FFmpeg: libavcodec/eamad.c Source File

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eamad.c

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1 /*

2 * Electronic Arts Madcow Video Decoder

4 *

5 * This file is part of FFmpeg.

6 *

7 * FFmpeg is free software; you can redistribute it and/or

8 * modify it under the terms of the GNU Lesser General Public

9 * License as published by the Free Software Foundation; either

10 * version 2.1 of the License, or (at your option) any later version.

11 *

12 * FFmpeg is distributed in the hope that it will be useful,

13 * but WITHOUT ANY WARRANTY; without even the implied warranty of

14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

15 * Lesser General Public License for more details.

16 *

17 * You should have received a copy of the GNU Lesser General Public

18 * License along with FFmpeg; if not, write to the Free Software

19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

20 */

22 /**

23 * @file

24 * Electronic Arts Madcow Video Decoder

25 * @author Peter Ross <pross@xvid.org>

26 *

27 * @see technical details at

28 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD

29 */

31 #include "avcodec.h"

32 #include "get_bits.h"

33 #include "aandcttab.h"

34 #include "eaidct.h"

35 #include "internal.h"

36 #include "mpeg12.h"

37 #include "mpeg12data.h"

38 #include "libavutil/imgutils.h"

40 #define EA_PREAMBLE_SIZE 8

41 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */

42 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */

43 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */

45 typedef struct MadContext {

46 AVCodecContext *avctx;

47 DSPContext dsp;

48 AVFrame last_frame;

49 GetBitContext gb;

50 void *bitstream_buf;

51 unsigned int bitstream_buf_size;

52 DECLARE_ALIGNED(16, int16_t, block)[64];

53 ScanTable scantable;

54 uint16_t quant_matrix[64];

55 int mb_x;

56 int mb_y;

57 } MadContext;

59 static av_cold int decode_init(AVCodecContext *avctx)

60 {

61 MadContext *s = avctx->priv_data;

62 s->avctx = avctx;

63 avctx->pix_fmt = AV_PIX_FMT_YUV420P;

64 ff_dsputil_init(&s->dsp, avctx);

65 ff_init_scantable_permutation(s->dsp.idct_permutation, FF_NO_IDCT_PERM);

66 ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);

67 ff_mpeg12_init_vlcs();

68 return 0;

69 }

71 static inline void comp(unsigned char *dst, int dst_stride,

72 unsigned char *src, int src_stride, int add)

73 {

74 int j, i;

75 for (j=0; j<8; j++)

76 for (i=0; i<8; i++)

77 dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);

78 }

80 static inline void comp_block(MadContext *t, AVFrame *frame,

81 int mb_x, int mb_y,

82 int j, int mv_x, int mv_y, int add)

83 {

84 if (j < 4) {

85 unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;

86 if (offset >= (t->avctx->height - 7) * t->last_frame.linesize[0] - 7)

87 return;

88 comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),

89 frame->linesize[0],

90 t->last_frame.data[0] + offset,

91 t->last_frame.linesize[0], add);

92 } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {

93 int index = j - 3;

94 unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2);

95 if (offset >= (t->avctx->height/2 - 7) * t->last_frame.linesize[index] - 7)

96 return;

97 comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,

98 frame->linesize[index],

99 t->last_frame.data[index] + offset,

100 t->last_frame.linesize[index], add);

101 }

102 }

103

104 static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,

105 int mb_x, int mb_y, int j)

106 {

107 if (j < 4) {

108 ff_ea_idct_put_c(

109 frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),

110 frame->linesize[0], block);

111 } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {

112 int index = j - 3;

113 ff_ea_idct_put_c(

114 frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,

115 frame->linesize[index], block);

116 }

117 }

118

119 static inline int decode_block_intra(MadContext *s, int16_t * block)

120 {

121 int level, i, j, run;

122 RLTable *rl = &ff_rl_mpeg1;

123 const uint8_t *scantable = s->scantable.permutated;

124 int16_t *quant_matrix = s->quant_matrix;

125

126 block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];

127

128 /* The RL decoder is derived from mpeg1_decode_block_intra;

129 Escaped level and run values a decoded differently */

130 i = 0;

131 {

132 OPEN_READER(re, &s->gb);

133 /* now quantify & encode AC coefficients */

134 for (;;) {

135 UPDATE_CACHE(re, &s->gb);

136 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

137

138 if (level == 127) {

139 break;

140 } else if (level != 0) {

141 i += run;

142 j = scantable[i];

143 level = (level*quant_matrix[j]) >> 4;

144 level = (level-1)|1;

145 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

146 LAST_SKIP_BITS(re, &s->gb, 1);

147 } else {

148 /* escape */

149 UPDATE_CACHE(re, &s->gb);

150 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);

151

152 UPDATE_CACHE(re, &s->gb);

153 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);

154

155 i += run;

156 j = scantable[i];

157 if (level < 0) {

158 level = -level;

159 level = (level*quant_matrix[j]) >> 4;

160 level = (level-1)|1;

161 level = -level;

162 } else {

163 level = (level*quant_matrix[j]) >> 4;

164 level = (level-1)|1;

165 }

166 }

167 if (i > 63) {

168 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);

169 return -1;

170 }

171

172 block[j] = level;

173 }

174 CLOSE_READER(re, &s->gb);

175 }

176 return 0;

177 }

178

179 static int decode_motion(GetBitContext *gb)

180 {

181 int value = 0;

182 if (get_bits1(gb)) {

183 if (get_bits1(gb))

184 value = -17;

185 value += get_bits(gb, 4) + 1;

186 }

187 return value;

188 }

189

190 static int decode_mb(MadContext *s, AVFrame *frame, int inter)

191 {

192 int mv_map = 0;

193 int mv_x, mv_y;

194 int j;

195

196 if (inter) {

197 int v = decode210(&s->gb);

198 if (v < 2) {

199 mv_map = v ? get_bits(&s->gb, 6) : 63;

200 mv_x = decode_motion(&s->gb);

201 mv_y = decode_motion(&s->gb);

202 }

203 }

204

205 for (j=0; j<6; j++) {

206 if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map

207 int add = 2*decode_motion(&s->gb);

208 if (s->last_frame.data[0])

209 comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);

210 } else {

211 s->dsp.clear_block(s->block);

212 if(decode_block_intra(s, s->block) < 0)

213 return -1;

214 idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);

215 }

216 }

217 return 0;

218 }

219

220 static void calc_quant_matrix(MadContext *s, int qscale)

221 {

222 int i;

223

224 s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;

225 for (i=1; i<64; i++)

226 s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;

227 }

228

229 static int decode_frame(AVCodecContext *avctx,

230 void *data, int *got_frame,

231 AVPacket *avpkt)

232 {

233 const uint8_t *buf = avpkt->data;

234 int buf_size = avpkt->size;

235 const uint8_t *buf_end = buf+buf_size;

236 MadContext *s = avctx->priv_data;

237 AVFrame *frame = data;

238 int width, height;

239 int chunk_type;

240 int inter, ret;

241

242 if (buf_size < 26) {

243 av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");

244 *got_frame = 0;

245 return AVERROR_INVALIDDATA;

246 }

247

248 chunk_type = AV_RL32(&buf[0]);

249 inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);

250 buf += 8;

251

252 av_reduce(&avctx->time_base.num, &avctx->time_base.den,

253 AV_RL16(&buf[6]), 1000, 1<<30);

254

255 width = AV_RL16(&buf[8]);

256 height = AV_RL16(&buf[10]);

257 calc_quant_matrix(s, buf[13]);

258 buf += 16;

259

260 if (width < 16 || height < 16) {

261 av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");

262 return AVERROR_INVALIDDATA;

263 }

264

265 if (avctx->width != width || avctx->height != height) {

266 if((width * height)/2048*7 > buf_end-buf)

267 return AVERROR_INVALIDDATA;

268 if ((ret = av_image_check_size(width, height, 0, avctx)) < 0)

269 return ret;

270 avcodec_set_dimensions(avctx, width, height);

271 av_frame_unref(&s->last_frame);

272 }

273

274 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)

275 return ret;

276

277 if (inter && !s->last_frame.data[0]) {

278 av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");

279 ret = ff_get_buffer(avctx, &s->last_frame, AV_GET_BUFFER_FLAG_REF);

280 if (ret < 0)

281 return ret;

282 memset(s->last_frame.data[0], 0, s->last_frame.height *

283 s->last_frame.linesize[0]);

284 memset(s->last_frame.data[1], 0x80, s->last_frame.height / 2 *

285 s->last_frame.linesize[1]);

286 memset(s->last_frame.data[2], 0x80, s->last_frame.height / 2 *

287 s->last_frame.linesize[2]);

288 }

289

290 av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,

291 buf_end - buf);

292 if (!s->bitstream_buf)

293 return AVERROR(ENOMEM);

294 s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);

295 memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);

296 init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));

297

298 for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)

299 for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)

300 if(decode_mb(s, frame, inter) < 0)

301 return AVERROR_INVALIDDATA;

302

303 *got_frame = 1;

304

305 if (chunk_type != MADe_TAG) {

306 av_frame_unref(&s->last_frame);

307 if ((ret = av_frame_ref(&s->last_frame, frame)) < 0)

308 return ret;

309 }

310

311 return buf_size;

312 }

313

314 static av_cold int decode_end(AVCodecContext *avctx)

315 {

316 MadContext *t = avctx->priv_data;

317 av_frame_unref(&t->last_frame);

318 av_free(t->bitstream_buf);

319 return 0;

320 }

321

322 AVCodec ff_eamad_decoder = {

323 .name = "eamad",

324 .type = AVMEDIA_TYPE_VIDEO,

325 .id = AV_CODEC_ID_MAD,

326 .priv_data_size = sizeof(MadContext),

327 .init = decode_init,

328 .close = decode_end,

329 .decode = decode_frame,

330 .capabilities = CODEC_CAP_DR1,

331 .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")

332 };

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