Linking to images and video

Images

If an image exists somewhere on the internet, you can link to it rather than uploading it to Scripta. Here is the model:

image ::URL[]

where URL is something like http://whatever. Thre is no space between 'image' and '::'

3307745854 b3662e0ab3 b d
3307745854 b3662e0ab3 b d
Figure 1. is this a kind of robin?

You can also format the images in various ways, as in the image on the right. Here we used float. Another useful word is align. Notice also that we put a caption on this image. i you are using the X option (see upper left), you see how this is done.

Youtube video

The same method works for YouTube video;

video ::URL[youtube]

Source YouTube

You can also set the width and height;

video ::URL[youtube, width=500px, height=279px]

You will want to preserve the width-to-height ratio — the so-called aspect ratios. For the bird video, I did this as follows. First, I measured the YouTube video on my screen: 30.5 cm wide and 17 cm high. The aspect ratio is \(30.5/17 = 1.794\). If I want to make the vide 500 pixels wide, I should make it \(500/1.794 = 279\) pixels tall. As a check, we compute the ratio \(500/279 = 1.792\) — close enough!

This reference has some good historical information.

Vimeo

The same principles apply:

Source; vimeo

*So the aspect ratio is \(26/11 = 2.363\). For a 500 pixel wide video the height is \(500/2.363 = 212\).

Geeky stuff about aspect ratios

The aspect ratio for old-style television is 4:3, and for HD it is 16:9. The "standard" ratio closest to the bird video above is 5:3. This fact can be deduced from the method of continued fractions or from the following simpler methid. Multiply the ratio 1.794 by the integers 2, 3, etc until you get a number close to an integer, as in the table below.

Multiplier Product Value Rounded Error

5

\(5\times1.749\)

8.97

9

\(-0.03\)

2

\(2\times1.749\)

3.588

4

0.588

3

\(3\times1.749\)

5.382

5

0.382

4

\(4\times1.749\)

7.176

7

0.176

Finding the aspect ratio

We conclude that aspect ratio is 9:5

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