1. The principle of streaming media technology
The implementation of streaming requires buffering. Because the Internet uses packet transmission as the basis for intermittent asynchronous transmission, for a real-time A/V source or stored A/V file, they must be broken down into many packets during transmission. Since the network changes dynamically, each packet is selected. The route may be different, so the time delay to reach the client is also different, and even the first data packet may arrive later. For this reason, a caching system is used to compensate for the effects of delay and jitter, and to ensure the correct sequence of data packets, so that the media data can be output continuously without pauses in playback due to temporary network congestion. Usually the cache capacity is not large, because the cache uses a circular linked list structure to store data: by discarding the content that has been played, the stream can reuse the free cache space to cache the subsequent unplayed content.
The realization of streaming requires a suitable transmission protocol. Because TCP requires more overhead, it is not suitable for transmitting real-time data. In the implementation of streaming, HTTP/TCP is generally used to transmit control information, while RTP/UDP is used to transmit real-time sound data.
The process of streaming transmission is generally like this: After the user selects a streaming media service, the Web browser and the Web server use HTTP/TCP to exchange control information, so that the real-time data that needs to be transmitted can be retrieved from the original information; then the client The web browser on the machine starts the A/VHelper program, and uses HTTP to retrieve the relevant parameters from the Web server to initialize the Helper program. These parameters may include directory information, encoding type of A/V data, or server address related to A/V retrieval.
A/VHelper program and A/V server run real-time flow control protocol (RTSP) to exchange control information required for A/V transmission. Similar to the functions provided by CD players or VCRs, RTSP provides methods to manipulate commands such as play, fast forward, fast rewind, pause, and record. The A/V server uses the RTP/UDP protocol to transmit A/V data to the A/V client program (generally, the client program can be regarded as equivalent to the Helper program). Once the A/V data arrives at the client, the A/V client program can be played Output.
It should be noted that in streaming, two different communication protocols, RTP/UDP and RTSP/TCP, are used to establish contact with the A/V server in order to be able to redirect the output of the server to a different one from running A/VHelper. The destination address of the client where the program is located. Realization of streaming generally requires a dedicated server and player.
2. Streaming media playback method
1) Unicast
A separate data channel needs to be established between the client and the media server. Each data packet sent from a server can only be transmitted to one client. This transmission method is called unicast. Each user must send a separate query to the media server, and the media server must send a copy of the requested data packet to each user. This huge redundancy first causes a heavy burden on the server, which takes a long time to respond, and even stops playing; managers are also forced to purchase hardware and bandwidth to ensure a certain quality of service.
2) Multicast
IP multicast technology builds a network with multicast capabilities, allowing routers to copy data packets to multiple channels at once. Using multicast, a single server can send continuous data streams to hundreds of thousands of clients at the same time without delay. The media server only needs to send one information packet, not multiple; all requesting clients share the same information packet. Information can be sent to clients at any address, reducing the total amount of information packets transmitted on the network. The network utilization efficiency is greatly improved, and the cost is greatly reduced.
3) On-demand and broadcast
On-demand connection is an active connection between the client and the server. In the on-demand connection, the user initiates the client connection by selecting a content item. The user can start, stop, rewind, fast forward, or pause the stream. The on-demand connection provides the greatest control over the flow, but this method will quickly use up the network bandwidth because each client connects to the server individually.
Broadcasting refers to the passive reception of the stream by the user. During the broadcast, the client receives the stream, but cannot control the stream. For example, the user cannot pause, fast forward, or rewind the stream. In the broadcast mode, a single copy of the data packet will be sent to all users on the network. When using unicast transmission, multiple copies of the data packet need to be duplicated and sent to those users who need it in multiple point-to-point manners, while using broadcast transmission, a single copy of the data packet will be sent to all users on the network Regardless of whether the user needs it or not, the above two transmission methods are very wasteful of network bandwidth. Multicast absorbs the advantages of the above two transmission methods, overcomes the weaknesses of the above two transmission methods, and sends a single copy of the data packet to those customers who need it. Multicast does not copy multiple copies of data packets to the network, nor does it send data packets to those customers who do not need it, ensuring that multimedia applications on the network occupy the minimum bandwidth of the network.
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How far(long) the transmitter cover?
The transmission range depends on many factors. The true distance is based on the antenna installing height , antenna gain, using environment like building and other obstructions , sensitivity of the receiver, antenna of the receiver . Installing antenna more high and using in the countryside , the distance will much more far.
EXAMPLE 5W FM Transmitter use in the city and hometown:
I have a USA customer use 5W fm transmitter with GP antenna in his hometown ,and he test it with a car, it cover 10km(6.21mile).
I test the 5W fm transmitter with GP antenna in my hometown ,it cover about 2km(1.24mile).
I test the 5W fm transmitter with GP antenna in Guangzhou city ,it cover about only 300meter(984ft).
Below are the approximate range of different power FM Transmitters. ( The range is diameter )
0.1W ~ 5W FM Transmitter ：100M ~1KM
5W ~15W FM Ttransmitter : 1KM ~ 3KM
15W ~ 80W FM Transmitter : 3KM ~10KM
80W ~500W FM Transmitter : 10KM ~30KM
500W ~1000W FM Transmitter : 30KM ~ 50KM
1KW ~ 2KW FM Transmitter : 50KM ~100KM
2KW ~5KW FM Transmitter : 100KM ~150KM
5KW ~10KW FM Transmitter : 150KM ~200KM
How to contact us for the transmitter?
Call me +8618078869184 OR
Email me [email protected]
1.How far you want to cover in diameter ?
2.How tall of you tower ?
3.Where are you from ?
And we will give you more professional advice.
About Us
FMUSER.ORG is a system integration company focusing on RF wireless transmission / studio video audio equipment / streaming and data processing .We are providing everything from advice and consultancy through rack integration to installation, commissioning and training.
We offer FM Transmitter, Analog TV Transmitter, Digital TV transmitter, VHF UHF Transmitter, Antennas, Coaxial Cable Connectors, STL, On Air Processing, Broadcast Products for the Studio, RF Signal Monitoring, RDS Encoders, Audio Processors and Remote Site Control Units, IPTV Products, Video / Audio Encoder / Decoder, designed to meet the needs of both large international broadcast networks and small private stations alike.
Our solution has FM Radio Station / Analog TV Station / Digital TV Station / Audio Video Studio Equipment / Studio Transmitter Link / Transmitter Telemetry System / Hotel TV System / IPTV Live Broadcasting / Streaming Live Broadcast / Video Conference / CATV Broadcasting system.
We are using advanced technology products for all the systems, because we know the high reliability and high performance are so important for the system and solution . At the same time we also have to make sure our products system with a very reasonable price.
We have customers of public and commercial broadcasters, telecom operators and regulation authorities , and we also offer solution and products to many hundreds of smaller, local and community broadcasters .
FMUSER.ORG has been exporting more than 15 years and have clients all over the world. With 13 years experience in this field ,we have a professional team to solve customer's all kinds of problems. We dedicated in supplying the extremely reasonable pricing of professional products & services. Contact email : [email protected]
Our Factory
We have modernization of the factory . You are welcome to visit our factory when you come to China.
At present , there are already 1095 customers around the world visited our Guangzhou Tianhe office . If you come to China , you are welcome to visit us .
At Fair
This is our participation in 2012 Global Sources Hong Kong Electronics Fair . Customers from all over the world finally have a chance to get together.
Where is Fmuser ?
You can search this numbers " 23.127460034623816,113.33224654197693 " in google map , then you can find our fmuser office .
FMUSER Guangzhou office is in Tianhe District which is the center of the Canton . Very near to the Canton Fair , guangzhou railway station, xiaobei road and dashatou , only need 10 minutes if take TAXI . Welcome friends around the world to visit and negotiate .
Contact: Sky Blue
Cellphone: +8618078869184
WhatsApp: +8618078869184
Wechat: +8618078869184
E-mail: [email protected]
QQ: 727926717
Skype: sky198710021
Address: No.305 Room HuiLan Building No.273 Huanpu Road Guangzhou China Zip:510620
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English: We accept all payments , such as PayPal, Credit Card, Western Union, Alipay, Money Bookers, T/T, LC, DP, DA, OA, Payoneer, If you have any question , please contact me [email protected] or WhatsApp +8618078869184
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Every of our item list page bottom on top have a paypal logo to pay.
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But if you have not a credit card and not have a paypal account or difficult to got a paypal accout ,You can use the following:
Western Union.  www.westernunion.com
Pay by Western Union to me :
First name/Given name: Yingfeng
Last name/Surname/ Family name: Zhang
Full name: Yingfeng Zhang
Country: China
City: Guangzhou
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T/T . Pay by T/T (wire transfer/ Telegraphic Transfer/ Bank Transfer)
First BANK INFORMATION (COMPANY ACCOUNT):
SWIFT BIC: BKCHHKHHXXX
Bank name: BANK OF CHINA (HONG KONG) LIMITED, HONG KONG
Bank Address: BANK OF CHINA TOWER, 1 GARDEN ROAD, CENTRAL, HONG KONG
BANK CODE: 012
Account Name : FMUSER INTERNATIONAL GROUP LIMITED
Account NO. : 012-676-2-007855-0
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Second BANK INFORMATION (COMPANY ACCOUNT):
Beneficiary: Fmuser International Group Inc
Account Number: 44050158090900000337
Beneficiary's Bank: China Construction Bank Guangdong Branch
SWIFT Code: PCBCCNBJGDX
Address: NO.553 Tianhe Road, Guangzhou, Guangdong,Tianhe District, China
**Note: When you transfer money to our bank account, please DO NOT write anything in the remark area, otherwise we won't be able to receive the payment due to government policy on international trade business.
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* It will be sent in 1-2 working days when payment clear.
* We will send it to your paypal address. If you want to change address, please send your correct address and phone number to my email [email protected]
* If the packages is below 2kg,we will be shipped via post airmail, it will take about 15-25days to your hand.
If the package is more than 2kg,we will ship via EMS , DHL , UPS, Fedex fast express delivery,it will take about 7~15days to your hand.
If the package more than 100kg , we will send via DHL or air freight. It will take about 3~7days to your hand.
All the packages are form China guangzhou.
* Package will be sent as a "gift" and declear as less as possible,buyer don't need to pay for "TAX".
* After ship, we will send you an E-mail and give you the tracking number.
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For Warranty .
Contact US--->>Return the item to us--->>Receive and send another replace .
Name: Liu xiaoxia
Address: 305Fang HuiLanGe HuangPuDaDaoXi 273Hao TianHeQu Guangzhou China.
ZIP:510620
Phone: +8618078869184
Please return to this address and write your paypal address,name,problem on note: |
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