FFmpeg: libavcodec/jpeglsdec.c Source File

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libavcodec

jpeglsdec.c

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1 /*

2 * JPEG-LS decoder

5 *

6 * This file is part of FFmpeg.

7 *

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

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

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

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

12 *

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

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

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

16 * Lesser General Public License for more details.

17 *

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

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

20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

21 */

23 /**

24 * @file

25 * JPEG-LS decoder.

26 */

28 #include "avcodec.h"

29 #include "get_bits.h"

30 #include "golomb.h"

31 #include "mathops.h"

32 #include "mjpeg.h"

33 #include "mjpegdec.h"

34 #include "jpegls.h"

35 #include "jpeglsdec.h"

38 /*

39 * Uncomment this to significantly speed up decoding of broken JPEG-LS

40 * (or test broken JPEG-LS decoder) and slow down ordinary decoding a bit.

41 *

42 * There is no Golomb code with length >= 32 bits possible, so check and

43 * avoid situation of 32 zeros, FFmpeg Golomb decoder is painfully slow

44 * on this errors.

45 */

46 //#define JLS_BROKEN

49 /**

50 * Decode LSE block with initialization parameters

51 */

52 int ff_jpegls_decode_lse(MJpegDecodeContext *s)

53 {

54 int id;

56 skip_bits(&s->gb, 16); /* length: FIXME: verify field validity */

57 id = get_bits(&s->gb, 8);

59 switch(id){

60 case 1:

61 s->maxval= get_bits(&s->gb, 16);

62 s->t1= get_bits(&s->gb, 16);

63 s->t2= get_bits(&s->gb, 16);

64 s->t3= get_bits(&s->gb, 16);

65 s->reset= get_bits(&s->gb, 16);

67 // ff_jpegls_reset_coding_parameters(s, 0);

68 //FIXME quant table?

69 break;

70 case 2:

71 case 3:

72 av_log(s->avctx, AV_LOG_ERROR, "palette not supported\n");

73 return -1;

74 case 4:

75 av_log(s->avctx, AV_LOG_ERROR, "oversize image not supported\n");

76 return -1;

77 default:

78 av_log(s->avctx, AV_LOG_ERROR, "invalid id %d\n", id);

79 return -1;

80 }

81 av_dlog(s->avctx, "ID=%i, T=%i,%i,%i\n", id, s->t1, s->t2, s->t3);

83 return 0;

84 }

86 /**

87 * Get context-dependent Golomb code, decode it and update context

88 */

89 static inline int ls_get_code_regular(GetBitContext *gb, JLSState *state, int Q){

90 int k, ret;

92 for(k = 0; (state->N[Q] << k) < state->A[Q]; k++);

94 #ifdef JLS_BROKEN

95 if(!show_bits_long(gb, 32))return -1;

96 #endif

97 ret = get_ur_golomb_jpegls(gb, k, state->limit, state->qbpp);

99 /* decode mapped error */

100 if(ret & 1)

101 ret = -((ret + 1) >> 1);

102 else

103 ret >>= 1;

104

105 /* for NEAR=0, k=0 and 2*B[Q] <= - N[Q] mapping is reversed */

106 if(!state->near && !k && (2 * state->B[Q] <= -state->N[Q]))

107 ret = -(ret + 1);

108

109 ret= ff_jpegls_update_state_regular(state, Q, ret);

110

111 return ret;

112 }

113

114 /**

115 * Get Golomb code, decode it and update state for run termination

116 */

117 static inline int ls_get_code_runterm(GetBitContext *gb, JLSState *state, int RItype, int limit_add){

118 int k, ret, temp, map;

119 int Q = 365 + RItype;

120

121 temp= state->A[Q];

122 if(RItype)

123 temp += state->N[Q] >> 1;

124

125 for(k = 0; (state->N[Q] << k) < temp; k++);

126

127 #ifdef JLS_BROKEN

128 if(!show_bits_long(gb, 32))return -1;

129 #endif

130 ret = get_ur_golomb_jpegls(gb, k, state->limit - limit_add - 1, state->qbpp);

131

132 /* decode mapped error */

133 map = 0;

134 if(!k && (RItype || ret) && (2 * state->B[Q] < state->N[Q]))

135 map = 1;

136 ret += RItype + map;

137

138 if(ret & 1){

139 ret = map - ((ret + 1) >> 1);

140 state->B[Q]++;

141 } else {

142 ret = ret >> 1;

143 }

144

145 /* update state */

146 state->A[Q] += FFABS(ret) - RItype;

147 ret *= state->twonear;

148 ff_jpegls_downscale_state(state, Q);

149

150 return ret;

151 }

152

153 /**

154 * Decode one line of image

155 */

156 static inline void ls_decode_line(JLSState *state, MJpegDecodeContext *s, void *last, void *dst, int last2, int w, int stride, int comp, int bits){

157 int i, x = 0;

158 int Ra, Rb, Rc, Rd;

159 int D0, D1, D2;

160

161 while(x < w) {

162 int err, pred;

163

164 /* compute gradients */

165 Ra = x ? R(dst, x - stride) : R(last, x);

166 Rb = R(last, x);

167 Rc = x ? R(last, x - stride) : last2;

168 Rd = (x >= w - stride) ? R(last, x) : R(last, x + stride);

169 D0 = Rd - Rb;

170 D1 = Rb - Rc;

171 D2 = Rc - Ra;

172 /* run mode */

173 if((FFABS(D0) <= state->near) && (FFABS(D1) <= state->near) && (FFABS(D2) <= state->near)) {

174 int r;

175 int RItype;

176

177 /* decode full runs while available */

178 while(get_bits1(&s->gb)) {

179 int r;

180 r = 1 << ff_log2_run[state->run_index[comp]];

181 if(x + r * stride > w) {

182 r = (w - x) / stride;

183 }

184 for(i = 0; i < r; i++) {

185 W(dst, x, Ra);

186 x += stride;

187 }

188 /* if EOL reached, we stop decoding */

189 if(r != (1 << ff_log2_run[state->run_index[comp]]))

190 return;

191 if(state->run_index[comp] < 31)

192 state->run_index[comp]++;

193 if(x + stride > w)

194 return;

195 }

196 /* decode aborted run */

197 r = ff_log2_run[state->run_index[comp]];

198 if(r)

199 r = get_bits_long(&s->gb, r);

200 if(x + r * stride > w) {

201 r = (w - x) / stride;

202 }

203 for(i = 0; i < r; i++) {

204 W(dst, x, Ra);

205 x += stride;

206 }

207

208 /* decode run termination value */

209 Rb = R(last, x);

210 RItype = (FFABS(Ra - Rb) <= state->near) ? 1 : 0;

211 err = ls_get_code_runterm(&s->gb, state, RItype, ff_log2_run[state->run_index[comp]]);

212 if(state->run_index[comp])

213 state->run_index[comp]--;

214

215 if(state->near && RItype){

216 pred = Ra + err;

217 } else {

218 if(Rb < Ra)

219 pred = Rb - err;

220 else

221 pred = Rb + err;

222 }

223 } else { /* regular mode */

224 int context, sign;

225

226 context = ff_jpegls_quantize(state, D0) * 81 + ff_jpegls_quantize(state, D1) * 9 + ff_jpegls_quantize(state, D2);

227 pred = mid_pred(Ra, Ra + Rb - Rc, Rb);

228

229 if(context < 0){

230 context = -context;

231 sign = 1;

232 }else{

233 sign = 0;

234 }

235

236 if(sign){

237 pred = av_clip(pred - state->C[context], 0, state->maxval);

238 err = -ls_get_code_regular(&s->gb, state, context);

239 } else {

240 pred = av_clip(pred + state->C[context], 0, state->maxval);

241 err = ls_get_code_regular(&s->gb, state, context);

242 }

243

244 /* we have to do something more for near-lossless coding */

245 pred += err;

246 }

247 if(state->near){

248 if(pred < -state->near)

249 pred += state->range * state->twonear;

250 else if(pred > state->maxval + state->near)

251 pred -= state->range * state->twonear;

252 pred = av_clip(pred, 0, state->maxval);

253 }

254

255 pred &= state->maxval;

256 W(dst, x, pred);

257 x += stride;

258 }

259 }

260

261 int ff_jpegls_decode_picture(MJpegDecodeContext *s, int near, int point_transform, int ilv){

262 int i, t = 0;

263 uint8_t *zero, *last, *cur;

264 JLSState *state;

265 int off = 0, stride = 1, width, shift;

266

267 zero = av_mallocz(s->picture.linesize[0]);

268 last = zero;

269 cur = s->picture.data[0];

270

271 state = av_mallocz(sizeof(JLSState));

272 /* initialize JPEG-LS state from JPEG parameters */

273 state->near = near;

274 state->bpp = (s->bits < 2) ? 2 : s->bits;

275 state->maxval = s->maxval;

276 state->T1 = s->t1;

277 state->T2 = s->t2;

278 state->T3 = s->t3;

279 state->reset = s->reset;

280 ff_jpegls_reset_coding_parameters(state, 0);

281 ff_jpegls_init_state(state);

282

283 if(s->bits <= 8)

284 shift = point_transform + (8 - s->bits);

285 else

286 shift = point_transform + (16 - s->bits);

287

288 if (s->avctx->debug & FF_DEBUG_PICT_INFO) {

289 av_log(s->avctx, AV_LOG_DEBUG, "JPEG-LS params: %ix%i NEAR=%i MV=%i T(%i,%i,%i) RESET=%i, LIMIT=%i, qbpp=%i, RANGE=%i\n",

290 s->width, s->height, state->near, state->maxval,

291 state->T1, state->T2, state->T3,

292 state->reset, state->limit, state->qbpp, state->range);

293 av_log(s->avctx, AV_LOG_DEBUG, "JPEG params: ILV=%i Pt=%i BPP=%i, scan = %i\n",

294 ilv, point_transform, s->bits, s->cur_scan);

295 }

296 if(ilv == 0) { /* separate planes */

297 stride = (s->nb_components > 1) ? 3 : 1;

298 off = av_clip(s->cur_scan - 1, 0, stride - 1);

299 width = s->width * stride;

300 cur += off;

301 for(i = 0; i < s->height; i++) {

302 if(s->bits <= 8){

303 ls_decode_line(state, s, last, cur, t, width, stride, off, 8);

304 t = last[0];

305 }else{

306 ls_decode_line(state, s, last, cur, t, width, stride, off, 16);

307 t = *((uint16_t*)last);

308 }

309 last = cur;

310 cur += s->picture.linesize[0];

311

312 if (s->restart_interval && !--s->restart_count) {

313 align_get_bits(&s->gb);

314 skip_bits(&s->gb, 16); /* skip RSTn */

315 }

316 }

317 } else if(ilv == 1) { /* line interleaving */

318 int j;

319 int Rc[3] = {0, 0, 0};

320 stride = (s->nb_components > 1) ? 3 : 1;

321 memset(cur, 0, s->picture.linesize[0]);

322 width = s->width * stride;

323 for(i = 0; i < s->height; i++) {

324 for(j = 0; j < stride; j++) {

325 ls_decode_line(state, s, last + j, cur + j, Rc[j], width, stride, j, 8);

326 Rc[j] = last[j];

327

328 if (s->restart_interval && !--s->restart_count) {

329 align_get_bits(&s->gb);

330 skip_bits(&s->gb, 16); /* skip RSTn */

331 }

332 }

333 last = cur;

334 cur += s->picture.linesize[0];

335 }

336 } else if(ilv == 2) { /* sample interleaving */

337 av_log(s->avctx, AV_LOG_ERROR, "Sample interleaved images are not supported.\n");

338 av_free(state);

339 av_free(zero);

340 return -1;

341 }

342

343 if(shift){ /* we need to do point transform or normalize samples */

344 int x, w;

345

346 w = s->width * s->nb_components;

347

348 if(s->bits <= 8){

349 uint8_t *src = s->picture.data[0];

350

351 for(i = 0; i < s->height; i++){

352 for(x = off; x < w; x+= stride){

353 src[x] <<= shift;

354 }

355 src += s->picture.linesize[0];

356 }

357 }else{

358 uint16_t *src = (uint16_t*) s->picture.data[0];

359

360 for(i = 0; i < s->height; i++){

361 for(x = 0; x < w; x++){

362 src[x] <<= shift;

363 }

364 src += s->picture.linesize[0]/2;

365 }

366 }

367 }

368 av_free(state);

369 av_free(zero);

370

371 return 0;

372 }

373

374

375 AVCodec ff_jpegls_decoder = {

376 .name = "jpegls",

377 .type = AVMEDIA_TYPE_VIDEO,

378 .id = AV_CODEC_ID_JPEGLS,

379 .priv_data_size = sizeof(MJpegDecodeContext),

380 .init = ff_mjpeg_decode_init,

381 .close = ff_mjpeg_decode_end,

382 .decode = ff_mjpeg_decode_frame,

383 .capabilities = CODEC_CAP_DR1,

384 .long_name = NULL_IF_CONFIG_SMALL("JPEG-LS"),

385 };

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