static struct rtmp_packet_t* rtmp_packet_parse(struct rtmp_t* rtmp, const uint8_t* buffer)
{
uint8_t fmt = 0;
uint32_t cid = 0;
struct rtmp_packet_t* packet;
// chunk base header
buffer += rtmp_chunk_basic_header_read(buffer, &fmt, &cid);
// load previous header
packet = rtmp_packet_find(rtmp, cid);
if (NULL == packet)
{
if (RTMP_CHUNK_TYPE_0 != fmt && RTMP_CHUNK_TYPE_1 != fmt)
return NULL; // don't know stream length
packet = rtmp_packet_create(rtmp, cid);
if (NULL == packet)
return NULL;
}
// chunk message header
packet->header.cid = cid;
packet->header.fmt = fmt;
rtmp_chunk_message_header_read(buffer, &packet->header);
return packet;
}
static struct rtmp_packet_t* rtmp_packet_create(struct rtmp_t* rtmp, uint32_t cid)
{
uint32_t i;
struct rtmp_packet_t* pkt;
// The protocol supports up to 65597 streams with IDs 3-65599
assert(cid <= 65535 + 64 && cid >= 2 /* Protocol Control Messages */);
assert(NULL == rtmp_packet_find(rtmp, cid));
for (i = 0; i < N_CHUNK_STREAM; i++)
{
pkt = rtmp->in_packets + ((i + cid) % N_CHUNK_STREAM);
if (0 == pkt->header.cid)
return pkt;
}
return NULL;
}
static const struct rtmp_chunk_header_t* rtmp_chunk_header_zip(struct rtmp_t* rtmp, const struct rtmp_chunk_header_t* header)
{
struct rtmp_packet_t* pkt; // previous saved chunk header
struct rtmp_chunk_header_t h;
assert(0 != header->cid && 1 != header->cid);
assert(RTMP_CHUNK_TYPE_0 == header->fmt || RTMP_CHUNK_TYPE_1 == header->fmt);
memcpy(&h, header, sizeof(h));
// find previous chunk header
pkt = rtmp_packet_find(rtmp, h.cid);
if (NULL == pkt)
{
//pkt = rtmp_packet_create(rtmp, h.cid);
//if (NULL == pkt)
// return NULL; // too many chunk stream id
assert(0);
return NULL; // can't find chunk stream id
}
h.fmt = RTMP_CHUNK_TYPE_0;
if (RTMP_CHUNK_TYPE_0 != header->fmt /* enable compress */
&& header->cid == pkt->header.cid /* not the first packet */
&& header->timestamp >= pkt->clock /* timestamp wrap */
&& header->timestamp - pkt->clock < 0xFFFFFF /* timestamp delta < 1 << 24 */
&& header->stream_id == pkt->header.stream_id /* message stream id */)
{
h.fmt = RTMP_CHUNK_TYPE_1;
h.timestamp -= pkt->clock; // timestamp delta
if (header->type == pkt->header.type && header->length == pkt->header.length)
{
h.fmt = RTMP_CHUNK_TYPE_2;
if (h.timestamp == pkt->header.timestamp)
h.fmt = RTMP_CHUNK_TYPE_3;
}
}
memcpy(&pkt->header, &h, sizeof(h));
pkt->clock = header->timestamp; // save timestamp
return &pkt->header;
}
