Video is very dark when I play on PC, but fine on the Camera LCD display

[Happy Hopping]

So it was 9 am in the morning at my front deck, I am using a Canon EOS 7D w/ a 70 to 200 L zoom lens to take 2 video of the squirrel at my deck. I use M mode at 1/60, F2.8. The LCD display on my camera is just fine, I can see the squirrel in the display just fine

But when I view the video on my PC, it's dark, can't make out most of it. I use VLC and also try Media Player Classic. How come the LCD display shows the video just fine, as I was recording it, but playing those 2 video on my PC turns out to be so dark

Is there anything I can do? at the very least, is there a way to view the video w/ the bightness up?

Update: the video is NORMAL by viewing on my upcoming PC w/ Nvidia 950GTX. However, by viewing the same video on my current PC, w/ 650GTX Ti, it's dark. I can't imagine why

 

[UnknownSouljer]

There are a few different things here, all of which could be issues.

1.) Exposure Problems: When in dark situations and looking at a 'lit screen', it's important to use objective tools to determine exposure. It's critical to know things like how to use waveform (and use IRE to know precisely the brightness levels of objects in a given scene). On a camera like the EOS 7D, unfortunately a lot of those exposure tools are unavailable. The best you can do is aim for -2 or -1 EV and hope that is bright enough. The point being is that how some things appear on a screen doesn't mean it's exposed properly. It still could be easily underexposed and you're dealing with brightness or gamma on your various displays being inaccurate on one or more devices whether they're too high or too low.

2.) Color Management Problems: The 'fun' thing about Windows is that there is no standardization and color management. In general it is terrible. Even getting full 10 bit support across everything is a pain in the ass on Windows. VLC as an example isn't color managed, which is a shock even to me as it more or less is the defacto player for a lot of people.
Color management problems can exist anywhere in your signal chain. The issue could be hardware, software (programs), drivers, monitor, and/or monitor calibration problems. If you can straighten all of that out, then you can reliably see how things "actually are" across all of your devices. Here are some fun examples: VLC isn't color managed, but on macOS Quicktime is. Safari is color managed. Firefox is not but it can be turned on through console commands. Making sure your display and calibration for your display is accurate to rec709 is another problem, etc. Again, it can be any number of items in your signal/software chain.

As far as you last question, yes you can brighten up your video in post, at least to a certain degree. You are just adding gain to the signal at that point, and you're likely dealing with not a lot of signal data (it was dark). Definitely expect your image to break up quick (increased noise, possibly banding, etc). The 7D is a low bitrate, 8-bit, 'video' camera. It really has to be shot fairly close to correct exposure to get good results. There isn't a lot of wiggle room in post, although more can be had if you shoot with profiles like the Technicolor Cinestyle profile.

It was designed for the 5D2 (the camera that revolutionized dSLR video), but it basically works exactly the same on every Canon dSLR from that era (5D2, 5D3, 7D, 6D, 6D2, etc). I wouldn't recommend it if you're not planning on editing in post though. It's designed to give more latitude, but then that requires adding contrast back into the image in post. In other words, it adds an extra step that you may not be interested in doing (color correction and color grading).

 

[Zepher]

Color settings in the PC's app or filter, or nvidia setting for that codec.

 

[Happy Hopping]

the video is not ideal. The front deck is somewhat dark, so I assume since the LCD is fine, the output would be. At the backyard w/ good sunshine, I don't have this problem. So in the future, I'll increase the brightness regardless. The only thing I didn't mention from the above, is that the nvidia driver on the new PC is 1 yr. newer than the one in the old PC