the I☬ bus is only available via the video function and the DVB stream is only available via the audio function. The two functions have different memory mappings although they have many similar registers - e.g. The BT878 provides one function each for Video and Audio onto the PCI bus. The original idea behind it was that when you had a window obscured on your display, or you wanted to crop a bit of the input image, you could build a RISC program that just copied the parts of the video lines you wanted, and thus not waste any PCI bandwidth. ![]() ![]() Like the Philips SAA7146 based DVB PCI card designs, this chipset misuses the analog video input of the chip to sample the MPEG-2 Transport Stream in video lines of the framebuffer, programming this is kind of a pain. When DVB came along, I guess the manufacturers of the TV cards were used to working with this chip so the digital audio input interface was co-opted to take the MPEG-2 transport stream. Note: This section below needs to be edited - remove: first person bias etc.
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