So, if you have made it this far you should have downloaded files from your TiVo, and gotten them into a standard format that is playable on most computers and/or devices. You could stop at this point, and thereby save yourself some additional work. But you may only want to save part of what you downloaded, or you don’t trust Comskip and want to remove any extraneous material yourself. This means editing. Please bear in mind that if you have never done any of this before it will take a few times for you to get comfortable, but I have found that you can quickly master the simple stuff needed to tidy up your downloaded video. So if this looks daunting at first, please do not give up, it isn’t really difficult, just new.
There are lots of video editors to choose from, and I can’t say that I have used them all. If you wanted to do really serious video editing, you might want to use Cinelerra, which is verging towards the professional end, and does both editing and compositing. I suspect that most people just trying to get a decent copy of a show they can keep would prefer something simpler. In that case I would suggest that if you are a Gnome desktop user, you might want to use PiTiVi. For the KDE desktop, the choice is kdenlive. These are products that are generally focused on ease of use for the home, non-professional user. While there can be some differences, generally they share certain characteristics. To begin with, a video signal really consists of a series of frames, each of which is in fact a still image. It is the rapid succession of those images that fools your eye into seeing motion. Generally video frame rates for television are either 25 or 30 frames per second (actually, that last number is more precisely 29.97 frames per second, but 30 is close enough for our purposes.) The United States is a 30 frame per second country, Europe is generally 25 frames per second, etc. When you edit video, at the lowest level you are deciding which frames to leave out. Now you don’t generally deal with frames one at a time, since one minute of US video is 30×60=1800 frames! So you will generally use a monitoring window to pick your start and stop points. But many editors will let you fine-tune your cuts at the frame level.
For my purposes here I am going to demonstrate using kdenlive because I am a KDE desktop user, but you will find that the principles do transfer. One of those principles is that video editors work in projects, and that you add clips to the project. So let’s say you have downloaded a video from TiVo, and you want to remove stuff like commercials, or parts of the program you don’t care about. You would first create a project for that video, and then import the video you downloaded into the project. So open kdenlive, and in the upper left there is an area marked Project Tree. There are four icons in the right of this area, and the one that is a downward arrow is Add Clip. Go find the file you have downloaded and converted from TiVo, and add it. Then drag this file into the Timeline area at the bottom. You are now ready to Edit the file.
First, for terminology. Kdenlive was made to allow you to mix different video clips together to make a single final video. That is why they distinguish between a clip and a project. If all you are doing is cutting stuff out of a single video, the distinction is less meaningful. But you should probably work out of the Project Monitor view since that reflects the edits you are making. the Clip Monitor view retains the full clip you are working from in an unaltered state. Then at the bottom you have a few interesting features. One is the zoom slider. When you are trying to get to the precise place for making a cut, you will probably want to zoom in, but if you want to jump to the next place in the video you may want to zoom out. If you zoom in far enough, you will see each second as a separate mark, and then you will see little tick marks within each second. These are frames. Depending on your profile there will be either 25 or 30 of them (mine is US NTSC, so I have 30 tick marks). Your place in the video is marked by a vertical line through all of the timeline. You can grab it and drag it when zoomed out, but you can move back and forth one frame at a time using the arrow keys on your keyboard. So you can make very precise edits.
For a typical TV show that TiVo records, you may find there is up to a minute of stuff you don’t want at the beginning. Run the video in the Project Monitor until the actual program begins, and click the button in the Project Monitor that pauses the video. chances are you overshot a little, given reaction time, so zoom in, and use the arrow keys, to get the precise placement. Then go to the bottom right and click on the Scissors icon to select the cut tool, and click on the marker line in the timeline to cut the video there. Then you go back to the bottom right and click the select icon, and go back up to your timeline, click on the area you just cut, and press the Delete key, and it is gone. Then go back down to the bottom right, click on the Spacer tool, and go back to the timeline, Go to the beginning of the rest of the video, and drag it to the left to get rid of the empty space from what you cut out. Then go through the rest of the video, find the beginning of a commercial, select the scissors, cut, then the end of the commercial break, scissors, cut, drag down, delete, and then get rid of the empty space. If you have trouble getting your cuts just where you want them, you are probably not zoomed in enough.