FFmpeg: libavcodec/mxpegdec.c Source File

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libavcodec

mxpegdec.c

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1 /*

2 * MxPEG 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 Street, Fifth Floor, Boston, MA 02110-1301 USA

20 */

23 /**

24 * @file

25 * MxPEG decoder

26 */

28 #include "internal.h"

29 #include "mjpeg.h"

30 #include "mjpegdec.h"

32 typedef struct MXpegDecodeContext {

33 MJpegDecodeContext jpg;

34 AVFrame picture[2]; /* pictures array */

35 int picture_index; /* index of current picture */

36 int got_sof_data; /* true if SOF data successfully parsed */

37 int got_mxm_bitmask; /* true if MXM bitmask available */

38 uint8_t *mxm_bitmask; /* bitmask buffer */

39 unsigned bitmask_size; /* size of bitmask */

40 int has_complete_frame; /* true if has complete frame */

41 uint8_t *completion_bitmask; /* completion bitmask of macroblocks */

42 unsigned mb_width, mb_height; /* size of picture in MB's from MXM header */

43 } MXpegDecodeContext;

45 static av_cold int mxpeg_decode_init(AVCodecContext *avctx)

46 {

47 MXpegDecodeContext *s = avctx->priv_data;

49 s->jpg.picture_ptr = &s->picture[0];

50 return ff_mjpeg_decode_init(avctx);

51 }

53 static int mxpeg_decode_app(MXpegDecodeContext *s,

54 const uint8_t *buf_ptr, int buf_size)

55 {

56 int len;

57 if (buf_size < 2)

58 return 0;

59 len = AV_RB16(buf_ptr);

60 skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));

62 return 0;

63 }

65 static int mxpeg_decode_mxm(MXpegDecodeContext *s,

66 const uint8_t *buf_ptr, int buf_size)

67 {

68 unsigned bitmask_size, mb_count;

69 int i;

71 s->mb_width = AV_RL16(buf_ptr+4);

72 s->mb_height = AV_RL16(buf_ptr+6);

73 mb_count = s->mb_width * s->mb_height;

75 bitmask_size = (mb_count + 7) >> 3;

76 if (bitmask_size > buf_size - 12) {

77 av_log(s->jpg.avctx, AV_LOG_ERROR,

78 "MXM bitmask is not complete\n");

79 return AVERROR(EINVAL);

80 }

82 if (s->bitmask_size != bitmask_size) {

83 s->bitmask_size = 0;

84 av_freep(&s->mxm_bitmask);

85 s->mxm_bitmask = av_malloc(bitmask_size);

86 if (!s->mxm_bitmask) {

87 av_log(s->jpg.avctx, AV_LOG_ERROR,

88 "MXM bitmask memory allocation error\n");

89 return AVERROR(ENOMEM);

90 }

92 av_freep(&s->completion_bitmask);

93 s->completion_bitmask = av_mallocz(bitmask_size);

94 if (!s->completion_bitmask) {

95 av_log(s->jpg.avctx, AV_LOG_ERROR,

96 "Completion bitmask memory allocation error\n");

97 return AVERROR(ENOMEM);

98 }

100 s->bitmask_size = bitmask_size;

101 }

102

103 memcpy(s->mxm_bitmask, buf_ptr + 12, bitmask_size);

104 s->got_mxm_bitmask = 1;

105

106 if (!s->has_complete_frame) {

107 uint8_t completion_check = 0xFF;

108 for (i = 0; i < bitmask_size; ++i) {

109 s->completion_bitmask[i] |= s->mxm_bitmask[i];

110 completion_check &= s->completion_bitmask[i];

111 }

112 s->has_complete_frame = !(completion_check ^ 0xFF);

113 }

114

115 return 0;

116 }

117

118 static int mxpeg_decode_com(MXpegDecodeContext *s,

119 const uint8_t *buf_ptr, int buf_size)

120 {

121 int len, ret = 0;

122 if (buf_size < 2)

123 return 0;

124 len = AV_RB16(buf_ptr);

125 if (len > 14 && len <= buf_size && !strncmp(buf_ptr + 2, "MXM", 3)) {

126 ret = mxpeg_decode_mxm(s, buf_ptr + 2, len - 2);

127 }

128 skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));

129

130 return ret;

131 }

132

133 static int mxpeg_check_dimensions(MXpegDecodeContext *s, MJpegDecodeContext *jpg,

134 AVFrame *reference_ptr)

135 {

136 if ((jpg->width + 0x0F)>>4 != s->mb_width ||

137 (jpg->height + 0x0F)>>4 != s->mb_height) {

138 av_log(jpg->avctx, AV_LOG_ERROR,

139 "Picture dimensions stored in SOF and MXM mismatch\n");

140 return AVERROR(EINVAL);

141 }

142

143 if (reference_ptr->data[0]) {

144 int i;

145 for (i = 0; i < MAX_COMPONENTS; ++i) {

146 if ( (!reference_ptr->data[i] ^ !jpg->picture_ptr->data[i]) ||

147 reference_ptr->linesize[i] != jpg->picture_ptr->linesize[i]) {

148 av_log(jpg->avctx, AV_LOG_ERROR,

149 "Dimensions of current and reference picture mismatch\n");

150 return AVERROR(EINVAL);

151 }

152 }

153 }

154

155 return 0;

156 }

157

158 static int mxpeg_decode_frame(AVCodecContext *avctx,

159 void *data, int *got_frame,

160 AVPacket *avpkt)

161 {

162 const uint8_t *buf = avpkt->data;

163 int buf_size = avpkt->size;

164 MXpegDecodeContext *s = avctx->priv_data;

165 MJpegDecodeContext *jpg = &s->jpg;

166 const uint8_t *buf_end, *buf_ptr;

167 const uint8_t *unescaped_buf_ptr;

168 int unescaped_buf_size;

169 int start_code;

170 int ret;

171

172 buf_ptr = buf;

173 buf_end = buf + buf_size;

174 jpg->got_picture = 0;

175 s->got_mxm_bitmask = 0;

176 while (buf_ptr < buf_end) {

177 start_code = ff_mjpeg_find_marker(jpg, &buf_ptr, buf_end,

178 &unescaped_buf_ptr, &unescaped_buf_size);

179 if (start_code < 0)

180 goto the_end;

181 {

182 init_get_bits(&jpg->gb, unescaped_buf_ptr, unescaped_buf_size*8);

183

184 if (start_code >= APP0 && start_code <= APP15) {

185 mxpeg_decode_app(s, unescaped_buf_ptr, unescaped_buf_size);

186 }

187

188 switch (start_code) {

189 case SOI:

190 if (jpg->got_picture) //emulating EOI

191 goto the_end;

192 break;

193 case EOI:

194 goto the_end;

195 case DQT:

196 ret = ff_mjpeg_decode_dqt(jpg);

197 if (ret < 0) {

198 av_log(avctx, AV_LOG_ERROR,

199 "quantization table decode error\n");

200 return ret;

201 }

202 break;

203 case DHT:

204 ret = ff_mjpeg_decode_dht(jpg);

205 if (ret < 0) {

206 av_log(avctx, AV_LOG_ERROR,

207 "huffman table decode error\n");

208 return ret;

209 }

210 break;

211 case COM:

212 ret = mxpeg_decode_com(s, unescaped_buf_ptr,

213 unescaped_buf_size);

214 if (ret < 0)

215 return ret;

216 break;

217 case SOF0:

218 s->got_sof_data = 0;

219 ret = ff_mjpeg_decode_sof(jpg);

220 if (ret < 0) {

221 av_log(avctx, AV_LOG_ERROR,

222 "SOF data decode error\n");

223 return ret;

224 }

225 if (jpg->interlaced) {

226 av_log(avctx, AV_LOG_ERROR,

227 "Interlaced mode not supported in MxPEG\n");

228 return AVERROR(EINVAL);

229 }

230 s->got_sof_data = 1;

231 break;

232 case SOS:

233 if (!s->got_sof_data) {

234 av_log(avctx, AV_LOG_WARNING,

235 "Can not process SOS without SOF data, skipping\n");

236 break;

237 }

238 if (!jpg->got_picture) {

239 if (jpg->first_picture) {

240 av_log(avctx, AV_LOG_WARNING,

241 "First picture has no SOF, skipping\n");

242 break;

243 }

244 if (!s->got_mxm_bitmask){

245 av_log(avctx, AV_LOG_WARNING,

246 "Non-key frame has no MXM, skipping\n");

247 break;

248 }

249 /* use stored SOF data to allocate current picture */

250 av_frame_unref(jpg->picture_ptr);

251 if ((ret = ff_get_buffer(avctx, jpg->picture_ptr,

252 AV_GET_BUFFER_FLAG_REF)) < 0)

253 return ret;

254 jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_P;

255 jpg->picture_ptr->key_frame = 0;

256 jpg->got_picture = 1;

257 } else {

258 jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_I;

259 jpg->picture_ptr->key_frame = 1;

260 }

261

262 if (s->got_mxm_bitmask) {

263 AVFrame *reference_ptr = &s->picture[s->picture_index ^ 1];

264 if (mxpeg_check_dimensions(s, jpg, reference_ptr) < 0)

265 break;

266

267 /* allocate dummy reference picture if needed */

268 if (!reference_ptr->data[0] &&

269 (ret = ff_get_buffer(avctx, reference_ptr,

270 AV_GET_BUFFER_FLAG_REF)) < 0)

271 return ret;

272

273 ret = ff_mjpeg_decode_sos(jpg, s->mxm_bitmask, reference_ptr);

274 if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))

275 return ret;

276 } else {

277 ret = ff_mjpeg_decode_sos(jpg, NULL, NULL);

278 if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))

279 return ret;

280 }

281

282 break;

283 }

284

285 buf_ptr += (get_bits_count(&jpg->gb)+7) >> 3;

286 }

287

288 }

289

290 the_end:

291 if (jpg->got_picture) {

292 int ret = av_frame_ref(data, jpg->picture_ptr);

293 if (ret < 0)

294 return ret;

295 *got_frame = 1;

296

297 s->picture_index ^= 1;

298 jpg->picture_ptr = &s->picture[s->picture_index];

299

300 if (!s->has_complete_frame) {

301 if (!s->got_mxm_bitmask)

302 s->has_complete_frame = 1;

303 else

304 *got_frame = 0;

305 }

306 }

307

308 return buf_ptr - buf;

309 }

310

311 static av_cold int mxpeg_decode_end(AVCodecContext *avctx)

312 {

313 MXpegDecodeContext *s = avctx->priv_data;

314 MJpegDecodeContext *jpg = &s->jpg;

315 int i;

316

317 jpg->picture_ptr = NULL;

318 ff_mjpeg_decode_end(avctx);

319

320 for (i = 0; i < 2; ++i)

321 av_frame_unref(&s->picture[i]);

322

323 av_freep(&s->mxm_bitmask);

324 av_freep(&s->completion_bitmask);

325

326 return 0;

327 }

328

329 AVCodec ff_mxpeg_decoder = {

330 .name = "mxpeg",

331 .long_name = NULL_IF_CONFIG_SMALL("Mobotix MxPEG video"),

332 .type = AVMEDIA_TYPE_VIDEO,

333 .id = AV_CODEC_ID_MXPEG,

334 .priv_data_size = sizeof(MXpegDecodeContext),

335 .init = mxpeg_decode_init,

336 .close = mxpeg_decode_end,

337 .decode = mxpeg_decode_frame,

338 .capabilities = CODEC_CAP_DR1,

339 .max_lowres = 3,

340 };

Generated on Wed Jul 10 2013 23:48:02 for FFmpeg by doxygen 1.8.2