I need to know if there will be any difference in the quality of the encoded video if the bitrate of the source file is, let's say 2000kbps and I encode it to 4000kbps.
Any help will be much appreciated.
Thanks in advance.
Yes, the quality will be worse. But probably not perceptually. Encoding ALWAYS loses a little information, that’s why it is called lossy compression. Increasing the bitrate will only reduce the information loss. The best you can do is lossless compression, and it will look exactly like the source
"Quality" is a tricky term. You need to define "quality" before asking whether it will be better or worse. What you surely will not get is more information — you will have only as much or less information that you started with. Visual quality, though may be improved depending on what you do to your video. If your video is interlaced, you can deinterlace it to get rid of combing. Moreover, if it has been incorrectly deinterlaced and the combing artefacts are already baked in, you can remove them. You can change contrast or color. You can change aspect ratio. You can digitally zoom into certain sections. If your video has visible tiling artefacts, a good decoder will smoothen them out, so you can get visually more pleasant video.
But if you are not planning any of the above, then better leave it as is, unless a specific format is required.