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 Libav 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 #endif
36 
37 #define BE_16(x) ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
38 
39 #define BE_32(x) ((((uint8_t*)(x))[0] << 24) | \
40  (((uint8_t*)(x))[1] << 16) | \
41  (((uint8_t*)(x))[2] << 8) | \
42  ((uint8_t*)(x))[3])
43 
44 #define BE_64(x) (((uint64_t)(((uint8_t*)(x))[0]) << 56) | \
45  ((uint64_t)(((uint8_t*)(x))[1]) << 48) | \
46  ((uint64_t)(((uint8_t*)(x))[2]) << 40) | \
47  ((uint64_t)(((uint8_t*)(x))[3]) << 32) | \
48  ((uint64_t)(((uint8_t*)(x))[4]) << 24) | \
49  ((uint64_t)(((uint8_t*)(x))[5]) << 16) | \
50  ((uint64_t)(((uint8_t*)(x))[6]) << 8) | \
51  ((uint64_t)( (uint8_t*)(x))[7]))
52 
53 #define BE_FOURCC(ch0, ch1, ch2, ch3) \
54  ( (uint32_t)(unsigned char)(ch3) | \
55  ((uint32_t)(unsigned char)(ch2) << 8) | \
56  ((uint32_t)(unsigned char)(ch1) << 16) | \
57  ((uint32_t)(unsigned char)(ch0) << 24) )
58 
59 #define QT_ATOM BE_FOURCC
60 /* top level atoms */
61 #define FREE_ATOM QT_ATOM('f', 'r', 'e', 'e')
62 #define JUNK_ATOM QT_ATOM('j', 'u', 'n', 'k')
63 #define MDAT_ATOM QT_ATOM('m', 'd', 'a', 't')
64 #define MOOV_ATOM QT_ATOM('m', 'o', 'o', 'v')
65 #define PNOT_ATOM QT_ATOM('p', 'n', 'o', 't')
66 #define SKIP_ATOM QT_ATOM('s', 'k', 'i', 'p')
67 #define WIDE_ATOM QT_ATOM('w', 'i', 'd', 'e')
68 #define PICT_ATOM QT_ATOM('P', 'I', 'C', 'T')
69 #define FTYP_ATOM QT_ATOM('f', 't', 'y', 'p')
70 #define UUID_ATOM QT_ATOM('u', 'u', 'i', 'd')
71 
72 #define CMOV_ATOM QT_ATOM('c', 'm', 'o', 'v')
73 #define STCO_ATOM QT_ATOM('s', 't', 'c', 'o')
74 #define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
75 
76 #define ATOM_PREAMBLE_SIZE 8
77 #define COPY_BUFFER_SIZE 1024
78 
79 int main(int argc, char *argv[])
80 {
81  FILE *infile = NULL;
82  FILE *outfile = NULL;
83  unsigned char atom_bytes[ATOM_PREAMBLE_SIZE];
84  uint32_t atom_type = 0;
85  uint64_t atom_size = 0;
86  uint64_t atom_offset = 0;
87  uint64_t last_offset;
88  unsigned char *moov_atom = NULL;
89  unsigned char *ftyp_atom = NULL;
90  uint64_t moov_atom_size;
91  uint64_t ftyp_atom_size = 0;
92  uint64_t i, j;
93  uint32_t offset_count;
94  uint64_t current_offset;
95  uint64_t start_offset = 0;
96  unsigned char copy_buffer[COPY_BUFFER_SIZE];
97  int bytes_to_copy;
98 
99  if (argc != 3) {
100  printf("Usage: qt-faststart <infile.mov> <outfile.mov>\n");
101  return 0;
102  }
103 
104  if (!strcmp(argv[1], argv[2])) {
105  fprintf(stderr, "input and output files need to be different\n");
106  return 1;
107  }
108 
109  infile = fopen(argv[1], "rb");
110  if (!infile) {
111  perror(argv[1]);
112  goto error_out;
113  }
114 
115  /* traverse through the atoms in the file to make sure that 'moov' is
116  * at the end */
117  while (!feof(infile)) {
118  if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
119  break;
120  }
121  atom_size = (uint32_t) BE_32(&atom_bytes[0]);
122  atom_type = BE_32(&atom_bytes[4]);
123 
124  /* keep ftyp atom */
125  if (atom_type == FTYP_ATOM) {
126  ftyp_atom_size = atom_size;
127  free(ftyp_atom);
128  ftyp_atom = malloc(ftyp_atom_size);
129  if (!ftyp_atom) {
130  printf("could not allocate %"PRIu64" bytes for ftyp atom\n",
131  atom_size);
132  goto error_out;
133  }
134  fseeko(infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR);
135  if (fread(ftyp_atom, atom_size, 1, infile) != 1) {
136  perror(argv[1]);
137  goto error_out;
138  }
139  start_offset = ftello(infile);
140  } else {
141 
142  /* 64-bit special case */
143  if (atom_size == 1) {
144  if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
145  break;
146  }
147  atom_size = BE_64(&atom_bytes[0]);
148  fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
149  } else {
150  fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
151  }
152  }
153  printf("%c%c%c%c %10"PRIu64" %"PRIu64"\n",
154  (atom_type >> 24) & 255,
155  (atom_type >> 16) & 255,
156  (atom_type >> 8) & 255,
157  (atom_type >> 0) & 255,
158  atom_offset,
159  atom_size);
160  if ((atom_type != FREE_ATOM) &&
161  (atom_type != JUNK_ATOM) &&
162  (atom_type != MDAT_ATOM) &&
163  (atom_type != MOOV_ATOM) &&
164  (atom_type != PNOT_ATOM) &&
165  (atom_type != SKIP_ATOM) &&
166  (atom_type != WIDE_ATOM) &&
167  (atom_type != PICT_ATOM) &&
168  (atom_type != UUID_ATOM) &&
169  (atom_type != FTYP_ATOM)) {
170  printf("encountered non-QT top-level atom (is this a QuickTime file?)\n");
171  break;
172  }
173  atom_offset += atom_size;
174 
175  /* The atom header is 8 (or 16 bytes), if the atom size (which
176  * includes these 8 or 16 bytes) is less than that, we won't be
177  * able to continue scanning sensibly after this atom, so break. */
178  if (atom_size < 8)
179  break;
180  }
181 
182  if (atom_type != MOOV_ATOM) {
183  printf("last atom in file was not a moov atom\n");
184  free(ftyp_atom);
185  fclose(infile);
186  return 0;
187  }
188 
189  /* moov atom was, in fact, the last atom in the chunk; load the whole
190  * moov atom */
191  fseeko(infile, -atom_size, SEEK_END);
192  last_offset = ftello(infile);
193  moov_atom_size = atom_size;
194  moov_atom = malloc(moov_atom_size);
195  if (!moov_atom) {
196  printf("could not allocate %"PRIu64" bytes for moov atom\n", atom_size);
197  goto error_out;
198  }
199  if (fread(moov_atom, atom_size, 1, infile) != 1) {
200  perror(argv[1]);
201  goto error_out;
202  }
203 
204  /* this utility does not support compressed atoms yet, so disqualify
205  * files with compressed QT atoms */
206  if (BE_32(&moov_atom[12]) == CMOV_ATOM) {
207  printf("this utility does not support compressed moov atoms yet\n");
208  goto error_out;
209  }
210 
211  /* close; will be re-opened later */
212  fclose(infile);
213  infile = NULL;
214 
215  /* crawl through the moov chunk in search of stco or co64 atoms */
216  for (i = 4; i < moov_atom_size - 4; i++) {
217  atom_type = BE_32(&moov_atom[i]);
218  if (atom_type == STCO_ATOM) {
219  printf(" patching stco atom...\n");
220  atom_size = BE_32(&moov_atom[i - 4]);
221  if (i + atom_size - 4 > moov_atom_size) {
222  printf(" bad atom size\n");
223  goto error_out;
224  }
225  offset_count = BE_32(&moov_atom[i + 8]);
226  for (j = 0; j < offset_count; j++) {
227  current_offset = BE_32(&moov_atom[i + 12 + j * 4]);
228  current_offset += moov_atom_size;
229  moov_atom[i + 12 + j * 4 + 0] = (current_offset >> 24) & 0xFF;
230  moov_atom[i + 12 + j * 4 + 1] = (current_offset >> 16) & 0xFF;
231  moov_atom[i + 12 + j * 4 + 2] = (current_offset >> 8) & 0xFF;
232  moov_atom[i + 12 + j * 4 + 3] = (current_offset >> 0) & 0xFF;
233  }
234  i += atom_size - 4;
235  } else if (atom_type == CO64_ATOM) {
236  printf(" patching co64 atom...\n");
237  atom_size = BE_32(&moov_atom[i - 4]);
238  if (i + atom_size - 4 > moov_atom_size) {
239  printf(" bad atom size\n");
240  goto error_out;
241  }
242  offset_count = BE_32(&moov_atom[i + 8]);
243  for (j = 0; j < offset_count; j++) {
244  current_offset = BE_64(&moov_atom[i + 12 + j * 8]);
245  current_offset += moov_atom_size;
246  moov_atom[i + 12 + j * 8 + 0] = (current_offset >> 56) & 0xFF;
247  moov_atom[i + 12 + j * 8 + 1] = (current_offset >> 48) & 0xFF;
248  moov_atom[i + 12 + j * 8 + 2] = (current_offset >> 40) & 0xFF;
249  moov_atom[i + 12 + j * 8 + 3] = (current_offset >> 32) & 0xFF;
250  moov_atom[i + 12 + j * 8 + 4] = (current_offset >> 24) & 0xFF;
251  moov_atom[i + 12 + j * 8 + 5] = (current_offset >> 16) & 0xFF;
252  moov_atom[i + 12 + j * 8 + 6] = (current_offset >> 8) & 0xFF;
253  moov_atom[i + 12 + j * 8 + 7] = (current_offset >> 0) & 0xFF;
254  }
255  i += atom_size - 4;
256  }
257  }
258 
259  /* re-open the input file and open the output file */
260  infile = fopen(argv[1], "rb");
261  if (!infile) {
262  perror(argv[1]);
263  goto error_out;
264  }
265 
266  if (start_offset > 0) { /* seek after ftyp atom */
267  fseeko(infile, start_offset, SEEK_SET);
268  last_offset -= start_offset;
269  }
270 
271  outfile = fopen(argv[2], "wb");
272  if (!outfile) {
273  perror(argv[2]);
274  goto error_out;
275  }
276 
277  /* dump the same ftyp atom */
278  if (ftyp_atom_size > 0) {
279  printf(" writing ftyp atom...\n");
280  if (fwrite(ftyp_atom, ftyp_atom_size, 1, outfile) != 1) {
281  perror(argv[2]);
282  goto error_out;
283  }
284  }
285 
286  /* dump the new moov atom */
287  printf(" writing moov atom...\n");
288  if (fwrite(moov_atom, moov_atom_size, 1, outfile) != 1) {
289  perror(argv[2]);
290  goto error_out;
291  }
292 
293  /* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
294  printf(" copying rest of file...\n");
295  while (last_offset) {
296  if (last_offset > COPY_BUFFER_SIZE)
297  bytes_to_copy = COPY_BUFFER_SIZE;
298  else
299  bytes_to_copy = last_offset;
300 
301  if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
302  perror(argv[1]);
303  goto error_out;
304  }
305  if (fwrite(copy_buffer, bytes_to_copy, 1, outfile) != 1) {
306  perror(argv[2]);
307  goto error_out;
308  }
309  last_offset -= bytes_to_copy;
310  }
311 
312  fclose(infile);
313  fclose(outfile);
314  free(moov_atom);
315  free(ftyp_atom);
316 
317  return 0;
318 
319 error_out:
320  if (infile)
321  fclose(infile);
322  if (outfile)
323  fclose(outfile);
324  free(moov_atom);
325  free(ftyp_atom);
326  return 1;
327 }