抓取RTP语音流

通过freeswitch的media-bug抓取RTP语音流，udp传输到第三方语音识别等

media-bug

case SWITCH_ABC_TYPE_READ_REPLACE:
                {
                        switch_frame_t *frame;
                        if ((frame = switch_core_media_bug_get_read_replace_frame(bug))) {
                                //switch_size_t frame_len = frame->datalen / 2;
                                switch_size_t frame_dlen = frame->datalen;
                                switch_core_media_bug_set_read_replace_frame(bug, frame);
                                if (frame->channels != 1)
                                {
                                        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "nonsupport channels:%d!\n",frame->channels);
                                        return SWITCH_FALSE;
                                }
                                switch_socket_sendto(globals.sip_socket, globals.sip_server_addr, 0, frame->data, &frame_dlen);
                        }
                }
                break;

udp-server

 connection, err := net.ListenUDP("udp", &net.UDPAddr{
                IP:   net.IPv4(0, 0, 0, 0),
                Port: 9527,
        })
        if err != nil {
                fmt.Println("connection failed, err:", err)
                return
        }
        defer connection.Close()

        for {
                buffer := make([]byte, 1024)
                n, _, err := connection.ReadFromUDP(buffer)

                if err != nil {
                        fmt.Println("error:  ", err)
                        break
                } else {
                        //sendData(nlsSession, g711.EncodeUlaw(buffer[:n]))
                        //sendData(nlsSession, g711.DecodeUlaw(g711.EncodeUlaw(buffer[:n])))
                        sendData(nlsSession, buffer[:n])
                }
        }