How Super Mario Bros. Does Scrolling

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Super Mario Brothers, released in 1985 is probably one of the most famous video games of all time, spawning countless incarnations and spin offs. Super Mario bros helped to define the modern side scroller and platformer genres. It’s simple mechanic of trying to get from the left off the level to the right by jumping on platforms whilst avoiding obstacles helped to cement it into the hearts of people everywhere. 

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So how does scrolling work in Super Mario Bros? One thing to keep in mind that compared to many modern computers, the 8-bit NES is fairly low powered, utilising a variety of the cheap 6502 processor that was popular at the time. Another thing to keep in mind is how graphics on the NES worked. NES games worked on the basis of a 256x240 screen. Everything that you saw on screen was made up of 8 by 8 tiles in the background, which combined into 16 by 16 groups of pixels called blocks. 8 by 8 or 8 by 16 sprites could be placed on top, which could be placed anywhere, although only 8 of these can be drawn in a given scan line.

Many early games on the NES did not even feature scrolling, instead opting to use static screens for different levels, or games like 'The Legend of Zelda' only scrolling under controlled conditions such as when changing between these static screens.

One thing that you’ll notice playing the original Super Mario Bros is that the screen can only scroll right. As you run to the right, the screen scrolls with you, but if you decide to go back the other way, the screen doesn’t scroll back with you and you hit the side of the screen. If a power up happens to go off the left side of the screen, you’ve lost it.

This mechanic of the screen only scrolling one way is intrinsic in simplifying how scrolling works, in order to allow for Super Mario Bros. to have clean scrolling like it does.

Super Mario Bros levels can be quite long. The NES can not hold an entire level in memory, instead it can only load a much smaller section of the level into memory. It holds the loaded section of the background in what is called a name table. The NES can hold 4 nametables, which consist of one byte for each 8 by 8 tile contained in those nametables, as well as space for storing colour palette information for the background. Each nametable consists of 32 tiles in width, by 30 tiles in height, for a total of 960 tiles. This is 960 bytes in size, and the attribute table, which is what stores the colour palette information, takes this up to a total of 1024 bytes, or 1 kibibyte. A screen displayed by the NES uses one of those name tables, and the tiles from them are displayed in the screen.

Scrolling on the NES basically works by applying an offset to which part of the nametable is being viewed, and as the visible portion moves past the right-most part of the nametable, it loops over back to the start.

Now, the NES could use this for scrolling with one of these nametables, but then this would just be the same screen repeating over and over again, as this is the size of the visible portion of the screen.

Instead, scrolling on the NES typically uses what is referred to as mirroring, more specifically, nametable mirroring. There are a few different types of nametable mirroring, which all join up different nametables and are generally used when doing different types of scrolling. Vertical mirroring joins nametables on a horizontal plane to each other, effectively creating a 64 by 30 sized nametable, twice the width of what is visible on the screen.

This is all well and good, but this only accounts for a level two screens wide, unless you want to have the level repeat again. If you’ve ever played or watched someone play Super Mario Bros., you’re probably very aware that levels can be much wider than two screens. So how does Super Mario Bros. achieve having much wider levels?

This has much to do with the fact that only half of the nametable when using this nametable mirroring method is visible on screen. Because only half of the nametable’s tiles are visible on screen, this leaves the other half to have its tiles freely manipulated without this change being noticeable to the end user. When a row of tiles disappears off of the left-hand side of the screen, it can be updated with the tiles that come after the last tiles on the right hand side of the nametable. This process continues as the screen scrolls further, so that when the visible portion of the screen reaches the right of the nametable and wraps back around to the start of the nametable, the tiles there have been replaced, making it seem as though the level continues past this point. To answer the question why Super Mario Bros. only allows you to scroll one way, well the answer is that it is to simplify the scrolling process, as you only need to keep track of scrolling for one direction to replace tiles, as if you allowed scrolling both ways, you would also need to account for replacing tiles as you scroll left, which makes it a lot more complicated.

Of course there are games on the NES that do allow scrolling both left and right, and games like Super Mario Bros. 3 allow you to scroll in all four directions, but how that is done can be a topic for another day.

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Best Free Anime Streaming Services in 2021

Every year, anime is becoming more and more popular worldwide. There are a lot of paid streaming services you can use to watch loads of anime, but there are also lots of free services available that you can use to watch anime. Here we are about to take a look at some of the best free anime streaming sites in 2021. Just keep in mind that some of these services may not be available in every country, and that availabilities of certain shows is often restricted to certain regions.

Crunchyroll

Crunchyroll is probably one of the best known anime streaming sites. This popular site has thousands of episodes of anime shows to watch. Compared to other sites, Crunchyroll has one of the largest catalogues of series available to watch. With a free account, you can watch episodes one week after release, or you can subscribe to Crunchyroll Premium to be able to watch episodes when they release. The site is ad-supported using frequent midrolls, although with a subscription you do not see any ads. Crunchyroll allows all users, regardless of their subscription status to watch series in up to 1080p if supported by that series. In addition to anime, Crunchyroll also has a collection of both Asian drama series as well as manga that you can enjoy.

AnimeLab

AnimeLab is a anime streaming service owned and operated by Madman in Australia and New Zealand. The service offers many series to view free of charge with ads, and also has a subscription to watch ad free. AnimeLab's library is made up by series in Madman's catalogue as well as many series from Funimation. With a free account, you are limited to only watching videos in up to 480p, and up to 1080p with a subscription, although as the licenses for many of these shows are held by Funimation, many of these shows can also be watched on Funimation in 1080p for free. While older series allow you to choose to watch them either subbed or dubbed, newer shows require a subscription to watch dubbed. Like Crunchyroll, AnimeLab allows free users to watch episodes one week after release on the platform. AnimeLab also has anime movies available to watch, as well as some live action anime adaptations, although these also require a subscription. If you live in Australia or New Zealand and can't find a series on a more popular platform like Crunchyroll, you might want to check out AnimeLab to see if they have it.

anime-planet

Anime-planet is an anime and manga fan site that has partnered with content providers such as Crunchyroll to provide episodes of popular anime free to watch on their site. The site features the same advertisements as if you watched on the respective platforms of the content providers, and as it uses the same libraries of these sites, you can also just watch these series on the platforms they come from. You may be wondering why you would want to watch these videos on anime-planet instead of their respective platforms, but as anime-planet gathers videos from different sites, this means that you can just watch videos here instead of having to go between the sites it has partnered with.

Funimation

Funimation has been in the anime distribution business for a long time, originally localising anime releases for a primarily American audience, and has since branched out into offering online streaming. Funimation has a large library of shows, although it appears much smaller than Crunchyroll. Funimation is ad-supported with a free account, but also offers a paid subscription. Free accounts, in addition to having ads also are not able to watch newly released videos. As of the time of writing, some series such as 'Cells at Work! CODE BLACK' may appear to not allow free accounts to watch the first episode, but this is because it defaults to the dub, which is currently not available to free accounts. To be able to watch episodes like these, you will have to go into the video then change the language to English. Funimation has a lot of exclusive series available, so if a series you want to watch isn't available on other platforms, you might want to check out Funimation.

TubiTV

TubiTV is a relatively new streaming site that services the United States, Canada, Mexico, Australia and New Zealand. The site is home to content licensed from content partners. The site has a large collection of film and TV content, including an anime category. While you won't find any hugely popular or new series from big studios, mainly only having older anime or cheap-to-license anime, it does have a lot of series that are hard to find on other sites, so TubiTV may be a good place to find some series that you otherwise would never have had the chance to watch. TubiTV doesn't release new episodes weekly through simulcasts, so don't look expecting to find the latest episodes of a show. A good thing about Tubi is that the site is completely free, with no paid subscriptions, meaning as soon as a series goes live, you can watch it without needing a subscription. One downside though, is that as there is no subscription, there is no way to get rid of ads if you are willing to pay.

iQIYI

iQIYI may be a weird choice for this list since it a Chinese streaming service, but they now also have a streaming service 'iq.com' aimed at an international audience. If I were to have a guess, I would probably say that the site is trying to compete with other sites such as Rakuten's Viki service given that it primarily focuses on Asian drama, and has user-generated subtitles in almost every conceivable language. The site does have an anime section, but as far as I can tell, it seems to all be Chinese animated series. I am however putting it on this list, as although many people likely wouldn't consider this anime, it does have a lot of shows in the general anime-esque art style. With a free account, you can watch episodes in up to 720p, and with a VIP account you can watch in up to 1080p. Some series are also only available to VIPs, as well as new episodes.

Domestic TV Broadcasters

This one is a little open ended, but many free-to-air TV station operators offer free streaming services that you can use to catch up on shows that have recently aired and that you may have missed. The catalogues on these sites are constantly changing, and you often only have a couple weeks to watch an episode, meaning you often won't get to binge a whole season at once. Some great examples of free streaming services provided by broadcasters are BBC iPlayer in the UK (although you will need a TV license) and ABC iView in Australia. Many other large broadcasters will also have their own, so if there is a large broadcaster in your area, you can do a quick web search to see if they have their own. Many of these sites do have a lot of interstitial or midroll advertisements, although a good thing about BBC iPlayer and ABC iView is that they feature no ads as they are paid for by the government either through TV licenses or taxes.

YouTube

YouTube may seem like an unusual place to go looking for free licensed anime, but there is actually quite a bit if you know where to look. At one point about a decade ago, Funimation used to upload anime episodes on their YouTube channel, although there are only in 360p or 480p. Funimation no longer uploads full episodes to YouTube, but as of recent, more and more studios and companies have. Recently a lot of animation studios have decided to start releasing content on YouTube in order to open up a new potentially profitable revenue stream. A few examples of these channels include 'Tezuka Production Offical', 'AnimeLog', and ' GundamInfo'. Based on the recent trend towards media releasing content for free on YouTube, there will probably be a lot more anime series legally available for free on YouTube in the coming years.

Today we have covered eight great places to look for free anime streaming online. For someone on a budget, or for those that don't mind having to watch ads, these sites are great places to get great quality free entertainment.

How to Crop Videos Using Avidemux

If you need to crop a video because you only need a small area of it, you can achieve this using the free program Avidemux.

In order to get started, you will need to first open the video file in Avidemux. As cropping the video cannot use the same frame data, you will need to re-encode the video. To do this, use the drop-down box under 'Video Output' to select the format you want the encoded video to be in. You can select anything except 'Copy'. 'Mpeg4 AVC (x264)' is the recommended setting, as it is a very common codec. To crop the video, click on the 'Filters' button below that, and click on 'Crop' under 'Available Filters' on the window that pops up.

After double-clicking on 'Crop', a new window will pop up displaying the video. You can adjust the crop using the four number fields in the top left-hand corner of the window, and you can adjust these values finely using the up and down arrows. You can also click and drag the red rubber band in order to set the crop[ that way, and you can use the 'Hide Rubber Band' checkbox to hide the red lines, so you can see exactly what your crop will look like. The 'Auto Crop' button in the top right-hand corner can also be used if you want to remove black bars from your video, it works best if there is a good contrast between the video and the black bars, so you can use the timeline to scrub through the video to find a good frame. Now just click 'Ok' to set your crop. Now just save the video, and it it will encode a cropped version and export it where you want. You can also combine this with other filters as well as only export a segment of it by 

How to Trim Videos Without Re-encoding Using Avidemux

Sometimes you need to trim a long video clip to get a much smaller section, whether you recorded a much longer video and only need a shorter segment, or need a short clip from an already existing video. The problem with trimming videos using traditional video editors is that they require you to re-encode your video, meaning that it takes a long time, especially on low-end computers, and results in a lowering of video quality. Due to these reasons, it can be useful to know how to trim videos without re-encoding, which essentially just takes the data for he frames you want along with its corresponding audio and copies it into a valid video file. Doing this means that it is super quick, only taking as long as it does to read the file from disk and write your new version.

In order to trim videos in Avidemux, first you need to open the video in Avidemux. This can be done either with using the 'File' menu, or by dragging and dropping the video file onto Avidemux. Then you need to select which part of the video you want. This can be achieved by dragging the selector to the part of the video you want to have as the start of your trimmed video. The use the red-coloured button with an 'A' on it. Then, drag the slider to what you want as the end of your video, and click on the button to the right of that 'A' button, which is labelled 'B'. At this point you have selected the part of your original video to use as your trimmed clip.

To export your clip, simply go 'File' then 'Save As'. This will export your video as an .mkv file, but if you want to change the export format, you can use the drop box directly under 'Output Format' on the left-hand side to change this.

How to Resize Batch Files and Command Prompt

While in Windows 10 you can resize command prompt windows however you want, on Windows 7 your options are much more limited, only allowing you to increase the width of the window to less than half the screen. Even though you can't resize it by dragging, you can still use commands to resize the command prompt window, or if you are making batch files and want to resize the window, you can use this simple command:

mode con cols=<width> lines=<height>

Simply replace the text between the '<' and '>' symbols with the width and height (in character width) you want respectively. You will also need to remove the '<' and '>' symbols, otherwise the code will not work. If you only want to change either the width or height of the window, you can use just the cols or lines part of the code after mode con, to just change that.