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ffmpeg / libavformat / rtpproto.c @ d7fb5a18

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/*
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 * RTP network protocol
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 * Copyright (c) 2002 Fabrice Bellard.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file rtpproto.c
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 * RTP protocol
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 */
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#include "libavutil/avstring.h"
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#include "avformat.h"
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#include <unistd.h>
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#include <stdarg.h>
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#include "network.h"
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#include "os_support.h"
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#include <fcntl.h>
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#ifdef HAVE_SYS_SELECT_H
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#include <sys/select.h>
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#endif
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#define RTP_TX_BUF_SIZE  (64 * 1024)
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#define RTP_RX_BUF_SIZE  (128 * 1024)
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typedef struct RTPContext {
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    URLContext *rtp_hd, *rtcp_hd;
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    int rtp_fd, rtcp_fd;
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} RTPContext;
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/**
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 * If no filename is given to av_open_input_file because you want to
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 * get the local port first, then you must call this function to set
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 * the remote server address.
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 *
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 * @param s1 media file context
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 * @param uri of the remote server
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 * @return zero if no error.
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 */
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int rtp_set_remote_url(URLContext *h, const char *uri)
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{
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    RTPContext *s = h->priv_data;
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    char hostname[256];
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    int port;
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    char buf[1024];
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    char path[1024];
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    url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,
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              path, sizeof(path), uri);
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    snprintf(buf, sizeof(buf), "udp://%s:%d%s", hostname, port, path);
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    udp_set_remote_url(s->rtp_hd, buf);
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    snprintf(buf, sizeof(buf), "udp://%s:%d%s", hostname, port + 1, path);
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    udp_set_remote_url(s->rtcp_hd, buf);
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    return 0;
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}
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/**
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 * add option to url of the form:
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 * "http://host:port/path?option1=val1&option2=val2...
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 */
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static void url_add_option(char *buf, int buf_size, const char *fmt, ...)
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{
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    char buf1[1024];
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    va_list ap;
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    va_start(ap, fmt);
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    if (strchr(buf, '?'))
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        av_strlcat(buf, "&", buf_size);
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    else
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        av_strlcat(buf, "?", buf_size);
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    vsnprintf(buf1, sizeof(buf1), fmt, ap);
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    av_strlcat(buf, buf1, buf_size);
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    va_end(ap);
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}
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static void build_udp_url(char *buf, int buf_size,
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                          const char *hostname, int port,
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                          int local_port, int ttl,
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                          int max_packet_size)
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{
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    snprintf(buf, buf_size, "udp://%s:%d", hostname, port);
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    if (local_port >= 0)
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        url_add_option(buf, buf_size, "localport=%d", local_port);
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    if (ttl >= 0)
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        url_add_option(buf, buf_size, "ttl=%d", ttl);
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    if (max_packet_size >=0)
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        url_add_option(buf, buf_size, "pkt_size=%d", max_packet_size);
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}
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/**
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 * url syntax: rtp://host:port[?option=val...]
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 * option: 'ttl=n'       : set the ttl value (for multicast only)
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 *         'localport=n' : set the local port to n
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 *         'pkt_size=n'  : set max packet size
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 *
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 */
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static int rtp_open(URLContext *h, const char *uri, int flags)
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{
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    RTPContext *s;
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    int port, is_output, ttl, local_port, max_packet_size;
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    char hostname[256];
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    char buf[1024];
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    char path[1024];
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    const char *p;
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    is_output = (flags & URL_WRONLY);
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    s = av_mallocz(sizeof(RTPContext));
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    if (!s)
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        return AVERROR(ENOMEM);
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    h->priv_data = s;
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    url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,
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              path, sizeof(path), uri);
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    /* extract parameters */
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    ttl = -1;
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    local_port = -1;
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    max_packet_size = -1;
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    p = strchr(uri, '?');
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    if (p) {
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        if (find_info_tag(buf, sizeof(buf), "ttl", p)) {
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            ttl = strtol(buf, NULL, 10);
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        }
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        if (find_info_tag(buf, sizeof(buf), "localport", p)) {
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            local_port = strtol(buf, NULL, 10);
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        }
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        if (find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
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            max_packet_size = strtol(buf, NULL, 10);
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        }
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    }
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    build_udp_url(buf, sizeof(buf),
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                  hostname, port, local_port, ttl, max_packet_size);
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    if (url_open(&s->rtp_hd, buf, flags) < 0)
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        goto fail;
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    local_port = udp_get_local_port(s->rtp_hd);
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    /* XXX: need to open another connection if the port is not even */
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    /* well, should suppress localport in path */
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    build_udp_url(buf, sizeof(buf),
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                  hostname, port + 1, local_port + 1, ttl, max_packet_size);
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    if (url_open(&s->rtcp_hd, buf, flags) < 0)
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        goto fail;
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    /* just to ease handle access. XXX: need to suppress direct handle
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       access */
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    s->rtp_fd = udp_get_file_handle(s->rtp_hd);
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    s->rtcp_fd = udp_get_file_handle(s->rtcp_hd);
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    h->max_packet_size = url_get_max_packet_size(s->rtp_hd);
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    h->is_streamed = 1;
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    return 0;
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 fail:
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    if (s->rtp_hd)
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        url_close(s->rtp_hd);
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    if (s->rtcp_hd)
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        url_close(s->rtcp_hd);
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    av_free(s);
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    return AVERROR(EIO);
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}
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static int rtp_read(URLContext *h, uint8_t *buf, int size)
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{
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    RTPContext *s = h->priv_data;
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    struct sockaddr_in from;
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    socklen_t from_len;
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    int len, fd_max, n;
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    fd_set rfds;
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#if 0
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    for(;;) {
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        from_len = sizeof(from);
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        len = recvfrom (s->rtp_fd, buf, size, 0,
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                        (struct sockaddr *)&from, &from_len);
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        if (len < 0) {
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            if (ff_neterrno() == FF_NETERROR(EAGAIN) ||
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                ff_neterrno() == FF_NETERROR(EINTR))
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                continue;
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            return AVERROR(EIO);
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        }
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        break;
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    }
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#else
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    for(;;) {
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        /* build fdset to listen to RTP and RTCP packets */
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        FD_ZERO(&rfds);
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        fd_max = s->rtp_fd;
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        FD_SET(s->rtp_fd, &rfds);
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        if (s->rtcp_fd > fd_max)
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            fd_max = s->rtcp_fd;
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        FD_SET(s->rtcp_fd, &rfds);
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        n = select(fd_max + 1, &rfds, NULL, NULL, NULL);
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        if (n > 0) {
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            /* first try RTCP */
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            if (FD_ISSET(s->rtcp_fd, &rfds)) {
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                from_len = sizeof(from);
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                len = recvfrom (s->rtcp_fd, buf, size, 0,
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                                (struct sockaddr *)&from, &from_len);
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                if (len < 0) {
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                    if (ff_neterrno() == FF_NETERROR(EAGAIN) ||
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                        ff_neterrno() == FF_NETERROR(EINTR))
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                        continue;
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                    return AVERROR(EIO);
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                }
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                break;
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            }
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            /* then RTP */
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            if (FD_ISSET(s->rtp_fd, &rfds)) {
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                from_len = sizeof(from);
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                len = recvfrom (s->rtp_fd, buf, size, 0,
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                                (struct sockaddr *)&from, &from_len);
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                if (len < 0) {
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                    if (ff_neterrno() == FF_NETERROR(EAGAIN) ||
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                        ff_neterrno() == FF_NETERROR(EINTR))
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                        continue;
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                    return AVERROR(EIO);
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                }
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                break;
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            }
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        }
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    }
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#endif
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    return len;
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}
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static int rtp_write(URLContext *h, uint8_t *buf, int size)
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{
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    RTPContext *s = h->priv_data;
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    int ret;
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    URLContext *hd;
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    if (buf[1] >= 200 && buf[1] <= 204) {
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        /* RTCP payload type */
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        hd = s->rtcp_hd;
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    } else {
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        /* RTP payload type */
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        hd = s->rtp_hd;
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    }
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    ret = url_write(hd, buf, size);
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#if 0
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    {
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        struct timespec ts;
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        ts.tv_sec = 0;
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        ts.tv_nsec = 10 * 1000000;
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        nanosleep(&ts, NULL);
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    }
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#endif
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    return ret;
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}
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static int rtp_close(URLContext *h)
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{
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    RTPContext *s = h->priv_data;
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    url_close(s->rtp_hd);
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    url_close(s->rtcp_hd);
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    av_free(s);
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    return 0;
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}
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/**
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 * Return the local port used by the RTP connection
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 * @param s1 media file context
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 * @return the local port number
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 */
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int rtp_get_local_port(URLContext *h)
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{
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    RTPContext *s = h->priv_data;
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    return udp_get_local_port(s->rtp_hd);
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}
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/**
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 * Return the rtp and rtcp file handles for select() usage to wait for
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 * several RTP streams at the same time.
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 * @param h media file context
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 */
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void rtp_get_file_handles(URLContext *h, int *prtp_fd, int *prtcp_fd)
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{
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    RTPContext *s = h->priv_data;
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    *prtp_fd = s->rtp_fd;
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    *prtcp_fd = s->rtcp_fd;
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}
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URLProtocol rtp_protocol = {
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    "rtp",
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    rtp_open,
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    rtp_read,
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    rtp_write,
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    NULL, /* seek */
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    rtp_close,
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};