What is Transcoding & What Role Does it Play in Streaming?

In its simplest terms, transcoding refers to the process of converting already compressed files, usually audio or video, into a different file format.

One of the most common uses for transcoding is streaming video content. In this context, files are converted from one format to another with the aim of maximizing the number of compatible devices on which a media file can be played. Converting the file to a different format, also ensures that consumers can stream files at the highest possible quality and with less buffering time.

This article will explain how transcoding works as one of the crucial streaming technologies and its importance to live streaming, as well as how it enhances the experience of both streamers and viewers alike.

Importance of Transcoding in Media Delivery

Transcoding plays a crucial role in ensuring smooth media delivery across various platforms and devices. It’s especially important when using an [adaptive bitrate] workflow, the most common and effective way of reaching a large number of end-users without compromising on video quality.

Video transcoding also encapsulates trans sizing, the process of scaling an image if the output resolution differs from that of the media, and transrating, where files are coded into a lower bitrate without changing the format. Given the range of streaming devices and capabilities these days, both of these are key to successful video delivery.

How Does Transcoding Work?

The transcoding process is two-staged. Firstly, the original file is converted into an uncompressed format through decoding. This file is then re-encoded into a target format which is then compatible with a host of different devices.

This could be a video file that is encoded and compressed using a codec software in a certain format which we then re-encode into an MP4 file, for example, making it possible to reach a wide audience. This process allows content providers to efficiently transmit data across various devices and networks, ensuring optimal delivery regardless of the end user’s setup.

The process of transcoding is often said to be ‘computationally intensive.’ While it can be carried out using built-in software, transcoding often benefits from dedicated, specialized hardware as it can take a desktop machine or laptop a long time to carry out the required functions.

If you are looking to transcode high-quality, large files then computer features such as a high-end CPU or large amounts of RAM would be extremely beneficial and are likely to decrease the time required to transcode.

Differences Between Transcoding, Encoding, and Transmuxing

While often used interchangeably, transcoding, encoding, and transmuxing are distinct processes in video delivery:

1. Transcoding: The process of de-encoding a file into an uncompressed format and converting it into another format.
2. Encoding: The compression of raw data to create a smaller, more transferable file.
3. Transmuxing: Changing the delivery format of audio and video files without altering the actual content.

Types of Transcoding in Video Delivery

Transcoding allows for conversion between different video protocols, ensuring wider compatibility across various playback devices and streaming platforms. This flexibility is crucial in the ever-evolving landscape of digital video consumption.

Lossy To Lossy

Lossy-to-lossy transcoding produces the lowest quality of video or audio file and is the least desirable type of transcoding. Lossy compression is when expendable data is removed from the file for the purpose of making it smaller. Essentially, quality is sacrificed in favor of having a smaller file. Lossy-to-lossy transcoding takes a file with already decreased quality and reduces it even further. While the resulting quality is poor, these files require little storage space making consumption on a portable device, such as tablets and mobile phones, more manageable.

Lossless to Lossless

Lossless compression is when a file does not lose any data as it’s compressed. As a file is transcoded into a different format, its quality remains the same. However, the resulting files require large storage space and are often unsuitable for smaller, portable devices. Lossless-to-lossless transcoding often requires good quality hardware to carry out the necessary functions.

Lossless to Lossy

While files transcoded using lossless-to-lossy are not as good quality as lossless-to-lossless, they are better than lossy-to-lossy. They are also small enough to be stored and consumed on portable devices which makes it a popular form of transcoding. It should be noted that once data is lost through encoding and compressing, it’s discarded and cannot be retrieved. As such, there is no such thing as lossy-to-lossless transcoding.

Real-time Transcoding

Real-time transcoding is crucial for live streaming applications. It involves converting video content on-the-fly as it’s being captured, allowing for immediate delivery to viewers. This type of transcoding is computationally intensive but essential for live events, news broadcasts, and interactive streaming experiences.

Batch Transcoding

Batch transcoding, also known as offline transcoding, is used for processing large volumes of pre-recorded content. This method is less time-sensitive and allows for more efficient use of computing resources. It’s commonly used in video-on-demand services, where content libraries are transcoded into multiple formats and qualities before being made available to viewers.

Use Cases for Transcoding

Live Streaming Applications

Live streaming heavily relies on transcoding to deliver high-quality, low-latency content to viewers across various devices and network conditions. Real-time transcoding ensures that live events, gaming streams, and webinars can reach a global audience with minimal delay and optimal quality.

Content Distribution Networks (CDNs)

CDNs utilize transcoding to optimize content delivery across their networks. By transcoding content into multiple formats and qualities, CDNs can efficiently cache and distribute video to edge servers, reducing bandwidth costs and improving viewer experience. Transcoding also enables CDNs to adapt content delivery based on regional network conditions and device preferences.

CDN technology relies heavily on transcoding to optimize content delivery. By leveraging transcoding capabilities, CDNs can adapt content on-the-fly to meet varying network conditions and device specifications.

Benefits of Transcoding in Video Delivery (Streamer’s Side)

Supports Multiple Formats

Transcoding allows your stream to be received by a large audience of end-users who may all be using different kinds of devices and require different video formats. Encoding video into different resolutions and bitrates for a diverse audience can be a complex task. However, transcoding is able to resolve this issue, delivering suitable video files to your viewership at relatively low time and cost for the streamer.

Optimized Video Quality

Achieving optimal video quality is a priority for streamers and can be the difference between losing or gaining regular viewers. Transcoding helps to optimize quality by delivering the best possible file for each user.

Enhanced Content Acceleration

Transcoding is a key component of content acceleration, improving delivery speed and quality. By optimizing file formats and sizes for different network conditions, transcoding enables faster load times and smoother playback, enhancing the overall user experience.

Significant Increase on Content Reach

While internet access has improved dramatically in the last few years, speeds differ widely between countries and regions.  A viewer in Hong Kong is able to access content far easier than someone in parts of South America, where internet speeds are low. Transcoding aids in content delivery and prevents large blocks of your audience from not being able to view content due to poor download capabilities.

Benefits of Transcoding in Video Delivery (Viewer’s Side)

Transcoding can negate many of the issues associated with streaming that are experienced by viewers.

Less Buffering

If viewers have to make do with poor bandwidth, then transcoding can help resolve the issue of buffering by delivering a file size that the viewer’s internet connection can handle.

Supports More Format

Given the huge array of different devices and hardware now available to users, incompatibility can be a real barrier to successful streaming.  Transcoding increases the chances of files being compatible with a given device by delivering an appropriately compressed file to each user.

Lessens Playback Failure

Streaming on a device with poor resolution and low streaming capabilities often leads to playback failure. Transcoding helps to sidestep this issue by delivering files that each device can manage, heightening user experience.

Better Resolution/ Video Quality

Conversely, a frustrating issue faced by some viewers is that of low-quality video delivery even when they have good connectivity and streaming capabilities. This is due to streamers wanting to reach as large an audience as possible and catering to people with a bad connection. Transcoding resolves this issue and means viewers can view videos in as good quality as their own bandwidth and resolution will allow.

Considerations for Media Workflows

Integrating transcoding into media workflows requires careful consideration of several factors:

1. File Size vs. Quality Trade-offs: Balancing the need for smaller file sizes with maintaining acceptable video quality.
2. Hardware Requirements: Assessing the computational power needed for efficient transcoding, especially for real-time applications.
3. Scalability: Ensuring the transcoding solution can handle increasing volumes of content and concurrent streams.
4. Format Compatibility: Staying up-to-date with evolving video codecs and container formats to maintain broad device support.
5. Workflow Integration: Seamlessly incorporating transcoding into existing content management and delivery systems.

Streaming Solutions That Offer Transcoding

Despite its uses, not all streaming services offer and support transcoding. Rather, many require files to match their own output format.

CDNetworks’ own Media Delivery service provides ultra-low latency streaming for both live broadcasting and video on demand.

This solution provides transcoding service, allowing it to pull content directly from CDNetworks Cloud Storage and an origin server and deliver high-quality video to a range of end users, no matter what device they’re streaming on.

Conclusion: The Future of Transcoding in Digital Media

As digital media consumption continues to evolve, transcoding will play an increasingly vital role in content delivery. Emerging technologies such as AI-driven transcoding optimization and cloud-based distributed transcoding are set to improve efficiency and quality further.

The future of transcoding will likely focus on:

1. Enhanced support for 4K and 8K video
2. Improved efficiency in handling HDR content
3. Integration with emerging codecs like AV1
4. Greater emphasis on low-latency delivery for interactive streaming experiences

Future developments may also see better integration with emerging protocols like QUIC, optimizing traffic delivery even further. As QUIC traffic becomes more prevalent, transcoding solutions will need to adapt to leverage its benefits for improved streaming performance.

As the digital landscape continues to diversify, transcoding will remain a critical component in ensuring that content reaches viewers seamlessly, regardless of their device or network conditions.