Digital Signal Processing Reference
In-Depth Information
Fig. 6
DLNA audio-video
interoperability stack
JPEG,LPCM, MPEG-2,Mp3,
MPEG-4,
AAC LC, AVC/H.264
+ optional formats
Media
Formats
Device
Discovery,
Control and
Media
Management
UPnP AV 1.0
UPnP Device Architecture 1.0
Media
Tansport
HTTP (mandatory)
RTP (optional)
Network
Stack
IPv4 Protocol Suite
Wired: 803.3i, 802.3u
Wireless: 802.11a/b/g
Bluetooth
Network
Connectivity
5.3
Digital Media Player
Digital media players (also known as digital media receivers) find content on digital
media servers and provide playback capabilities. Figure
7
shows a typical interaction
between a DLNA client and a DLNA server. The devices use HTTP for media
transport and may also include a local user interface for setup and control. Examples
of digital media players include connected TVs and game consoles. Today, digital
media players combine wired and wireless connectivity and a powerful digital
signal processor. However, despite the efforts of the standardization committees to
establish standards for the coding of pictures, audio, and video, this did not stop
the proliferation of other coding formats. For example, just for video, the coding
alphabet soup for audio/video codecs includes DivX, xvid, Real Video, Windows
Media Video (WMV), Adobe Flash video, and Matroska video, to name just a few.
This proliferation of coding formats is a major challenge for consumer electronics
manufacturers who strive to provide their customers a seamless experience. How-
ever, while it is rather easy to upload a new codec on a PC, this may not be the case
for a set-top box, a DMR, or a mobile client. While manufacturers work on the next
generation of multi-format players, it is not uncommon to see now PC-based media
transcoders. These transcoders interact with media servers and allow for on-the-fly
transcoding of any media format to the most commonly used formats, like MPEG-2
or WMV.
