Libav 0.7.1
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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 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 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 #include "libavutil/imgutils.h" 00038 00039 #define EA_PREAMBLE_SIZE 8 00040 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */ 00041 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */ 00042 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */ 00043 00044 typedef struct MadContext { 00045 MpegEncContext s; 00046 AVFrame frame; 00047 AVFrame last_frame; 00048 void *bitstream_buf; 00049 unsigned int bitstream_buf_size; 00050 DECLARE_ALIGNED(16, DCTELEM, block)[64]; 00051 } MadContext; 00052 00053 static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count) 00054 { 00055 int i; 00056 for (i=0; i<count; i++) 00057 dst[i] = av_bswap16(src[i]); 00058 } 00059 00060 static av_cold int decode_init(AVCodecContext *avctx) 00061 { 00062 MadContext *t = avctx->priv_data; 00063 MpegEncContext *s = &t->s; 00064 s->avctx = avctx; 00065 avctx->pix_fmt = PIX_FMT_YUV420P; 00066 if (avctx->idct_algo == FF_IDCT_AUTO) 00067 avctx->idct_algo = FF_IDCT_EA; 00068 dsputil_init(&s->dsp, avctx); 00069 ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct); 00070 ff_mpeg12_init_vlcs(); 00071 return 0; 00072 } 00073 00074 static inline void comp(unsigned char *dst, int dst_stride, 00075 unsigned char *src, int src_stride, int add) 00076 { 00077 int j, i; 00078 for (j=0; j<8; j++) 00079 for (i=0; i<8; i++) 00080 dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add); 00081 } 00082 00083 static inline void comp_block(MadContext *t, int mb_x, int mb_y, 00084 int j, int mv_x, int mv_y, int add) 00085 { 00086 MpegEncContext *s = &t->s; 00087 if (j < 4) { 00088 comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3), 00089 t->frame.linesize[0], 00090 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, 00091 t->last_frame.linesize[0], add); 00092 } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) { 00093 int index = j - 3; 00094 comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8, 00095 t->frame.linesize[index], 00096 t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2), 00097 t->last_frame.linesize[index], add); 00098 } 00099 } 00100 00101 static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j) 00102 { 00103 MpegEncContext *s = &t->s; 00104 if (j < 4) { 00105 s->dsp.idct_put( 00106 t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3), 00107 t->frame.linesize[0], block); 00108 } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) { 00109 int index = j - 3; 00110 s->dsp.idct_put( 00111 t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8, 00112 t->frame.linesize[index], block); 00113 } 00114 } 00115 00116 static inline void decode_block_intra(MadContext * t, DCTELEM * block) 00117 { 00118 MpegEncContext *s = &t->s; 00119 int level, i, j, run; 00120 RLTable *rl = &ff_rl_mpeg1; 00121 const uint8_t *scantable = s->intra_scantable.permutated; 00122 int16_t *quant_matrix = s->intra_matrix; 00123 00124 block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0]; 00125 00126 /* The RL decoder is derived from mpeg1_decode_block_intra; 00127 Escaped level and run values a decoded differently */ 00128 i = 0; 00129 { 00130 OPEN_READER(re, &s->gb); 00131 /* now quantify & encode AC coefficients */ 00132 for (;;) { 00133 UPDATE_CACHE(re, &s->gb); 00134 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0); 00135 00136 if (level == 127) { 00137 break; 00138 } else if (level != 0) { 00139 i += run; 00140 j = scantable[i]; 00141 level = (level*quant_matrix[j]) >> 4; 00142 level = (level-1)|1; 00143 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); 00144 LAST_SKIP_BITS(re, &s->gb, 1); 00145 } else { 00146 /* escape */ 00147 UPDATE_CACHE(re, &s->gb); 00148 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10); 00149 00150 UPDATE_CACHE(re, &s->gb); 00151 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6); 00152 00153 i += run; 00154 j = scantable[i]; 00155 if (level < 0) { 00156 level = -level; 00157 level = (level*quant_matrix[j]) >> 4; 00158 level = (level-1)|1; 00159 level = -level; 00160 } else { 00161 level = (level*quant_matrix[j]) >> 4; 00162 level = (level-1)|1; 00163 } 00164 } 00165 if (i > 63) { 00166 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y); 00167 return; 00168 } 00169 00170 block[j] = level; 00171 } 00172 CLOSE_READER(re, &s->gb); 00173 } 00174 } 00175 00176 static int decode_motion(GetBitContext *gb) 00177 { 00178 int value = 0; 00179 if (get_bits1(gb)) { 00180 if (get_bits1(gb)) 00181 value = -17; 00182 value += get_bits(gb, 4) + 1; 00183 } 00184 return value; 00185 } 00186 00187 static void decode_mb(MadContext *t, int inter) 00188 { 00189 MpegEncContext *s = &t->s; 00190 int mv_map = 0; 00191 int mv_x, mv_y; 00192 int j; 00193 00194 if (inter) { 00195 int v = decode210(&s->gb); 00196 if (v < 2) { 00197 mv_map = v ? get_bits(&s->gb, 6) : 63; 00198 mv_x = decode_motion(&s->gb); 00199 mv_y = decode_motion(&s->gb); 00200 } else { 00201 mv_map = 0; 00202 } 00203 } 00204 00205 for (j=0; j<6; j++) { 00206 if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map 00207 int add = 2*decode_motion(&s->gb); 00208 comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add); 00209 } else { 00210 s->dsp.clear_block(t->block); 00211 decode_block_intra(t, t->block); 00212 idct_put(t, t->block, s->mb_x, s->mb_y, j); 00213 } 00214 } 00215 } 00216 00217 static void calc_intra_matrix(MadContext *t, int qscale) 00218 { 00219 MpegEncContext *s = &t->s; 00220 int i; 00221 00222 if (s->avctx->idct_algo == FF_IDCT_EA) { 00223 s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11; 00224 for (i=1; i<64; i++) 00225 s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10; 00226 } else { 00227 s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0]; 00228 for (i=1; i<64; i++) 00229 s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1; 00230 } 00231 } 00232 00233 static int decode_frame(AVCodecContext *avctx, 00234 void *data, int *data_size, 00235 AVPacket *avpkt) 00236 { 00237 const uint8_t *buf = avpkt->data; 00238 int buf_size = avpkt->size; 00239 const uint8_t *buf_end = buf+buf_size; 00240 MadContext *t = avctx->priv_data; 00241 MpegEncContext *s = &t->s; 00242 int chunk_type; 00243 int inter; 00244 00245 if (buf_size < 17) { 00246 av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n"); 00247 *data_size = 0; 00248 return -1; 00249 } 00250 00251 chunk_type = AV_RL32(&buf[0]); 00252 inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG); 00253 buf += 8; 00254 00255 av_reduce(&avctx->time_base.num, &avctx->time_base.den, 00256 AV_RL16(&buf[6]), 1000, 1<<30); 00257 00258 s->width = AV_RL16(&buf[8]); 00259 s->height = AV_RL16(&buf[10]); 00260 calc_intra_matrix(t, buf[13]); 00261 buf += 16; 00262 00263 if (avctx->width != s->width || avctx->height != s->height) { 00264 if (av_image_check_size(s->width, s->height, 0, avctx) < 0) 00265 return -1; 00266 avcodec_set_dimensions(avctx, s->width, s->height); 00267 if (t->frame.data[0]) 00268 avctx->release_buffer(avctx, &t->frame); 00269 } 00270 00271 t->frame.reference = 1; 00272 if (!t->frame.data[0]) { 00273 if (avctx->get_buffer(avctx, &t->frame) < 0) { 00274 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00275 return -1; 00276 } 00277 } 00278 00279 av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE); 00280 if (!t->bitstream_buf) 00281 return AVERROR(ENOMEM); 00282 bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2); 00283 init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf)); 00284 00285 for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++) 00286 for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++) 00287 decode_mb(t, inter); 00288 00289 *data_size = sizeof(AVFrame); 00290 *(AVFrame*)data = t->frame; 00291 00292 if (chunk_type != MADe_TAG) 00293 FFSWAP(AVFrame, t->frame, t->last_frame); 00294 00295 return buf_size; 00296 } 00297 00298 static av_cold int decode_end(AVCodecContext *avctx) 00299 { 00300 MadContext *t = avctx->priv_data; 00301 if (t->frame.data[0]) 00302 avctx->release_buffer(avctx, &t->frame); 00303 if (t->last_frame.data[0]) 00304 avctx->release_buffer(avctx, &t->last_frame); 00305 av_free(t->bitstream_buf); 00306 return 0; 00307 } 00308 00309 AVCodec ff_eamad_decoder = { 00310 "eamad", 00311 AVMEDIA_TYPE_VIDEO, 00312 CODEC_ID_MAD, 00313 sizeof(MadContext), 00314 decode_init, 00315 NULL, 00316 decode_end, 00317 decode_frame, 00318 CODEC_CAP_DR1, 00319 .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video") 00320 };