ffmpeg describes itself on the official website: it is a complete cross-platform solution for recording, converting, and streaming video and audio. In fact, there are many tools that are based on ffmpeg for video and audio processing tools. For example, the famous format factory uses ffmpeg as the kernel transcoding tool.
Understand some audio and video coding knowledge.
The video file format we usually watch: mp4/rmvb/mkv/avi is actually a container. The contents of this container are divided into two categories: audio and video. For this part of the video, it contains encoding formats: H264/H265/VP8/VC1, etc. For the audio part, it contains encoding formats: AAC/MP3/mid, etc. Therefore, the [video format] we usually say generally includes three parts: video encoding, audio encoding, and container format. The [encoding] mentioned here actually contains two layers: encoding and decoding. For example, video encoding is the process of converting video images into binary data. Video decoding is the process of converting binary data into images. Audio coding is the same. Then when we look at a video file, we can see the sound and image at the same time, which means that we have at least two sets of data for video encoding and audio encoding at the same time. So what are the rules for organizing these two sets of data? It depends on the regulations of [Container Format]. The data stored in the container may use many different encoding methods. For example, avi files usually store xvid or divx encoded video and mp3 encoded audio. The rmvb file usually stores RV40 encoded video and cook encoded audio. The mp4 file usually stores H.264 encoded video and AAC encoded audio. The mkv file may contain the previous ones.
If you have installed ffmpeg, you can use ffmpeg -codecs to see which audio and video codecs are supported by ffmpeg (almost already includes most of the existing codecs). Intercept part of it:
Codecs:
D..... = Decoding supported (decoding supported)
.E.... = Encoding supported (encoding supported)
..V... = Video codec (video codec)
..A... = Audio codec (audio codec)
..S... = Subtitle codec (Subtitle codec)
...I.. = Intra frame-only codec (frame codec)
....L. = Lossy compression
.....S = Lossless compression
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D.V.L. 4xm 4X Movie
D.VI.S 8bps QuickTime 8BPS video
.EVIL. a64_multi Multicolor charset for Commodore 64 (encoders: a64multi)
.EVIL. a64_multi5 Multicolor charset for Commodore 64, extended with 5th color (colram) (encoders: a64multi5)
D.V..S aasc Autodesk RLE
DEVIL. amv AMV Video
D.V.L. anm Deluxe Paint Animation
D.V.L. ansi ASCII/ANSI art
Well, the transcoding we often talk about is actually this process:
Original video - Decoding - Pixel data - Encoding - Target video
Original Audio - Decoding - Audio Data - Encoding - Target Audio
We use the example of aac to mp3 to see the use of ffmpeg in audio transcoding.
The name aac is very big, advanced audio coding, appeared in 1997, the purpose of appearing is to replace the MP3 format. Compared with the MP3 format, its compression algorithm is better, and it is a high compression ratio encoding. It is jointly developed by companies such as Apple and Nokia. Now the iTunes music player on Apple mobile phones supports and uses AAC files.
However, audio files in aac format are not supported by all browsers in html5. The browser's support for audio files is as follows:
Image
Back to the ffmpeg tool, its format is like this:
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
So suppose I have an aac file at this location:
/home/web/mycareer/upload/61/1d0452670723c3ba2e1b10d02d789c61.aac
I need to convert it into an mp3 file:
/home/web/mycareer/upload/61/1d0452670723c3ba2e1b10d02d789c61.mp3
First of all, ffmpeg has a decoder with aac, but there is no encoder with mp3. When you need to compile, bring --enable-libmp3lame
Of course this requires you to install libmp3lame first
tar xzvf lame-3.99.5.tar.gz
make
make install
Then bring it when compiling and installing ffmpeg: --enable-libmp3lame
Then the ffmpeg command is:
ffmpeg -i /home/web/mycareer/upload/61/1d0452670723c3ba2e1b10d02d789c61.aac -acodec libmp3lame /home/web/mycareer/upload/61/1d0452670723c3ba2e1b10d02d789c61.mp3
Remember to explain here -acodec libmp3lame
The transcoding is complete.v
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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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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.
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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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