When we first started in this business some four decades ago post production was often the limiting factor in the complexity of your presentation and, since everything was analog, the sound and picture quality as well.
Back then, every single time you edited, changed, put in effects and distributed your production it "lost a generation." This means that it got worse and worse and worse every time you touched it.
Today it's all digital. We shoot with HD full digital cameras. We record both video and audio onto HD full digital storage. We transcode the video and sound into an HD full digital editing system. Editing of video and audio and effects are all performed in full digital HD with 5.1 surround sound if needed. Finally, distribution is fully digital direct to the broadcast facilities or onto DVD or the Web.
Now it's true that all of this "HD full digital" stuff sounds repetitive....but it IS important.
It means that from the initial capture of scenes through the post production and broadcast or DVD distribution, your presentation remains fully digital. It NEVER goes through the horrible loss of quality that comes with any move into the analog world.