Live streaming is, for the most part, an activity that’s really easy to get into. You don’t need much in terms of software or hardware to get started — you can easily broadcast with nothing more than your smartphone.
But no matter how low the barrier to entry is set, there are still plenty of technical processes that happen under the hood to make live streaming possible. Transcoding, for example, can ensure your stream is watchable on lower-speed internet connections.
Let’s look at what transcoding is and how it works — and why it’s important for streamers.
👀 What is transcoding?
Transcoding is the process of taking a video file that’s been encoded, decoding it, making some kind of alternation to it, and then encoding it again. Since the encoding of data determines the type of compression, as well as the bitrate and resolution of the video, these are the things you can change during transcoding.
⚙️ How does transcoding work?
Let’s look at an example. You create a video using the MPEG-4 codec (a piece of software that got its name from its main function as coder-decoder). However, the source where you’re sending the file can only ingest files encoded with the H.264 codec. In that case, you would transcode it using the H.264 codec to get a file with a different type of compression.
Other types of changes that happen during transcoding are more obvious since they affect the quality of video in a more immediate and visual way. These are:
- Transrating: a type of change where the bitrate of the video is lowered, reducing its quality and size for easier ingestion over lower-bandwidth connections.
- Transsizing: a process of changing the resolution of the video, also reducing its quality and size and making it easier for ingestion over low-bandwidth connections.
What you can’t get while transcoding is a file with a different extension. That would require the change of the file format, and that’s not something that happens during transcoding. Transcoding changes the contents of the file. If you need to change the container, the process is called transmuxing.
🤔 Encoding vs. transcoding
To better understand transcoding, it helps to know what encoding is as well. Encoding is the process of taking the data from the devices that capture video and audio information — your webcam, microphone, capture card, or streaming software — and converting it into a digital format you can send to streaming platforms. In a regular streaming setup, encoding plays a middleman role by helping the input and the output communicate.
The encoder relies on a codec to dictate how the raw data from your webcam, for example, is compressed and formatted. H.264 is arguably the most popular codec for live streaming, and you can use it to create video files of up to 8K resolution.
The important thing to remember is that, during the encoding, the various parameters that determine the quality and size of your video (such as compression, resolution and bitrate) are determined. That data is packed in a container, which is what holds the information about the structuring of the data and the file metadata, and at that point you have a video file.
🕹 Why is video transcoding important to streamers?
Transcoding is a resource-intensive process, but lots of platforms are still offering it, and that makes both the streamers and their viewers happy. You see, live streaming tends to attract global audiences.
The world’s average fixed broadband download speed has increased by 31% in just one year and is now around 67 Mbsp. However, the actual speeds vary widely between different countries, different regions in the same country, and different types of connections available.
A viewer in Singapore, for example, can easily handle watching your 4K@60fps stream. Viewers in most South American countries will not have enough download speed to watch it at all, and in a fair share of European countries, people wouldn’t be able to view you on mobile devices.
How does transcoding help?
Broadcasting a stream solely at a high bitrate and resolution, without the option to downgrade the quality, might inadvertently prevent a sizable chunk of your audience from watching you. And that’s the problem transcoding solves.
So let’s say you’re streaming live video to a network at its maximum recommended settings — a 1080p resolution at 60 frames per second with a bitrate of 6000 kbps. These are the highest recommended settings for Twitch. You never want to go over the maximum recommended settings because that can cause your stream to become unstable.
When the platform ingests your high-resolution, high-bitrate stream, it can transcode the stream to create an array of streams at different resolutions and bitrates. Then, the platform can use adaptive bitrate streaming to deliver the content that fits the viewers’ bandwidths the best.
On the viewers’ end, it would look like this: someone viewing your video on a desktop computer using a broadband connection with a high download speed would enjoy the full quality of your stream. If they have a temporary slowdown of their internet connection, the quality of the stream might be lowered to allow for an uninterrupted streaming experience.
At the same time, people can watch your stream on mobile devices at a lower resolution, with a lower bitrate and a significantly lower download speed requirement. Thanks to transcoding, you only have to make the one, original stream, and the platforms take care of the rest.
💻 Do all platforms offer to transcode?
Even though it’s a very useful feature, transcoding isn’t supported by all platforms at all levels of access. This is one of the reasons behind the differing stream qualities on streaming platforms.
Some platforms don’t offer much in terms of transcoding. These usually have rigid quality requirements that match the output on the platform. Other platforms, however, might offer some transcoding services. On Twitch, for example, all streamers have access to transcoding as it’s available. Twitch Affiliates, however, get priority access to transcoding, while partners have full access to transcoding options. Meanwhile, you can freely choose to stream at lower bitrates and resolutions if you worry your audience might not be able to see you. Twitch is more flexible in that regard than other platforms.
And then there’s YouTube, the platform that recommends you stream at a quality that ensures a stable live stream, and takes care of all the rest. That’s because it offers full transcoding of all streams. It will also give you the ability to use a variable bitrate for your stream, which is something Twitch doesn’t do.
↔️ Transcoding examples
Here are some ways transcoding is used:
- Changing a high-definition video file to a lower resolution
- Converting from a high-res editing format like Apple ProRes to a delivery format like H.264
- Converting a Windows Media File into an MP4 format so it can be played on another device
- Making videos uploaded to YouTube’s site available in multiple qualities and formats
🦑 Transcoding and streaming to multiple platforms
If you want to stream your video to multiple platforms at the same time, you might wonder how is it possible to simultaneously stream to a no-transcoding, fixed-video-quality platform and a platform such as YouTube that lets you really push the quality of your stream to the limits.
Well, you have two options. You can either set the streaming quality to that of the lower quality platform, or you can let Restream handle transcoding for you. That way, you can stream at the highest quality to Restream, and then Restream will transcode your stream to meet the requirement of the platform that offers lower-quality streams.
After you’ve purchased a certain amount of hours of transcoding from Restream, you’ll have the option to set it up to match the specific channels’ requirements.
Does transcoding reduce quality?
Yes, transcoding can reduce the resolution quality of a video in order to meet the limits of an end platform. Downgrading quality for a specific platform without having to compromise the quality of the original video is one of the main use cases for transcoding and live video.
How long does it take to transcode a video?
The time to transcode a video is usually 1:1, meaning it takes as long as the duration of the video to transcode. So a 10-minute video would take 10 minutes or less to transcode. The time also depends on the tool you use to transcode.
Is transcoding the same as encoding?
Transcoding and encoding are not the same process. Encoding refers to taking a raw video source and compressing it; smaller files are easier to use with more devices and platforms. Transcoding is taking a video that is already compressed and transferring it to a different quality or format.
Why do you need to transcode footage?
Transcoding video is important for streamers because it makes the video accessible to almost all types of viewers, no matter the internet download speed in their geographic area. It downgrades the quality of the video so that a viewer with slower internet isn’t sitting in front of a buffering wheel the entire time your stream is up.
Let’s wrap it up!
For streamers and platforms alike, the ability to attract the most viewers possible is a natural imperative. There’s so much noise and competition out there, and serious streamers and platforms need to be able to reach their potential audience with the best user experience possible.
Transcoding is just the tool for the job. It’s what helps viewers with slower download speeds get a stable version of your high-quality stream. This makes your content watchable to them, and it makes the platforms that offer transcoding more attractive and inclusive.
As far as multistreaming goes, however, the bulk of the responsibility for transcoding will fall on the streamer. If you have to deal with streaming to multiple platforms with strict quality guidelines, don’t worry. Restream will be there with all the transcoding hours you need.