Virtualdub vs TMPEGEnc Resolution/Aspect Ratio Differences
1 Attachment(s)
When using Virtualdub to capture with my JVC S9800 > VC500, the video is being captured at 720x480. When I take the resulting AVI file and run it thru TMPGEnc, it still comes out with a frame size of 720x480, however, the actual image is now 640x480. Obviously I know that 640x480 is 4:3 which is the correct aspect ratio for VHS, but so then what's the best way to convert my loseless AVI's so that they also use the correct aspect ratio? Also, is there a setting in TMPGEnc that will allow me to use the original 720x480 frame size and NOT change it to 640x480? Not that I want to do this but I'm just wondering if there is actually a setting that will allow me to.
Here's a sample of what I'm talking about... Attachment 10489 Here's the MediaInfo Data for both files... Virtualdub Original Code:
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Lossless, unencoded 720x480 AVI has no imbedded display aspect ratio data. Its physical aspect ratio (3:2) and display aspect ratio (3:2) are the same.
Encoded 720x480 DVD and 720x480 standard definition Bluray and 720x480 consumer DV-AVI have physical aspect ratios of 3:2, but they can be encoded for display aspect ratios (DAR) of 4:3 or 16:9. The playback display information is imbedded in the encoded video to tell players how to play the video. Playback information does not exist for lossless, unencoded video media -- a player will play them as-is. For posting on the internet, anamorphic frame sizes such as 720x480 are seldom allowed. Internet video players cannot handle those files. Instead, the internet accepts only square-pixel video, i.e, the video's display aspect ratio is the same as its frame size, whether it's 640x480 (4:3), 400x300 (4:3), 856x480 (16:9), 1280x720 (16:9), etc., etc. Anamorphic frame sizes (where the display aspect ratio information is different than the physical aspect ratio) have been in use for more than 70 years. And by the way, a 4:3 video doesn't play at 640x480 on a 1920x1080 display. At full screen size the players play it as 1440x1080. "4:3" is an aspect ratio -- it is not a frame size. A PAL DVD video file at 720x576 has a physical aspect ratio of 5:4 but it can be encoded and play at either 4:3 DAR or as 16:9 DAR. |
I'm only concerned with playing the videos on my PC via MPC-BE and VLC. The only other place I will watch them is on the HTPC in my living room. I don't get involved in social media or any of that garbage, my friends and family actually come visit me in person where we have real life conversations face to face, not over an ethernet cable. :D
So what's the consensus on how to handle this type situation? Do I just let TMPGEnc do it's thing and leave it as it is, or is there a better solution? |
Let TMPGenc and other MPEG encoders do their thing. Further processing of your captures will involve quality issues, depending on how you do it. Your workflow isn't that advanced and you don't yet understand much of it anyway, so continue with the standard way you're doing it now. What you are now getting for final output is standard-spec MPEG for DVD, which is universally playable on anything.
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Not sure how you prepared the sample.
Your player may allow you select the aspect ratio for viewing (VLC does from the VIDEO drop down). |
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I think you just have a problem understanding the format. You are using a DVD encoder. A standard NTSC DVD is interlaced 720x480 encoded using the MPEG2 codec and set for 4:3 playback. That is what standard DVD is, and it is universally playable on HTPC's, TV's, DVD players, Bluray players, and media servers. You can't change the frame size to 640x480 because it's not valid for DVD. If 640x480 is the physical frame size you want, you'll have to do more processing, which will involve deinterlacing and several other things.
If you want your editor or VirtualDub to display the 720x480 frame as a 4:3 image, tell your editor to do so. You can do that for display only, without physically changing the frame size. In VirtualDub, right-click on either the input panel or the output panel (or both) and select your desired display aspect ratio from the list in the resulting menu. If you want your PC media player to display your lossless 720x480 capture as 4:3, you can tell your PC media player to do so. Meanwhile your MPEG encoded final output will display as 4:3 anywhere, by default. If you want another format or different physical frame size, then you don't want DVD encoding and you have some learning ahead of you about formats, processing, and encoding. |
My question is not how you encoded the two files. Both are 720x480.
The question is how did you prepare the GIF file. To repeat what sanlyn in somewhat different words: The VDUB looks like a 4:3 aspect image that is stretched to display as a 3:2 aspect ratio with square pixels. This is not not the normal pixel aspect for SD video in NTSC or PAL, wide screen or 4:3. If you are viewing the VDUB file with VLC, select the 4:3 aspect ration to get it to display right. The image portion (excluding the white edge bars) of the TMPGEnc looks like a normal 4:3 display. And that corresponds to the MediaInfo report. How many pixels it occupies on the display will depend on scaling by the display system. Most computer displays are based on square pixels, but analog SD video and CRT TVs were NOT. It was based on raster lines - pixels only came into play with the move to digital. A not uncommon issue these days with HDMI-connected systems is getting the aspect ratio information correct, otherwise the display may show the video incorrectly. The HDMI connection may preclude the user selecting a different aspect ratio for the program material. |
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