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 <stdio.h>#include <stdlib.h>#include <inttypes.h>#include <string.h>#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   1024int 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 <infile.mov> <outfile.mov>\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]);}