CBR & VBR

Constant bit rate (CBR)

When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant.
CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity.

Encode according to a fixed bit rate.

In the case of streaming video as a CBR, the source could be under the CBR data rate target. So in order to complete the stream, it's necessary to add stuffing packets in the stream to reach the data rate wanted. These packets are totally neutral and don't affect the stream.

Some useless bytes will be filled.

Constant bit rate (CBR) encoding persists the set data rate to your setting over the whole video clip. Use CBR only if your clip contains a similar motion level across the entire duration. CBR is most commonly used for streaming video content using the Flash Media Server (rtmp).

advantage:
Stable code stream
Fixed stream control can reduce the influence of network jitter.
Disadvantage 1:not allocate enough data for complex section

CBR would not be the optimal choice for storage as it would not allocate enough data for complex sections (resulting in degraded quality) while wasting data on simple sections.
The problem of not allocating enough data for complex sections could be solved by choosing a high bitrate to ensure that there will be enough bits for the entire encoding process, though the size of the file at the end would be proportionally larger.

Disadvantage 2: Cannot effectively adapt to variable length coding

Most coding schemes such as Huffman coding or run-length encoding produce variable-length codes, making perfect CBR difficult to achieve.
This is partly solved by varying the quantization (quality), and fully solved by the use of padding.
(However, CBR is implied in a simple scheme like reducing all 16-bit audio samples to 8 bits.)

Variable bit rate (VBR)
As opposed to constant bitrate (CBR), VBR files vary the amount of output data per time segment.
VBR allows a higher bitrate (and therefore requires more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments.
The average of these rates can be calculated to produce an average bitrate for the file.

Complex segments allocate more space (more space for more complex segments),
Less complex segments allocate less space (less space for less complex segments).

Variable bit rate (VBR) encoding adjusts the data rate down and to the upper limit you set, based on the data required by the compressor.
VBR takes longer to encode but produces the most favorable results.
VBR is most commonly used for http delivery if video content (http progressive)

VBR can adapt to a bit rate lower than the upper limit.
When encoding, it takes longer than CBR, but the encoding effect is better.

Files that can be encoded with VBR
Opus, Vorbis, MP3, WMA and** AAC** audio files can optionally be encoded in VBR.
Variable bit rate encoding is also commonly used on MPEG-2 video,MPEG-4 Part 2 video (Xvid, DivX, etc.), MPEG-4 Part 10/H.264 video, Theora, Dirac and other video compression formats.

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
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E-mail: [email protected]
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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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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:

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