = s->exponents[ch];
00132     q_end = q + s->block_len;
00133     if (s->version == 1) {
00134         last_exp= *exp_param++;
00135         assert(last_exp-10 >= 0 && last_exp-10 < 32);
00136         put_bits(&s->pb, 5, last_exp - 10);
00137         q+= *ptr++;
00138     }else
00139         last_exp = 36;
00140     while (q < q_end) {
00141         int exp = *exp_param++;
00142         int code = exp - last_exp + 60;
00143         assert(code >= 0 && code < 120);
00144         put_bits(&s->pb, ff_aac_scalefactor_bits[code], ff_aac_scalefactor_code[code]);
00145         /* XXX: use a table */
00146         q+= *ptr++;
00147         last_exp= exp;
00148     }
00149 }
00150 
00151 static int encode_block(WMACodecContext *s, float (*src_coefs)[BLOCK_MAX_SIZE], int total_gain){
00152     int v, bsize, ch, coef_nb_bits, parse_exponents;
00153     float mdct_norm;
00154     int nb_coefs[MAX_CHANNELS];
00155     static const int fixed_exp[25]={20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20};
00156 
00157     //FIXME remove duplication relative to decoder
00158     if (s->use_variable_block_len) {
00159         assert(0); //FIXME not implemented
00160     }else{
00161         /* fixed block len */
00162         s->next_block_len_bits = s->frame_len_bits;
00163         s->prev_block_len_bits = s->frame_len_bits;
00164         s->block_len_bits = s->frame_len_bits;
00165     }
00166 
00167     s->block_len = 1 << s->block_len_bits;
00168 //     assert((s->block_pos + s->block_len) <= s->frame_len);
00169     bsize = s->frame_len_bits - s->block_len_bits;
00170 
00171     //FIXME factor
00172     v = s->coefs_end[bsize] - s->coefs_start;
00173     for(ch = 0; ch < s->nb_channels; ch++)
00174         nb_coefs[ch] = v;
00175     {
00176         int n4 = s->block_len / 2;
00177         mdct_norm = 1.0 / (float)n4;
00178         if (s->version == 1) {
00179             mdct_norm *= sqrt(n4);
00180         }
00181     }
00182 
00183     if (s->nb_channels == 2) {
00184         put_bits(&s->pb, 1, s->ms_stereo= 1);
00185     }
00186 
00187     for(ch = 0; ch < s->nb_channels; ch++) {
00188         s->channel_coded[ch] = 1; //FIXME only set channel_coded when needed, instead of always
00189         if (s->channel_coded[ch]) {
00190             init_exp(s, ch, fixed_exp);
00191         }
00192     }
00193 
00194     for(ch = 0; ch < s->nb_channels; ch++) {
00195         if (s->channel_coded[ch]) {
00196             WMACoef *coefs1;
00197             float *coefs, *exponents, mult;
00198             int i, n;
00199 
00200             coefs1 = s->coefs1[ch];
00201             exponents = s->exponents[ch];
00202             mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];
00203             mult *= mdct_norm;
00204             coefs = src_coefs[ch];
00205             if (s->use_noise_coding && 0) {
00206                 assert(0); //FIXME not implemented
00207             } else {
00208                 coefs += s->coefs_start;
00209                 n = nb_coefs[ch];
00210                 for(i = 0;i < n; i++){
00211                     double t= *coefs++ / (exponents[i] * mult);
00212                     if(t<-32768 || t>32767)
00213                         return -1;
00214 
00215                     coefs1[i] = lrint(t);
00216                 }
00217             }
00218         }
00219     }
00220 
00221     v = 0;
00222     for(ch = 0; ch < s->nb_channels; ch++) {
00223         int a = s->channel_coded[ch];
00224         put_bits(&s->pb, 1, a);
00225         v |= a;
00226     }
00227 
00228     if (!v)
00229         return 1;
00230 
00231     for(v= total_gain-1; v>=127; v-= 127)
00232         put_bits(&s->pb, 7, 127);
00233     put_bits(&s->pb, 7, v);
00234 
00235     coef_nb_bits= ff_wma_total_gain_to_bits(total_gain);
00236 
00237     if (s->use_noise_coding) {
00238         for(ch = 0; ch < s->nb_channels; ch++) {
00239             if (s->channel_coded[ch]) {
00240                 int i, n;
00241                 n = s->exponent_high_sizes[bsize];
00242                 for(i=0;i<n;i++) {
00243                     put_bits(&s->pb, 1, s->high_band_coded[ch][i]= 0);
00244                     if (0)
00245                         nb_coefs[ch] -= s->exponent_high_bands[bsize][i];
00246                 }
00247             }
00248         }
00249     }
00250 
00251     parse_exponents = 1;
00252     if (s->block_len_bits != s->frame_len_bits) {
00253         put_bits(&s->pb, 1, parse_exponents);
00254     }
00255 
00256     if (parse_exponents) {
00257         for(ch = 0; ch < s->nb_channels; ch++) {
00258             if (s->channel_coded[ch]) {
00259                 if (s->use_exp_vlc) {
00260                     encode_exp_vlc(s, ch, fixed_exp);
00261                 } else {
00262                     assert(0); //FIXME not implemented
00263 //                    encode_exp_lsp(s, ch);
00264                 }
00265             }
00266         }
00267     } else {
00268         assert(0); //FIXME not implemented
00269     }
00270 
00271     for(ch = 0; ch < s->nb_channels; ch++) {
00272         if (s->channel_coded[ch]) {
00273             int run, tindex;
00274             WMACoef *ptr, *eptr;
00275             tindex = (ch == 1 && s->ms_stereo);
00276             ptr = &s->coefs1[ch][0];
00277             eptr = ptr + nb_coefs[ch];
00278 
00279             run=0;
00280             for(;ptr < eptr; ptr++){
00281                 if(*ptr){
00282                     int level= *ptr;
00283                     int abs_level= FFABS(level);
00284                     int code= 0;
00285                     if(abs_level <= s->coef_vlcs[tindex]->max_level){
00286                         if(run < s->coef_vlcs[tindex]->levels[abs_level-1])
00287                             code= run + s->int_table[tindex][abs_level-1];
00288                     }
00289 
00290                     assert(code < s->coef_vlcs[tindex]->n);
00291                     put_bits(&s->pb, s->coef_vlcs[tindex]->huffbits[code], s->coef_vlcs[tindex]->huffcodes[code]);
00292 
00293                     if(code == 0){
00294                         if(1<<coef_nb_bits <= abs_level)
00295                             return -1;
00296 
00297 
00298                         //Workaround minor rounding differences for the regression tests, FIXME we should find and replace the problematic float by fixpoint for reg tests
00299                         if(abs_level == 0x71B && (s->avctx->flags & CODEC_FLAG_BITEXACT)) abs_level=0x71A;
00300 
00301                         put_bits(&s->pb, coef_nb_bits, abs_level);
00302                         put_bits(&s->pb, s->frame_len_bits, run);
00303                     }
00304                     put_bits(&s->pb, 1, level < 0); //FIXME the sign is fliped somewhere
00305                     run=0;
00306                 }else{
00307                     run++;
00308                 }
00309             }
00310             if(run)
00311                 put_bits(&s->pb, s->coef_vlcs[tindex]->huffbits[1], s->coef_vlcs[tindex]->huffcodes[1]);
00312         }
00313         if (s->version == 1 && s->nb_channels >= 2) {
00314             align_put_bits(&s->pb);
00315         }
00316     }
00317     return 0;
00318 }
00319 
00320 static int encode_frame(WMACodecContext *s, float (*src_coefs)[BLOCK_MAX_SIZE], uint8_t *buf, int buf_size, int total_gain){
00321     init_put_bits(&s->pb, buf, buf_size);
00322 
00323     if (s->use_bit_reservoir) {
00324         assert(0);//FIXME not implemented
00325     }else{
00326         if(encode_block(s, src_coefs, total_gain) < 0)
00327             return INT_MAX;
00328     }
00329 
00330     align_put_bits(&s->pb);
00331 
00332     return put_bits_count(&s->pb)/8 - s->block_align;
00333 }
00334 
00335 static int encode_superframe(AVCodecContext *avctx,
00336                             unsigned char *buf, int buf_size, void *data){
00337     WMACodecContext *s = avctx->priv_data;
00338     const short *samples = data;
00339     int i, total_gain;
00340 
00341     s->block_len_bits= s->frame_len_bits; //required by non variable block len
00342     s->block_len = 1 << s->block_len_bits;
00343 
00344     apply_window_and_mdct(avctx, samples, avctx->frame_size);
00345 
00346     if (s->ms_stereo) {
00347         float a, b;
00348         int i;
00349 
00350         for(i = 0; i < s->block_len; i++) {
00351             a = s->coefs[0][i]*0.5;
00352             b = s->coefs[1][i]*0.5;
00353             s->coefs[0][i] = a + b;
00354             s->coefs[1][i] = a - b;
00355         }
00356     }
00357 
00358 #if 1
00359     total_gain= 128;
00360     for(i=64; i; i>>=1){
00361         int error= encode_frame(s, s->coefs, buf, buf_size, total_gain-i);
00362         if(error<0)
00363             total_gain-= i;
00364     }
00365 #else
00366     total_gain= 90;
00367     best= encode_frame(s, s->coefs, buf, buf_size, total_gain);
00368     for(i=32; i; i>>=1){
00369         int scoreL= encode_frame(s, s->coefs, buf, buf_size, total_gain-i);
00370         int scoreR= encode_frame(s, s->coefs, buf, buf_size, total_gain+i);
00371         av_log(NULL, AV_LOG_ERROR, "%d %d %d (%d)\n", scoreL, best, scoreR, total_gain);
00372         if(scoreL < FFMIN(best, scoreR)){
00373             best = scoreL;
00374             total_gain -= i;
00375         }else if(scoreR < best){
00376             best = scoreR;
00377             total_gain += i;
00378         }
00379     }
00380 #endif
00381 
00382     encode_frame(s, s->coefs, buf, buf_size, total_gain);
00383     assert((put_bits_count(&s->pb) & 7) == 0);
00384     i= s->block_align - (put_bits_count(&s->pb)+7)/8;
00385     assert(i>=0);
00386     while(i--)
00387         put_bits(&s->pb, 8, 'N');
00388 
00389     flush_put_bits(&s->pb);
00390     return put_bits_ptr(&s->pb) - s->pb.buf;
00391 }
00392 
00393 AVCodec ff_wmav1_encoder =
00394 {
00395     "wmav1",
00396     AVMEDIA_TYPE_AUDIO,
00397     CODEC_ID_WMAV1,
00398     sizeof(WMACodecContext),
00399     encode_init,
00400     encode_superframe,
00401     ff_wma_end,
00402     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00403     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"),
00404 };
00405 
00406 AVCodec ff_wmav2_encoder =
00407 {
00408     "wmav2",
00409     AVMEDIA_TYPE_AUDIO,
00410     CODEC_ID_WMAV2,
00411     sizeof(WMACodecContext),
00412     encode_init,
00413     encode_superframe,
00414     ff_wma_end,
00415     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00416     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"),
00417 };