Lower picture quality w/ Cable Cards??

If your cable box displayed 480p on standard definition programs, it's because it was programmed to output that type of signal. CableCards have nothing to do with it.

You can do the same with your TiVoHD or S3 model. If you choose "hybrid" all standard definition programs will be output in 480p.

 

Settings -> Display

If you want all SD and HD to be converted to 720p, select fixed 720p. If you want all SD and HD to be converted to 1080i, select fixed 1080i. Both of these settings will also eliminate the display resyncs that occur when switching between the menu, SD, and HD channels.

If you want everything output in its original format (i.e. 480i as 480i, 480p as 480p, 720p as 720p, and 1080i as 1080i), then choose Native. If you want HD output in its original format, but want 480i SD converted to 480p, then choose Hybrid. With both of these settings, your display will have to resync when the resolutions change; some displays sync to new input resolutions faster than others.

 

The CableCARDs are not involved in the actual image processing pipeline, so they wouldn't make a difference in the video quality. All they do is decrypt a digital stream. As was suggested previously, maybe flip your TiVo into hybrid mode?

 

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Without CableCARDs, TiVo will record from the analog channel sources for many channels (the "expanded basic" channels). This gives TiVo control over the encoding quality (Best, Good, etc) and can produce very good results, depending on your analog signal quality. With CableCARDs, it is possible for your cable company to remap all or some of these channels to "digital simulcast" versions instead. If this is the case, there is no way to get TiVo to "see" the analog versions...TiVo follows the mapping information it gets from the CableCARD and won't allow you to tune the analog versions. You are then stuck with the cable company's digital encoding (the TiVo records it verbatim), which can often be inferior to the TiVo's encoding quality and you cannot vary the encoding quality to save space.

 

It's possible your cable box was showing you digital versions of your analog channels. Some cable companies don't setup their CableCards to use ADS so they aren't tuning the digital versions of those channels even though they are available.

However, if this isn't the case, then you would actually be viewing the same signal so the only difference you would probably notice is if the output modes are different.

 

But many (most?) do. This means that without CableCARDs, you are recording the analog channels; with CableCARDs, you are recording the Digital Simulcast channels. The quality can be different.

Another thing to keep in mind is that cable companies are free to lock down their Digital Simulcast channels with DRM (by setting the CCI byte to something other than Copy Freely). If this is the case, it can break TiVo-To-Go for these channels (i.e. TTG won't allow you to transfer shows to your PC).

Unfortunately, TiVo doesn't allow you to manually enter channel mapping information. If it did, then you could override the CableCARD map and point TiVo to the analog channels instead (there is nothing subversive here...those channels are freely available to tune however you want). And, you wouldn't even need CableCARDs at all if all you wanted to record was the unencrypted digital channels (as it is today, you need CableCARDs to provide the channel mapping in order to associate guide data with these channels).

Hopefully TiVo will support manually-entered channel mapping someday.