#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <stdint.h>
#define FLVF_HEADER 1
#define FLVF_SCRIPT 2
struct flvhdr
{
char fh_magic[3];
char fh_version;
char fh_flags;
char fh_hlen[4];
char fh_pads[4];
}__attribute__((packed));
struct taghdr
{
uint8_t th_type;
uint8_t th_dlen[3];
uint8_t th_tstamp[3];
uint8_t th_xstamp;
uint8_t th_streamid[3];
}__attribute__((packed));
struct flvcombine
{
FILE * fc_file;
uint32_t fc_flags;
uint32_t fc_timestamp;
uint32_t fc_filesize;
double fc_duration;
int fc_filesize_offset;
int fc_duration_offset;
};
/* duration, filesize */
uint32_t buftoint(const void *buf, size_t len)
{
uint32_t bufint = 0;
const uint8_t *pval = (const uint8_t *)buf;
while (len-- > 0)
bufint = (bufint << 8) + *pval++;
return bufint;
}
int dd_copy(FILE * dst_fp, FILE * src_fp, size_t dlen)
{
size_t len;
char buf[64 * 1024];
while (dlen > 0 && !feof(src_fp)) {
len = fread(buf, 1, dlen < sizeof(buf)? dlen: sizeof(buf), src_fp);
if (fwrite(buf, 1, len, dst_fp) != len)
break;
dlen -= len;
}
return dlen;
}
void adjtimestamp(struct taghdr *header, uint32_t stampbase)
{
uint32_t netval = 0;
uint32_t adjtime = stampbase;
adjtime += buftoint(&header->th_tstamp, sizeof(header->th_tstamp));
adjtime += (header->th_xstamp << 24);
header->th_xstamp = (adjtime >> 24);
header->th_tstamp[0] = (adjtime >> 16);
header->th_tstamp[1] = (adjtime >> 8);
header->th_tstamp[2] = (adjtime >> 0);
}
void update_metainfo(struct flvcombine *combine, FILE *fp, size_t dlen)
{
int i;
size_t len;
char *pmem = NULL;
char buf[256 * 1024];
double duration = 0.0;
uint8_t duration_bytes[8];
printf("dlen: %d\n", dlen);
assert (dlen < (256 * 1024));
len = fread(buf, 1, dlen < sizeof(buf)? dlen: sizeof(buf), fp);
if (len == 0)
return;
pmem = (char *)memmem(buf, len, "duration", 8);
if (pmem == NULL || pmem + 17l - buf > len)
return;
memcpy(&duration_bytes, pmem + 9, 8);
for (i = 0; i < 4; i ++) {
uint8_t tmp = duration_bytes[i];
duration_bytes[i] = duration_bytes[7 - i];
duration_bytes[7 - i] = tmp;
}
memcpy(&duration, &duration_bytes, 8);
combine->fc_duration += duration;
if (combine->fc_flags & FLVF_SCRIPT)
return;
combine->fc_duration_offset =
combine->fc_filesize + (pmem + 9l - buf) + sizeof(struct taghdr);
pmem = (char *)memmem(buf, len, "filesize", 8);
if (pmem == NULL || pmem + 17l - buf > len)
return;
combine->fc_filesize_offset =
combine->fc_filesize + (pmem + 9l - buf) + sizeof(struct taghdr);
}
int addflv(struct flvcombine *combine, const char *path)
{
int error = 0;
FILE *fp, *fout;
char magic[4];
long savepos;
size_t len, dlen, flags;
struct flvhdr header;
struct taghdr *last;
struct taghdr tagvideo;
struct taghdr tagaudio;
struct taghdr tagheader;
fp = fopen(path, "rb");
fout = combine->fc_file;
if (fp == NULL || fout == NULL)
return 0;
last = NULL;
memset(magic, 0, sizeof(magic));
memset(&tagvideo, 0, sizeof(tagvideo));
memset(&tagaudio, 0, sizeof(tagaudio));
if ( !fread(&header, sizeof(header), 1, fp) )
goto fail;
memcpy(magic, header.fh_magic, 3);
if ( strcmp("FLV", magic) )
goto fail;
if ((combine->fc_flags & FLVF_HEADER) == 0) {
fwrite(&header, sizeof(header), 1, fout);
combine->fc_filesize += sizeof(header);
combine->fc_flags |= FLVF_HEADER;
}
printf("magic: %s\n", magic);
printf("flags: 0x%02x\n", header.fh_flags);
printf("version: 0x%02x\n", header.fh_version);
printf("header len: %d\n", buftoint(header.fh_hlen, sizeof(header.fh_hlen)));
while (feof(fp) == 0) {
if ( !fread(&tagheader, sizeof(tagheader), 1, fp) )
goto fail;
dlen = buftoint(tagheader.th_dlen, sizeof(tagheader.th_dlen));
switch (tagheader.th_type)
{
case 0x09:
adjtimestamp(&tagheader, combine->fc_timestamp);
tagvideo = tagheader;
last = &tagvideo;
break;
case 0x08:
adjtimestamp(&tagheader, combine->fc_timestamp);
tagaudio = tagheader;
last = &tagaudio;
break;
default:
flags = combine->fc_flags;
savepos = ftell(fp);
if (savepos == -1)
goto fail;
savepos = (flags & FLVF_SCRIPT)? (savepos + dlen + 4): savepos;
update_metainfo(combine, fp, dlen);
combine->fc_flags |= FLVF_SCRIPT;
if ( fseek(fp, savepos, SEEK_SET) )
goto fail;
if (flags & FLVF_SCRIPT)
continue;
break;
}
fwrite(&tagheader, sizeof(tagheader), 1, fout);
combine->fc_filesize += sizeof(tagheader);
combine->fc_filesize += (dlen + 4);
if ( dd_copy(fout, fp, dlen + 4)) {
error = -__LINE__;
break;
}
}
fail:
fclose(fp);
if (last == &tagvideo || last == &tagaudio) {
combine->fc_timestamp = buftoint(last->th_tstamp, sizeof(last->th_tstamp));
combine->fc_timestamp |= (last->th_xstamp << 24);
printf("time stamp: %d\n", combine->fc_timestamp);
}
return 0;
}
void fixedflv(struct flvcombine *context)
{
int i;
double dblval = 0.0;
uint8_t dblbytes[8];
FILE *fout = context->fc_file;
if (context->fc_filesize_offset > 0) {
if ( fseek(fout, context->fc_filesize_offset, SEEK_SET) )
return;
dblval = context->fc_filesize;
memcpy(dblbytes, &dblval, 8);
for (i = 0; i < 4; i ++) {
uint8_t tmp = dblbytes[i];
dblbytes[i] = dblbytes[7 - i];
dblbytes[7 - i] = tmp;
}
fwrite(dblbytes, 8, 1, fout);
}
if (context->fc_duration_offset > 0) {
if ( fseek(fout, context->fc_duration_offset, SEEK_SET) )
return;
dblval = context->fc_duration;
memcpy(dblbytes, &dblval, 8);
for (i = 0; i < 4; i ++) {
uint8_t tmp = dblbytes[i];
dblbytes[i] = dblbytes[7 - i];
dblbytes[7 - i] = tmp;
}
fwrite(dblbytes, 8, 1, fout);
}
}
int main(int argc, char *argv[])
{
int i;
struct flvcombine context;
memset(&context, 0, sizeof(context));
context.fc_file = fopen("out.flv", "wb");
if (context.fc_file == NULL)
return -1;
context.fc_duration = 0;
for (i = 1; i < argc; i++)
addflv(&context, argv[i]);
fixedflv(&context);
fclose(context.fc_file); printf("seconds: %d\n", context.fc_timestamp);
return 0;
}
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