Streaming Media (2)

Problems

 

Streaming Media Technology is not a single technology, it is an organic combination of network technology and video/audio technology. To implement Streaming Media Technology on the network, you need to solve the problems of making, releasing, transmitting, and playing streaming media. These problems need to be solved by using the video and audio technology and network technology, as shown below:

(1) problems solved by the Streaming Media Production Technology
For streaming media transmission on the Internet, the transmitted files must be made into streaming media format files suitable for streaming media transmission. Because the size of multimedia files stored in this format is usually very large, it takes a very long time to transmit the files on the existing narrowband network. If the network is busy, it will also cause transmission interruption. In addition, streaming media in the common format cannot be transmitted according to the streaming media transmission protocol. Therefore, files that need to be transmitted in the streaming media format should be preprocessed to compress the files to generate streaming media files. Two points should be noted here: first, use the appropriate Compression Algorithm for compression, so that the generated file capacity is small. Second, you need to add stream information to the file.

(2) problems to be solved in streaming media transmission
Streaming media transmission requires a suitable transmission protocol. Currently, most file transmission over the Internet is based on the TCP protocol, and some are transmitted over FTP, however, none of these transmission protocols can achieve real-time transmission. With the in-depth study of streaming media technology, the mature stream media transmission is generally based on the UDP protocol RTP/RTSP real-time transmission protocol.

Why do we need to transmit real-time data over UDP instead of TCP? This is because the reliability of UDP and TCP in data transmission is very different. The TCP protocol includes a special data transfer verification mechanism. When the data receiver receives the data, it will automatically send a confirmation message to the sender, and the sender will continue to transmit the data after receiving the confirmation information, otherwise, the Instance remains in the waiting status. The UDP protocol is different, and the UDP protocol itself cannot perform any verification. It can be seen that the TCP protocol focuses on transmission quality, while the UDP Protocol focuses on transmission speed. therefore, for video and audio streaming files that do not require high transmission quality and have high transmission speeds, UDP protocol is more suitable.

(3) cache support is required during streaming media transmission.

Streaming Media TV

Because Interent performs asynchronous transmission based on packets, multimedia data is divided into many packets during transmission. Due to the instability of network transmission, the routes selected for each packet are different, therefore, the time order to arrive at the client may change or even cause packet loss. therefore, the cache technology must be used to correct the confusion caused by a change in the Data arrival order, and the cache can be used to correctly sort the arrived data packets, this enables video and audio data to be played continuously and correctly. the cache stores data for a certain period of time. The data stored in the cache is temporary, and the cached data is dynamic and constantly updated. streaming media constantly reads cached data during playback for playing. After playing, the data is immediately cleared and new data is saved to the cache. therefore, streaming media files do not need to occupy a large amount of cache space.

 

(4) problems to be solved in Streaming Media Playback
Streaming media playback requires browser support. generally, the browser uses mime to identify different simple file formats. All Web browsers are based on the HTTP protocol, and the HTTP protocol has mime. therefore, the wed browser can mark many multimedia file formats on the Web through the built-in mime in the HTTP protocol, including various streaming media formats.

Streaming media-streaming media TV

Different from ordinary TVs, the bottom of a flat-screen streaming media TV has the same USB interface as that on the computer. You only need to insert a USB interface into the USB drive to play the image and audio.

Streaming Media TV

The difference is that playing on a computer requires keyboard and mouse control, while playing on a TV only requires an ordinary remote control. The reporter found that the remote control of streaming media TV has nothing special than the ordinary remote control. Users only need to follow the menu prompts on the TV interface and press the upper and lower keys to control it, children and the elderly who do not know the computer can easily perform operations. It is more convenient to copy audio and video files downloaded from the Internet to a USB flash drive or a mobile hard disk, and then play them directly on a streaming media TV, you do not need a dedicated DVD player at home.

 

Sales staff told reporters that compared with computers, streaming media TV saves data lines and card readers. It has a dedicated card slot that can directly read the built-in SD card of a digital camera. In addition, the card slot can also be compatible with a variety of memory cards and memory sticks other than the SD card.

 

Streaming media-streaming media transmission

With the popularization of the Internet, the demand for transmitting sound and video signals over the network is also growing. After broadcasting and television and other media access the Internet, they also want to publish their own audio and video programs over the Internet. However, the volume of audio and video files during storage is generally very large. When the network bandwidth is very limited, it takes tens of minutes or even longer to wait for the transmission of an audio/video file. The emergence of streaming media technology makes it difficult to transmit audio and video over the Internet to a certain extent.

Streaming Media Technology

 

The traditional method of transmitting audio and video information over the network is to completely download and play back the audio and video, which usually takes several minutes or even hours. Streaming Media Technology enables stream transmission. Audio, images, or animations are continuously transmitted from the server to the user's computer. You do not have to wait until the entire file is downloaded, however, you only need to watch the video after several or dozens of seconds of startup latency. When audio and video are played on the user's machine, the remaining part of the file will be downloaded from the server.

If we regard file transmission as a water-receiving process, the transmission method in the past is like setting a rule for users to use it only when a bucket of water is fully occupied, the waiting time is naturally affected by the water flow and bucket size. Streaming Transmission is to open the water head dragon, wait for a short while, the water will flow continuously, and can be used with, therefore, regardless of the size of the water flow, regardless of the bucket size, users can access the water at any time. In this sense, the word streaming media is very vivid.

Stream Transmission is divided into two types: Sequential stream transmission and real-time stream transmission.

Ordered stream transmission downloads objects in sequence. Users can watch the objects while downloading them. However, users' views are not synchronized with those transmitted on the server, after a delay, the user can see the Information uploaded by the server, or the user can see the information transmitted by the server several times ago. In this process, the user can only view the downloaded part, rather than the part that has not been downloaded. Ordered stream transmission is suitable for high-quality short video segments because it can ensure the final quality of program playback. It is suitable for audio and video programs released on websites for on-demand users.

In real-time stream transmission, audio and video information can be viewed in real time. During the viewing process, users can quickly forward or backward to view the content of the front or back, but in this transmission mode, if the network transmission is not ideal, the signal received is relatively poor.

Streaming media-audio files

When using streaming media technology, audio and video files must adopt the corresponding format. Files of different formats must be played using different player software ". Currently, audio and video files using streaming media technology mainly have three major "schools ".

Streaming media communication platform

 

First, Microsoft's ASF (Advanced stream format ). The suffixes of such files are. ASF and. wmv. The corresponding player is Microsoft's "media player ". You can combine graphics, sound, and animation data into an asfformat file, or convert videos and audio from other formats to asfformat, in addition, you can use sound cards and video capture cards to save data from peripherals such as microphones and video recorders to asfformat.

The second is RealNetworks's RealMedia, which includes three types of files: RealAudio, realvideo, and realflash. RealAudio is used to transmit audio data close to the CD sound quality, and realvideo is used to transmit uninterrupted video data, realflash is a high compression ratio animation format jointly launched by RealNetworks and Macromedia. The suffix of such files is. rm. The Player corresponding to the file is "RealPlayer ".

The third is Apple's QuickTime. This type of file extension is usually. mov, and its corresponding player is "QuickTime ."

In addition, MPEG, Avi, DVI, SwF, and so on are all file formats suitable for streaming media technology.

Streaming Media Technology breaks through the network bandwidth limit on multimedia information transmission to a certain extent, therefore, apsaradb for memcache is widely used in many fields such as online live broadcasting, online advertising, on-demand video, distance education, telemedicine, video conferencing, enterprise training, and e-commerce.

Streaming media-news media

For news media, streaming media brings both opportunities and challenges. Streaming Media Technology makes it possible for traditional media to open up a broader space on the Internet. The Internet access of broadcast and television media programs is more convenient, and the on-demand broadcast programs of audience and audience are simpler. the live broadcast of online audio and video will also be widely used.

Streaming Media TV

 

Streaming Media Technology changes the traditional media's "push" type communication into the "pull" Type Communication of the audience, and the audience no longer passively accepts programs from radio and television, instead, you can receive the information you need at your convenience. This will increase the status of the audience to a certain extent, give them the initiative in news dissemination, and make their needs have a more direct impact on the activities of the news media.

The widespread use of streaming media technology will also blur the boundaries between broadcasting, television and the network. The network is both a helper and extension of broadcasting and television, and will also become a powerful competitor of broadcasting and television. Using Streaming Media Technology, the network will provide new audio and video program styles and form new business methods, such as paid on-demand services. Leveraging the advantages of traditional media and the expertise of online media, maintaining good competition and cooperation among media is the path to the development of the network and the development of traditional media in the future. The use of streaming media technology is just the beginning, and the new technology is still waiting for us.

Interactive streaming media business platform