Both SRT and NDI® technologies are examples of low-latency transmission. The SRT protocol helps users to safely and reliably transmit video on the complex and unpredictable Internet. The NDI protocol focuses on realizing high-quality, low-latency audio and video transmission through the IP network in the local area network. How to choose between SRT and NDI? It is recommended that everyone can go to the SRT knowledge base to learn and understand. Now let's talk about the direct difference and respective characteristics of the two low-latency transmission protocols, SRT and NDI.
About SRT: SRT is an Internet transmission protocol jointly created by Haivision and Wowza. It is a very popular open source low-latency video transmission protocol. The use of SRT transmission technology can successfully achieve safe and reliable high-definition video transmission and distribution under ordinary Internet environments and between multiple locations.
About NDI: NDI is a network device interface protocol launched by NewTek in 2015. It is a signal transmission protocol based on local area networks. Using NDI transmission technology, a device in the local area network can output or receive multiple NDI signals through one network cable, which can completely replace the traditional SDI/HDMI video cable transmission. It enables simple and efficient video transmission in the IP space has become a reality.
1. SRT and NDI: Use bandwidth
The SRT protocol is a transmission protocol based on the H.264/H.265 compression scheme. The transmission bandwidth is adjustable. For example, high-definition video can be customized to 4-20Mbps. SRT's anti-packet loss mechanism is ARQ (Automatic Repeat Request) error correction mechanism. In network transmission, bandwidth jitter and packet loss usually occur randomly. The error correction mechanism is only needed when there is a problem in the network. The ARQ mechanism only requires the sender to retransmit the lost data packet after the packet loss occurs. That is, this not only guarantees the quality of the transmission, but also reduces unnecessary consumption of transmission bandwidth.
There are two versions of NDI World, one is NDI|HX and the other is FullNDI. NDI|HX is a variant of H.264. It has been iterated to NDI|HX2. The transmission bandwidth is adjustable. The default value of 1080P60 video is 10Mbps. FullNDI is an I-frame intra-frame compression scheme. It has been iterated to NDI 4.5. In the transmission process, FullNDI needs to occupy a certain bandwidth. HD bandwidth is 90-180Mbps, 4K bandwidth is 200-300Mbps. NDI transmission is recommended to use Gigabit network, which is suitable for Applications that require high image quality, such as program production work scenes.
2. SRT and NDI: Transmission delay
SRT is a network transmission technology that can transmit data streams in real time and accurately in a complex network environment. It uses the UDP protocol at the transmission layer, has the transmission characteristics of UDP fast speed and low overhead, supports point-to-point transmission, without intermediate server transfer (It only needs to have a fixed public IP address on either end), and the point-to-point transmission of the Internet can be less than 1s. NDI is able to allow devices in the local area network to transmit high-quality signals. A device in the local area network can output or receive multiple NDI signals through a network cable, without complicated wiring, and the end-to-end delay in the local area network is only 1 -3 frames (less than 100ms). From the practical application point of view, the end-to-end delay of FullNDI is less than 100ms, and the end-to-end delay of NDI|HX is about 100+ms.
3. SRT and NDI: application scenarios
SRT can be widely used in industries such as remote program production (on the cloud), live event live video connection of the main branch venue, Internet remote teaching and training, group company video supervision of off-site construction sites, remote connection of court hearings, and other industries that need to be remotely connected to the Internet. Video transmission occasions. At the same time, it should be noted that the SRT transmission application requires a fixed public IP address on either the sender or the receiver. NDI is widely used in industries such as local/remote production of TV programs, NDI projection, NDI video conferencing, ultra-low latency surgical teaching, and some video transmission scenarios that require more convenience, low latency, and high image quality. NDI is currently only suitable for transmission within the local area network, but through the protocol conversion technical solution, the NDI stream can also be transmitted across the Internet (for details, you can learn more about the Qianshi electronic video gateway product).
4. Summary:
Internet SRT technology and local area network NDI technology are the two most popular low-latency transmission protocols at the moment, and a suitable solution can be selected according to the actual application between the two. There are 2 world versions of NDI, NDI | HX and FULL NDI. NDI | HX is a compressed version of the long GOP H.264 variant, which has the advantage of low bandwidth requirements and allows a simple gigabit network to carry multiple video streams without Consumes a lot of network traffic, for example, a single 1080p60 NDI stream only needs about 10 Mbps.
The end-to-end delay in FULL NDI LAN is only 1-3 frames (about tens of milliseconds, while the traditional RTSP transmission end-to-end takes about 300 milliseconds). It is a typical representative of low-latency transmission technology in the current market. Gigabit network environment support. A single 1080P60 NDI stream requires 125Mbps, and a single 4KP60 NDI stream requires 250Mbps. Users can transmit multi-stream high-definition NDI streams in a gigabit network environment, and FULL NDI is widely used in on-site production solutions. FULL NDI delay: The end-to-end delay of FULL NDI is within 80ms.
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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
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E-mail: [email protected]
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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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Beneficiary: Fmuser International Group Inc
Account Number: 44050158090900000337
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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.
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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
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