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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 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 
00029 #include <limits.h>
00030 #include "avcodec.h"
00031 #include "bytestream.h"
00032 #include "get_bits.h"
00033 #include "golomb.h"
00034 
00035 #define MAX_CHANNELS 8
00036 #define MAX_BLOCKSIZE 65535
00037 
00038 #define OUT_BUFFER_SIZE 16384
00039 
00040 #define ULONGSIZE 2
00041 
00042 #define WAVE_FORMAT_PCM 0x0001
00043 
00044 #define DEFAULT_BLOCK_SIZE 256
00045 
00046 #define TYPESIZE 4
00047 #define CHANSIZE 0
00048 #define LPCQSIZE 2
00049 #define ENERGYSIZE 3
00050 #define BITSHIFTSIZE 2
00051 
00052 #define TYPE_S16HL 3
00053 #define TYPE_S16LH 5
00054 
00055 #define NWRAP 3
00056 #define NSKIPSIZE 1
00057 
00058 #define LPCQUANT 5
00059 #define V2LPCQOFFSET (1 << LPCQUANT)
00060 
00061 #define FNSIZE 2
00062 #define FN_DIFF0        0
00063 #define FN_DIFF1        1
00064 #define FN_DIFF2        2
00065 #define FN_DIFF3        3
00066 #define FN_QUIT         4
00067 #define FN_BLOCKSIZE    5
00068 #define FN_BITSHIFT     6
00069 #define FN_QLPC         7
00070 #define FN_ZERO         8
00071 #define FN_VERBATIM     9
00072 
00074 static const uint8_t is_audio_command[10] = { 1, 1, 1, 1, 0, 0, 0, 1, 1, 0 };
00075 
00076 #define VERBATIM_CKSIZE_SIZE 5
00077 #define VERBATIM_BYTE_SIZE 8
00078 #define CANONICAL_HEADER_SIZE 44
00079 
00080 typedef struct ShortenContext {
00081     AVCodecContext *avctx;
00082     AVFrame frame;
00083     GetBitContext gb;
00084 
00085     int min_framesize, max_framesize;
00086     int channels;
00087 
00088     int32_t *decoded[MAX_CHANNELS];
00089     int32_t *decoded_base[MAX_CHANNELS];
00090     int32_t *offset[MAX_CHANNELS];
00091     int *coeffs;
00092     uint8_t *bitstream;
00093     int bitstream_size;
00094     int bitstream_index;
00095     unsigned int allocated_bitstream_size;
00096     int header_size;
00097     uint8_t header[OUT_BUFFER_SIZE];
00098     int version;
00099     int cur_chan;
00100     int bitshift;
00101     int nmean;
00102     int internal_ftype;
00103     int nwrap;
00104     int blocksize;
00105     int bitindex;
00106     int32_t lpcqoffset;
00107     int got_header;
00108     int got_quit_command;
00109 } ShortenContext;
00110 
00111 static av_cold int shorten_decode_init(AVCodecContext * avctx)
00112 {
00113     ShortenContext *s = avctx->priv_data;
00114     s->avctx = avctx;
00115     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00116 
00117     avcodec_get_frame_defaults(&s->frame);
00118     avctx->coded_frame = &s->frame;
00119 
00120     return 0;
00121 }
00122 
00123 static int allocate_buffers(ShortenContext *s)
00124 {
00125     int i, chan;
00126     int *coeffs;
00127     void *tmp_ptr;
00128 
00129     for (chan=0; chan<s->channels; chan++) {
00130         if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
00131             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
00132             return -1;
00133         }
00134         if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
00135             av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
00136             return -1;
00137         }
00138 
00139         tmp_ptr = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
00140         if (!tmp_ptr)
00141             return AVERROR(ENOMEM);
00142         s->offset[chan] = tmp_ptr;
00143 
00144         tmp_ptr = av_realloc(s->decoded_base[chan], (s->blocksize + s->nwrap) *
00145                              sizeof(s->decoded_base[0][0]));
00146         if (!tmp_ptr)
00147             return AVERROR(ENOMEM);
00148         s->decoded_base[chan] = tmp_ptr;
00149         for (i=0; i<s->nwrap; i++)
00150             s->decoded_base[chan][i] = 0;
00151         s->decoded[chan] = s->decoded_base[chan] + s->nwrap;
00152     }
00153 
00154     coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs));
00155     if (!coeffs)
00156         return AVERROR(ENOMEM);
00157     s->coeffs = coeffs;
00158 
00159     return 0;
00160 }
00161 
00162 
00163 static inline unsigned int get_uint(ShortenContext *s, int k)
00164 {
00165     if (s->version != 0)
00166         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
00167     return get_ur_golomb_shorten(&s->gb, k);
00168 }
00169 
00170 
00171 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
00172 {
00173     int i;
00174 
00175     if (s->bitshift != 0)
00176         for (i = 0; i < s->blocksize; i++)
00177             buffer[i] <<= s->bitshift;
00178 }
00179 
00180 
00181 static int init_offset(ShortenContext *s)
00182 {
00183     int32_t mean = 0;
00184     int  chan, i;
00185     int nblock = FFMAX(1, s->nmean);
00186     /* initialise offset */
00187     switch (s->internal_ftype)
00188     {
00189         case TYPE_S16HL:
00190         case TYPE_S16LH:
00191             mean = 0;
00192             break;
00193         default:
00194             av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
00195             return AVERROR_INVALIDDATA;
00196     }
00197 
00198     for (chan = 0; chan < s->channels; chan++)
00199         for (i = 0; i < nblock; i++)
00200             s->offset[chan][i] = mean;
00201     return 0;
00202 }
00203 
00204 static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header,
00205                               int header_size)
00206 {
00207     int len;
00208     short wave_format;
00209 
00210 
00211     if (bytestream_get_le32(&header) != MKTAG('R','I','F','F')) {
00212         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
00213         return -1;
00214     }
00215 
00216     header += 4; /* chunk size */;
00217 
00218     if (bytestream_get_le32(&header) != MKTAG('W','A','V','E')) {
00219         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
00220         return -1;
00221     }
00222 
00223     while (bytestream_get_le32(&header) != MKTAG('f','m','t',' ')) {
00224         len = bytestream_get_le32(&header);
00225         header += len;
00226     }
00227     len = bytestream_get_le32(&header);
00228 
00229     if (len < 16) {
00230         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
00231         return -1;
00232     }
00233 
00234     wave_format = bytestream_get_le16(&header);
00235 
00236     switch (wave_format) {
00237         case WAVE_FORMAT_PCM:
00238             break;
00239         default:
00240             av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
00241             return -1;
00242     }
00243 
00244     header += 2;        // skip channels    (already got from shorten header)
00245     avctx->sample_rate = bytestream_get_le32(&header);
00246     header += 4;        // skip bit rate    (represents original uncompressed bit rate)
00247     header += 2;        // skip block align (not needed)
00248     avctx->bits_per_coded_sample = bytestream_get_le16(&header);
00249 
00250     if (avctx->bits_per_coded_sample != 16) {
00251         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
00252         return -1;
00253     }
00254 
00255     len -= 16;
00256     if (len > 0)
00257         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
00258 
00259     return 0;
00260 }
00261 
00262 static void interleave_buffer(int16_t *samples, int nchan, int blocksize,
00263                               int32_t **buffer)
00264 {
00265     int i, chan;
00266     for (i=0; i<blocksize; i++)
00267         for (chan=0; chan < nchan; chan++)
00268             *samples++ = av_clip_int16(buffer[chan][i]);
00269 }
00270 
00271 static const int fixed_coeffs[3][3] = {
00272     { 1,  0,  0 },
00273     { 2, -1,  0 },
00274     { 3, -3,  1 }
00275 };
00276 
00277 static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
00278                                int residual_size, int32_t coffset)
00279 {
00280     int pred_order, sum, qshift, init_sum, i, j;
00281     const int *coeffs;
00282 
00283     if (command == FN_QLPC) {
00284         /* read/validate prediction order */
00285         pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
00286         if (pred_order > s->nwrap) {
00287             av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n", pred_order);
00288             return AVERROR(EINVAL);
00289         }
00290         /* read LPC coefficients */
00291         for (i=0; i<pred_order; i++)
00292             s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
00293         coeffs = s->coeffs;
00294 
00295         qshift = LPCQUANT;
00296     } else {
00297         /* fixed LPC coeffs */
00298         pred_order = command;
00299         coeffs     = fixed_coeffs[pred_order-1];
00300         qshift     = 0;
00301     }
00302 
00303     /* subtract offset from previous samples to use in prediction */
00304     if (command == FN_QLPC && coffset)
00305         for (i = -pred_order; i < 0; i++)
00306             s->decoded[channel][i] -= coffset;
00307 
00308     /* decode residual and do LPC prediction */
00309     init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
00310     for (i=0; i < s->blocksize; i++) {
00311         sum = init_sum;
00312         for (j=0; j<pred_order; j++)
00313             sum += coeffs[j] * s->decoded[channel][i-j-1];
00314         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> qshift);
00315     }
00316 
00317     /* add offset to current samples */
00318     if (command == FN_QLPC && coffset)
00319         for (i = 0; i < s->blocksize; i++)
00320             s->decoded[channel][i] += coffset;
00321 
00322     return 0;
00323 }
00324 
00325 static int read_header(ShortenContext *s)
00326 {
00327     int i, ret;
00328     int maxnlpc = 0;
00329     /* shorten signature */
00330     if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
00331         av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
00332         return -1;
00333     }
00334 
00335     s->lpcqoffset = 0;
00336     s->blocksize = DEFAULT_BLOCK_SIZE;
00337     s->nmean = -1;
00338     s->version = get_bits(&s->gb, 8);
00339     s->internal_ftype = get_uint(s, TYPESIZE);
00340 
00341     s->channels = get_uint(s, CHANSIZE);
00342     if (s->channels > MAX_CHANNELS) {
00343         av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
00344         return -1;
00345     }
00346     s->avctx->channels = s->channels;
00347 
00348     /* get blocksize if version > 0 */
00349     if (s->version > 0) {
00350         int skip_bytes, blocksize;
00351 
00352         blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
00353         if (!blocksize || blocksize > MAX_BLOCKSIZE) {
00354             av_log(s->avctx, AV_LOG_ERROR, "invalid or unsupported block size: %d\n",
00355                    blocksize);
00356             return AVERROR(EINVAL);
00357         }
00358         s->blocksize = blocksize;
00359 
00360         maxnlpc = get_uint(s, LPCQSIZE);
00361         s->nmean = get_uint(s, 0);
00362 
00363         skip_bytes = get_uint(s, NSKIPSIZE);
00364         for (i=0; i<skip_bytes; i++) {
00365             skip_bits(&s->gb, 8);
00366         }
00367     }
00368     s->nwrap = FFMAX(NWRAP, maxnlpc);
00369 
00370     if ((ret = allocate_buffers(s)) < 0)
00371         return ret;
00372 
00373     if ((ret = init_offset(s)) < 0)
00374         return ret;
00375 
00376     if (s->version > 1)
00377         s->lpcqoffset = V2LPCQOFFSET;
00378 
00379     if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
00380         av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at beginning of stream\n");
00381         return -1;
00382     }
00383 
00384     s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
00385     if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
00386         av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
00387         return -1;
00388     }
00389 
00390     for (i=0; i<s->header_size; i++)
00391         s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
00392 
00393     if (decode_wave_header(s->avctx, s->header, s->header_size) < 0)
00394         return -1;
00395 
00396     s->cur_chan = 0;
00397     s->bitshift = 0;
00398 
00399     s->got_header = 1;
00400 
00401     return 0;
00402 }
00403 
00404 static int shorten_decode_frame(AVCodecContext *avctx, void *data,
00405                                 int *got_frame_ptr, AVPacket *avpkt)
00406 {
00407     const uint8_t *buf = avpkt->data;
00408     int buf_size = avpkt->size;
00409     ShortenContext *s = avctx->priv_data;
00410     int i, input_buf_size = 0;
00411     int ret;
00412 
00413     /* allocate internal bitstream buffer */
00414     if(s->max_framesize == 0){
00415         void *tmp_ptr;
00416         s->max_framesize= 1024; // should hopefully be enough for the first header
00417         tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size,
00418                                   s->max_framesize);
00419         if (!tmp_ptr) {
00420             av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n");
00421             return AVERROR(ENOMEM);
00422         }
00423         s->bitstream = tmp_ptr;
00424     }
00425 
00426     /* append current packet data to bitstream buffer */
00427     if(1 && s->max_framesize){//FIXME truncated
00428         buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
00429         input_buf_size= buf_size;
00430 
00431         if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
00432             memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
00433             s->bitstream_index=0;
00434         }
00435         if (buf)
00436             memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
00437         buf= &s->bitstream[s->bitstream_index];
00438         buf_size += s->bitstream_size;
00439         s->bitstream_size= buf_size;
00440 
00441         /* do not decode until buffer has at least max_framesize bytes or
00442            the end of the file has been reached */
00443         if (buf_size < s->max_framesize && avpkt->data) {
00444             *got_frame_ptr = 0;
00445             return input_buf_size;
00446         }
00447     }
00448     /* init and position bitstream reader */
00449     init_get_bits(&s->gb, buf, buf_size*8);
00450     skip_bits(&s->gb, s->bitindex);
00451 
00452     /* process header or next subblock */
00453     if (!s->got_header) {
00454         if ((ret = read_header(s)) < 0)
00455             return ret;
00456         *got_frame_ptr = 0;
00457         goto finish_frame;
00458     }
00459 
00460     /* if quit command was read previously, don't decode anything */
00461     if (s->got_quit_command) {
00462         *got_frame_ptr = 0;
00463         return avpkt->size;
00464     }
00465 
00466     s->cur_chan = 0;
00467     while (s->cur_chan < s->channels) {
00468         int cmd;
00469         int len;
00470 
00471         if (get_bits_left(&s->gb) < 3+FNSIZE) {
00472             *got_frame_ptr = 0;
00473             break;
00474         }
00475 
00476         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
00477 
00478         if (cmd > FN_VERBATIM) {
00479             av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
00480             *got_frame_ptr = 0;
00481             break;
00482         }
00483 
00484         if (!is_audio_command[cmd]) {
00485             /* process non-audio command */
00486             switch (cmd) {
00487                 case FN_VERBATIM:
00488                     len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
00489                     while (len--) {
00490                         get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
00491                     }
00492                     break;
00493                 case FN_BITSHIFT:
00494                     s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
00495                     break;
00496                 case FN_BLOCKSIZE: {
00497                     int blocksize = get_uint(s, av_log2(s->blocksize));
00498                     if (blocksize > s->blocksize) {
00499                         av_log(avctx, AV_LOG_ERROR, "Increasing block size is not supported\n");
00500                         return AVERROR_PATCHWELCOME;
00501                     }
00502                     if (!blocksize || blocksize > MAX_BLOCKSIZE) {
00503                         av_log(avctx, AV_LOG_ERROR, "invalid or unsupported "
00504                                "block size: %d\n", blocksize);
00505                         return AVERROR(EINVAL);
00506                     }
00507                     s->blocksize = blocksize;
00508                     break;
00509                 }
00510                 case FN_QUIT:
00511                     s->got_quit_command = 1;
00512                     break;
00513             }
00514             if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) {
00515                 *got_frame_ptr = 0;
00516                 break;
00517             }
00518         } else {
00519             /* process audio command */
00520             int residual_size = 0;
00521             int channel = s->cur_chan;
00522             int32_t coffset;
00523 
00524             /* get Rice code for residual decoding */
00525             if (cmd != FN_ZERO) {
00526                 residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
00527                 /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
00528                 if (s->version == 0)
00529                     residual_size--;
00530             }
00531 
00532             /* calculate sample offset using means from previous blocks */
00533             if (s->nmean == 0)
00534                 coffset = s->offset[channel][0];
00535             else {
00536                 int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
00537                 for (i=0; i<s->nmean; i++)
00538                     sum += s->offset[channel][i];
00539                 coffset = sum / s->nmean;
00540                 if (s->version >= 2)
00541                     coffset >>= FFMIN(1, s->bitshift);
00542             }
00543 
00544             /* decode samples for this channel */
00545             if (cmd == FN_ZERO) {
00546                 for (i=0; i<s->blocksize; i++)
00547                     s->decoded[channel][i] = 0;
00548             } else {
00549                 if ((ret = decode_subframe_lpc(s, cmd, channel, residual_size, coffset)) < 0)
00550                     return ret;
00551             }
00552 
00553             /* update means with info from the current block */
00554             if (s->nmean > 0) {
00555                 int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
00556                 for (i=0; i<s->blocksize; i++)
00557                     sum += s->decoded[channel][i];
00558 
00559                 for (i=1; i<s->nmean; i++)
00560                     s->offset[channel][i-1] = s->offset[channel][i];
00561 
00562                 if (s->version < 2)
00563                     s->offset[channel][s->nmean - 1] = sum / s->blocksize;
00564                 else
00565                     s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
00566             }
00567 
00568             /* copy wrap samples for use with next block */
00569             for (i=-s->nwrap; i<0; i++)
00570                 s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
00571 
00572             /* shift samples to add in unused zero bits which were removed
00573                during encoding */
00574             fix_bitshift(s, s->decoded[channel]);
00575 
00576             /* if this is the last channel in the block, output the samples */
00577             s->cur_chan++;
00578             if (s->cur_chan == s->channels) {
00579                 /* get output buffer */
00580                 s->frame.nb_samples = s->blocksize;
00581                 if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
00582                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00583                     return ret;
00584                 }
00585                 /* interleave output */
00586                 interleave_buffer((int16_t *)s->frame.data[0], s->channels,
00587                                   s->blocksize, s->decoded);
00588 
00589                 *got_frame_ptr   = 1;
00590                 *(AVFrame *)data = s->frame;
00591             }
00592         }
00593     }
00594     if (s->cur_chan < s->channels)
00595         *got_frame_ptr = 0;
00596 
00597 finish_frame:
00598     s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
00599     i= (get_bits_count(&s->gb))/8;
00600     if (i > buf_size) {
00601         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
00602         s->bitstream_size=0;
00603         s->bitstream_index=0;
00604         return -1;
00605     }
00606     if (s->bitstream_size) {
00607         s->bitstream_index += i;
00608         s->bitstream_size  -= i;
00609         return input_buf_size;
00610     } else
00611         return i;
00612 }
00613 
00614 static av_cold int shorten_decode_close(AVCodecContext *avctx)
00615 {
00616     ShortenContext *s = avctx->priv_data;
00617     int i;
00618 
00619     for (i = 0; i < s->channels; i++) {
00620         s->decoded[i] = NULL;
00621         av_freep(&s->decoded_base[i]);
00622         av_freep(&s->offset[i]);
00623     }
00624     av_freep(&s->bitstream);
00625     av_freep(&s->coeffs);
00626 
00627     return 0;
00628 }
00629 
00630 AVCodec ff_shorten_decoder = {
00631     .name           = "shorten",
00632     .type           = AVMEDIA_TYPE_AUDIO,
00633     .id             = CODEC_ID_SHORTEN,
00634     .priv_data_size = sizeof(ShortenContext),
00635     .init           = shorten_decode_init,
00636     .close          = shorten_decode_close,
00637     .decode         = shorten_decode_frame,
00638     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
00639     .long_name= NULL_IF_CONFIG_SMALL("Shorten"),
00640 };
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