FFmpeg: libavcodec/mpc7.c Source File

00001 /*
00002  * Musepack SV7 decoder
00003  * Copyright (c) 2006 Konstantin Shishkov
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include "libavutil/lfg.h"
00029 #include "avcodec.h"
00030 #include "get_bits.h"
00031 #include "dsputil.h"
00032 #include "mpegaudio.h"
00033 
00034 #include "mpc.h"
00035 #include "mpc7data.h"
00036 
00037 #define BANDS            32
00038 #define SAMPLES_PER_BAND 36
00039 #define MPC_FRAME_SIZE   (BANDS * SAMPLES_PER_BAND)
00040 
00041 static VLC scfi_vlc, dscf_vlc, hdr_vlc, quant_vlc[MPC7_QUANT_VLC_TABLES][2];
00042 
00043 static const uint16_t quant_offsets[MPC7_QUANT_VLC_TABLES*2 + 1] =
00044 {
00045        0, 512, 1024, 1536, 2052, 2564, 3076, 3588, 4100, 4612, 5124,
00046        5636, 6164, 6676, 7224
00047 };
00048 
00049 
00050 static av_cold int mpc7_decode_init(AVCodecContext * avctx)
00051 {
00052     int i, j;
00053     MPCContext *c = avctx->priv_data;
00054     GetBitContext gb;
00055     uint8_t buf[16];
00056     static int vlc_initialized = 0;
00057 
00058     static VLC_TYPE scfi_table[1 << MPC7_SCFI_BITS][2];
00059     static VLC_TYPE dscf_table[1 << MPC7_DSCF_BITS][2];
00060     static VLC_TYPE hdr_table[1 << MPC7_HDR_BITS][2];
00061     static VLC_TYPE quant_tables[7224][2];
00062 
00063     if(avctx->extradata_size < 16){
00064         av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
00065         return -1;
00066     }
00067     memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
00068     av_lfg_init(&c->rnd, 0xDEADBEEF);
00069     dsputil_init(&c->dsp, avctx);
00070     c->dsp.bswap_buf((uint32_t*)buf, (const uint32_t*)avctx->extradata, 4);
00071     ff_mpc_init();
00072     init_get_bits(&gb, buf, 128);
00073 
00074     c->IS = get_bits1(&gb);
00075     c->MSS = get_bits1(&gb);
00076     c->maxbands = get_bits(&gb, 6);
00077     if(c->maxbands >= BANDS){
00078         av_log(avctx, AV_LOG_ERROR, "Too many bands: %i\n", c->maxbands);
00079         return -1;
00080     }
00081     skip_bits_long(&gb, 88);
00082     c->gapless = get_bits1(&gb);
00083     c->lastframelen = get_bits(&gb, 11);
00084     av_log(avctx, AV_LOG_DEBUG, "IS: %d, MSS: %d, TG: %d, LFL: %d, bands: %d\n",
00085             c->IS, c->MSS, c->gapless, c->lastframelen, c->maxbands);
00086     c->frames_to_skip = 0;
00087 
00088     avctx->sample_fmt = SAMPLE_FMT_S16;
00089     avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
00090 
00091     if(vlc_initialized) return 0;
00092     av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");
00093     scfi_vlc.table = scfi_table;
00094     scfi_vlc.table_allocated = 1 << MPC7_SCFI_BITS;
00095     if(init_vlc(&scfi_vlc, MPC7_SCFI_BITS, MPC7_SCFI_SIZE,
00096                 &mpc7_scfi[1], 2, 1,
00097                 &mpc7_scfi[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
00098         av_log(avctx, AV_LOG_ERROR, "Cannot init SCFI VLC\n");
00099         return -1;
00100     }
00101     dscf_vlc.table = dscf_table;
00102     dscf_vlc.table_allocated = 1 << MPC7_DSCF_BITS;
00103     if(init_vlc(&dscf_vlc, MPC7_DSCF_BITS, MPC7_DSCF_SIZE,
00104                 &mpc7_dscf[1], 2, 1,
00105                 &mpc7_dscf[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
00106         av_log(avctx, AV_LOG_ERROR, "Cannot init DSCF VLC\n");
00107         return -1;
00108     }
00109     hdr_vlc.table = hdr_table;
00110     hdr_vlc.table_allocated = 1 << MPC7_HDR_BITS;
00111     if(init_vlc(&hdr_vlc, MPC7_HDR_BITS, MPC7_HDR_SIZE,
00112                 &mpc7_hdr[1], 2, 1,
00113                 &mpc7_hdr[0], 2, 1, INIT_VLC_USE_NEW_STATIC)){
00114         av_log(avctx, AV_LOG_ERROR, "Cannot init HDR VLC\n");
00115         return -1;
00116     }
00117     for(i = 0; i < MPC7_QUANT_VLC_TABLES; i++){
00118         for(j = 0; j < 2; j++){
00119             quant_vlc[i][j].table = &quant_tables[quant_offsets[i*2 + j]];
00120             quant_vlc[i][j].table_allocated = quant_offsets[i*2 + j + 1] - quant_offsets[i*2 + j];
00121             if(init_vlc(&quant_vlc[i][j], 9, mpc7_quant_vlc_sizes[i],
00122                         &mpc7_quant_vlc[i][j][1], 4, 2,
00123                         &mpc7_quant_vlc[i][j][0], 4, 2, INIT_VLC_USE_NEW_STATIC)){
00124                 av_log(avctx, AV_LOG_ERROR, "Cannot init QUANT VLC %i,%i\n",i,j);
00125                 return -1;
00126             }
00127         }
00128     }
00129     vlc_initialized = 1;
00130     return 0;
00131 }
00132 
00136 static inline void idx_to_quant(MPCContext *c, GetBitContext *gb, int idx, int *dst)
00137 {
00138     int i, i1, t;
00139     switch(idx){
00140     case -1:
00141         for(i = 0; i < SAMPLES_PER_BAND; i++){
00142             *dst++ = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
00143         }
00144         break;
00145     case 1:
00146         i1 = get_bits1(gb);
00147         for(i = 0; i < SAMPLES_PER_BAND/3; i++){
00148             t = get_vlc2(gb, quant_vlc[0][i1].table, 9, 2);
00149             *dst++ = mpc7_idx30[t];
00150             *dst++ = mpc7_idx31[t];
00151             *dst++ = mpc7_idx32[t];
00152         }
00153         break;
00154     case 2:
00155         i1 = get_bits1(gb);
00156         for(i = 0; i < SAMPLES_PER_BAND/2; i++){
00157             t = get_vlc2(gb, quant_vlc[1][i1].table, 9, 2);
00158             *dst++ = mpc7_idx50[t];
00159             *dst++ = mpc7_idx51[t];
00160         }
00161         break;
00162     case  3: case  4: case  5: case  6: case  7:
00163         i1 = get_bits1(gb);
00164         for(i = 0; i < SAMPLES_PER_BAND; i++)
00165             *dst++ = get_vlc2(gb, quant_vlc[idx-1][i1].table, 9, 2) - mpc7_quant_vlc_off[idx-1];
00166         break;
00167     case  8: case  9: case 10: case 11: case 12:
00168     case 13: case 14: case 15: case 16: case 17:
00169         t = (1 << (idx - 2)) - 1;
00170         for(i = 0; i < SAMPLES_PER_BAND; i++)
00171             *dst++ = get_bits(gb, idx - 1) - t;
00172         break;
00173     default: // case 0 and -2..-17
00174         return;
00175     }
00176 }
00177 
00178 static int get_scale_idx(GetBitContext *gb, int ref)
00179 {
00180     int t = get_vlc2(gb, dscf_vlc.table, MPC7_DSCF_BITS, 1) - 7;
00181     if (t == 8)
00182         return get_bits(gb, 6);
00183     return ref + t;
00184 }
00185 
00186 static int mpc7_decode_frame(AVCodecContext * avctx,
00187                             void *data, int *data_size,
00188                             AVPacket *avpkt)
00189 {
00190     const uint8_t *buf = avpkt->data;
00191     int buf_size = avpkt->size;
00192     MPCContext *c = avctx->priv_data;
00193     GetBitContext gb;
00194     uint8_t *bits;
00195     int i, ch;
00196     int mb = -1;
00197     Band *bands = c->bands;
00198     int off;
00199     int bits_used, bits_avail;
00200 
00201     memset(bands, 0, sizeof(bands));
00202     if(buf_size <= 4){
00203         av_log(avctx, AV_LOG_ERROR, "Too small buffer passed (%i bytes)\n", buf_size);
00204     }
00205 
00206     bits = av_malloc(((buf_size - 1) & ~3) + FF_INPUT_BUFFER_PADDING_SIZE);
00207     c->dsp.bswap_buf((uint32_t*)bits, (const uint32_t*)(buf + 4), (buf_size - 4) >> 2);
00208     init_get_bits(&gb, bits, (buf_size - 4)* 8);
00209     skip_bits(&gb, buf[0]);
00210 
00211     /* read subband indexes */
00212     for(i = 0; i <= c->maxbands; i++){
00213         for(ch = 0; ch < 2; ch++){
00214             int t = 4;
00215             if(i) t = get_vlc2(&gb, hdr_vlc.table, MPC7_HDR_BITS, 1) - 5;
00216             if(t == 4) bands[i].res[ch] = get_bits(&gb, 4);
00217             else bands[i].res[ch] = bands[i-1].res[ch] + t;
00218         }
00219 
00220         if(bands[i].res[0] || bands[i].res[1]){
00221             mb = i;
00222             if(c->MSS) bands[i].msf = get_bits1(&gb);
00223         }
00224     }
00225     /* get scale indexes coding method */
00226     for(i = 0; i <= mb; i++)
00227         for(ch = 0; ch < 2; ch++)
00228             if(bands[i].res[ch]) bands[i].scfi[ch] = get_vlc2(&gb, scfi_vlc.table, MPC7_SCFI_BITS, 1);
00229     /* get scale indexes */
00230     for(i = 0; i <= mb; i++){
00231         for(ch = 0; ch < 2; ch++){
00232             if(bands[i].res[ch]){
00233                 bands[i].scf_idx[ch][2] = c->oldDSCF[ch][i];
00234                 bands[i].scf_idx[ch][0] = get_scale_idx(&gb, bands[i].scf_idx[ch][2]);
00235                 switch(bands[i].scfi[ch]){
00236                 case 0:
00237                     bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
00238                     bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
00239                     break;
00240                 case 1:
00241                     bands[i].scf_idx[ch][1] = get_scale_idx(&gb, bands[i].scf_idx[ch][0]);
00242                     bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1];
00243                     break;
00244                 case 2:
00245                     bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
00246                     bands[i].scf_idx[ch][2] = get_scale_idx(&gb, bands[i].scf_idx[ch][1]);
00247                     break;
00248                 case 3:
00249                     bands[i].scf_idx[ch][2] = bands[i].scf_idx[ch][1] = bands[i].scf_idx[ch][0];
00250                     break;
00251                 }
00252                 c->oldDSCF[ch][i] = bands[i].scf_idx[ch][2];
00253             }
00254         }
00255     }
00256     /* get quantizers */
00257     memset(c->Q, 0, sizeof(c->Q));
00258     off = 0;
00259     for(i = 0; i < BANDS; i++, off += SAMPLES_PER_BAND)
00260         for(ch = 0; ch < 2; ch++)
00261             idx_to_quant(c, &gb, bands[i].res[ch], c->Q[ch] + off);
00262 
00263     ff_mpc_dequantize_and_synth(c, mb, data);
00264 
00265     av_free(bits);
00266 
00267     bits_used = get_bits_count(&gb);
00268     bits_avail = (buf_size - 4) * 8;
00269     if(!buf[1] && ((bits_avail < bits_used) || (bits_used + 32 <= bits_avail))){
00270         av_log(NULL,0, "Error decoding frame: used %i of %i bits\n", bits_used, bits_avail);
00271         return -1;
00272     }
00273     if(c->frames_to_skip){
00274         c->frames_to_skip--;
00275         *data_size = 0;
00276         return buf_size;
00277     }
00278     *data_size = (buf[1] ? c->lastframelen : MPC_FRAME_SIZE) * 4;
00279 
00280     return buf_size;
00281 }
00282 
00283 static void mpc7_decode_flush(AVCodecContext *avctx)
00284 {
00285     MPCContext *c = avctx->priv_data;
00286 
00287     memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
00288     c->frames_to_skip = 32;
00289 }
00290 
00291 AVCodec mpc7_decoder = {
00292     "mpc7",
00293     AVMEDIA_TYPE_AUDIO,
00294     CODEC_ID_MUSEPACK7,
00295     sizeof(MPCContext),
00296     mpc7_decode_init,
00297     NULL,
00298     NULL,
00299     mpc7_decode_frame,
00300     .flush = mpc7_decode_flush,
00301     .long_name = NULL_IF_CONFIG_SMALL("Musepack SV7"),
00302 };