1 /*
2 * qt-faststart.c, v0.2
3 * by Mike Melanson (melanson@pcisys.net)
4 * This file is placed in the public domain. Use the program however you
5 * see fit.
6 *
7 * This utility rearranges a Quicktime file such that the moov atom
8 * is in front of the data, thus facilitating network streaming.
9 *
10 * To compile this program, start from the base directory from which you
11 * are building FFmpeg and type:
12 * make tools/qt-faststart
13 * The qt-faststart program will be built in the tools/ directory. If you
14 * do not build the program in this manner, correct results are not
15 * guaranteed, particularly on 64-bit platforms.
16 * Invoke the program with:
17 * qt-faststart <infile.mov> <outfile.mov>
18 *
19 * Notes: Quicktime files can come in many configurations of top-level
20 * atoms. This utility stipulates that the very last atom in the file needs
21 * to be a moov atom. When given such a file, this utility will rearrange
22 * the top-level atoms by shifting the moov atom from the back of the file
23 * to the front, and patch the chunk offsets along the way. This utility
24 * presently only operates on uncompressed moov atoms.
25 */
26
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <inttypes.h>
30 #include <string.h>
31 #include <limits.h>
32
33 #ifdef __MINGW32__
34 #undef fseeko
35 #define fseeko(x, y, z) fseeko64(x, y, z)
36 #undef ftello
37 #define ftello(x) ftello64(x)
38 #elif defined(_WIN32)
39 #undef fseeko
40 #define fseeko(x, y, z) _fseeki64(x, y, z)
41 #undef ftello
42 #define ftello(x) _ftelli64(x)
43 #endif
44
45 #define MIN(a,b) ((a) > (b) ? (b) : (a))
46
47 #define BE_32(x) (((uint32_t)(((uint8_t*)(x))[0]) << 24) | \
48 (((uint8_t*)(x))[1] << 16) | \
49 (((uint8_t*)(x))[2] << 8) | \
50 ((uint8_t*)(x))[3])
51
52 #define BE_64(x) (((uint64_t)(((uint8_t*)(x))[0]) << 56) | \
53 ((uint64_t)(((uint8_t*)(x))[1]) << 48) | \
54 ((uint64_t)(((uint8_t*)(x))[2]) << 40) | \
55 ((uint64_t)(((uint8_t*)(x))[3]) << 32) | \
56 ((uint64_t)(((uint8_t*)(x))[4]) << 24) | \
57 ((uint64_t)(((uint8_t*)(x))[5]) << 16) | \
58 ((uint64_t)(((uint8_t*)(x))[6]) << 8) | \
59 ((uint64_t)( (uint8_t*)(x))[7]))
60
61 #define AV_WB32(p, val) { \
62 ((uint8_t*)(p))[0] = ((val) >> 24) & 0xff; \
63 ((uint8_t*)(p))[1] = ((val) >> 16) & 0xff; \
64 ((uint8_t*)(p))[2] = ((val) >> 8) & 0xff; \
65 ((uint8_t*)(p))[3] = (val) & 0xff; \
66 }
67
68 #define AV_WB64(p, val) { \
69 AV_WB32(p, (val) >> 32) \
70 AV_WB32(p + 4, val) \
71 }
72
73 #define BE_FOURCC(ch0, ch1, ch2, ch3) \
74 ( (uint32_t)(unsigned char)(ch3) | \
75 ((uint32_t)(unsigned char)(ch2) << 8) | \
76 ((uint32_t)(unsigned char)(ch1) << 16) | \
77 ((uint32_t)(unsigned char)(ch0) << 24) )
78
79 #define QT_ATOM BE_FOURCC
80 /* top level atoms */
81 #define FREE_ATOM QT_ATOM('f', 'r', 'e', 'e')
82 #define JUNK_ATOM QT_ATOM('j', 'u', 'n', 'k')
83 #define MDAT_ATOM QT_ATOM('m', 'd', 'a', 't')
84 #define MOOV_ATOM QT_ATOM('m', 'o', 'o', 'v')
85 #define PNOT_ATOM QT_ATOM('p', 'n', 'o', 't')
86 #define SKIP_ATOM QT_ATOM('s', 'k', 'i', 'p')
87 #define WIDE_ATOM QT_ATOM('w', 'i', 'd', 'e')
88 #define PICT_ATOM QT_ATOM('P', 'I', 'C', 'T')
89 #define FTYP_ATOM QT_ATOM('f', 't', 'y', 'p')
90 #define UUID_ATOM QT_ATOM('u', 'u', 'i', 'd')
91
92 #define CMOV_ATOM QT_ATOM('c', 'm', 'o', 'v')
93 #define TRAK_ATOM QT_ATOM('t', 'r', 'a', 'k')
94 #define MDIA_ATOM QT_ATOM('m', 'd', 'i', 'a')
95 #define MINF_ATOM QT_ATOM('m', 'i', 'n', 'f')
96 #define STBL_ATOM QT_ATOM('s', 't', 'b', 'l')
97 #define STCO_ATOM QT_ATOM('s', 't', 'c', 'o')
98 #define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
99
100 #define ATOM_PREAMBLE_SIZE 8
101 #define COPY_BUFFER_SIZE 33554432
102 #define MAX_FTYP_ATOM_SIZE 1048576
103
104 typedef struct {
105 uint32_t type;
106 uint32_t header_size;
107 uint64_t size;
108 unsigned char *data;
109 } atom_t;
110
111 typedef struct {
112 uint64_t moov_atom_size;
113 uint64_t stco_offset_count;
114 uint64_t stco_data_size;
115 int stco_overflow;
116 uint32_t depth;
117 } update_chunk_offsets_context_t;
118
119 typedef struct {
120 unsigned char *dest;
121 uint64_t original_moov_size;
122 uint64_t new_moov_size;
123 } upgrade_stco_context_t;
124
125 typedef int (*parse_atoms_callback_t)(void *context, atom_t *atom);
126
parse_atoms(unsigned char * buf,uint64_t size,parse_atoms_callback_t callback,void * context)127 static int parse_atoms(
128 unsigned char *buf,
129 uint64_t size,
130 parse_atoms_callback_t callback,
131 void *context)
132 {
133 unsigned char *pos = buf;
134 unsigned char *end = pos + size;
135 atom_t atom;
136 int ret;
137
138 while (end - pos >= ATOM_PREAMBLE_SIZE) {
139 atom.size = BE_32(pos);
140 atom.type = BE_32(pos + 4);
141 pos += ATOM_PREAMBLE_SIZE;
142 atom.header_size = ATOM_PREAMBLE_SIZE;
143
144 switch (atom.size) {
145 case 1:
146 if (end - pos < 8) {
147 fprintf(stderr, "not enough room for 64 bit atom size\n");
148 return -1;
149 }
150
151 atom.size = BE_64(pos);
152 pos += 8;
153 atom.header_size = ATOM_PREAMBLE_SIZE + 8;
154 break;
155
156 case 0:
157 atom.size = ATOM_PREAMBLE_SIZE + end - pos;
158 break;
159 }
160
161 if (atom.size < atom.header_size) {
162 fprintf(stderr, "atom size %"PRIu64" too small\n", atom.size);
163 return -1;
164 }
165
166 atom.size -= atom.header_size;
167
168 if (atom.size > end - pos) {
169 fprintf(stderr, "atom size %"PRIu64" too big\n", atom.size);
170 return -1;
171 }
172
173 atom.data = pos;
174 ret = callback(context, &atom);
175 if (ret < 0) {
176 return ret;
177 }
178
179 pos += atom.size;
180 }
181
182 return 0;
183 }
184
update_stco_offsets(update_chunk_offsets_context_t * context,atom_t * atom)185 static int update_stco_offsets(update_chunk_offsets_context_t *context, atom_t *atom)
186 {
187 uint32_t current_offset;
188 uint32_t offset_count;
189 unsigned char *pos;
190 unsigned char *end;
191
192 printf(" patching stco atom...\n");
193 if (atom->size < 8) {
194 fprintf(stderr, "stco atom size %"PRIu64" too small\n", atom->size);
195 return -1;
196 }
197
198 offset_count = BE_32(atom->data + 4);
199 if (offset_count > (atom->size - 8) / 4) {
200 fprintf(stderr, "stco offset count %"PRIu32" too big\n", offset_count);
201 return -1;
202 }
203
204 context->stco_offset_count += offset_count;
205 context->stco_data_size += atom->size - 8;
206
207 for (pos = atom->data + 8, end = pos + offset_count * 4;
208 pos < end;
209 pos += 4) {
210 current_offset = BE_32(pos);
211 if (current_offset > UINT_MAX - context->moov_atom_size) {
212 context->stco_overflow = 1;
213 }
214 current_offset += context->moov_atom_size;
215 AV_WB32(pos, current_offset);
216 }
217
218 return 0;
219 }
220
update_co64_offsets(update_chunk_offsets_context_t * context,atom_t * atom)221 static int update_co64_offsets(update_chunk_offsets_context_t *context, atom_t *atom)
222 {
223 uint64_t current_offset;
224 uint32_t offset_count;
225 unsigned char *pos;
226 unsigned char *end;
227
228 printf(" patching co64 atom...\n");
229 if (atom->size < 8) {
230 fprintf(stderr, "co64 atom size %"PRIu64" too small\n", atom->size);
231 return -1;
232 }
233
234 offset_count = BE_32(atom->data + 4);
235 if (offset_count > (atom->size - 8) / 8) {
236 fprintf(stderr, "co64 offset count %"PRIu32" too big\n", offset_count);
237 return -1;
238 }
239
240 for (pos = atom->data + 8, end = pos + offset_count * 8;
241 pos < end;
242 pos += 8) {
243 current_offset = BE_64(pos);
244 current_offset += context->moov_atom_size;
245 AV_WB64(pos, current_offset);
246 }
247
248 return 0;
249 }
250
update_chunk_offsets_callback(void * ctx,atom_t * atom)251 static int update_chunk_offsets_callback(void *ctx, atom_t *atom)
252 {
253 update_chunk_offsets_context_t *context = ctx;
254 int ret;
255
256 switch (atom->type) {
257 case STCO_ATOM:
258 return update_stco_offsets(context, atom);
259
260 case CO64_ATOM:
261 return update_co64_offsets(context, atom);
262
263 case MOOV_ATOM:
264 case TRAK_ATOM:
265 case MDIA_ATOM:
266 case MINF_ATOM:
267 case STBL_ATOM:
268 context->depth++;
269 if (context->depth > 10) {
270 fprintf(stderr, "atoms too deeply nested\n");
271 return -1;
272 }
273
274 ret = parse_atoms(
275 atom->data,
276 atom->size,
277 update_chunk_offsets_callback,
278 context);
279 context->depth--;
280 return ret;
281 }
282
283 return 0;
284 }
285
set_atom_size(unsigned char * header,uint32_t header_size,uint64_t size)286 static void set_atom_size(unsigned char *header, uint32_t header_size, uint64_t size)
287 {
288 switch (header_size) {
289 case 8:
290 AV_WB32(header, size);
291 break;
292
293 case 16:
294 AV_WB64(header + 8, size);
295 break;
296 }
297 }
298
upgrade_stco_atom(upgrade_stco_context_t * context,atom_t * atom)299 static void upgrade_stco_atom(upgrade_stco_context_t *context, atom_t *atom)
300 {
301 unsigned char *pos;
302 unsigned char *end;
303 uint64_t new_offset;
304 uint32_t offset_count;
305 uint32_t original_offset;
306
307 /* Note: not performing validations since they were performed on the first pass */
308
309 offset_count = BE_32(atom->data + 4);
310
311 /* write the header */
312 memcpy(context->dest, atom->data - atom->header_size, atom->header_size + 8);
313 AV_WB32(context->dest + 4, CO64_ATOM);
314 set_atom_size(context->dest, atom->header_size, atom->header_size + 8 + offset_count * 8);
315 context->dest += atom->header_size + 8;
316
317 /* write the data */
318 for (pos = atom->data + 8, end = pos + offset_count * 4;
319 pos < end;
320 pos += 4) {
321 original_offset = BE_32(pos) - context->original_moov_size;
322 new_offset = (uint64_t)original_offset + context->new_moov_size;
323 AV_WB64(context->dest, new_offset);
324 context->dest += 8;
325 }
326 }
327
upgrade_stco_callback(void * ctx,atom_t * atom)328 static int upgrade_stco_callback(void *ctx, atom_t *atom)
329 {
330 upgrade_stco_context_t *context = ctx;
331 unsigned char *start_pos;
332 uint64_t copy_size;
333
334 switch (atom->type) {
335 case STCO_ATOM:
336 upgrade_stco_atom(context, atom);
337 break;
338
339 case MOOV_ATOM:
340 case TRAK_ATOM:
341 case MDIA_ATOM:
342 case MINF_ATOM:
343 case STBL_ATOM:
344 /* write the atom header */
345 memcpy(context->dest, atom->data - atom->header_size, atom->header_size);
346 start_pos = context->dest;
347 context->dest += atom->header_size;
348
349 /* parse internal atoms*/
350 if (parse_atoms(
351 atom->data,
352 atom->size,
353 upgrade_stco_callback,
354 context) < 0) {
355 return -1;
356 }
357
358 /* update the atom size */
359 set_atom_size(start_pos, atom->header_size, context->dest - start_pos);
360 break;
361
362 default:
363 copy_size = atom->header_size + atom->size;
364 memcpy(context->dest, atom->data - atom->header_size, copy_size);
365 context->dest += copy_size;
366 break;
367 }
368
369 return 0;
370 }
371
update_moov_atom(unsigned char ** moov_atom,uint64_t * moov_atom_size)372 static int update_moov_atom(
373 unsigned char **moov_atom,
374 uint64_t *moov_atom_size)
375 {
376 update_chunk_offsets_context_t update_context = { 0 };
377 upgrade_stco_context_t upgrade_context;
378 unsigned char *new_moov_atom;
379
380 update_context.moov_atom_size = *moov_atom_size;
381
382 if (parse_atoms(
383 *moov_atom,
384 *moov_atom_size,
385 update_chunk_offsets_callback,
386 &update_context) < 0) {
387 return -1;
388 }
389
390 if (!update_context.stco_overflow) {
391 return 0;
392 }
393
394 printf(" upgrading stco atoms to co64...\n");
395 upgrade_context.new_moov_size = *moov_atom_size +
396 update_context.stco_offset_count * 8 -
397 update_context.stco_data_size;
398
399 new_moov_atom = malloc(upgrade_context.new_moov_size);
400 if (new_moov_atom == NULL) {
401 fprintf(stderr, "could not allocate %"PRIu64" bytes for updated moov atom\n",
402 upgrade_context.new_moov_size);
403 return -1;
404 }
405
406 upgrade_context.original_moov_size = *moov_atom_size;
407 upgrade_context.dest = new_moov_atom;
408
409 if (parse_atoms(
410 *moov_atom,
411 *moov_atom_size,
412 upgrade_stco_callback,
413 &upgrade_context) < 0) {
414 free(new_moov_atom);
415 return -1;
416 }
417
418 free(*moov_atom);
419 *moov_atom = new_moov_atom;
420 *moov_atom_size = upgrade_context.new_moov_size;
421
422 if (upgrade_context.dest != *moov_atom + *moov_atom_size) {
423 fprintf(stderr, "unexpected - wrong number of moov bytes written\n");
424 return -1;
425 }
426
427 return 0;
428 }
429
main(int argc,char * argv[])430 int main(int argc, char *argv[])
431 {
432 FILE *infile = NULL;
433 FILE *outfile = NULL;
434 unsigned char atom_bytes[ATOM_PREAMBLE_SIZE];
435 uint32_t atom_type = 0;
436 uint64_t atom_size = 0;
437 uint64_t atom_offset = 0;
438 int64_t last_offset;
439 unsigned char *moov_atom = NULL;
440 unsigned char *ftyp_atom = NULL;
441 uint64_t moov_atom_size;
442 uint64_t ftyp_atom_size = 0;
443 int64_t start_offset = 0;
444 unsigned char *copy_buffer = NULL;
445 int bytes_to_copy;
446 uint64_t free_size = 0;
447 uint64_t moov_size = 0;
448
449 if (argc != 3) {
450 printf("Usage: qt-faststart <infile.mov> <outfile.mov>\n"
451 "Note: alternatively you can use -movflags +faststart in ffmpeg\n");
452 return 0;
453 }
454
455 if (!strcmp(argv[1], argv[2])) {
456 fprintf(stderr, "input and output files need to be different\n");
457 return 1;
458 }
459
460 infile = fopen(argv[1], "rb");
461 if (!infile) {
462 perror(argv[1]);
463 goto error_out;
464 }
465
466 /* traverse through the atoms in the file to make sure that 'moov' is
467 * at the end */
468 while (!feof(infile)) {
469 if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
470 break;
471 }
472 atom_size = BE_32(&atom_bytes[0]);
473 atom_type = BE_32(&atom_bytes[4]);
474
475 /* keep ftyp atom */
476 if (atom_type == FTYP_ATOM) {
477 if (atom_size > MAX_FTYP_ATOM_SIZE) {
478 fprintf(stderr, "ftyp atom size %"PRIu64" too big\n",
479 atom_size);
480 goto error_out;
481 }
482 ftyp_atom_size = atom_size;
483 free(ftyp_atom);
484 ftyp_atom = malloc(ftyp_atom_size);
485 if (!ftyp_atom) {
486 fprintf(stderr, "could not allocate %"PRIu64" bytes for ftyp atom\n",
487 atom_size);
488 goto error_out;
489 }
490 if (fseeko(infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR) ||
491 fread(ftyp_atom, atom_size, 1, infile) != 1 ||
492 (start_offset = ftello(infile)) < 0) {
493 perror(argv[1]);
494 goto error_out;
495 }
496 } else {
497 int ret;
498 /* 64-bit special case */
499 if (atom_size == 1) {
500 if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
501 break;
502 }
503 atom_size = BE_64(&atom_bytes[0]);
504 ret = fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
505 } else {
506 ret = fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
507 }
508 if (ret) {
509 perror(argv[1]);
510 goto error_out;
511 }
512 }
513 printf("%c%c%c%c %10"PRIu64" %"PRIu64"\n",
514 (atom_type >> 24) & 255,
515 (atom_type >> 16) & 255,
516 (atom_type >> 8) & 255,
517 (atom_type >> 0) & 255,
518 atom_offset,
519 atom_size);
520 if ((atom_type != FREE_ATOM) &&
521 (atom_type != JUNK_ATOM) &&
522 (atom_type != MDAT_ATOM) &&
523 (atom_type != MOOV_ATOM) &&
524 (atom_type != PNOT_ATOM) &&
525 (atom_type != SKIP_ATOM) &&
526 (atom_type != WIDE_ATOM) &&
527 (atom_type != PICT_ATOM) &&
528 (atom_type != UUID_ATOM) &&
529 (atom_type != FTYP_ATOM)) {
530 fprintf(stderr, "encountered non-QT top-level atom (is this a QuickTime file?)\n");
531 break;
532 }
533 atom_offset += atom_size;
534
535 /* The atom header is 8 (or 16 bytes), if the atom size (which
536 * includes these 8 or 16 bytes) is less than that, we won't be
537 * able to continue scanning sensibly after this atom, so break. */
538 if (atom_size < 8)
539 break;
540
541 if (atom_type == MOOV_ATOM)
542 moov_size = atom_size;
543
544 if (moov_size && atom_type == FREE_ATOM) {
545 free_size += atom_size;
546 atom_type = MOOV_ATOM;
547 atom_size = moov_size;
548 }
549 }
550
551 if (atom_type != MOOV_ATOM) {
552 printf("last atom in file was not a moov atom\n");
553 free(ftyp_atom);
554 fclose(infile);
555 return 0;
556 }
557
558 if (atom_size < 16) {
559 fprintf(stderr, "bad moov atom size\n");
560 goto error_out;
561 }
562
563 /* moov atom was, in fact, the last atom in the chunk; load the whole
564 * moov atom */
565 if (fseeko(infile, -(atom_size + free_size), SEEK_END)) {
566 perror(argv[1]);
567 goto error_out;
568 }
569 last_offset = ftello(infile);
570 if (last_offset < 0) {
571 perror(argv[1]);
572 goto error_out;
573 }
574 moov_atom_size = atom_size;
575 moov_atom = malloc(moov_atom_size);
576 if (!moov_atom) {
577 fprintf(stderr, "could not allocate %"PRIu64" bytes for moov atom\n", atom_size);
578 goto error_out;
579 }
580 if (fread(moov_atom, atom_size, 1, infile) != 1) {
581 perror(argv[1]);
582 goto error_out;
583 }
584
585 /* this utility does not support compressed atoms yet, so disqualify
586 * files with compressed QT atoms */
587 if (BE_32(&moov_atom[12]) == CMOV_ATOM) {
588 fprintf(stderr, "this utility does not support compressed moov atoms yet\n");
589 goto error_out;
590 }
591
592 /* close; will be re-opened later */
593 fclose(infile);
594 infile = NULL;
595
596 if (update_moov_atom(&moov_atom, &moov_atom_size) < 0) {
597 goto error_out;
598 }
599
600 /* re-open the input file and open the output file */
601 infile = fopen(argv[1], "rb");
602 if (!infile) {
603 perror(argv[1]);
604 goto error_out;
605 }
606
607 if (start_offset > 0) { /* seek after ftyp atom */
608 if (fseeko(infile, start_offset, SEEK_SET)) {
609 perror(argv[1]);
610 goto error_out;
611 }
612
613 last_offset -= start_offset;
614 }
615
616 outfile = fopen(argv[2], "wb");
617 if (!outfile) {
618 perror(argv[2]);
619 goto error_out;
620 }
621
622 /* dump the same ftyp atom */
623 if (ftyp_atom_size > 0) {
624 printf(" writing ftyp atom...\n");
625 if (fwrite(ftyp_atom, ftyp_atom_size, 1, outfile) != 1) {
626 perror(argv[2]);
627 goto error_out;
628 }
629 }
630
631 /* dump the new moov atom */
632 printf(" writing moov atom...\n");
633 if (fwrite(moov_atom, moov_atom_size, 1, outfile) != 1) {
634 perror(argv[2]);
635 goto error_out;
636 }
637
638 /* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
639 bytes_to_copy = MIN(COPY_BUFFER_SIZE, last_offset);
640 copy_buffer = malloc(bytes_to_copy);
641 if (!copy_buffer) {
642 fprintf(stderr, "could not allocate %d bytes for copy_buffer\n", bytes_to_copy);
643 goto error_out;
644 }
645 printf(" copying rest of file...\n");
646 while (last_offset) {
647 bytes_to_copy = MIN(bytes_to_copy, last_offset);
648
649 if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
650 perror(argv[1]);
651 goto error_out;
652 }
653 if (fwrite(copy_buffer, bytes_to_copy, 1, outfile) != 1) {
654 perror(argv[2]);
655 goto error_out;
656 }
657 last_offset -= bytes_to_copy;
658 }
659
660 fclose(infile);
661 fclose(outfile);
662 free(moov_atom);
663 free(ftyp_atom);
664 free(copy_buffer);
665
666 return 0;
667
668 error_out:
669 if (infile)
670 fclose(infile);
671 if (outfile)
672 fclose(outfile);
673 free(moov_atom);
674 free(ftyp_atom);
675 free(copy_buffer);
676 return 1;
677 }
678