mpv/stream/rtp.c

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/* Imported from the dvbstream-0.2 project
*
* Modified for use with MPlayer, for details see the changelog at
* http://svn.mplayerhq.hu/mplayer/trunk/
* $Id$
*/
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <ctype.h>
#include "config.h"
#ifndef HAVE_WINSOCK2
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define closesocket close
#else
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
#include <errno.h>
#include "stream.h"
/* MPEG-2 TS RTP stack */
#define DEBUG 1
#include "mp_msg.h"
#include "rtp.h"
// RTP reorder routines
// Also handling of repeated UDP packets (a bug of ExtremeNetworks switches firmware)
// rtpreord procedures
// write rtp packets in cache
// get rtp packets reordered
#define MAXRTPPACKETSIN 32 // The number of max packets being reordered
struct rtpbits {
unsigned int v:2; /* version: 2 */
unsigned int p:1; /* is there padding appended: 0 */
unsigned int x:1; /* number of extension headers: 0 */
unsigned int cc:4; /* number of CSRC identifiers: 0 */
unsigned int m:1; /* marker: 0 */
unsigned int pt:7; /* payload type: 33 for MPEG2 TS - RFC 1890 */
unsigned int sequence:16; /* sequence number: random */
};
struct rtpheader { /* in network byte order */
struct rtpbits b;
int timestamp; /* start: random */
int ssrc; /* random */
};
struct rtpbuffer
{
unsigned char data[MAXRTPPACKETSIN][STREAM_BUFFER_SIZE];
unsigned short seq[MAXRTPPACKETSIN];
unsigned short len[MAXRTPPACKETSIN];
unsigned short first;
};
static struct rtpbuffer rtpbuf;
static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData);
// RTP Reordering functions
// Algorithm works as follows:
// If next packet is in sequence just copy it to buffer
// Otherwise copy it in cache according to its sequence number
// Cache is a circular array where "rtpbuf.first" points to next sequence slot
// and keeps track of expected sequence
// Initialize rtp cache
static void rtp_cache_reset(unsigned short seq)
{
int i;
rtpbuf.first = 0;
rtpbuf.seq[0] = ++seq;
for (i=0; i<MAXRTPPACKETSIN; i++) {
rtpbuf.len[i] = 0;
}
}
// Write in a cache the rtp packet in right rtp sequence order
static int rtp_cache(int fd, char *buffer, int length)
{
struct rtpheader rh;
int newseq;
char *data;
unsigned short seq;
static int is_first = 1;
getrtp2(fd, &rh, &data, &length);
if(!length)
return 0;
seq = rh.b.sequence;
newseq = seq - rtpbuf.seq[rtpbuf.first];
if ((newseq == 0) || is_first)
{
is_first = 0;
//mp_msg(MSGT_NETWORK, MSGL_DBG4, "RTP (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
rtpbuf.seq[rtpbuf.first] = ++seq;
goto feed;
}
if (newseq > MAXRTPPACKETSIN)
{
mp_msg(MSGT_NETWORK, MSGL_DBG2, "Overrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
rtp_cache_reset(seq);
goto feed;
}
if (newseq < 0)
{
int i;
// Is it a stray packet re-sent to network?
for (i=0; i<MAXRTPPACKETSIN; i++) {
if (rtpbuf.seq[i] == seq) {
mp_msg(MSGT_NETWORK, MSGL_ERR, "Stray packet (seq[%d]=%d seq=%d, newseq=%d found at %d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq, i);
return 0; // Yes, it is!
}
}
// Some heuristic to decide when to drop packet or to restart everything
if (newseq > -(3 * MAXRTPPACKETSIN)) {
mp_msg(MSGT_NETWORK, MSGL_ERR, "Too Old packet (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
return 0; // Yes, it is!
}
mp_msg(MSGT_NETWORK, MSGL_ERR, "Underrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
rtp_cache_reset(seq);
goto feed;
}
mp_msg(MSGT_NETWORK, MSGL_DBG4, "Out of Seq (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
newseq = ( newseq + rtpbuf.first ) % MAXRTPPACKETSIN;
memcpy (rtpbuf.data[newseq], data, length);
rtpbuf.len[newseq] = length;
rtpbuf.seq[newseq] = seq;
return 0;
feed:
memcpy (buffer, data, length);
return length;
}
// Get next packet in cache
// Look in cache to get first packet in sequence
static int rtp_get_next(int fd, char *buffer, int length)
{
int i;
unsigned short nextseq;
// If we have empty buffer we loop to fill it
for (i=0; i < MAXRTPPACKETSIN -3; i++) {
if (rtpbuf.len[rtpbuf.first] != 0) break;
length = rtp_cache(fd, buffer, length) ;
// returns on first packet in sequence
if (length > 0) {
//mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp [%d] %hu\n", i, rtpbuf.first);
return length;
} else if (length < 0) break;
// Only if length == 0 loop continues!
}
i = rtpbuf.first;
while (rtpbuf.len[i] == 0) {
mp_msg(MSGT_NETWORK, MSGL_ERR, "Lost packet %hu\n", rtpbuf.seq[i]);
i = ( 1 + i ) % MAXRTPPACKETSIN;
if (rtpbuf.first == i) break;
}
rtpbuf.first = i;
// Copy next non empty packet from cache
mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp from cache [%d] %hu\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first]);
memcpy (buffer, rtpbuf.data[rtpbuf.first], rtpbuf.len[rtpbuf.first]);
length = rtpbuf.len[rtpbuf.first]; // can be zero?
// Reset fisrt slot and go next in cache
rtpbuf.len[rtpbuf.first] = 0;
nextseq = rtpbuf.seq[rtpbuf.first];
rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
rtpbuf.seq[rtpbuf.first] = nextseq + 1;
return length;
}
// Read next rtp packet using cache
int read_rtp_from_server(int fd, char *buffer, int length) {
// Following test is ASSERT (i.e. uneuseful if code is correct)
if(buffer==NULL || length<STREAM_BUFFER_SIZE) {
mp_msg(MSGT_NETWORK, MSGL_ERR, "RTP buffer invalid; no data return from network\n");
return 0;
}
// loop just to skip empty packets
while ((length = rtp_get_next(fd, buffer, length)) == 0) {
mp_msg(MSGT_NETWORK, MSGL_ERR, "Got empty packet from RTP cache!?\n");
}
return(length);
}
static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData) {
static char buf[1600];
unsigned int intP;
char* charP = (char*) &intP;
int headerSize;
int lengthPacket;
lengthPacket=recv(fd,buf,1590,0);
if (lengthPacket<0)
mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: socket read error\n");
else if (lengthPacket<12)
mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: packet too small (%d) to be an rtp frame (>12bytes)\n", lengthPacket);
if(lengthPacket<12) {
*lengthData = 0;
return 0;
}
rh->b.v = (unsigned int) ((buf[0]>>6)&0x03);
rh->b.p = (unsigned int) ((buf[0]>>5)&0x01);
rh->b.x = (unsigned int) ((buf[0]>>4)&0x01);
rh->b.cc = (unsigned int) ((buf[0]>>0)&0x0f);
rh->b.m = (unsigned int) ((buf[1]>>7)&0x01);
rh->b.pt = (unsigned int) ((buf[1]>>0)&0x7f);
intP = 0;
memcpy(charP+2,&buf[2],2);
rh->b.sequence = ntohl(intP);
intP = 0;
memcpy(charP,&buf[4],4);
rh->timestamp = ntohl(intP);
headerSize = 12 + 4*rh->b.cc; /* in bytes */
*lengthData = lengthPacket - headerSize;
*data = (char*) buf + headerSize;
// mp_msg(MSGT_NETWORK,MSGL_DBG2,"Reading rtp: v=%x p=%x x=%x cc=%x m=%x pt=%x seq=%x ts=%x lgth=%d\n",rh->b.v,rh->b.p,rh->b.x,rh->b.cc,rh->b.m,rh->b.pt,rh->b.sequence,rh->timestamp,lengthPacket);
return(0);
}