HLS and Http Live Streaming are protocols for real-time streaming defined by Apple. HLS is implemented based on the HTTP protocol. The transmission content includes two parts, one is the M3U8 description file, and the other is the TS media file.
1. M3U8 file
The media file is described in text, which is composed of a series of tags.
#EXTM3U
#EXT-X-TARGETDURATION:5
#EXTINF:5,
./0.ts
#EXTINF:5,
./1.ts
#EXTM3U: The first line of each M3U8 file must be this tag.
#EXT-X-TARGETDURATION: Specify the maximum media segment time length (seconds). The time length specified in #EXTINF must be less than or equal to this maximum value. This value can only appear once.
#EXTINF: Describe the length of a single media file. Media files follow, such as ./0.ts
It can be distributed by HTTP on iOS device and mac. The playlist standard is the m3u8 file extended by m3u, and the media file is MPEG2-TS or AAC file (audio only).
There are two application scenarios for m3u8 files:
Multi-rate adaptation stream,
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1280000
http://example.com/low.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=2560000
http://example.com/mid.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=7680000
http://example.com/hi.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=65000,CODECS="mp4a.40.5"
http://example.com/audio-only.m3u8
Single rate adaptation stream
#EXTM3U
#EXT-X-TARGETDURATION:5220
#EXTINF:5220,
http://media.example.com/entire.ts
#EXT-X-ENDLIST
The International Standards Organization defines this rfc doc:
http://tools.ietf.org/html/draft-pantos-http-live-streaming-06
The m3u8 file is an extension of the m3u file. The extended keywords are defined in the rfc:
among them:
#EXT-X-TARGETDURATION
Define the maximum duration of each TS.
#EXT-X-MEDIA-SEQUENCE
Define the serial number of the first file in the current m3u8 file. Each ts file has a fixed and unique serial number in the m3u8 file. The serial number is used to switch the code rate for alignment during MBR.
#EXT-X-KEY
Define the encryption method and the url of the key file, used to obtain the 16bytes key file to decode the ts file.
Attributes:
METHOD
URL
#EXT-X-PROGRAM-DATE-TIME
Absolute time of the first file
#EXT-X-ALLOW-CACHE
Whether to allow cache.
#EXT-X-ENDLIST
Indicates the end of the m3u8 file. Live m3u8 does not have this tag.
#EXT-X-STREAM-INF
Attributes:
BANDWIDTH specifies the bit rate
PROGRAM-ID unique ID
CODECS specifies the encoding type of the stream
#EXT-X-DISCONTINUITY
When the tag is encountered, the following attributes have changed:
file format
number and type of tracks
encoding parameters
encoding sequence
timestamp sequence
#EXT-X-VERSION This attribute can be used or not, you can have none
M3U8 is divided into top-level M3U8 and second-level M3U8. The top-level M3U8 is mainly used for multi-rate adaptation. The second-level M3U8 is the real slice file.
By default, the client will first select the request with the highest bitrate. If it finds that the bitrate cannot be reached, it will request a stream with a low bitrate
A top-level M3U8 file in actual use is as follows:
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=201273221265,BANDWIDTH=358400
11.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=201273221265,BANDWIDTH=972800
22.m3u8
The top-level M3U8 file above defines two second-level files, 11.m3u8 and 22.m3u8, and the client will select one of them to get its content.
The content of the secondary M3U8 file is as follows:
#EXTM3U
#EXT-X-VERSION:1
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:3,
1-4.ts
#EXTINF:8,
1-6.ts
#EXTINF:8,
1-8.ts
#EXTINF:8,
1-10.ts
#EXTINF:8,
1-12.ts
#EXTINF:8,
1-14.ts
#EXTINF:8,
1-16.ts
#EXTINF:9,
1-18.ts
#EXTINF:6,
1-20.ts
#EXTINF:8,
1-22.ts
#EXTINF:9,
1-24.ts
#EXTINF:3,
1-26.ts
#EXT-X-ENDLIST
After the client gets the above secondary M3U8 file, it will continue to request the file inside, and then it can be played.
The above is about the on-demand situation and the situation of live broadcast, there will be attributes in the M3U8 file to tell it is live, and the client will periodically request new M3U8 files.
//When HLS realizes on-demand and live broadcast, the difference of M3U8 file
1. Problem description
Recently I did a transcoded slice playback test, using HLS (HTTP Live Streaming) to do the live broadcast. Each TS segmentation time is 10s, and the following live m3u8 files are generated according to the TS segmentation files
Copy code
#EXTM3U
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-TARGETDURATION:10
#EXTINF:10
hls/1.ts
#EXTINF:10
hls/2.ts
#EXTINF:10
hls/3.ts
#EXTINF:10
hls/4.ts
#EXTINF:10
hls/5.ts
#EXTINF:10
hls/6.ts
#EXTINF:10
hls/7.ts
#EXTINF:10
hls/8.ts
#EXTINF:10
hls/9.ts
#EXTINF:10
hls/10.ts
Copy code
Save the above m3u8 file as live.m3u8, put it in the Apache document directory, and play the following URL with VLC:
http://localhost/live.m3u8
The test found that the first file to start playing was not 1.ts. After several tests, it was found that:
As long as there are more than three files in the list, the last three files in the list are always played
2. Problem solving
It's very sad that after searching the Internet, I didn't find any effective information. A buddy encountered the same situation, did he share his experience after solving it?
After consulting with a colleague, the colleague said that it is possible because the live m3u8 file list needs to be updated in real time. If we do a test, we can add #EXT-X-ENDLIST at the end first. This method has been tested It works, but this is no longer live m3u8 mode
After searching the Internet again, I confirmed that I finally found a live m3u8 description
Live Playlist (Sliding Window)
For live sessions, the index file is updated by removing media URIs from the file as new media files are created and made available.
Important: The EXT-X-ENDLIST tag is not present in the Live playlist, indicating that new media files will be added to the index file as they become available.
See Listing 3 for an example live playlist as it would appear at the beginning of a session.
Listing 3 Live Playlist at the beginning of a session.
Copy code
#EXTM3U
#EXT-X-TARGETDURATION:10
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:1
#EXTINF:10,
fileSequence1.ts
#EXTINF:10,
fileSequence2.ts
#EXTINF:10,
fileSequence3.ts
#EXTINF:10,
fileSequence4.ts
#EXTINF:10,
fileSequence5.ts
Copy code
The EXT-X-MEDIA-SEQUENCE tag value MUST be incremented by 1 for every media URI that is removed from the playlist file. Media URIsmust be removed from the playlist file in the order that they appear in the playlist. The updated index file presents a moving window into a continuous stream. This type of session is suitable for continuous broadcasts.
Here's the same playlist after it has been updated with new media URIs:
Listing 4 Live Playlist after updating the media URIs.
Copy code
#EXTM3U
#EXT-X-TARGETDURATION:10
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:2
#EXTINF:10,
fileSequence2.ts
#EXTINF:10,
fileSequence3.ts
#EXTINF:10,
fileSequence4.ts
#EXTINF:10,
fileSequence5.ts
#EXTINF:10,
fileSequence6.ts
Copy code
3.live m3u8 update rules
The list of live m3u8 files needs to be updated continuously, update rules:
Remove the top (think played) file in a file playlist
Continuously update the EXT-X-MEDIA-SEQUENCE tag, increment by 1
4. Experiment
Write a small program to generate live m3u8 for testing
Usage:
m3u8_gen.exe start_num list_count duration filename.m3u8 [prefix]
Usage example:
m3u8_gen.exe 1 3 10 live.m3u8 hls/
Generate live.m3u8 file as
Copy code
#EXTM3U
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-TARGETDURATION:10
#EXTINF:10
hls/1.ts
#EXTINF:10
hls/2.ts
#EXTINF:10
hls/3.ts
Copy code
Write a BAT script to update the live.m3u8 file every 10s
Copy code
@echo off
f
|
|
|
|
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.
---------------------------------------------------------------------
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
|
---------------------------------------------------------------------
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
---------------------------------------------------------------------
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: |
|
