Tech Talk - Videos
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This page was last updated on December 21, 2014.
I have several DVDs and VHS tapes with railroad films from the 1940s, 1950s, and 1960s, produced as promotional films by the AAR and the railroads. To preserve these as digital programs, I capture them as large single files from either the VHS tape or the DVD, then trim them down to their individual parts.
I have found that by converting VHS tapes to standard MPG and MP4 digital files, I can watch them on my computer. I can also copy them to a data DVD, or to a USB thumb drive, which then plays in a wide variety of devices. My video DVD/Blu-ray player will accept a data DVD with both MPG files and MP4 files. My DVD/ Blu-ray player and my Roku streaming video device both have a USB port, and accept a USB thumb drive, making it the preferred method of viewing MPG and MP4 video files. A USB thumb drive also works on desktop and laptop computers.
Much research was done to find the most common, most usable format codec (code/decode) and container combination for standard definition (640x480) videos. Since there really is no uncompressed codec for video, I will default to MPEG-2 for video and MPEG-1 for audio, in the MPG container.
To determine what codec and what container a video file has, I use MediaInfo, a free program that displays "the most relevant technical and tag data for video and audio files."
I use Avidemux (free) to either split a large MPG file into separate files, or delete unwanted portions. The resulting file is saved as an MPG file, which can be cropped in Vegas Movie Studio. The finished MPG file is then converted to a compressed MP4 file, using either Vegas (formerly Sony) Movie Studio, or the (free) VLC player.
VHS tapes, which are Standard Definition 640x480, were played in a new Magnavox ZV427MG9 VCR-DVD Combo. The quality of the picture is the best I've ever seen from a standard definition VHS tape. (As of 2020, this machine has been discontinued, without a replacement.)
The video from the VHS tapes is captured with an analog video capture device (currently a Roxio Easy VHS To DVD USB Dongle) as standard 720x480 MPEG 2 video and MPEG 1 audio, in an MPG container. This file is then loaded in Vegas Movie Studio. The process also includes using the Audicity free audio editor to normalize the audio and fix the DC Offset, a factor of all video captured from VHS tapes. The video image is cropped to remove the fuzzy lines at the bottom of every video displayed from a VHS tape, and the video given a light Unsharp Mask to clean up the resolution a small bit. The video is then rendered as a 640x480 MP4 compressed file.
After trying several video editing programs (including Adobe Premiere and Premiere Elements, and many other editing programs of varying quality and price), I have found Vegas Movie Studio to be, by far, the easiest to use for this basic and minimal effort at capturing and preserving VHS and other analog videos. The program's big brother, Sony Vegas Pro (at four times the price) has become the number one suite for Windows-based video editing. The amount of in-program help, known as "Show Me How," is a wonderful benefit that none of the other programs have, including the high-end Adobe Premiere.
To capture video from a DVD, of all the programs that have flooded the market, I find the Xilisoft DVD Ripper to be the easiest to use, and which produces the largest files, meaning that they are the least compressed. It produces MPG files with 720x480 MPEG-2 video and MPEG-1 audio that open nicely in Avidemux and Vegas Movie Studio.
Both Roxio Easy VHS to DVD, and Xilisoft DVD Ripper capture video as 720x480, which is the standard 3:2 aspect ratio for DVDs. The movies being captured are from the 1940s through the 1960s, and were produced as 4:3 aspect ratio, which is the same as television and VHS tapes, or 640x480. This difference means that they need to be re-formatted, which is done in Vegas Movie Studio. At the same time, I crop off any top or side black bars, and the fuzz at the bottom of the image. The video is also de-interlaced.
For DVDs, standard definition aspect ratio is 3:2, also known as wide screen, or 480p. High definition television (HDTV) video is 16:9 aspect ratio, and can be either 720p (1280x720) or 1080p (1920x1080).
In a recent discussion of VHS tapes and DVD video, one reply included the following information:
NTSC DVDs are indeed 720x480 pixels, but never have a 3:2 aspect ratio. How? First, 8 pixels on either side are supposed to be unused, which trims the DVD to 704x480. Second, the pixels are rectangular, not square.
On a "full screen" DVD the aspect ratio is 4:3, just like tapes, and the pixels are thin (taller than they are wide, width:height is 10:11). On a "wide screen" DVD the ratio is 16:9, and the same 704x480 pixels are fat (wider than they are tall, width:height is 40:33). A single bit in each track's header specifies whether the track should be interpreted as "full screen" or "wide screen."
HD pixels are square, which makes the math a lot simpler.
Editing Video Files
To perform basic editing (such as trimming and splitting), which does not require the video and audio streams to be re-coded, I use Avidemux. This description comes from their web site: "Avidemux is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types, including AVI, DVD compatible MPEG files, MP4 and ASF, using a variety of codecs." I always save the result as "Copy - Copy - Mpeg-PS (ff)" which results in a Program Stream MPG file with MPEG-2 video and MPEG-1 audio.
I have already mentioned that I use Vegas Movie Studio. This allows me to change the aspect ratio of the captured videos from 720x480 (3:2), to the original 640x480 (4:3), the ratio of the original productions. Rendering them to the different aspect ratio also allows me to crop out the VHS fuzz at the bottom, and any minor black bars on the sides or the top. I also de-interlace the video, and do some minor unsharp mask sharpening and if needed, some minor de-saturation of the colors.
I have used Handbrake (free) and the VLC player (free) to do simple re-coding from MPG to MP4. Both work fine, and they are both free. Handbrake allows cropping, but not trimming or splitting, and will only save as MP4 or MKV. The MP4s produced by Handbrake are larger files than MP4s created by VLC; both are larger than MP4s rendered by Vegas Movie Studio.
I have noticed that for video that I recorded with my own VHS video camera many years ago, the video and audio are in sync for the original captured MPG files, but are out of sync on MP4s produced by Vegas Movie Studio. However, the audio and video are in sync for MP4s produced by Handbrake and VLC. This means that the MPG files need to be properly cropped and processed prior to re-coding to MP4. Of course, this is not an issue for much larger MPG files.
I use the VLC Media Player from VideoLan as my "double-click to open" player for MPG and MP4 video files.
VideoLan (VLC) Player -- A free, open-source video player, for Windows and Mac. Plays MPG, MP4, AVI, and MKV very nicely (and TS if the need arises). The VLC Player also works very well to play standard video DVDs in any computer.
Wikipedia AVI Container (AVI)
Wikipedia MP4 Container (MP4)
Video Codecs and Formats
Codec = Coder/Decoder
Wikipedia MPEG 2 Format (MPG) (used for digital broadcast and DVDs)
Wikipedia H.264/MPEG-4 Format (AVC) (used for Blu-ray discs)
Video Help and Advice
In addition to using Google search to find answers, I use two sites to help me better understand digital video:
Videohelp.com -- Advice and reviews of a wide variety of digital video hardware and software; a large user community provides lots of help.
Afterdawn.com -- Their "Guides" and "Glossary" are especially useful.
Working With Digital Audio
Tech Talk -- Audio -- How I do audio.