How many transistors/logic gates are used in the signal path between a TV studio and the restitution of the image on my HD-TV?
Here are the functional blocks:


Video camera


1920x1080 pixels, CCD, modeled as DRAM for simplicity, giving 1920x1080=2073600T
columns dump to analog multiplexors, which I'll guess to have 1080x10=10800T
1080/2^3=135 ADC blocks -- will make them 24-bit delta-sigma ADCs, giving it around 135x(24x2+50)=13230T
memory buffer should hold at least 2 frames, giving 24x1920x1080=49766400T
high speed bus driver will add another 10^3T or so

Encoding DSP


x264 codec requires 32-bit DSP processor with ??? T
should buffer (SRAM) at least 10 frames for codec compression, giving 10*9*49766400=4478976000T

Transmission


Going with 2 Windows PCs to prep the stream and send it to a server, then 5 LAMP servers to get it to the end user, giving 7x2000000000=14000000000T
modems and switches ignored

Decoding DSP: make equal to encoding
Display: make equal to capture


TOTAL: 23061682060 transistors
ERROR: ±2628%, possible error in error calculation