What are CBR, VBV and CPB?

It’s common mistake to to consider CBR (Constant Bit Rate) as “every frame is allocated the same number of bits”. If it were the case, then what would be the purpose of P or B frames? The whole purpose of P/B frame is to reduce the number of bits by referencing another frame. Of course, there are a lot of CBR streams with P or B frames. You can easily see every frame have very different number of bits even in a CBR stream.

So, what is CBR? In MPEG-2 and H.264, CBR means the number of bits fed to the decoder is constant over time. In other words, the data transfer rate to the decoder is constant. It’s nothing to do with the number of bits of individual frames.

Confused? How is it possible to allocate different number of bits to frames while keeping the incoming data rate constant?

Answer: you need a buffer. To understand the logic, consider a water outlet, a water tank, and a series of “picture decode guys” lined up in front of the tank.

The water (coded MPEG-2 or H.264 stream) is constantly flowing into the tank. The guys are lined up in front of the tank and remove the water for each frame to be decoded. The removal happens at the fixed time interval in most cases.

Even though Mr.I, P, and B are removing different amount of water (=each frame needs different number of bits), the water outlet speed is constant thanks to the tank (buffer).

In MPEG-2, the buffer is called VBV buffer (Video Buffer Verifier Buffer). In H.264, the buffer is called CPB (Coded Picture Buffer).

The water level of the tank at certain time instance is called buffer fullness and described in number of bits. The size of the tank is called VBV buffer size in MPEG-2 and CPB buffer size in H.264.

The coded stream must be constructed so that the tank (=buffer) never overflow or underflow. There are commercial/non-commercial software called “buffer verifier” to check the errors.

When the buffer size is set to large value (it’s an encoded stream parameter), the encoder can use large variance of bits for each frame which generally results in better video quality. However, the decoder needs to have the large buffer, which means more expensive hardware.

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

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

PayPal. www.paypal.com

We recommend you use Paypal to buy our items ,The Paypal is a secure way to buy on internet .

Every of our item list page bottom on top have a paypal logo to pay.

Credit Card.If you do not have paypal,but you have credit card,you also can click the Yellow PayPal button to pay with your credit card.

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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.

* 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.

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: