newb: what resolution when going from avi -> DVD?

[vinyl_warrior]

I tried to make a DVD from a widescreen avi using the DVD preset, but when it finished, it didn't look like a normal widescreen DVD. It looked all squished at some kind of 4:3.

When we play DVDs with DVD player, the window is the proper resolution size. That's kinda what I"m shooting for with my DVD conversion (if it's possible). I'm not getting what I think the end result should be.

I tried another avi that seems to be at 1.80:1 ratio, and I used the 1.85:1 video parameter. I ended up with a 4:3 video with black bars, and my video feature was not centered ... it was hanging out in the upper third of the screen.

I really just don't understand how to make a properly formatted DVD, and the simple guide didn't really help.

[edDV]

Use DVD player software and all will be well.

DVD/DV and SDTV resolutions don't use square pixels.

And more, they are non-square in different ways for PAL and NTSC.

[vinyl_warrior]

how do you mean? Just use the DVD preset and everything will be fine? WHen I used DVD player, things weren't fine. I was pretty desperate to have a disc, so I ended up burning one of the converted avis to DVD, and in a standalone DVD player, it didn't display properly either.

I was using the ffmpeg codec, if it makes any difference.

[edDV]

The idea is if you make your 720x480 DVD file with DVD supported pixel aspect ratios and with appropriate 4x3 or 16x9 flags, it will play back properly in a hardware or software DVD player but will not play back in correct aspect when viewed as square pixels straight to a computer monitor.

Same with DV, SD ATSC or any other CCIR-601 derived spec.

HD 1080i and 720p do use square pixels but not 480i/480p.

It doesn't matter what encoder you use. DVD is a spec.
https://www.videohelp.com/dvd

[Case]

- By 'widescreen avi' do you mean 16:9? For wider, you'll need to letterbox to 16:9, either automatic (checkbox) or manual (pixel values).
- For a widescreen DVD, set Autosize to 'DVD 16:9'.

[vinyl_warrior]

the first video file that I had was 624*352. I just used the DVD preset. I understand that DVD is a format, but my video was still all squished. Does that mean that the proper tags weren't added?

- By 'widescreen avi' do you mean 16:9? For wider, you'll need to letterbox to 16:9, either automatic (checkbox) or manual (pixel values).
- For a widescreen DVD, set Autosize to 'DVD 16:9'.

Case, I don't understand most of what you just said. I think I understand that you're saying I will need to add black bars to any video that's over 16:9, but that should just add a bit on the top and bottom to shrink things to spec. I don't know the automatic and manual you're talking about. Are you referring to the Decode with Quicktime option?
And when you say 'widescreen dvd', what do you mean? Does the aspect ratio matter?

One thing that screws me up is the Video Size in the video parameter. It's values never seem to make any sense. They change in weird ways based on what you're selecting from the drop down, and if you select A, then B, then A, A actually has a different value than it did the first time, so it's more of a C value.

[edDV]

624x352 isn't a DVD supported resolution you will need to scale it to 720x480 or 704x480 in pixel aspect ratios that meet DVD standard for 16x9. 624x352 is near 16:9 in ratio but has square pixels. 16x9 DVD pixels are wider than tall.

I'll let others tell you how to do this in ffmpeg. I haven't used it.

[Case]

Case, I don't understand most of what you just said. I think I understand that you're saying I will need to add black bars to any video that's over 16:9, but that should just add a bit on the top and bottom to shrink things to spec.

Exactly. But with your 624*352 avi, you won't need letterboxing, as your source movie is already 16:9 (624/352 = 1.77:1 = 16:9).

I don't know the automatic and manual you're talking about. Are you referring to the Decode with Quicktime option?

In ffmpegX, if you select 'Decode with Quicktime', there is also a checkbox for 'letterbox'. That option will make the black bars to fit, if needed. Only use this if the source file plays well in QuickTime Player. If you do not 'Decode with Quicktime', then the letterbox effect can be done by the manual values in the Image Filters section.

And when you say 'widescreen dvd', what do you mean? Does the aspect ratio matter?

Yes, aspect ratio matters. DVDs can be "enhanced for 16:9 widescreen TVs" aka presented in "anamorphic widescreen". Widescreen DVDs look good on 16:9 and 4:3 screens, but letterboxed 4:3 DVDs look less on a 16:9 screen. It's about preserving 25% more vertical resolution. For this to work, the encoder (ffmpegX) has to know about it and set a "16:9" flag.

[vinyl_warrior]

ok, this information has helped give me some insight into how the DVD format works, but it still hasn't really helped me figure out what to actually do when I want to convert a video. Sorry!

Can we run through a couple scenarios so that I can start to understand the methodology and how it translates into ffmpegx settings?

1. avi 624 X 352 -> DVD
2. avi 865 X 480 -> DVD
3. avi 720 X 400 -> DVD
4. avi 720 X 320 -> DVD

I think these resolutions should all be slightly different enough that I can learn from the differences between them.

[Case]

1. avi 624 X 352 (ar 1.77:1) No letterboxing needed
2. avi 865 X 480 (ar 1.80:1) Letterboxing 3px+3px (*)
3. avi 720 X 400 (ar 1.80:1) Letterboxing 3px+3px (*)
4. avi 720 X 320 (ar 2.25:1) Letterboxing 50px+50px

(*) on 2 and 3, 3px is so small, that nobody would notice if you did not letterbox.


Drop avi, select DVD ffmpeg, set Autosize to DVD 16:9, leave letterbox at 0,0,0,0 for avi 1-3 and 50,50,0,0 for avi 4, encode.

[vinyl_warrior]

so even though they are at certain aspect ratios, I don't select those specific rations from the drop down?

[Case]

From the developer's site:

[Autosize] Use this pulldown menu to set a predefined video size values (eg VCD or SVCD), or to calculates the height from the width by applying the specified ratio (eg 2.35:1, 16:9 or 4:3). Using 16:9 ratios or presets also apply a 16:9 special flag to mpeg-2 streams.

For DVD, you have to use a valid predefined size (VCD, Half DVD, DVD, DVD 16:9).
For video with no predefined size, the drop down is just a tool to set the height according to width, or vise versa.

[vinyl_warrior]

what do I have to do with the video size setting? do I have to manually put in the scaled 16:9 resolution?

one of the videos is strange (the 865*480 one). that's a resolution I get from playing it in quicktime, but ffmpegx lists a different resolution for it in the source format menu: 712*480.

Also, in order to make the letterboxing happen, do I have to decode with quicktime?

[Case]

what do I have to do with the video size setting? do I have to manually put in the scaled 16:9 resolution?

If you select 'DVD' or 'DVD 16:9', then ffmpegX will fill in a size of 720x480 for NTSC or 720x576 for PAL. Leave it at that. DVD stores different than it displays. It's part of the DVD specs.

one of the videos is strange (the 865*480 one). that's a resolution I get from playing it in quicktime, but ffmpegx lists a different resolution for it in the source format menu: 712*480.

I thought that was strange, as most codecs require/work best with a res that is a multiple of 8 or 16, which 865 is obviously not. For some reason QuickTime thinks it needs to stretch it for playback. QuickTime shows the display resolution, which can be different from the stored resolution. This may influence the conversion aspect ratio, whether you choose QT decoding or not. Using the Play button in ffmpegX may show the video in 712 wide. See which looks best for aspect ratio.

Also, in order to make the letterboxing happen, do I have to decode with quicktime?

No, you don't have to. For QuickTime decoding, use the LBX checkbox. With QT decoding off, use the Image Filters fields. Pick one.