Video quality is an important part of a viewer’s live streaming experience. Blurry images, pixelated faces or objects can all detract from the message of the video. So for new streamers learning the ins and outs of how to live stream, it’s useful to know about video resolution — specifically around SD vs HD — and how it impacts the quality of a stream.

In the early days of television broadcast (you know, back in the times of antennas and radio waves) resolution was set at a 480i video format. This “standard definition” format was often displayed in the 4:3 aspect ratio and was meant for display with the same box format television screens of the time.

As we’ve advanced in terms of television and streaming content, we’ve embraced wider screens and newer 720p or 1080p “high-definition” video formats. These are set at the 16:9 widescreen aspect ratio and are ideal for HDTV displays. We’ll get more into what all these details mean later but, rest assured, HD has become the norm for television and video content.

But what about online content and live streaming? Let’s dive into the world of video resolutions, SD vs HD, and review some terms you’ll want to know.

The basics of video resolution

What is video resolution? It’s all in the pixels.

Pixels are individual units of color information. Thousands or even millions of pixels may combine to constitute a visual image. Generally speaking, the more pixels per given amount of screen real estate, the sharper and more detailed the image will appear. The number of pixels displayed on a screen is commonly expressed as resolution. Resolution is presented as (number of pixels in a row) x (number of rows). Common screen resolutions, and hence video resolutions, are 720 x 480 (SD), 1280 x 720 (HD), 1920 x 1080 (Full HD), and 3480 x 2160 (4k).

Another important measure of video quality, frame rate, refers to how quickly the frames, or individual images, of a video change. Frame rate is commonly measured in the unit frames per second (fps). Generally, the faster the frame rate, the smoother the video will appear. The two most common frame rates are 30 fps and 60 fps. 30 fps is on the lower end of the range at which the human eye can detect the pause between individual frames. 60 fps is on the higher end. Hence, videos viewed at 60 fps will generally look better.

You may occasionally notice a resolution followed by either a “p” or an “i”. Without going too in-depth, these simply represent how the video is scanned. The “p” stands for “progressive” which is a more true representation of the display of each pixel as it should be. The “i” stands for “interlaced” which is an alternative technique using shortcuts to display every other line of an image. Progressive will look better, whereas interlaced will often look not as good but can be broadcast easier.

What is SD?

SD stands for standard definition. And while we’ve progressed since the days of 4:3 television broadcast and display, SD is still useful when it comes to the world of live streaming. SD represents what is often thought of as the base level resolution for broadcast and streaming. And while you could technically stream in lower resolutions like 144p, 240p and 360p, you probably won’t want to dip lower than SD at 480p.

However, SD at 480p does have its advantages. Its small size also means less bandwidth, which could help out with your live streaming when you’re in less than optimal internet or upload situations.

Does SD stream faster than HD?

Both SD and HD should stream equally well if there is a sufficiently fast internet connection. If your internet connection is slower, SD may have an advantage. SD requires less bandwidth to stream and will offer a more reliable streaming experience.

Resolution is also relevant to display size, so watching a live stream on a smaller smartphone screen when compared to a larger digital television makes a difference. In the right circumstances, like live streaming from your phone, SD can be a good option, but more often than not you’re going to want to live stream in HD.

What is HD?

HD stands for high definition. For live streaming, HD can refer to a resolution of 720 or 1080 pixels. 720p HD is often referred to as “Standard HD” and is one of the more basic resolution formats for most internet video and streaming. And in many instances it might be the best option when you’re live streaming to social media channels. 1080p HD is often referred to as “Full HD” and is more regularly used for higher quality video and streams.

What is the difference between SD and HD streaming?

HD streaming is higher quality but requires more bandwidth, SD streaming is lower quality but requires less bandwidth.

When looking to stream in HD, you’ll always want to be sure to consider your internet bandwidth. For streaming at 720p resolution, you’ll want to have upload speeds of at least 2.5 Mbps. And for streaming at 1080p you’ll want to have at least double that.

Should I stream in 1080p or 720p?

In many instances 720p should be just fine, however if you’re looking to stream higher quality content than 1080p will always be better.

What’s the difference between SD and HD live streaming?

Hopefully you’ve come to a stronger understanding of the SD vs HD conversation. The main differences between SD and HD live streaming is video quality and the bandwidth required to stream. HD offers superior video quality, but requires more bandwidth. 

So which resolution is right for your live stream? In most instances, the decision between SD and HD live streaming will be based on the amount of bandwidth available to you. Issues with internet and upload speed, views and network availability will all come into factor.

Pulling from Vimeo’s list of live streaming tips, here are some technical questions to ask before you setup your next live stream:

  • Do I have a dedicated Ethernet connection?
  • What is my upload speed? 
  • How many people will tune in? 
  • Is your content private or public?
  • How stressed will your networks be?

Generally speaking, if you can test your upload speeds, internet connection, and meet the Vimeo recommendation for at least 2.2 Mbps, then HD is certainly the preferred option. HD streaming will always be clearer, crisper, and higher quality. Regardless of your content the added detail and sharpness will put you and your subjects in the best light possible.

Thankfully, if the technical side of video resolution has your head spinning, Vimeo offers a live streaming platform that automatically optimizes the video resolution for each viewer based on the users available bandwidth and local computing resources. In addition, users have the option to override and choose their preferred video resolution.

So if you’re a first time streamer looking for an easy way to live stream, consider platforms that can automatically adjust streaming quality so that you can focus on the content of your stream.

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