Version 7 has significantly extended the quality and breadth of Help+Manual's media support:
All images, images with hotspots, toggle images and videos now have an additional display option: they can auto-scale with the document window.
The new option "Zoom is proportional to document width" in the Insert Image and Insert Video dialogs changes the function of the Zoom setting. A zoom percentage of 50% then defines the image or video as 50% of the available document width. If the browser or viewer window is made wider, the image or video expands with it.
If the width is defined as any percentage less than 100% (i.e. up to 99%), the image will only expand up to its native width but will not zoom further to prevent excessive scaling. Setting a width of 100% turns this off and allows unlimited scaling.
This is essential for responsive design in websites. But it is also useful in static formats like PDF, because it defines the width of images precisely as a percentage of the page width.
Help+Manual now directly supports SVG (scalable vector graphics) images as a regular web image format. You can open and insert SVGs in topics in the same way as any other images, using the Insert Image tool.
The display of SVG graphics in the Help+Manual editor may not be 100% identical to the display in web browsers. This is a limitation that applies to editing and printing only. When you publish to HTML-based output formats (WebHelp, HTML Help, ePUB, eWriter, Mobi etc), the SVG display in the browser depends on the SVG capabilities of the web browser.
In CHM the limited embedded Microsoft browser may cause problems for some SVGs and because of this they are converted to PNG files by default. You can disable this if you want in Configuration > Publishing Options > Microsoft HTML Help > HTML Export Options, to force export of SVG images in their native format. See here for details.
In DOCX SVG files are always converted to PNG because only Word 2016 in the Office 365 suite supports SVG graphics. All earlier versions of Word don't, so they are converted to PNG for maximum compatibility.
The video tool now includes dedicated support for YouTube and Vimeo videos and Prezi web-based presentations. You can embed them directly in your topics in the same way as you would by getting the embed code direct from the original sites.
It does this by embedding an iFrame that allows the online media site to deliver the content directly in the most appropriate format for the user's device and browser. This provides much more universal compatibility across all desktop and mobile device types.
See Videos and Animated Media for details on using these new features. Also see the Interactive Media tutorial project that you can access directly in the Welcome page at the top of the Project Explorer on the left.
Local video files have always been problematic in CHM files because of limited media support in the Microsoft CHM viewer. Web-based video on sites like Vimeo, YouTube and Prezi are the best way to provide modern video content in CHM with a high level of compatibility.
However, you don't want CHM files to establish a connection to the Internet unless it's really necessary. By default, online videos in CHMs will only display a placeholder image when the topic containing them is displayed. The video won't actually connect to the online media site and start streaming until the user explicitly starts it. Then the preview image is replaced by the iFrame which loads the online site and streams the video.
Using this two-step mechanism, the CHM file stays "silent" and does not request an Internet connection unless the video has been started by the user.
Note that videos in CHMs can also be responsive, scaling automatically with the viewer window.