DLNA architecture playback of cloud storage files on set-top boxes

DLNA architecture playback of cloud storage files on set-top boxes

absrtact: as more and more digital devices, audio-visual equipment, such as the support and popularization of the UPNP protocol, the industry's demand for multimedia content to provide services more and more strong, in order to comply with the UPnP protocol and DLNA architecture to provide multimedia content services, multimedia server DMS Is the only device that can serve that need. This article focuses on how to achieve the playback of the cloud media files on the set-top box based on the DLNA architecture.

Key words: DLNA, UPNP, DMS, cloud storage, fuse

1 , DLNA Introduction

Digital Living Network Alliance (DLNA) is a consortium of consumer electronics, mobile phones, and computer manufacturers. The goal of the organization is to create an industry standard that allows manufacturers to connect and adapt to each other's products, thus enabling consumers to live digitally. Members of the alliance currently include many industry leaders, including Philips, Samsung, Panasonic, Hewlett-Packard, Sony, Microsoft, Intel and Nokia.

2 , DMS Introduction

Digital Media Server (DMS) provides the ability to capture, record, store, and source media files. Of course, if necessary, the copyright protection mechanism of multimedia files can also be included. DMS will provide multimedia file servo capabilities to provide direct access to a variety of digital media players and playback capabilities. This type of device includes a set-top box, a video recorder, a PC with multimedia server functions, a home theater with a hard drive, a broadcast receiver, an image capture device, and other embedded devices.

3 , UPNP Introduction

The full name of UPnP is Universal Plug and Play, primarily a standard that Microsoft is implementing. Simply put, UPnP's biggest vision is to want any device (note, "Any device", such as a TV, computer, stereo, refrigerator, alarm clock, electric light ... etc.) as soon as the network is connected, all the devices on the network will immediately be able to know the "new device join", the devices can communicate with each other, more directly use or control it, everything does not need to be set, completely Plug and Play. For example: Before if you bought a printer in your home, when you want to make the printer available at home, you need to install the printer, then you need to set up printer sharing, and then install this network share printer on another computer, is it troublesome? If you have 10 computers, it's scary to think about how each one is going to be set. Now, with UPnP, as long as your home computer and printer support UPnP, when you pick up a new printer, all the computers on the Internet will find a printer available, all the settings do not need, immediately can directly use, completely Plug and Play! It sounds great, and this is what UPnP wants to create in an environment that simplifies and improves our quality of life, so UPnP's main appeal is to create a "home network" setting automation.

4 , cloud storage Introduction

Cloud storage is a new concept that extends and develops in cloud computing (cloud computing), which refers to the combination of many different types of storage devices in the network through application software, such as cluster application, grid technology or Distributed file system, to work together. A system that provides both data storage and business access capabilities to the outside. Cloud storage is a cloud system that is the core of data storage and management, when the core of cloud computing system operation and processing is the storage and management of large amount of data, and the cloud computing system needs to configure a large number of storage devices.

5 , DLNA data transfer mechanism

The DLNA standard is based on the middle layer of the original network architecture, which enables the devices that support this layer definition to communicate with each other without additional set-up actions, supported by the 1.0 version of the DLNA Standard, Ethernet (IEEE803.3U) and Wi-Fi (802.11 a/ b/g), as a DLNA standard device, network support is a must.

As for the mutual detection between the devices, the UPnP standard is used. The DMP device uses the UPnP mechanism to search for a DMS device that can be matched on the network, and can then perform subsequent playback or transmission actions after a successful connection. This action is fully automatic, so the user is not required to intervene. In terms of media content discovery, the UPnP mechanism is also used. On the transport side, it is still only supported by the HTTP standard protocol, and subsequent versions will not join the RTP (Real-time Transport Protocol) transport protocol.

In the multimedia format can be transferred, it is divided into the necessary support and optional support two aspects, in the necessary support, the graphics file format is JPG, the audio format is LPCM, the film format is MPEG-2. In the alternative format, the graphics file is PNG, GIF and TIFF, the sound compression format is AAC, AC-3, ATRAC3plus, MP3, WMA9, etc., as for the film compression format, it contains MPEG-1, MPEG-4, AVC and WMV9, etc., by At present the network transmission speed still waits for the breakthrough, therefore the manufacturer mostly also favors the compression format which supports the high compression ratio.

As for product testing certification, DLNA provides standard specifications, as well as software tools that can be tested by the manufacturer, the initial confirmation can be carried out after the normal implementation, and then sent to the DLNA Certification Body certification, certification will be awarded DLNA mark.

DLNA's vision is quite good, the current way to solve the device communication is also quite appropriate, but currently DLNA in the standard specification is still a little inadequate, such as multimedia files in the digital copyright protection mechanism is still quite scarce, and the DLNA network also lacks security capabilities, but also easy for hackers or viruses, Trojan and other intrusion, causing the entire DLNA environment worries. Coupled with the network architecture for the real-time video playback capabilities have yet to be strengthened, even if the QoS mechanism, but before the overall bandwidth is not a breakthrough (such as the new 802.11n standard through), simultaneous multi-party high-quality audio and video playback, is still very difficult to achieve.

6 , DLNA features that you must have

6.1 Playing multimedia files

6.2 Uploading multimedia files to the server

6.3 Copying multimedia data from the server to the current device

6.4 Share media resources on the current device to other devices

7 , DLNA grafting with cloud storage systems

The goal of the DLNA architecture design is to implement Plug and Play and share of devices in the same LAN, the current transport protocol is Wi-Fi (802.11 a/b/g), HTTP-based transmission, and RTP is not supported. And the cloud storage system is based on the Internet, in order to let the Internet files can be detected and broadcast locally through DLNA, need the corresponding technical implementation, this article through fuse to map the cloud files into the local system files. DMS discovers cloud-based files by scanning the mapped local system files before they can be shared and discovered by other devices. The playback process is also consistent with the local file playback mechanism. DMS does not know that its scanned catalog files are files in the cloud. This causes the DMS to scan the media file information for a longer period of time, causing problems for the user experience.

8 , DMS mechanism to get media files

When DMS starts, it scans the local system directory, iterates through all the files, and then reads the file information to determine its media format, as shown in the current DMS supported media Format:

ac3, AAC, mp3,wma9, ATRAC3plus

TD valign= "Top" width= "321" >

media type	must support formats	optional supported formats
image	jpeg	png, GIF, TIFF
audio	LPCM
video	mpeg2	MPEG1, MPEG4,VC1, MPV1

In order to obtain all media files, DMS must read the file, determine its file format, and also have to read the specific information according to the file format, such as copyright information, the author, if it is a MP3 file to read the lyrics, etc., if the TS file also read the key frame of the file, in order to generate a fast forward fallback index file. The mechanism of the above DMS scanning file shows that when these operations are on a local file, the time delay can be within the accepted range, if the file on the Internet, the user experience will be a straight down, because the DMS to obtain this information will cause the download of the entire file from the cloud, this time, the network becomes a bottleneck. In view of this problem, we must analyze its principle in detail and find out the problem that solves the network as a bottleneck.

9 and the problem of playing cloud files via set-top box

At present on the set-top box, due to network limitations, the file delay time to play the cloud longer. As we all know, IPTV has been popularized, IPTV is also playing the video on the Internet, in the network speed of up to 2mbps/seconds can also be smooth playback, which proves that can improve the DMS processing file mechanism, to smooth play the cloud files. From the current test on the set-top box, in addition to scanning media files for too long, the speed of playing media files is quite smooth, and the scanning process caused by the download of the cloud file is a bottleneck, if the DMS only get the basic information of the file, for the cloud storage file for some special processing, We can improve the user experience and play the cloud storage files smoothly.

Ten , optimization and improvement methods

1, the DMS Scan directory, only get the basic information of the file, such as file size, filename, file creation time, file suffix name and so on. Instead of getting the file's content information, minimize the time it takes to scan the process.

2, by the player to identify the format of media files, can play the play, not play prompts the user.

After this processing, the DMS scan media files can be limited to a small range of time, the player plays in the formal reading of the file content information to play processing.

http://blog.csdn.net/langeldep/article/details/6462489

DLNA architecture playback of cloud storage files on set-top boxes