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libavcodec/shorten.c

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00001 /*
00002  * Shorten decoder
00003  * Copyright (c) 2005 Jeff Muizelaar
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 
00029 #include <limits.h>
00030 #include "avcodec.h"
00031 #include "get_bits.h"
00032 #include "golomb.h"
00033 
00034 #define MAX_CHANNELS 8
00035 #define MAX_BLOCKSIZE 65535
00036 
00037 #define OUT_BUFFER_SIZE 16384
00038 
00039 #define ULONGSIZE 2
00040 
00041 #define WAVE_FORMAT_PCM 0x0001
00042 
00043 #define DEFAULT_BLOCK_SIZE 256
00044 
00045 #define TYPESIZE 4
00046 #define CHANSIZE 0
00047 #define LPCQSIZE 2
00048 #define ENERGYSIZE 3
00049 #define BITSHIFTSIZE 2
00050 
00051 #define TYPE_S16HL 3
00052 #define TYPE_S16LH 5
00053 
00054 #define NWRAP 3
00055 #define NSKIPSIZE 1
00056 
00057 #define LPCQUANT 5
00058 #define V2LPCQOFFSET (1 << LPCQUANT)
00059 
00060 #define FNSIZE 2
00061 #define FN_DIFF0        0
00062 #define FN_DIFF1        1
00063 #define FN_DIFF2        2
00064 #define FN_DIFF3        3
00065 #define FN_QUIT         4
00066 #define FN_BLOCKSIZE    5
00067 #define FN_BITSHIFT     6
00068 #define FN_QLPC         7
00069 #define FN_ZERO         8
00070 #define FN_VERBATIM     9
00071 
00072 #define VERBATIM_CKSIZE_SIZE 5
00073 #define VERBATIM_BYTE_SIZE 8
00074 #define CANONICAL_HEADER_SIZE 44
00075 
00076 typedef struct ShortenContext {
00077     AVCodecContext *avctx;
00078     GetBitContext gb;
00079 
00080     int min_framesize, max_framesize;
00081     int channels;
00082 
00083     int32_t *decoded[MAX_CHANNELS];
00084     int32_t *decoded_base[MAX_CHANNELS];
00085     int32_t *offset[MAX_CHANNELS];
00086     int *coeffs;
00087     uint8_t *bitstream;
00088     int bitstream_size;
00089     int bitstream_index;
00090     unsigned int allocated_bitstream_size;
00091     int header_size;
00092     uint8_t header[OUT_BUFFER_SIZE];
00093     int version;
00094     int cur_chan;
00095     int bitshift;
00096     int nmean;
00097     int internal_ftype;
00098     int nwrap;
00099     int blocksize;
00100     int bitindex;
00101     int32_t lpcqoffset;
00102 } ShortenContext;
00103 
00104 static av_cold int shorten_decode_init(AVCodecContext * avctx)
00105 {
00106     ShortenContext *s = avctx->priv_data;
00107     s->avctx = avctx;
00108     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00109 
00110     return 0;
00111 }
00112 
00113 static int allocate_buffers(ShortenContext *s)
00114 {
00115     int i, chan;
00116     int *coeffs;
00117     void *tmp_ptr;
00118 
00119     for (chan=0; chan<s->channels; chan++) {
00120         if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
00121             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
00122             return -1;
00123         }
00124         if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
00125             av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
00126             return -1;
00127         }
00128 
00129         tmp_ptr = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
00130         if (!tmp_ptr)
00131             return AVERROR(ENOMEM);
00132         s->offset[chan] = tmp_ptr;
00133 
00134         tmp_ptr = av_realloc(s->decoded_base[chan], (s->blocksize + s->nwrap) *
00135                              sizeof(s->decoded_base[0][0]));
00136         if (!tmp_ptr)
00137             return AVERROR(ENOMEM);
00138         s->decoded_base[chan] = tmp_ptr;
00139         for (i=0; i<s->nwrap; i++)
00140             s->decoded_base[chan][i] = 0;
00141         s->decoded[chan] = s->decoded_base[chan] + s->nwrap;
00142     }
00143 
00144     coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs));
00145     if (!coeffs)
00146         return AVERROR(ENOMEM);
00147     s->coeffs = coeffs;
00148 
00149     return 0;
00150 }
00151 
00152 
00153 static inline unsigned int get_uint(ShortenContext *s, int k)
00154 {
00155     if (s->version != 0)
00156         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
00157     return get_ur_golomb_shorten(&s->gb, k);
00158 }
00159 
00160 
00161 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
00162 {
00163     int i;
00164 
00165     if (s->bitshift != 0)
00166         for (i = 0; i < s->blocksize; i++)
00167             buffer[i] <<= s->bitshift;
00168 }
00169 
00170 
00171 static void init_offset(ShortenContext *s)
00172 {
00173     int32_t mean = 0;
00174     int  chan, i;
00175     int nblock = FFMAX(1, s->nmean);
00176     /* initialise offset */
00177     switch (s->internal_ftype)
00178     {
00179         case TYPE_S16HL:
00180         case TYPE_S16LH:
00181             mean = 0;
00182             break;
00183         default:
00184             av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
00185             abort();
00186     }
00187 
00188     for (chan = 0; chan < s->channels; chan++)
00189         for (i = 0; i < nblock; i++)
00190             s->offset[chan][i] = mean;
00191 }
00192 
00193 static inline int get_le32(GetBitContext *gb)
00194 {
00195     return av_bswap32(get_bits_long(gb, 32));
00196 }
00197 
00198 static inline short get_le16(GetBitContext *gb)
00199 {
00200     return av_bswap16(get_bits_long(gb, 16));
00201 }
00202 
00203 static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
00204 {
00205     GetBitContext hb;
00206     int len;
00207     short wave_format;
00208 
00209     init_get_bits(&hb, header, header_size*8);
00210     if (get_le32(&hb) != MKTAG('R','I','F','F')) {
00211         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
00212         return -1;
00213     }
00214 
00215     skip_bits_long(&hb, 32);    /* chunk_size */
00216 
00217     if (get_le32(&hb) != MKTAG('W','A','V','E')) {
00218         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
00219         return -1;
00220     }
00221 
00222     while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
00223         len = get_le32(&hb);
00224         skip_bits(&hb, 8*len);
00225     }
00226     len = get_le32(&hb);
00227 
00228     if (len < 16) {
00229         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
00230         return -1;
00231     }
00232 
00233     wave_format = get_le16(&hb);
00234 
00235     switch (wave_format) {
00236         case WAVE_FORMAT_PCM:
00237             break;
00238         default:
00239             av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
00240             return -1;
00241     }
00242 
00243     avctx->channels = get_le16(&hb);
00244     avctx->sample_rate = get_le32(&hb);
00245     avctx->bit_rate = get_le32(&hb) * 8;
00246     avctx->block_align = get_le16(&hb);
00247     avctx->bits_per_coded_sample = get_le16(&hb);
00248 
00249     if (avctx->bits_per_coded_sample != 16) {
00250         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
00251         return -1;
00252     }
00253 
00254     len -= 16;
00255     if (len > 0)
00256         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
00257 
00258     return 0;
00259 }
00260 
00261 static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
00262     int i, chan;
00263     for (i=0; i<blocksize; i++)
00264         for (chan=0; chan < nchan; chan++)
00265             *samples++ = FFMIN(buffer[chan][i], 32768);
00266     return samples;
00267 }
00268 
00269 static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
00270 {
00271     int sum, i, j;
00272     int *coeffs = s->coeffs;
00273 
00274     for (i=0; i<pred_order; i++)
00275         coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
00276 
00277     for (i=0; i < s->blocksize; i++) {
00278         sum = s->lpcqoffset;
00279         for (j=0; j<pred_order; j++)
00280             sum += coeffs[j] * s->decoded[channel][i-j-1];
00281         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
00282     }
00283 }
00284 
00285 
00286 static int shorten_decode_frame(AVCodecContext *avctx,
00287         void *data, int *data_size,
00288         AVPacket *avpkt)
00289 {
00290     const uint8_t *buf = avpkt->data;
00291     int buf_size = avpkt->size;
00292     ShortenContext *s = avctx->priv_data;
00293     int i, input_buf_size = 0;
00294     int16_t *samples = data;
00295     if(s->max_framesize == 0){
00296         void *tmp_ptr;
00297         s->max_framesize= 1024; // should hopefully be enough for the first header
00298         tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size,
00299                                   s->max_framesize);
00300         if (!tmp_ptr) {
00301             av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n");
00302             return AVERROR(ENOMEM);
00303         }
00304         s->bitstream = tmp_ptr;
00305     }
00306 
00307     if(1 && s->max_framesize){//FIXME truncated
00308         buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
00309         input_buf_size= buf_size;
00310 
00311         if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
00312             //                printf("memmove\n");
00313             memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
00314             s->bitstream_index=0;
00315         }
00316         memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
00317         buf= &s->bitstream[s->bitstream_index];
00318         buf_size += s->bitstream_size;
00319         s->bitstream_size= buf_size;
00320 
00321         if(buf_size < s->max_framesize){
00322             *data_size = 0;
00323             return input_buf_size;
00324         }
00325     }
00326     init_get_bits(&s->gb, buf, buf_size*8);
00327     skip_bits(&s->gb, s->bitindex);
00328     if (!s->blocksize)
00329     {
00330         int maxnlpc = 0;
00331         /* shorten signature */
00332         if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
00333             av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
00334             return -1;
00335         }
00336 
00337         s->lpcqoffset = 0;
00338         s->blocksize = DEFAULT_BLOCK_SIZE;
00339         s->channels = 1;
00340         s->nmean = -1;
00341         s->version = get_bits(&s->gb, 8);
00342         s->internal_ftype = get_uint(s, TYPESIZE);
00343 
00344         s->channels = get_uint(s, CHANSIZE);
00345         if (s->channels > MAX_CHANNELS) {
00346             av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
00347             return -1;
00348         }
00349 
00350         /* get blocksize if version > 0 */
00351         if (s->version > 0) {
00352             int skip_bytes;
00353             s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
00354             maxnlpc = get_uint(s, LPCQSIZE);
00355             s->nmean = get_uint(s, 0);
00356 
00357             skip_bytes = get_uint(s, NSKIPSIZE);
00358             for (i=0; i<skip_bytes; i++) {
00359                 skip_bits(&s->gb, 8);
00360             }
00361         }
00362         s->nwrap = FFMAX(NWRAP, maxnlpc);
00363 
00364         if (allocate_buffers(s))
00365             return -1;
00366 
00367         init_offset(s);
00368 
00369         if (s->version > 1)
00370             s->lpcqoffset = V2LPCQOFFSET;
00371 
00372         if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
00373             av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at beginning of stream\n");
00374             return -1;
00375         }
00376 
00377         s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
00378         if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
00379             av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
00380             return -1;
00381         }
00382 
00383         for (i=0; i<s->header_size; i++)
00384             s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
00385 
00386         if (decode_wave_header(avctx, s->header, s->header_size) < 0)
00387             return -1;
00388 
00389         s->cur_chan = 0;
00390         s->bitshift = 0;
00391     }
00392     else
00393     {
00394         int cmd;
00395         int len;
00396         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
00397         switch (cmd) {
00398             case FN_ZERO:
00399             case FN_DIFF0:
00400             case FN_DIFF1:
00401             case FN_DIFF2:
00402             case FN_DIFF3:
00403             case FN_QLPC:
00404                 {
00405                     int residual_size = 0;
00406                     int channel = s->cur_chan;
00407                     int32_t coffset;
00408                     if (cmd != FN_ZERO) {
00409                         residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
00410                         /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
00411                         if (s->version == 0)
00412                             residual_size--;
00413                     }
00414 
00415                     if (s->nmean == 0)
00416                         coffset = s->offset[channel][0];
00417                     else {
00418                         int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
00419                         for (i=0; i<s->nmean; i++)
00420                             sum += s->offset[channel][i];
00421                         coffset = sum / s->nmean;
00422                         if (s->version >= 2)
00423                             coffset >>= FFMIN(1, s->bitshift);
00424                     }
00425                     switch (cmd) {
00426                         case FN_ZERO:
00427                             for (i=0; i<s->blocksize; i++)
00428                                 s->decoded[channel][i] = 0;
00429                             break;
00430                         case FN_DIFF0:
00431                             for (i=0; i<s->blocksize; i++)
00432                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
00433                             break;
00434                         case FN_DIFF1:
00435                             for (i=0; i<s->blocksize; i++)
00436                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
00437                             break;
00438                         case FN_DIFF2:
00439                             for (i=0; i<s->blocksize; i++)
00440                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
00441                                                                                                       -   s->decoded[channel][i-2];
00442                             break;
00443                         case FN_DIFF3:
00444                             for (i=0; i<s->blocksize; i++)
00445                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
00446                                                                                                       - 3*s->decoded[channel][i-2]
00447                                                                                                       +   s->decoded[channel][i-3];
00448                             break;
00449                         case FN_QLPC:
00450                             {
00451                                 int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
00452                                 if (pred_order > s->nwrap) {
00453                                     av_log(avctx, AV_LOG_ERROR,
00454                                            "invalid pred_order %d\n",
00455                                            pred_order);
00456                                     return -1;
00457                                 }
00458                                 for (i=0; i<pred_order; i++)
00459                                     s->decoded[channel][i - pred_order] -= coffset;
00460                                 decode_subframe_lpc(s, channel, residual_size, pred_order);
00461                                 if (coffset != 0)
00462                                     for (i=0; i < s->blocksize; i++)
00463                                         s->decoded[channel][i] += coffset;
00464                             }
00465                     }
00466                     if (s->nmean > 0) {
00467                         int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
00468                         for (i=0; i<s->blocksize; i++)
00469                             sum += s->decoded[channel][i];
00470 
00471                         for (i=1; i<s->nmean; i++)
00472                             s->offset[channel][i-1] = s->offset[channel][i];
00473 
00474                         if (s->version < 2)
00475                             s->offset[channel][s->nmean - 1] = sum / s->blocksize;
00476                         else
00477                             s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
00478                     }
00479                     for (i=-s->nwrap; i<0; i++)
00480                         s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
00481 
00482                     fix_bitshift(s, s->decoded[channel]);
00483 
00484                     s->cur_chan++;
00485                     if (s->cur_chan == s->channels) {
00486                         int out_size = s->blocksize * s->channels *
00487                                        av_get_bytes_per_sample(avctx->sample_fmt);
00488                         if (*data_size < out_size) {
00489                             av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
00490                             return AVERROR(EINVAL);
00491                         }
00492                         samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
00493                         s->cur_chan = 0;
00494                         goto frame_done;
00495                     }
00496                     break;
00497                 }
00498                 break;
00499             case FN_VERBATIM:
00500                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
00501                 while (len--) {
00502                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
00503                 }
00504                 break;
00505             case FN_BITSHIFT:
00506                 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
00507                 break;
00508             case FN_BLOCKSIZE: {
00509                 int blocksize = get_uint(s, av_log2(s->blocksize));
00510                 if (blocksize > s->blocksize) {
00511                     av_log(avctx, AV_LOG_ERROR, "Increasing block size is not supported\n");
00512                     return AVERROR_PATCHWELCOME;
00513                 }
00514                 s->blocksize = blocksize;
00515                 break;
00516             }
00517             case FN_QUIT:
00518                 *data_size = 0;
00519                 return buf_size;
00520                 break;
00521             default:
00522                 av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
00523                 return -1;
00524                 break;
00525         }
00526     }
00527 frame_done:
00528     *data_size = (int8_t *)samples - (int8_t *)data;
00529 
00530     //    s->last_blocksize = s->blocksize;
00531     s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
00532     i= (get_bits_count(&s->gb))/8;
00533     if (i > buf_size) {
00534         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
00535         s->bitstream_size=0;
00536         s->bitstream_index=0;
00537         return -1;
00538     }
00539     if (s->bitstream_size) {
00540         s->bitstream_index += i;
00541         s->bitstream_size  -= i;
00542         return input_buf_size;
00543     } else
00544         return i;
00545 }
00546 
00547 static av_cold int shorten_decode_close(AVCodecContext *avctx)
00548 {
00549     ShortenContext *s = avctx->priv_data;
00550     int i;
00551 
00552     for (i = 0; i < s->channels; i++) {
00553         s->decoded[i] = NULL;
00554         av_freep(&s->decoded_base[i]);
00555         av_freep(&s->offset[i]);
00556     }
00557     av_freep(&s->bitstream);
00558     av_freep(&s->coeffs);
00559     return 0;
00560 }
00561 
00562 static void shorten_flush(AVCodecContext *avctx){
00563     ShortenContext *s = avctx->priv_data;
00564 
00565     s->bitstream_size=
00566         s->bitstream_index= 0;
00567 }
00568 
00569 AVCodec ff_shorten_decoder = {
00570     "shorten",
00571     AVMEDIA_TYPE_AUDIO,
00572     CODEC_ID_SHORTEN,
00573     sizeof(ShortenContext),
00574     shorten_decode_init,
00575     NULL,
00576     shorten_decode_close,
00577     shorten_decode_frame,
00578     .flush= shorten_flush,
00579     .long_name= NULL_IF_CONFIG_SMALL("Shorten"),
00580 };

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