Video quality is a very important part of a viewer’s streaming experience. Blurry images, pixelated faces or objects can all detract from the message of the video. For streamers learning the ins and outs of how to live stream, it’s also useful to know about video resolution — specifically around SD vs. HD — and how it impacts the quality of a stream.
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.
When it comes to streaming online content to your audiences, you're going to want to make the best decision around video resolution for those viewers. So let's dive into the world of video resolutions, SD vs. HD, and review everything you should know.
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The basics of video resolution
Before jumping into the nitty-gritty details of SD resolution and HD resolution, let’s review a few other important components of video resolution: pixel size, frame rate, and “progressive” vs. “interlaced” scanning techniques.
Resolution = (number of pixels in a row) x (number of rows)
🔲 Pixel size
What is video resolution? It’s all in the pixels.
Pixels are units of color information. Thousands, even millions, of pixels combine to create visual images. Generally speaking, the more pixels per screen real estate, the more detailed the image will appear.
The number of pixels on a screen display is commonly expressed as the resolution.
Common screen resolutions (hence video resolutions) are:
- SD video quality: 720 x 480
- HD 720 resolution: 1280 x 720
- HD 1080 resolution (full HD resolution size): 1920 x 1080
- 4K resolution: 3480 x 2160
🎞️ Frame rate
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. On the lower end is 30 fps, the range at which the human eye can detect the pause between individual frames. On the higher end is 60 fps. Videos viewed at 60 fps will generally look better.
🔎 Progressive vs. interlaced scanning
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 accurate 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 not look as crisp, but it can be broadcast easier.
What is SD video?
SD stands for standard definition video and has an aspect ratio of 4:3. And while we’ve progressed since the days of the 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.
Does SD stream faster than HD?
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 are experiencing less-than-optimal internet or video upload situations.
Resolution is also relevant to display size, so watching a live stream on a smaller screen smartphone or laptop compared to a larger screen 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’ll want to live stream high-quality video in HD.
Standard definition vs. high-definition streaming
What is HD video?
HD stands for high definition and has an aspect ratio of 16:9. For live streaming, HD can refer to a resolution of 720 or 1080 pixels.
- “Standard HD” is often thought of as 720p 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.
- “Full HD” is often thought of as 1080p HD — or 1080 video — and is used more regularly for high-resolution, higher-quality video and streams.
When looking to stream HD videos, 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.
- For streaming at 1080p, you’ll want to have at least double that speed.
What does the "p" in 1080p stand for?
The "p" in 720p and 1080p stands for progressive scan, where all lines of pixels are displayed simultaneously, which is what provides a smoother image to the viewer.
The "i" in 1080i and 720i stands for interlaced scan, which displays lines in alternating fields. In other words, 1080i is a video format with 1080 lines of vertical resolution, using interlaced scanning to display the image. To that same end, 720i has 720 lines of vertical resolution.
Should I stream in 1080p or 720p?
What’s the difference between SD and HD live streaming?
Hopefully, you have a better understanding of the SD vs. HD conversation. The main differences between standard definition and high-definition video streaming are 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 factor in.
Pulling from Vimeo’s list of live streaming tips, here are some technical questions to consider before you set up your next live stream:
- Do you have a dedicated Ethernet connection?
- What is your 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 speed and internet connection and meet the Vimeo recommendation of at least 2.2 Mbps, then HD is the preferred option. HD streaming will always be crisper, clearer, and provide a higher picture quality. Regardless of your content, the added detail and sharpness will put you and your subjects in the best light possible.
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SD vs. HD video quality for streaming movies
As with live streaming, streaming movies — from an OTT like Netflix or Amazon Prime, for example — in SD will result in lower video quality than streaming in HD. If you have a 4K TV, HDTV, or other device that can display a higher resolution — and fast internet with high bandwidth — HD will give you a better quality stream.
Video optimization FAQ
Is 4K video HD or 1080p?
4K video resolution has four times the resolution of 1080p. Both are considered HD video.
What is full HD resolution?
Full HD resolution is another term used to describe 1080p.
What is the highest-quality video resolution?
In the TV and camera markets, an 8K resolution is the highest-quality video resolution you can find. 8K resolution devices have a pixel count of 7680 x 4320. Both 8K and 4K videos are considered UHD or Ultra HD (Ultra High Definition).
What pixel size is 1080p video?
1080p has become the “industry standard” for clean, crisp HD videos. These “full HD” videos have 1920 x 1080 pixels.
What affects video streaming quality the most?
The single factor that affects video streaming quality the most is the speed of your internet. If you have a high-speed network, you’ll likely be able to stream without experiencing buffering or a drop in image quality.
How do video resolution differences affect the viewing experience?
HD provides a clearer and more detailed picture. It can be especially noticeable on larger screens, where SD can appear blurrier or more pixelated.
Do HD videos need more bandwidth and storage space than SD?
Yes, due to the higher amount of detail (i.e., more pixels), HD video files do tend to be generally larger and may require more bandwidth to obtain smoother streaming compared to SD.
What is the difference between HD and 4K Ultra HD?
HD (720p and 1080p) is a step up from SD. 4K and 8K video resolutions are further advancements with even higher pixel counts, offering greater detail than HD resolution.
Does streaming in HD guarantee a high-quality stream?
HD resolution is necessary for a high-quality video, but it's important to note that consistent quality depends on factors the video's compression, the quality of the original recording, and external factors like internet speed.
When should you choose to record or stream in HD instead of SD?
You should choose HD when you want a smoother experience, when the video is being displayed on larger screens, or when your audience has sufficient bandwidth to support the higher data rate for the more professional viewing experience.
For maintaining high video resolution, there’s no place like Vimeo
If the technical side of video resolution has your head spinning, Vimeo offers a live streaming platform that automatically optimizes video resolution based on the users’ video format, available bandwidth, internet speed, and viewing experience. In addition, users have the option to override and choose their preferred video resolution and have access to tools like Vimeo's teleprompter, video editor, and translation and transcription tools.
So if you’re a first-timer looking for an easy way to live stream, consider a platform that can automatically adjust streaming quality so you can focus on your video content.
