DTV & STB tech

Set-top box & Digital TV dev process highlights

The STB is a device capable to receive video content via DVB standard and display it on TV. The development of IP networks and broadband/ADSL made possible to deliver a high-quality video content through IPTV set-top boxes.

Here we describe the main aspects of hardware development in STB & Digital TV area. We'll focus on DTV standards, STB classification, and the overview of SoC manufacturers for STB.

STB classification

All set-top boxes can be divided into four major groups depending on source of digital TV signal:

STB for terrestrial digital video broadcast (DVB-T)
STB for satellite digital video broadcast (DVB-S)
STB for cable digital video broadcast (DVB-C)
IPTV set-top boxes receiving video streams via IP network (Ethernet or Wi-Fi)

Set-top boxes with MPEG-2 transport stream support are quite widespread in Europe and USA. Usually, STB consists of:

Frontend with tuner and DVB demodulator. There is also Digital Satellite Equipment Control (DiSEqC) module in case of satellite antenna setup

Demuxer filters incoming DVB stream and splits a transport stream into video and audio parts. Transport stream can contain some special streams like teletext or subtitles

Conditional Access (CA) module or smartcard slot performs real-time decoding of encrypted transport stream

Separated video and audio streams are directed to corresponding decoders

Digital TV standards

DVB-S

digital video broadcast by satellite

DVB-S2

digital video broadcast by satellite, standard updated in 2004

DVB-SH

digital video broadcast by satellite for portable and mobile devices

DVB-C

digital video broadcast by cable

DVB-T

digital video broadcast, terrestrial television

DVB-T2

digital video broadcast, terrestrial television, standard updated in 2008

DVB-H

digital video broadcast, terrestrial television for mobile devices

Overview of processor manufacturers for STB

Being oriented to the mass-production consumer electronics, STB chipset manufacturers are forced to integrate more peripherals in a chip and to produce lower cost single chip solutions for BOM reduction and cutting price of a final STB device.

Usually, the chip inside STB consists of 3 or more cores: a general purpose application processor and additional DSP-like cores dedicated to audio and video decoding. Let's give a short overview of major semiconductor companies which produce processors (system-on-chip) for set-top boxes:

STMicroelectronics

ST is a top semiconductor player for STB chipsets. Currently the company's portfolio has the following processors: STi5100, STi5188, STi5105, STi5200, STi5205, STi5300, STi5516, STi5517, STi7141, STi7101, STi7105, STi7108, STi7167, STi7710, STi7200. There are many development kits from vendor with Linux, WinCE and custom RTOS support – OS21 and additional software components named OSPlus.

NXP

NXP Semiconductors

This Dutch chipmaker company become an active player in STB chipsets (especially for DVB-T) after acquisition of STB business from Connexant. However, in October of 2009, NXP refocused on automotive IC business and sold its set-top box and digital TV assets to USA based Trident Microsystems. Products are: Nexperia PNX8735 (low cost HD set-top-box decoder) & Nexperia PNX8732 (low cost SD set-top-box decoder).

Broadcom

Broadcom is a middle cost processors vendor for IPTV set-top boxes with a wide range of solutions: CM7038 Dual High Definition Digital Video System-on-Chip Solution for Cable, Satellite and DTV; BCM7043, BCM7118, BCM7309, BCM7400, BCM7403, BCM7404, BCM7405, BCM7410, BCM7420, BCM7452, etc.

Sigma Designs

Sigma Designs — middle cost processors for IPTV set-top boxes with the following solutions: EM8620L family, SMP8630 family, SMP8640 and SMP8650 families.

NationalChip

NationalChip – a strong player on the Chinese and Asian markets, which has a set-top box IC portfolio for standard definition and MPEG2 video decoding: GX1xxx – demodulator IC series (DVB-T, DVB-S, DVB-C, DTMB+DVB-C, ABS-C): GX3xxx, GX2xxx – video post-processing and MPEG2 decoder IC series; and GX6xxx – demodulator, video post processing, MPEG2 decoder System-on-Chip series.

ALi

ALi Corporation

This is another Asian manufacturer with the solutions: M3501 – DVB-S/DVB-S2 demodulator IC; M3602 – HD, MPEG-2, H.264 set-top box SoC; and M3381 – SD, MPEG-2, H.264 set-top box SoC.

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