Symbol/Company        Product                                                  Link
BRCM  Broadcom Corp.  
BCM7315 Single-Chip Satellite Set-Top Box Decoder   broadcom.com
BCM97315 DBS Set-Top Box Reference Design           broadcom.com
BCM7100 SINGLE-CHIP CABLE SET-TOP BOX SYSTEM        broadcom.com
BCM7110 SINGLE-CHIP SET-TOP BOX WITH DOCSIS/PVR     broadcom.com
BCM7115 SINGLE-CHIP SET-TOP BOX WITH PVR            broadcom.com
BCM3300 QAMLink® SINGLE-CHIP DOCSIS/EURODOCSIS      broadcom.com

CRUS  Cirrus Logic</B.
CS7808 processor is a single chip solution that provides all of the processing functions you need for a broad range of audio and video applications including thin media clients, CD recorders, advanced set-top boxes, interactive TV and much more.
cirrus.com
C49310 family audio decoder dsp
cirrus.com

PHG  Philips Semiconductors
Nexperia PNX831x for STB and iDTVsystems semiconductors.philips.com
Nexperia PNX8525 Home Entertainment Engine = compr. source decoder, interactive TV, Internet, telephony, and digital recording functions on a single chip
semiconductors.philips.com
PNX8510/11 is intended to serve as an analog back end "companion" for digital ICs dealing with video and audio signal processing. 
semiconductors.philips.com
PNX300x 'Digital One Chip' (DOC) enables digital processing in analog TVs
semiconductors.philips.com

STM  STMicroelectronics
System-on-Chip From STMicroelectronics Increases Set-Top Box Performance and Security
(Note: in this PR STM claims to be the world's nr.1 set-top box chip supplier)
us.st.com
STMicroelectronics Passes the 100 Million Mark for Set-Top Box OMEGA MPEG-2 Chips
us.st.com