I don't believe the Denon has any feature for dealing with the problem and even those that do like Onkyo (IntelliVolume) are hit and miss.
IntelliVolume lets you set correction factors for each input. So if you find that on average your CDs are 5dB louder than the cable connected to Video 1, you can set the CD input IntelliVolume setting to -5dB in an attempt to compensate. There was a recent thread discussing volume trim for Yamaha that sounds like the same deal.
Here is why it isn't all that helpful:
Every source has a different average power level. -- Older CDs have much lower average power while newer CDs are compressed and very loud. So if you set a -5dB correction for the CD input but then play a lower power CD, it will be made even lower in volume relative to the cable input. Playing a newer loud CD, the 5dB correction won't be enough!
- Cable channels vary from analog audio to digital audio. Sometimes the analog channels are louder and sometimes the digital channels are louder. The level even varies comparing one analog channel to another analog channel or one digital channel to another digital channel.
There are no standards for mastering audio or broadcast levels so this situation will be with us for a very long time. The best you can realistically do is use the 'dynamic compression' mode (aka 'Midnight Mode') on receivers to compress the dynamic range of Dolby Digital so that the loud explosions aren't so loud. For the analog channels, you are out of luck and just have to keep that remote in your hand to change the volume when necessary.
