Different tape playback devices, different recording devices, different capture devices, different broadcast processes, different retail tape mastering processes, and different display devices will render borders and border signals/pulses differently, even from the same tape played in different machines. One SMPTE tape standard places the core image inside the middle 704 pixels of a 720-wide frame, sometimes making black borders equal on each side, sometimes placing the image off to the left or right with uneven side borders. Some players create 2 to 4 pixels of bottom-border head-switching noise, another player with the same tape will have 8 to 12 pixels of bottom noise.
Users who are new to capturing are often surprised by border effects that are usually masked by TV overscan (yes, your HDTV does indeed use overscan by default, and it can't be disabled on cheap TVs). Newcomers are also surprised to learn that, for more advanced users, analog tape digitizing involves (a) lossless capture, (b) lossless repair and restoration of common defects and other imperfections, (c) lossless final edits, and (d) final encoding and output. Capture is only the first step, and there is often a great difference between capture and final output.
Advanced users are also accustomed to viewing video frames directly from the video, well aware that media players are not the way to create samples and that media player display often has little accuracy compared to more conventional methods of analyzing video and making frame images. Media players are exceptionally poor editors. The easiest way to get direct copies of frames from a video is to open the video in
VirtualDub or your editor and copy the frame directly to the Windows clipboard, then use a graphics editor to create an unaltered image. In
VirtualDub you make a direct frame copy by clicking the top-menu "Video" item and then clicking "copy source frame to clipboard". For purposes of analysis, the way your video looks in your media player is irrelevant unless your question deals with a media player problem.
One example of a typical border and noise problem from earlier and different players is a VHS recording I made with a cheap RCA 2-head VCR back in 1979 from a bad analog cable signal. For many years of playing this tape on CRTs I was never aware of the border noise that the original cheap VCR placed on the tapes it recorded. Played back with different VCRs and capture devices today, the side borders are sometimes very slightly wider or shifted to one side, and the 4 pixels of bottom border noise show up as 8 pixels on other players. You will get accustomed to these effects early on and will soon learn that most users have several methods for correcting the situation without affecting or distorting the core image.
An unfiltered and unaltered mp4 of the original telecined capture with odd and annoying border noise is
Liv5A_cut_EP_original_cap.mp4 (33 mb).
The repaired and restored final version is
Liv5A_ivtc_cut_EP_playback sample.mp4 (33 mb).
You didn't post capture or processing information for your screen captures, but I will post info on my capture and processing; the original telecined capture was made with a Panasonic PV-S4670 SVHS VCR, a Panasonic DMR-ES10 tbc pass-thru, an AVT-8710 frame tbc, and an All-In_Wonder 9600XT AGP capture card to lossless
huffYUV YUY2. The repair, restoration, telecine removal and color grading were done with free filters and tools from Avisynth and Virtualdub. The mp4's were encoded at moderate bitrates for demo purposes with TMPGenc software.
