FFmpeg: libavcodec/pngenc.c Source File

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libavcodec

pngenc.c

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1 /*

2 * PNG image format

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 */

21 #include "avcodec.h"

22 #include "internal.h"

23 #include "bytestream.h"

24 #include "dsputil.h"

25 #include "png.h"

27 #include "libavutil/avassert.h"

28 #include "libavutil/opt.h"

30 /* TODO:

31 * - add 2, 4 and 16 bit depth support

32 */

34 #include <zlib.h>

36 #define IOBUF_SIZE 4096

38 typedef struct PNGEncContext {

39 AVClass *class;

40 DSPContext dsp;

42 uint8_t *bytestream;

43 uint8_t *bytestream_start;

44 uint8_t *bytestream_end;

45 AVFrame picture;

47 int filter_type;

49 z_stream zstream;

50 uint8_t buf[IOBUF_SIZE];

51 int dpi; ///< Physical pixel density, in dots per inch, if set

52 int dpm; ///< Physical pixel density, in dots per meter, if set

53 } PNGEncContext;

55 static void png_get_interlaced_row(uint8_t *dst, int row_size,

56 int bits_per_pixel, int pass,

57 const uint8_t *src, int width)

58 {

59 int x, mask, dst_x, j, b, bpp;

60 uint8_t *d;

61 const uint8_t *s;

62 static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};

64 mask = masks[pass];

65 switch(bits_per_pixel) {

66 case 1:

67 memset(dst, 0, row_size);

68 dst_x = 0;

69 for(x = 0; x < width; x++) {

70 j = (x & 7);

71 if ((mask << j) & 0x80) {

72 b = (src[x >> 3] >> (7 - j)) & 1;

73 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));

74 dst_x++;

75 }

76 }

77 break;

78 default:

79 bpp = bits_per_pixel >> 3;

80 d = dst;

81 s = src;

82 for(x = 0; x < width; x++) {

83 j = x & 7;

84 if ((mask << j) & 0x80) {

85 memcpy(d, s, bpp);

86 d += bpp;

87 }

88 s += bpp;

89 }

90 break;

91 }

92 }

94 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)

95 {

96 int i;

97 for(i = 0; i < w; i++) {

98 int a, b, c, p, pa, pb, pc;

100 a = src[i - bpp];

101 b = top[i];

102 c = top[i - bpp];

103

104 p = b - c;

105 pc = a - c;

106

107 pa = abs(p);

108 pb = abs(pc);

109 pc = abs(p + pc);

110

111 if (pa <= pb && pa <= pc)

112 p = a;

113 else if (pb <= pc)

114 p = b;

115 else

116 p = c;

117 dst[i] = src[i] - p;

118 }

119 }

120

121 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,

122 uint8_t *src, uint8_t *top, int size, int bpp)

123 {

124 int i;

125

126 switch(filter_type) {

127 case PNG_FILTER_VALUE_NONE:

128 memcpy(dst, src, size);

129 break;

130 case PNG_FILTER_VALUE_SUB:

131 dsp->diff_bytes(dst, src, src-bpp, size);

132 memcpy(dst, src, bpp);

133 break;

134 case PNG_FILTER_VALUE_UP:

135 dsp->diff_bytes(dst, src, top, size);

136 break;

137 case PNG_FILTER_VALUE_AVG:

138 for(i = 0; i < bpp; i++)

139 dst[i] = src[i] - (top[i] >> 1);

140 for(; i < size; i++)

141 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);

142 break;

143 case PNG_FILTER_VALUE_PAETH:

144 for(i = 0; i < bpp; i++)

145 dst[i] = src[i] - top[i];

146 sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);

147 break;

148 }

149 }

150

151 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,

152 uint8_t *src, uint8_t *top, int size, int bpp)

153 {

154 int pred = s->filter_type;

155 av_assert0(bpp || !pred);

156 if(!top && pred)

157 pred = PNG_FILTER_VALUE_SUB;

158 if(pred == PNG_FILTER_VALUE_MIXED) {

159 int i;

160 int cost, bcost = INT_MAX;

161 uint8_t *buf1 = dst, *buf2 = dst + size + 16;

162 for(pred=0; pred<5; pred++) {

163 png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);

164 buf1[0] = pred;

165 cost = 0;

166 for(i=0; i<=size; i++)

167 cost += abs((int8_t)buf1[i]);

168 if(cost < bcost) {

169 bcost = cost;

170 FFSWAP(uint8_t*, buf1, buf2);

171 }

172 }

173 return buf2;

174 } else {

175 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);

176 dst[0] = pred;

177 return dst;

178 }

179 }

180

181 static void png_write_chunk(uint8_t **f, uint32_t tag,

182 const uint8_t *buf, int length)

183 {

184 uint32_t crc;

185 uint8_t tagbuf[4];

186

187 bytestream_put_be32(f, length);

188 crc = crc32(0, Z_NULL, 0);

189 AV_WL32(tagbuf, tag);

190 crc = crc32(crc, tagbuf, 4);

191 bytestream_put_be32(f, av_bswap32(tag));

192 if (length > 0) {

193 crc = crc32(crc, buf, length);

194 memcpy(*f, buf, length);

195 *f += length;

196 }

197 bytestream_put_be32(f, crc);

198 }

199

200 /* XXX: do filtering */

201 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)

202 {

203 int ret;

204

205 s->zstream.avail_in = size;

206 s->zstream.next_in = (uint8_t *)data;

207 while (s->zstream.avail_in > 0) {

208 ret = deflate(&s->zstream, Z_NO_FLUSH);

209 if (ret != Z_OK)

210 return -1;

211 if (s->zstream.avail_out == 0) {

212 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)

213 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);

214 s->zstream.avail_out = IOBUF_SIZE;

215 s->zstream.next_out = s->buf;

216 }

217 }

218 return 0;

219 }

220

221 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,

222 const AVFrame *pict, int *got_packet)

223 {

224 PNGEncContext *s = avctx->priv_data;

225 AVFrame * const p= &s->picture;

226 int bit_depth, color_type, y, len, row_size, ret, is_progressive;

227 int bits_per_pixel, pass_row_size, enc_row_size;

228 int64_t max_packet_size;

229 int compression_level;

230 uint8_t *ptr, *top;

231 uint8_t *crow_base = NULL, *crow_buf, *crow;

232 uint8_t *progressive_buf = NULL;

233 uint8_t *top_buf = NULL;

234

235 *p = *pict;

236 p->pict_type= AV_PICTURE_TYPE_I;

237 p->key_frame= 1;

238

239 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);

240 switch(avctx->pix_fmt) {

241 case AV_PIX_FMT_RGBA64BE:

242 bit_depth = 16;

243 color_type = PNG_COLOR_TYPE_RGB_ALPHA;

244 break;

245 case AV_PIX_FMT_RGB48BE:

246 bit_depth = 16;

247 color_type = PNG_COLOR_TYPE_RGB;

248 break;

249 case AV_PIX_FMT_RGBA:

250 bit_depth = 8;

251 color_type = PNG_COLOR_TYPE_RGB_ALPHA;

252 break;

253 case AV_PIX_FMT_RGB24:

254 bit_depth = 8;

255 color_type = PNG_COLOR_TYPE_RGB;

256 break;

257 case AV_PIX_FMT_GRAY16BE:

258 bit_depth = 16;

259 color_type = PNG_COLOR_TYPE_GRAY;

260 break;

261 case AV_PIX_FMT_GRAY8:

262 bit_depth = 8;

263 color_type = PNG_COLOR_TYPE_GRAY;

264 break;

265 case AV_PIX_FMT_GRAY8A:

266 bit_depth = 8;

267 color_type = PNG_COLOR_TYPE_GRAY_ALPHA;

268 break;

269 case AV_PIX_FMT_MONOBLACK:

270 bit_depth = 1;

271 color_type = PNG_COLOR_TYPE_GRAY;

272 break;

273 case AV_PIX_FMT_PAL8:

274 bit_depth = 8;

275 color_type = PNG_COLOR_TYPE_PALETTE;

276 break;

277 default:

278 return -1;

279 }

280 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;

281 row_size = (avctx->width * bits_per_pixel + 7) >> 3;

282

283 s->zstream.zalloc = ff_png_zalloc;

284 s->zstream.zfree = ff_png_zfree;

285 s->zstream.opaque = NULL;

286 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?

287 Z_DEFAULT_COMPRESSION :

288 av_clip(avctx->compression_level, 0, 9);

289 ret = deflateInit2(&s->zstream, compression_level,

290 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);

291 if (ret != Z_OK)

292 return -1;

293

294 enc_row_size = deflateBound(&s->zstream, row_size);

295 max_packet_size = avctx->height * (int64_t)(enc_row_size +

296 ((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)

297 + FF_MIN_BUFFER_SIZE;

298 if (max_packet_size > INT_MAX)

299 return AVERROR(ENOMEM);

300 if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0)

301 return ret;

302

303 s->bytestream_start =

304 s->bytestream = pkt->data;

305 s->bytestream_end = pkt->data + pkt->size;

306

307 crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));

308 if (!crow_base)

309 goto fail;

310 crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it

311 if (is_progressive) {

312 progressive_buf = av_malloc(row_size + 1);

313 if (!progressive_buf)

314 goto fail;

315 }

316 if (is_progressive) {

317 top_buf = av_malloc(row_size + 1);

318 if (!top_buf)

319 goto fail;

320 }

321

322 /* write png header */

323 AV_WB64(s->bytestream, PNGSIG);

324 s->bytestream += 8;

325

326 AV_WB32(s->buf, avctx->width);

327 AV_WB32(s->buf + 4, avctx->height);

328 s->buf[8] = bit_depth;

329 s->buf[9] = color_type;

330 s->buf[10] = 0; /* compression type */

331 s->buf[11] = 0; /* filter type */

332 s->buf[12] = is_progressive; /* interlace type */

333

334 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);

335

336 if (s->dpm) {

337 AV_WB32(s->buf, s->dpm);

338 AV_WB32(s->buf + 4, s->dpm);

339 s->buf[8] = 1; /* unit specifier is meter */

340 } else {

341 AV_WB32(s->buf, avctx->sample_aspect_ratio.num);

342 AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);

343 s->buf[8] = 0; /* unit specifier is unknown */

344 }

345 png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);

346

347 /* put the palette if needed */

348 if (color_type == PNG_COLOR_TYPE_PALETTE) {

349 int has_alpha, alpha, i;

350 unsigned int v;

351 uint32_t *palette;

352 uint8_t *alpha_ptr;

353

354 palette = (uint32_t *)p->data[1];

355 ptr = s->buf;

356 alpha_ptr = s->buf + 256 * 3;

357 has_alpha = 0;

358 for(i = 0; i < 256; i++) {

359 v = palette[i];

360 alpha = v >> 24;

361 if (alpha != 0xff)

362 has_alpha = 1;

363 *alpha_ptr++ = alpha;

364 bytestream_put_be24(&ptr, v);

365 }

366 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);

367 if (has_alpha) {

368 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);

369 }

370 }

371

372 /* now put each row */

373 s->zstream.avail_out = IOBUF_SIZE;

374 s->zstream.next_out = s->buf;

375 if (is_progressive) {

376 int pass;

377

378 for(pass = 0; pass < NB_PASSES; pass++) {

379 /* NOTE: a pass is completely omitted if no pixels would be

380 output */

381 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);

382 if (pass_row_size > 0) {

383 top = NULL;

384 for(y = 0; y < avctx->height; y++) {

385 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {

386 ptr = p->data[0] + y * p->linesize[0];

387 FFSWAP(uint8_t*, progressive_buf, top_buf);

388 png_get_interlaced_row(progressive_buf, pass_row_size,

389 bits_per_pixel, pass,

390 ptr, avctx->width);

391 crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);

392 png_write_row(s, crow, pass_row_size + 1);

393 top = progressive_buf;

394 }

395 }

396 }

397 }

398 } else {

399 top = NULL;

400 for(y = 0; y < avctx->height; y++) {

401 ptr = p->data[0] + y * p->linesize[0];

402 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);

403 png_write_row(s, crow, row_size + 1);

404 top = ptr;

405 }

406 }

407 /* compress last bytes */

408 for(;;) {

409 ret = deflate(&s->zstream, Z_FINISH);

410 if (ret == Z_OK || ret == Z_STREAM_END) {

411 len = IOBUF_SIZE - s->zstream.avail_out;

412 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {

413 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);

414 }

415 s->zstream.avail_out = IOBUF_SIZE;

416 s->zstream.next_out = s->buf;

417 if (ret == Z_STREAM_END)

418 break;

419 } else {

420 goto fail;

421 }

422 }

423 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);

424

425 pkt->size = s->bytestream - s->bytestream_start;

426 pkt->flags |= AV_PKT_FLAG_KEY;

427 *got_packet = 1;

428 ret = 0;

429

430 the_end:

431 av_free(crow_base);

432 av_free(progressive_buf);

433 av_free(top_buf);

434 deflateEnd(&s->zstream);

435 return ret;

436 fail:

437 ret = -1;

438 goto the_end;

439 }

440

441 static av_cold int png_enc_init(AVCodecContext *avctx){

442 PNGEncContext *s = avctx->priv_data;

443

444 switch(avctx->pix_fmt) {

445 case AV_PIX_FMT_RGBA:

446 avctx->bits_per_coded_sample = 32;

447 break;

448 case AV_PIX_FMT_RGB24:

449 avctx->bits_per_coded_sample = 24;

450 break;

451 case AV_PIX_FMT_GRAY8:

452 avctx->bits_per_coded_sample = 0x28;

453 break;

454 case AV_PIX_FMT_MONOBLACK:

455 avctx->bits_per_coded_sample = 1;

456 break;

457 case AV_PIX_FMT_PAL8:

458 avctx->bits_per_coded_sample = 8;

459 }

460

461 avcodec_get_frame_defaults(&s->picture);

462 avctx->coded_frame= &s->picture;

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

464

465 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);

466 if(avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)

467 s->filter_type = PNG_FILTER_VALUE_NONE;

468

469 if (s->dpi && s->dpm) {

470 av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");

471 return AVERROR(EINVAL);

472 } else if (s->dpi) {

473 s->dpm = s->dpi * 10000 / 254;

474 }

475

476 return 0;

477 }

478

479 #define OFFSET(x) offsetof(PNGEncContext, x)

480 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

481 static const AVOption options[] = {

482 {"dpi", "Set image resolution (in dots per inch)", OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},

483 {"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},

484 { NULL }

485 };

486

487 static const AVClass pngenc_class = {

488 .class_name = "PNG encoder",

489 .item_name = av_default_item_name,

490 .option = options,

491 .version = LIBAVUTIL_VERSION_INT,

492 };

493

494 AVCodec ff_png_encoder = {

495 .name = "png",

496 .type = AVMEDIA_TYPE_VIDEO,

497 .id = AV_CODEC_ID_PNG,

498 .priv_data_size = sizeof(PNGEncContext),

499 .init = png_enc_init,

500 .encode2 = encode_frame,

501 .capabilities = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,

502 .pix_fmts = (const enum AVPixelFormat[]){

503 AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,

504 AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,

505 AV_PIX_FMT_PAL8,

506 AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,

507 AV_PIX_FMT_GRAY16BE,

508 AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE

509 },

510 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),

511 .priv_class = &pngenc_class,

512 };

Generated on Wed Jul 10 2013 23:48:03 for FFmpeg by doxygen 1.8.2