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qt-faststart.c
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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 
32 #ifdef __MINGW32__
33 #define fseeko(x, y, z) fseeko64(x, y, z)
34 #define ftello(x) ftello64(x)
35 #elif defined(_WIN32)
36 #define fseeko(x, y, z) _fseeki64(x, y, z)
37 #define ftello(x) _ftelli64(x)
38 #endif
39 
40 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
41 
42 #define BE_16(x) ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
43 
44 #define BE_32(x) ((((uint8_t*)(x))[0] << 24) | \
45  (((uint8_t*)(x))[1] << 16) | \
46  (((uint8_t*)(x))[2] << 8) | \
47  ((uint8_t*)(x))[3])
48 
49 #define BE_64(x) (((uint64_t)(((uint8_t*)(x))[0]) << 56) | \
50  ((uint64_t)(((uint8_t*)(x))[1]) << 48) | \
51  ((uint64_t)(((uint8_t*)(x))[2]) << 40) | \
52  ((uint64_t)(((uint8_t*)(x))[3]) << 32) | \
53  ((uint64_t)(((uint8_t*)(x))[4]) << 24) | \
54  ((uint64_t)(((uint8_t*)(x))[5]) << 16) | \
55  ((uint64_t)(((uint8_t*)(x))[6]) << 8) | \
56  ((uint64_t)( (uint8_t*)(x))[7]))
57 
58 #define BE_FOURCC(ch0, ch1, ch2, ch3) \
59  ( (uint32_t)(unsigned char)(ch3) | \
60  ((uint32_t)(unsigned char)(ch2) << 8) | \
61  ((uint32_t)(unsigned char)(ch1) << 16) | \
62  ((uint32_t)(unsigned char)(ch0) << 24) )
63 
64 #define QT_ATOM BE_FOURCC
65 /* top level atoms */
66 #define FREE_ATOM QT_ATOM('f', 'r', 'e', 'e')
67 #define JUNK_ATOM QT_ATOM('j', 'u', 'n', 'k')
68 #define MDAT_ATOM QT_ATOM('m', 'd', 'a', 't')
69 #define MOOV_ATOM QT_ATOM('m', 'o', 'o', 'v')
70 #define PNOT_ATOM QT_ATOM('p', 'n', 'o', 't')
71 #define SKIP_ATOM QT_ATOM('s', 'k', 'i', 'p')
72 #define WIDE_ATOM QT_ATOM('w', 'i', 'd', 'e')
73 #define PICT_ATOM QT_ATOM('P', 'I', 'C', 'T')
74 #define FTYP_ATOM QT_ATOM('f', 't', 'y', 'p')
75 #define UUID_ATOM QT_ATOM('u', 'u', 'i', 'd')
76 
77 #define CMOV_ATOM QT_ATOM('c', 'm', 'o', 'v')
78 #define STCO_ATOM QT_ATOM('s', 't', 'c', 'o')
79 #define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
80 
81 #define ATOM_PREAMBLE_SIZE 8
82 #define COPY_BUFFER_SIZE 33554432
83 
84 int main(int argc, char *argv[])
85 {
86  FILE *infile = NULL;
87  FILE *outfile = NULL;
88  unsigned char atom_bytes[ATOM_PREAMBLE_SIZE];
89  uint32_t atom_type = 0;
90  uint64_t atom_size = 0;
91  uint64_t atom_offset = 0;
92  uint64_t last_offset;
93  unsigned char *moov_atom = NULL;
94  unsigned char *ftyp_atom = NULL;
95  uint64_t moov_atom_size;
96  uint64_t ftyp_atom_size = 0;
97  uint64_t i, j;
98  uint32_t offset_count;
99  uint64_t current_offset;
100  int64_t start_offset = 0;
101  unsigned char *copy_buffer = NULL;
102  int bytes_to_copy;
103 
104  if (argc != 3) {
105  printf("Usage: qt-faststart <infile.mov> <outfile.mov>\n");
106  return 0;
107  }
108 
109  if (!strcmp(argv[1], argv[2])) {
110  fprintf(stderr, "input and output files need to be different\n");
111  return 1;
112  }
113 
114  infile = fopen(argv[1], "rb");
115  if (!infile) {
116  perror(argv[1]);
117  goto error_out;
118  }
119 
120  /* traverse through the atoms in the file to make sure that 'moov' is
121  * at the end */
122  while (!feof(infile)) {
123  if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
124  break;
125  }
126  atom_size = (uint32_t) BE_32(&atom_bytes[0]);
127  atom_type = BE_32(&atom_bytes[4]);
128 
129  /* keep ftyp atom */
130  if (atom_type == FTYP_ATOM) {
131  ftyp_atom_size = atom_size;
132  free(ftyp_atom);
133  ftyp_atom = malloc(ftyp_atom_size);
134  if (!ftyp_atom) {
135  printf("could not allocate %"PRIu64" bytes for ftyp atom\n",
136  atom_size);
137  goto error_out;
138  }
139  if ( fseeko(infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR)
140  || fread(ftyp_atom, atom_size, 1, infile) != 1
141  || (start_offset = ftello(infile))<0) {
142  perror(argv[1]);
143  goto error_out;
144  }
145  } else {
146  int ret;
147  /* 64-bit special case */
148  if (atom_size == 1) {
149  if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
150  break;
151  }
152  atom_size = BE_64(&atom_bytes[0]);
153  ret = fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
154  } else {
155  ret = fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
156  }
157  if(ret) {
158  perror(argv[1]);
159  goto error_out;
160  }
161  }
162  printf("%c%c%c%c %10"PRIu64" %"PRIu64"\n",
163  (atom_type >> 24) & 255,
164  (atom_type >> 16) & 255,
165  (atom_type >> 8) & 255,
166  (atom_type >> 0) & 255,
167  atom_offset,
168  atom_size);
169  if ((atom_type != FREE_ATOM) &&
170  (atom_type != JUNK_ATOM) &&
171  (atom_type != MDAT_ATOM) &&
172  (atom_type != MOOV_ATOM) &&
173  (atom_type != PNOT_ATOM) &&
174  (atom_type != SKIP_ATOM) &&
175  (atom_type != WIDE_ATOM) &&
176  (atom_type != PICT_ATOM) &&
177  (atom_type != UUID_ATOM) &&
178  (atom_type != FTYP_ATOM)) {
179  printf("encountered non-QT top-level atom (is this a QuickTime file?)\n");
180  break;
181  }
182  atom_offset += atom_size;
183 
184  /* The atom header is 8 (or 16 bytes), if the atom size (which
185  * includes these 8 or 16 bytes) is less than that, we won't be
186  * able to continue scanning sensibly after this atom, so break. */
187  if (atom_size < 8)
188  break;
189  }
190 
191  if (atom_type != MOOV_ATOM) {
192  printf("last atom in file was not a moov atom\n");
193  free(ftyp_atom);
194  fclose(infile);
195  return 0;
196  }
197 
198  /* moov atom was, in fact, the last atom in the chunk; load the whole
199  * moov atom */
200  if (fseeko(infile, -atom_size, SEEK_END)) {
201  perror(argv[1]);
202  goto error_out;
203  }
204  last_offset = ftello(infile);
205  moov_atom_size = atom_size;
206  moov_atom = malloc(moov_atom_size);
207  if (!moov_atom) {
208  printf("could not allocate %"PRIu64" bytes for moov atom\n", atom_size);
209  goto error_out;
210  }
211  if (fread(moov_atom, atom_size, 1, infile) != 1) {
212  perror(argv[1]);
213  goto error_out;
214  }
215 
216  /* this utility does not support compressed atoms yet, so disqualify
217  * files with compressed QT atoms */
218  if (BE_32(&moov_atom[12]) == CMOV_ATOM) {
219  printf("this utility does not support compressed moov atoms yet\n");
220  goto error_out;
221  }
222 
223  /* close; will be re-opened later */
224  fclose(infile);
225  infile = NULL;
226 
227  /* crawl through the moov chunk in search of stco or co64 atoms */
228  for (i = 4; i < moov_atom_size - 4; i++) {
229  atom_type = BE_32(&moov_atom[i]);
230  if (atom_type == STCO_ATOM) {
231  printf(" patching stco atom...\n");
232  atom_size = BE_32(&moov_atom[i - 4]);
233  if (i + atom_size - 4 > moov_atom_size) {
234  printf(" bad atom size\n");
235  goto error_out;
236  }
237  offset_count = BE_32(&moov_atom[i + 8]);
238  if (i + 12LL + offset_count * 4LL > moov_atom_size) {
239  printf(" bad atom size\n");
240  goto error_out;
241  }
242  for (j = 0; j < offset_count; j++) {
243  current_offset = BE_32(&moov_atom[i + 12 + j * 4]);
244  current_offset += moov_atom_size;
245  moov_atom[i + 12 + j * 4 + 0] = (current_offset >> 24) & 0xFF;
246  moov_atom[i + 12 + j * 4 + 1] = (current_offset >> 16) & 0xFF;
247  moov_atom[i + 12 + j * 4 + 2] = (current_offset >> 8) & 0xFF;
248  moov_atom[i + 12 + j * 4 + 3] = (current_offset >> 0) & 0xFF;
249  }
250  i += atom_size - 4;
251  } else if (atom_type == CO64_ATOM) {
252  printf(" patching co64 atom...\n");
253  atom_size = BE_32(&moov_atom[i - 4]);
254  if (i + atom_size - 4 > moov_atom_size) {
255  printf(" bad atom size\n");
256  goto error_out;
257  }
258  offset_count = BE_32(&moov_atom[i + 8]);
259  if (i + 12LL + offset_count * 8LL > moov_atom_size) {
260  printf(" bad atom size\n");
261  goto error_out;
262  }
263  for (j = 0; j < offset_count; j++) {
264  current_offset = BE_64(&moov_atom[i + 12 + j * 8]);
265  current_offset += moov_atom_size;
266  moov_atom[i + 12 + j * 8 + 0] = (current_offset >> 56) & 0xFF;
267  moov_atom[i + 12 + j * 8 + 1] = (current_offset >> 48) & 0xFF;
268  moov_atom[i + 12 + j * 8 + 2] = (current_offset >> 40) & 0xFF;
269  moov_atom[i + 12 + j * 8 + 3] = (current_offset >> 32) & 0xFF;
270  moov_atom[i + 12 + j * 8 + 4] = (current_offset >> 24) & 0xFF;
271  moov_atom[i + 12 + j * 8 + 5] = (current_offset >> 16) & 0xFF;
272  moov_atom[i + 12 + j * 8 + 6] = (current_offset >> 8) & 0xFF;
273  moov_atom[i + 12 + j * 8 + 7] = (current_offset >> 0) & 0xFF;
274  }
275  i += atom_size - 4;
276  }
277  }
278 
279  /* re-open the input file and open the output file */
280  infile = fopen(argv[1], "rb");
281  if (!infile) {
282  perror(argv[1]);
283  goto error_out;
284  }
285 
286  if (start_offset > 0) { /* seek after ftyp atom */
287  if (fseeko(infile, start_offset, SEEK_SET)) {
288  perror(argv[1]);
289  goto error_out;
290  }
291 
292  last_offset -= start_offset;
293  }
294 
295  outfile = fopen(argv[2], "wb");
296  if (!outfile) {
297  perror(argv[2]);
298  goto error_out;
299  }
300 
301  /* dump the same ftyp atom */
302  if (ftyp_atom_size > 0) {
303  printf(" writing ftyp atom...\n");
304  if (fwrite(ftyp_atom, ftyp_atom_size, 1, outfile) != 1) {
305  perror(argv[2]);
306  goto error_out;
307  }
308  }
309 
310  /* dump the new moov atom */
311  printf(" writing moov atom...\n");
312  if (fwrite(moov_atom, moov_atom_size, 1, outfile) != 1) {
313  perror(argv[2]);
314  goto error_out;
315  }
316 
317  /* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
318  bytes_to_copy = FFMIN(COPY_BUFFER_SIZE, last_offset);
319  copy_buffer = malloc(bytes_to_copy);
320  if (!copy_buffer) {
321  printf("could not allocate %d bytes for copy_buffer\n", bytes_to_copy);
322  goto error_out;
323  }
324  printf(" copying rest of file...\n");
325  while (last_offset) {
326  bytes_to_copy = FFMIN(bytes_to_copy, last_offset);
327 
328  if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
329  perror(argv[1]);
330  goto error_out;
331  }
332  if (fwrite(copy_buffer, bytes_to_copy, 1, outfile) != 1) {
333  perror(argv[2]);
334  goto error_out;
335  }
336  last_offset -= bytes_to_copy;
337  }
338 
339  fclose(infile);
340  fclose(outfile);
341  free(moov_atom);
342  free(ftyp_atom);
343  free(copy_buffer);
344 
345  return 0;
346 
347 error_out:
348  if (infile)
349  fclose(infile);
350  if (outfile)
351  fclose(outfile);
352  free(moov_atom);
353  free(ftyp_atom);
354  free(copy_buffer);
355  return 1;
356 }
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