Libav
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00001 /* 00002 * Electronic Arts Madcow Video Decoder 00003 * Copyright (c) 2007-2009 Peter Ross 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 St, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00031 #include "avcodec.h" 00032 #include "get_bits.h" 00033 #include "dsputil.h" 00034 #include "aandcttab.h" 00035 #include "mpeg12.h" 00036 #include "mpeg12data.h" 00037 00038 #define EA_PREAMBLE_SIZE 8 00039 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */ 00040 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */ 00041 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */ 00042 00043 typedef struct MadContext { 00044 MpegEncContext s; 00045 AVFrame frame; 00046 AVFrame last_frame; 00047 void *bitstream_buf; 00048 unsigned int bitstream_buf_size; 00049 DECLARE_ALIGNED(16, DCTELEM, block)[64]; 00050 } MadContext; 00051 00052 static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count) 00053 { 00054 int i; 00055 for (i=0; i<count; i++) 00056 dst[i] = bswap_16(src[i]); 00057 } 00058 00059 static av_cold int decode_init(AVCodecContext *avctx) 00060 { 00061 MadContext *t = avctx->priv_data; 00062 MpegEncContext *s = &t->s; 00063 s->avctx = avctx; 00064 avctx->pix_fmt = PIX_FMT_YUV420P; 00065 if (avctx->idct_algo == FF_IDCT_AUTO) 00066 avctx->idct_algo = FF_IDCT_EA; 00067 dsputil_init(&s->dsp, avctx); 00068 ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct); 00069 ff_mpeg12_init_vlcs(); 00070 return 0; 00071 } 00072 00073 static inline void comp(unsigned char *dst, int dst_stride, 00074 unsigned char *src, int src_stride, int add) 00075 { 00076 int j, i; 00077 for (j=0; j<8; j++) 00078 for (i=0; i<8; i++) 00079 dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add); 00080 } 00081 00082 static inline void comp_block(MadContext *t, int mb_x, int mb_y, 00083 int j, int mv_x, int mv_y, int add) 00084 { 00085 MpegEncContext *s = &t->s; 00086 if (j < 4) { 00087 comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3), 00088 t->frame.linesize[0], 00089 t->last_frame.data[0] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x, 00090 t->last_frame.linesize[0], add); 00091 } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) { 00092 int index = j - 3; 00093 comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8, 00094 t->frame.linesize[index], 00095 t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2), 00096 t->last_frame.linesize[index], add); 00097 } 00098 } 00099 00100 static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j) 00101 { 00102 MpegEncContext *s = &t->s; 00103 if (j < 4) { 00104 s->dsp.idct_put( 00105 t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3), 00106 t->frame.linesize[0], block); 00107 } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) { 00108 int index = j - 3; 00109 s->dsp.idct_put( 00110 t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8, 00111 t->frame.linesize[index], block); 00112 } 00113 } 00114 00115 static inline void decode_block_intra(MadContext * t, DCTELEM * block) 00116 { 00117 MpegEncContext *s = &t->s; 00118 int level, i, j, run; 00119 RLTable *rl = &ff_rl_mpeg1; 00120 const uint8_t *scantable = s->intra_scantable.permutated; 00121 int16_t *quant_matrix = s->intra_matrix; 00122 00123 block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0]; 00124 00125 /* The RL decoder is derived from mpeg1_decode_block_intra; 00126 Escaped level and run values a decoded differently */ 00127 i = 0; 00128 { 00129 OPEN_READER(re, &s->gb); 00130 /* now quantify & encode AC coefficients */ 00131 for (;;) { 00132 UPDATE_CACHE(re, &s->gb); 00133 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0); 00134 00135 if (level == 127) { 00136 break; 00137 } else if (level != 0) { 00138 i += run; 00139 j = scantable[i]; 00140 level = (level*quant_matrix[j]) >> 4; 00141 level = (level-1)|1; 00142 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); 00143 LAST_SKIP_BITS(re, &s->gb, 1); 00144 } else { 00145 /* escape */ 00146 UPDATE_CACHE(re, &s->gb); 00147 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10); 00148 00149 UPDATE_CACHE(re, &s->gb); 00150 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6); 00151 00152 i += run; 00153 j = scantable[i]; 00154 if (level < 0) { 00155 level = -level; 00156 level = (level*quant_matrix[j]) >> 4; 00157 level = (level-1)|1; 00158 level = -level; 00159 } else { 00160 level = (level*quant_matrix[j]) >> 4; 00161 level = (level-1)|1; 00162 } 00163 } 00164 if (i > 63) { 00165 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y); 00166 return; 00167 } 00168 00169 block[j] = level; 00170 } 00171 CLOSE_READER(re, &s->gb); 00172 } 00173 } 00174 00175 static int decode_motion(GetBitContext *gb) 00176 { 00177 int value = 0; 00178 if (get_bits1(gb)) { 00179 if (get_bits1(gb)) 00180 value = -17; 00181 value += get_bits(gb, 4) + 1; 00182 } 00183 return value; 00184 } 00185 00186 static void decode_mb(MadContext *t, int inter) 00187 { 00188 MpegEncContext *s = &t->s; 00189 int mv_map = 0; 00190 int mv_x, mv_y; 00191 int j; 00192 00193 if (inter) { 00194 int v = decode210(&s->gb); 00195 if (v < 2) { 00196 mv_map = v ? get_bits(&s->gb, 6) : 63; 00197 mv_x = decode_motion(&s->gb); 00198 mv_y = decode_motion(&s->gb); 00199 } else { 00200 mv_map = 0; 00201 } 00202 } 00203 00204 for (j=0; j<6; j++) { 00205 if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map 00206 int add = 2*decode_motion(&s->gb); 00207 comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add); 00208 } else { 00209 s->dsp.clear_block(t->block); 00210 decode_block_intra(t, t->block); 00211 idct_put(t, t->block, s->mb_x, s->mb_y, j); 00212 } 00213 } 00214 } 00215 00216 static void calc_intra_matrix(MadContext *t, int qscale) 00217 { 00218 MpegEncContext *s = &t->s; 00219 int i; 00220 00221 if (s->avctx->idct_algo == FF_IDCT_EA) { 00222 s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11; 00223 for (i=1; i<64; i++) 00224 s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10; 00225 } else { 00226 s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0]; 00227 for (i=1; i<64; i++) 00228 s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1; 00229 } 00230 } 00231 00232 static int decode_frame(AVCodecContext *avctx, 00233 void *data, int *data_size, 00234 AVPacket *avpkt) 00235 { 00236 const uint8_t *buf = avpkt->data; 00237 int buf_size = avpkt->size; 00238 const uint8_t *buf_end = buf+buf_size; 00239 MadContext *t = avctx->priv_data; 00240 MpegEncContext *s = &t->s; 00241 int chunk_type; 00242 int inter; 00243 00244 if (buf_size < 17) { 00245 av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n"); 00246 *data_size = 0; 00247 return -1; 00248 } 00249 00250 chunk_type = AV_RL32(&buf[0]); 00251 inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG); 00252 buf += 8; 00253 00254 av_reduce(&avctx->time_base.num, &avctx->time_base.den, 00255 AV_RL16(&buf[6]), 1000, 1<<30); 00256 00257 s->width = AV_RL16(&buf[8]); 00258 s->height = AV_RL16(&buf[10]); 00259 calc_intra_matrix(t, buf[13]); 00260 buf += 16; 00261 00262 if (avctx->width != s->width || avctx->height != s->height) { 00263 if (avcodec_check_dimensions(avctx, s->width, s->height) < 0) 00264 return -1; 00265 avcodec_set_dimensions(avctx, s->width, s->height); 00266 if (t->frame.data[0]) 00267 avctx->release_buffer(avctx, &t->frame); 00268 } 00269 00270 t->frame.reference = 1; 00271 if (!t->frame.data[0]) { 00272 if (avctx->get_buffer(avctx, &t->frame) < 0) { 00273 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00274 return -1; 00275 } 00276 } 00277 00278 av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE); 00279 if (!t->bitstream_buf) 00280 return AVERROR(ENOMEM); 00281 bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2); 00282 init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf)); 00283 00284 for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++) 00285 for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++) 00286 decode_mb(t, inter); 00287 00288 *data_size = sizeof(AVFrame); 00289 *(AVFrame*)data = t->frame; 00290 00291 if (chunk_type != MADe_TAG) 00292 FFSWAP(AVFrame, t->frame, t->last_frame); 00293 00294 return buf_size; 00295 } 00296 00297 static av_cold int decode_end(AVCodecContext *avctx) 00298 { 00299 MadContext *t = avctx->priv_data; 00300 if (t->frame.data[0]) 00301 avctx->release_buffer(avctx, &t->frame); 00302 if (t->last_frame.data[0]) 00303 avctx->release_buffer(avctx, &t->last_frame); 00304 av_free(t->bitstream_buf); 00305 return 0; 00306 } 00307 00308 AVCodec eamad_decoder = { 00309 "eamad", 00310 AVMEDIA_TYPE_VIDEO, 00311 CODEC_ID_MAD, 00312 sizeof(MadContext), 00313 decode_init, 00314 NULL, 00315 decode_end, 00316 decode_frame, 00317 CODEC_CAP_DR1, 00318 .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video") 00319 };