Which resolution to choose?

Hello,

1) "On the other hand, why use the resolution 624x352 in my settings instead of 512x288 or 720x405 since in all three cases we end up with the same image format as indicated on the DVDs (but maybe not when played on TV)? "
For nothing, it's just to say that it amounts to the same thing, that is to say the same impression when watching on a television. You choose what you want ;)

We don't see a difference when watching on a TV screen since the image adapts to the screen dimensions for a standard television. I suppose it must be the same for an HD screen, but I don't own one. So why use 720x405 instead of 512x288? That's a good question... I don't really know.
For example, according to standardized disc formats, in PAL, DVD-Video (720x576), SVCD (480×576) or VCD (352×288), we have different resolutions but we don't notice it when watching this type of disc on a television. For compressed formats, like DivX/XviD, it must be the same.
However, for devices like digital players or mobile phones, image resolution is an important parameter, otherwise, it's impossible to watch the video. It's the same for standard televisions (non-HD) that cannot play beyond a certain resolution, as in the case of so-called HD films with a high resolution, I believe. These screens (SD for Standard Definition: PAL, NTSC or SECAM), I believe do not support more than 720 pixels in width and 576 pixels in height, noted in shorthand as 720 x 576 but I'm not sure. Because I can indeed watch HD channels on my standard television thanks to my FreeBox, so I still don't understand everything.

Important:
Moreover, in terms of video, it doesn't matter regarding the weight (size) of the file. It's the bitrate, or video bitrate, expressed in Kbps, that counts. The higher it is, the "better" the "quality" can be and vice versa. It’s basically the amount of data per pixel that makes the quality finer or less fine, thus of better quality. You have more information in an image, so it's heavier, it seems to me.
I had fun some time ago encoding the same file with two different resolutions while keeping the same bitrate, and I did indeed get two files of the same size but with different resolutions. See Image: http://img17.imageshack.us/img17/163/rsolution01.jpg

Caution, everything I write below should be taken with caution, as I'm not sure about what I'm saying. I tend to confuse resolution and image definition, which are two different things. I'm drafting as I go along as I find information!
You have this article on Wikipedia: https://fr.wikipedia.org/wiki/R%C3%A9solution_num%C3%A9rique
Very good article: http://www.plasmareview.fr/articletechnique.php3?id_article=801
According to this tip: https://www.commentcamarche.net/contents/1191-infographie
The image is calculated in pixels, the higher the resolution with big numbers, the more pixels you have. For example 720x405= 291600 and 512*288 = 147456. This is more complicated to process because the calculations are more complex and require a more powerful computer (graphics card, among others) to support it (is this the case for HD?).
You can check this page: http://www.planetenumerique.com/guides-dossiers/Le-DivX-demystifie-Partie-2.html?artsuite=3
But also look at article 1 and the article 2 dedicated to demystifying DivX; they are very instructive.
On the other hand, on a computer, with a player like VLC or MPC that adjusts the resolution to the dimensions, you notice that the size is different, without using full screen.
=> For me, opting for one resolution or another is just a matter of visual comfort, but I could be wrong because my skills and knowledge are not top-notch on technical matters.

2)
I'm not very strong in math either. But it seems to me that the rule of three applies.
For example, knowing that the ratio is 1.7777 and the height of the image is 405, 1.7777*405 equals about 720. To find the height, you divide the width by the ratio, so 720/1.777 is about 405.

A+
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Hello zorbek,

Look here, for example the main resolution standards: http://www.gouvenelstudio.com/homecinema/resolution.htm
1.33 (or 4/3) image format used by television
1.37 cinema image format
1.5 (or 3/2) image format used in 24*36 film photography
1.66 35 mm European cinema image format
1.77 (or 16/9) television image format
1.85 PANAVISION cinema image format 35 mm film
2.35 CINEMASCOPE cinema image format 70 mm or 35 mm anamorphic film

There is no strict (HxL) ratio but a few standards to know.
For a non-HD television, a resolution with a 1.77 ratio is quite satisfactory; it's a compromise between 1.85 and 1.66 in 16/9 format. This gives resolutions like 512x288 or 720x405, or about 624x352; you can use your computer's calculator ;)
The 640x480 (ratio of 1.33) corresponds to a classic 4/3 resolution.

For your information, the resolution of a standard DVD-Video is 720x576 in PAL (Europe) and 720x480 in NTSC (North America).

See you later
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Hello,

I think of 640 * 480

Yes, I think it’s important to avoid image issues (too wide or otherwise)

But still test it in 720*480 on a CD-RW and you’ll see what it gives ^^

I'm adding that since you have a 16/9 television of 82 cm, you can probably increase the image resolution. Perhaps 1280x720 might also be suitable.

Now regarding the bitrate, this determines the size of the output file. A DVD-Video has a bitrate ranging from 4500 Kbps to 8000 Kbps broadly speaking, so there’s no point in trying to convert by setting something higher. Moreover, I don't think that's possible. Typically, a DivX movie of about 700 MB has a video bitrate of between 600 and 1000 Kbps.
However, if you choose to make a "HD" movie in quotes, that is to say with a high image dimension (See HERE), you can also increase the bitrate but your file will be larger; however, the "quality" will be better. I believe I read on the forum that some people had "AVI HD" files of over 4 GB or more, but I can't remember where.
So, you see how you want to proceed. Either you choose to make films of about 700 MB, so you can fit 6 per DVD, or you opt for larger films and you will be able to fit fewer on your disk.

Well, I believe you have all the elements in your possession to carry out your conversions, it's up to you to see what suits you best, knowing that this is a relative criterion ;)

See you later
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