mp4文件moov atom放置在mdat atom之前 代码实现
使用nginx搭建http mp4/flv流媒体服务器，要求mp4文件moov atom要放置在mdat atom前，才能边下载边播放。参考php-qtfaststart项目，测试代码如下：
#include
#include
#include
#include
#ifdef __MINGW32__
#define fseeko(x, y, z) fseeko64(x, y, z)
#define ftello(x) ftello64(x)
#endif
#define BE_16(x) ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
#define BE_32(x) ((((uint8_t*)(x))[0] << 24) | \
(((uint8_t*)(x))[1] << 16) | \
(((uint8_t*)(x))[2] << 8) | \
((uint8_t*)(x))[3])
#define BE_64(x) (((uint64_t)(((uint8_t*)(x))[0]) << 56) | \
((uint64_t)(((uint8_t*)(x))[1]) << 48) | \
((uint64_t)(((uint8_t*)(x))[2]) << 40) | \
((uint64_t)(((uint8_t*)(x))[3]) << 32) | \
((uint64_t)(((uint8_t*)(x))[4]) << 24) | \
((uint64_t)(((uint8_t*)(x))[5]) << 16) | \
((uint64_t)(((uint8_t*)(x))[6]) << 8) | \
((uint64_t)( (uint8_t*)(x))[7]))
#define BE_FOURCC(ch0, ch1, ch2, ch3) \
( (uint32_t)(unsigned char)(ch3) | \
((uint32_t)(unsigned char)(ch2) << 8) | \
((uint32_t)(unsigned char)(ch1) << 16) | \
((uint32_t)(unsigned char)(ch0) << 24) )
#define QT_ATOM BE_FOURCC
/* top level atoms */
#define FREE_ATOM QT_ATOM('f', 'r', 'e', 'e')
#define JUNK_ATOM QT_ATOM('j', 'u', 'n', 'k')
#define MDAT_ATOM QT_ATOM('m', 'd', 'a', 't')
#define MOOV_ATOM QT_ATOM('m', 'o', 'o', 'v')
#define PNOT_ATOM QT_ATOM('p', 'n', 'o', 't')
#define SKIP_ATOM QT_ATOM('s', 'k', 'i', 'p')
#define WIDE_ATOM QT_ATOM('w', 'i', 'd', 'e')
#define PICT_ATOM QT_ATOM('P', 'I', 'C', 'T')
#define FTYP_ATOM QT_ATOM('f', 't', 'y', 'p')
#define UUID_ATOM QT_ATOM('u', 'u', 'i', 'd')
#define CMOV_ATOM QT_ATOM('c', 'm', 'o', 'v')
#define STCO_ATOM QT_ATOM('s', 't', 'c', 'o')
#define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
#define ATOM_PREAMBLE_SIZE 8
#define COPY_BUFFER_SIZE 1024
int do_faststart(char *in, char *out)
{
FILE *infile = NULL;
FILE *outfile = NULL;
unsigned char atom_bytes[ATOM_PREAMBLE_SIZE];
uint32_t atom_type = 0;
uint64_t atom_size = 0;
uint64_t atom_offset = 0;
uint64_t last_offset;
unsigned char *moov_atom = NULL;
unsigned char *ftyp_atom = NULL;
uint64_t moov_atom_size;
uint64_t ftyp_atom_size = 0;
uint64_t i, j;
uint32_t offset_count;
uint64_t current_offset;
uint64_t start_offset = 0;
uint64_t moov_offset = 0;
uint64_t moov_size = 0;
uint64_t mdat_offset = 0;
uint64_t mdat_size = 0;
unsigned char copy_buffer[COPY_BUFFER_SIZE];
int bytes_to_copy;
infile = fopen(in, "rb");
if (!infile) {
//perror(in);
goto error_out;
}
/* traverse through the atoms in the file to make sure that 'moov' is
* at the end */
while (!feof(infile)) {
if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
break;
}
atom_size = (uint32_t) BE_32(&atom_bytes[0]);
atom_type = BE_32(&atom_bytes[4]);
/* keep ftyp atom */
if (atom_type == FTYP_ATOM) {
ftyp_atom_size = atom_size;
free(ftyp_atom);
ftyp_atom = malloc(ftyp_atom_size);
if (!ftyp_atom) {
//printf("could not allocate %"PRIu64" bytes for ftyp atom\n",atom_size);
goto error_out;
}
fseeko(infile, -ATOM_PREAMBLE_SIZE, SEEK_CUR);
if (fread(ftyp_atom, atom_size, 1, infile) != 1) {
//perror(in);
goto error_out;
}
start_offset = ftello(infile);
} else {
/* 64-bit special case */
if (atom_size == 1) {
if (fread(atom_bytes, ATOM_PREAMBLE_SIZE, 1, infile) != 1) {
break;
}
atom_size = BE_64(&atom_bytes[0]);
fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE * 2, SEEK_CUR);
} else {
fseeko(infile, atom_size - ATOM_PREAMBLE_SIZE, SEEK_CUR);
}
}
printf("%c%c%c%c %10"PRIu64" %"PRIu64"\n",
(atom_type >> 24) & 255,
(atom_type >> 16) & 255,
(atom_type >> 8) & 255,
(atom_type >> 0) & 255,
atom_offset,
atom_size);
if(atom_type == MOOV_ATOM){
moov_offset = atom_offset;
moov_size = atom_size;
}else if(atom_type == MDAT_ATOM){
mdat_offset = atom_offset;
mdat_size = atom_size;
}
if ((atom_type != FREE_ATOM) &&
(atom_type != JUNK_ATOM) &&
(atom_type != MDAT_ATOM) &&
(atom_type != MOOV_ATOM) &&
(atom_type != PNOT_ATOM) &&
(atom_type != SKIP_ATOM) &&
(atom_type != WIDE_ATOM) &&
(atom_type != PICT_ATOM) &&
(atom_type != UUID_ATOM) &&
(atom_type != FTYP_ATOM)) {
//printf("encountered non-QT top-level atom (is this a QuickTime file?)\n");
break;
}
atom_offset += atom_size;
/* The atom header is 8 (or 16 bytes), if the atom size (which
* includes these 8 or 16 bytes) is less than that, we won't be
* able to continue scanning sensibly after this atom, so break. */
if (atom_size < 8)
break;
}
/*
if (atom_type != MOOV_ATOM) {
printf("last atom in file was not a moov atom\n");
free(ftyp_atom);
fclose(infile);
return 0;
}*/
if(moov_offset < mdat_offset){
printf("moov atom is before in mdat atom\n");
free(ftyp_atom);
fclose(infile);
return 0;
}
if(moov_offset == 0 || moov_size == 0){
printf("don't found moov atom in file\n");
free(ftyp_atom);
fclose(infile);
return 0;
}
/* moov atom was, in fact, the last atom in the chunk; load the whole
* moov atom */
//fseeko(infile, -atom_size, SEEK_END);
fseeko(infile, moov_offset, SEEK_SET);
printf("seek to moov atom:%x\n",moov_offset);
last_offset = ftello(infile);
//moov_atom_size = atom_size;
moov_atom_size = moov_size;
moov_atom = malloc(moov_atom_size);
if (!moov_atom) {
//printf("could not allocate %"PRIu64" bytes for moov atom\n", atom_size);
goto error_out;
}
if (fread(moov_atom, moov_atom_size, 1, infile) != 1) {
//perror(in);
goto error_out;
}
/* this utility does not support compressed atoms yet, so disqualify
* files with compressed QT atoms */
if (BE_32(&moov_atom[12]) == CMOV_ATOM) {
//printf("this utility does not support compressed moov atoms yet\n");
goto error_out;
}
/* close; will be re-opened later */
fclose(infile);
infile = NULL;
/* crawl through the moov chunk in search of stco or co64 atoms */
for (i = 4; i < moov_atom_size - 4; i++) {
atom_type = BE_32(&moov_atom[i]);
if (atom_type == STCO_ATOM) {
printf(" patching stco atom...\n");
atom_size = BE_32(&moov_atom[i - 4]);
if (i + atom_size - 4 > moov_atom_size) {
//printf(" bad atom size\n");
goto error_out;
}
offset_count = BE_32(&moov_atom[i + 8]);
for (j = 0; j < offset_count; j++) {
current_offset = BE_32(&moov_atom[i + 12 + j * 4]);
current_offset += moov_atom_size;
moov_atom[i + 12 + j * 4 + 0] = (current_offset >> 24) & 0xFF;
moov_atom[i + 12 + j * 4 + 1] = (current_offset >> 16) & 0xFF;
moov_atom[i + 12 + j * 4 + 2] = (current_offset >> 8) & 0xFF;
moov_atom[i + 12 + j * 4 + 3] = (current_offset >> 0) & 0xFF;
}
i += atom_size - 4;
} else if (atom_type == CO64_ATOM) {
printf(" patching co64 atom...\n");
atom_size = BE_32(&moov_atom[i - 4]);
if (i + atom_size - 4 > moov_atom_size) {
//printf(" bad atom size\n");
goto error_out;
}
offset_count = BE_32(&moov_atom[i + 8]);
for (j = 0; j < offset_count; j++) {
current_offset = BE_64(&moov_atom[i + 12 + j * 8]);
current_offset += moov_atom_size;
moov_atom[i + 12 + j * 8 + 0] = (current_offset >> 56) & 0xFF;
moov_atom[i + 12 + j * 8 + 1] = (current_offset >> 48) & 0xFF;
moov_atom[i + 12 + j * 8 + 2] = (current_offset >> 40) & 0xFF;
moov_atom[i + 12 + j * 8 + 3] = (current_offset >> 32) & 0xFF;
moov_atom[i + 12 + j * 8 + 4] = (current_offset >> 24) & 0xFF;
moov_atom[i + 12 + j * 8 + 5] = (current_offset >> 16) & 0xFF;
moov_atom[i + 12 + j * 8 + 6] = (current_offset >> 8) & 0xFF;
moov_atom[i + 12 + j * 8 + 7] = (current_offset >> 0) & 0xFF;
}
i += atom_size - 4;
}
}
/* re-open the input file and open the output file */
infile = fopen(in, "rb");
if (!infile) {
//perror(in);
goto error_out;
}
if (start_offset > 0) { /* seek after ftyp atom */
fseeko(infile, start_offset, SEEK_SET);
last_offset -= start_offset;
}
fseeko(infile, start_offset, SEEK_SET);
outfile = fopen(out, "wb");
if (!outfile) {
//perror(out);
goto error_out;
}
/* dump the same ftyp atom */
if (ftyp_atom_size > 0) {
//printf(" writing ftyp atom...\n");
if (fwrite(ftyp_atom, ftyp_atom_size, 1, outfile) != 1) {
//perror(out);
goto error_out;
}
}
/* dump the new moov atom */
//printf(" writing moov atom...\n");
if (fwrite(moov_atom, moov_atom_size, 1, outfile) != 1) {
//perror(out);
goto error_out;
}
/* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
//printf(" copying rest of file...\n");
while (last_offset) {
if (last_offset > COPY_BUFFER_SIZE)
bytes_to_copy = COPY_BUFFER_SIZE;
else
bytes_to_copy = last_offset;
if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
//perror(in);
goto error_out;
}
if (fwrite(copy_buffer, bytes_to_copy, 1, outfile) != 1) {
//perror(out);
goto error_out;
}
last_offset -= bytes_to_copy;
}
fclose(infile);
fclose(outfile);
free(moov_atom);
free(ftyp_atom);
return 0;
error_out:
printf("transcode %s to %s failed.\n",in, out);
if (infile)
fclose(infile);
if (outfile)
fclose(outfile);
free(moov_atom);
free(ftyp_atom);
return 1;
}
int main(int argc, char *argv[])
{
if (argc != 3) {
printf("Usage: qt-faststart \n");
return 0;
}
if (!strcmp(argv[1], argv[2])) {
fprintf(stderr, "input and output files need to be different\n");
return 1;
}
return do_faststart(argv[1],argv[2]);
}