I usually use Baidu Cloud to download audio and video resources offline, and then use a third party to download from Baidu Cloud. However, when using it recently, I found that Baidu Cloud has turned off the offline function (as shown in the figure below), and no resources can be offline. I think this has something to do with Baidu being interviewed a few days ago.

Does this allow me to honestly buy members of various video sites? It's too naive, since it can't be offline, then I'll download it directly.

This article contains the following content: magnet link, DHT network, how to download, copyright related.

# Magnet link

Magnet URI scheme is a computer program for information retrieval and document download in a peer-to-peer network. Unlike Uniform Resource Locators based on "location" links, magnet links are based on metadata file content, which is a Uniform Resource Name. In other words, magnet links are not based on the IP address or locator of the document, but in the distributed database, the document is identified, searched and downloaded by the value of the hash function. Because it does not rely on an active host to download files, it is especially suitable for peer-to-peer networks without a central server. Although it matches open source standards, it is shut out by individuals, organizations, businesses, and governments that monopolize information resources and monitor user behavior.
-Wikipedia

The magnet link format is similar to magnet:?xt=urn:btih:E7FC73D9E20697C6C440203F5884EF52F9E4BD28

Break down this link:

magnet: protocol name. xt: The abbreviation of exact topic, which means resource anchor point. BTIH (BitTorrent Info Hash) indicates the hash method name, and SHA1 and MD5 can also be used here. This value is the identifier of the file and is required.

A magnet link only needs the above two parameters to find the unique corresponding resource. There are other optional parameters that provide more detailed information.

dn: the abbreviation of display name, indicating the file name displayed to the user, optional. tr: the abbreviation of tracker, indicating the address of the tracker server, optional. kt: keywords, more general search, specify search keywords instead of specific files, optional. mt: list of files, linked to a metafile containing magnet links (MAGMA - MAGnet MAnifest), optional.

# DHT network

In the past, if you want to use Torrent to download files, you must first connect to the tracker server, and then you can connect to other clients to download after obtaining the IP addresses of other clients from the tracker. During the transmission process, it will also communicate with the tracker all the time, upload its own information, and obtain information from other clients.

The tracker server becomes the most critical link in the entire BitTorrent network. If the tracker servers are all shut down, the entire BitTorrent network will be shut down. Since the tracker server is very easy to be blocked, and once blocked, it will seriously affect the BT download, which prompts each BT client to support DHT technology.

DHT is a distributed tracker. For details about the protocol, you can view [DHT Protocol original text] (http://www.bittorrent.org/beps/bep_0005.html) or [DHT Protocol: Chinese translation of BitTorrent DHT protocol] (https ://justjavac.com/other/2015/02/01/bittorrent-dht-protocol.html), in the DHT network, each client is a node/peer, and each node will save all peer information and some other node information.

When you want to download a file, your BitTorrent client will contact other nodes in the DHT to get the location of the peer, and then download it through the BitTorrent protocol.

# how to download

Magnet link downloads can be found on major resource websites, and it looks like this:

magnet:?xt=urn:btih:E7FC73D9E20697C6C440203F5884EF52F9E4BD28

Copy it to the download tool, I recommend qBittorrent as a download tool, because I have been using this, and there have been basically no problems until now.

Then just let it download slowly. The download speed depends on how many people are downloading/seeding the resource. If the speed is 0 for a long time, it is recommended to change to a magnet link/seed.

If it is home broadband, it is recommended to call the operator to apply for a public network IP, otherwise it will display yellow not connected (as shown in the figure below), so you will completely rely on the tracker server when downloading. If the tracker server information contained in the seed is not available, it must not be downloaded. Make sure that the DHT network is online. When I first started using BitTorrent to download, I foolishly thought that there was something wrong with the software, so I was so angry that I deleted the software directly.

If it is a campus network or a company, give it up.

# Copyright related

All the movies I downloaded have been watched in theaters, but when I want to rewatch them, the movie theaters have already closed their schedule, and the cost of buying Blu-ray discs is too high. In the future, I will definitely buy Blu-ray discs. After all, it is convenient. You can find them in the hard disk Looking for a long time. At present, it is more appropriate to directly download and put it on the hard disk.

All the movies I have watched are archived here. Each movie has a magnet link attached, and you can download it directly if you need it. These links are available for personal testing.

If the real person is abroad, it is strongly not recommended to download any pirated things, except for mines at home.

# PS

After using the BT tool to download, please do not close the software, let it seed for a while, which can help other people download faster, because when you download, others are seeding and sharing it with you. It is recommended to set the sharing rate to 1, so that 1GB will be uploaded when 1GB is downloaded. Anyway, uploading broadband is basically useless, uploading while watching a movie, and it will be more than 1 after watching the movie. For example like me:

Although it looks very communist...but this is the basis for the existence of the BT network. It is recommended to find more seeds and go to the English resource station, because no one is doing seeds in China because Thunder and the like, because Thunder only Downloading but not uploading is commonly known as "blood-sucking".

BT is about the same. If you want better speed and better resources, it is recommended to go to the PT station, but its requirements are higher, and selfish people who do not share will be kicked out of the Internet every minute.