Virgin Media Cable TV and MythTV

From MythTV Official Wiki
Jump to: navigation, search

AV Capture from Scientific Atlanta/Cisco 4200DVB

Until my 4200DVB's PSU died, I was able to successfully capture video data from the "VCR" SCART socket (via a ProfiGold SCART-to-RCA/S-video adaptor, switch set to "output") into my Hauppauge HVR-4000 card. Video was output from the adaptor's composite RCA output (yellow), and taken via a composite video lead and the Hauppauge-supplied RCA-to-7-pin mini-DIN S-video lead to the HVR-4000 composite/S-video input. Stereo audio was output on the red/white RCA outputs of the adaptor and input into my mobo's "Line In" jack via a 2xRCA-to-stereo jack cable.

With the SCART adaptor plugged into the STB's "VCR" SCART socket, it's S-video output, when captured by the HVR-4000, gave a black-and-white picture with a shifting, Moire-like interference. This was thought to be due to the SCART socket (and thus the S-video output of the adaptor) either:

a) outputting only luminance (Y) data (doesn't explain the interference, though)

or

b) outputting composite video on the Y channel

This latter case would explain the black-and-white picture seen, the additional chroma (C) data present in the composite signal being interpreted as interference to the luma signal.

Important.png Note: The "S-video" output displayed correctly on my Sony TV, although I suspect that this may be due to the TV simply merging the C/Y channels to give a composite signal before displaying, therefore being insensitive to the case where a composite signal is provided on the Y channel and no signal is present on the C channel.

Case a) is supported by reports of SCART "down" sockets (of which the STB's "VCR" socket is probably an example) rarely implementing the "S-Video C down" function on Pin 7, whilst case b) is supported by the fact that the VirginMedia STB software did not give the user the choice of S-video as a SCART output format, probably meaning that the shared Pin 19 would always output composite video.

Unfortunately, I wasn't able to progress the capture of S-video data from the 4200DVB before it passed away. All I can say is that capture of composite video worked OK.

AV Capture from V HD Box (Cisco 4585DVB)

Links

Virgin Media Channel Guide

Red-Eye Serial

Scientific Atlanta/Cisco 4200DVB STB User Manual

TrustedReviews.com review of V HD Box (Cisco 4585DVB) inc. photo of back panel connections

Wikipedia entry for SCART