Video encoding and video codecs- what you need to know
The OTT shows you so fondly binge on wouldn’t be there without video codecs. Distributors can use this two-part compression tool to compress a video file and deliver it over the internet using a method called “video encoding.” Codecs allow us to conduct business meetings via Zoom or watch our favorite TV shows on our mobile devices, even when the bandwidth is limited.
Netflix delivers over 404,000 hours of streams per minute— thanks to codecs. The OTT platform uses both tried-and-true codecs and new ones to deliver those streams to end-users devices.
For anyone looking to launch an OTT platform, it’s important to understand how codecs work. But before that, it’s vital to have some knowledge about the process of encoding.
Video Encoding: What it actually means?
Video encoding is the process of providing a digital format to raw videos. The assigned format shows compatibility across devices. When streaming videos, they are compressed from gigabytes to megabytes of data. Live streaming, its speedy delivery, and playback are all made possible by video encoding.
The process of encoding might take place via a standalone device, on software within a browser, or an IP camera. Note that encoders use audio and video codecs to reduce videos to a manageable size.
It’s simple to say that encoding refers to the process of moving from an uncompressed source to its compressed version, but you may be curious as to what is a good example of the uncompressed, raw source video. It’s any file that has data directly from a camera sensor, which is not encoded. This raw content can be either in the SDI or HDMI standard. Although both are popular, HDMI is often found in small devices such as a mini camcorder. HDMI can sometimes be found in professional settings too, but SDI is still more common because of its reliability. Another uncompressed source example would be something analog such as VHS tapes. The transfer of data from VHS to digital is also an example of encoding. However, this is rarely done today.
Significance of encoding
There are two main reasons video encoding matters. It makes it easier for videos to be transmitted over the Internet, particularly in relation to streaming. Compression reduces bandwidth while still delivering a high-quality experience. It would not be possible for many to watch anything online if only raw uncompressed video content were delivered over the Internet. Why? Because streaming such large files with a normal connection speed simply isn’t possible. Since the bit rate, or the data per second in a video, is higher for uncompressed videos, a lot of users fail to view them as not all devices and connections are able to handle high bitrate content. The bitrate determines if a viewer will be able to stream a particular video quickly or will have to witness buffering.
So, now you know that the Internet’s bandwidth might not be sufficient to support all sizes of video content. This is an obstacle when it comes to offering widespread video playback services. Video encoding is responsible for the ability to stream video from multiple devices, including mobile phones. Not just that, it also makes it possible to do video chats with people scattered across the world, even at low bandwidth.
Compatibility is the second reason why video encoding is used. Sometimes, content that has been compressed to a manageable size still needs to be encoded for compatibility. This process is actually called transcoding. Compatibility needs to be ensured as there are many programs or services that require specific encoding specifications. This can also mean enhancing compatibility for playback.
Note that video codecs or video compression standards are used to guide the process of video encoding.
Codecs: What do they do?
To compress a video to a size that can be streamed, content distributors use a technology known as a codec. Codecs are a way to compress large streams for storage and delivery.
Codec, which expands to “compressor-decompressor” or “coder-decoder,” applies algorithms to a video and creates an approximation of it. Codecs use lossy compression to remove unnecessary data when streaming. The video is compressed for storing and transmitting it and then decompressed to view it.
Streaming needs both video and audio codecs. Advanced Audio Coding or AAC and Advanced Video Coding or AVC or H.264 are the most popular audio and video codecs, respectively.
AAC is the industry standard for audio. AAC is supported almost everywhere and holds the biggest share in the market. Flac, Dolby audio, and Opus are other audio codecs that are used. YouTube uses Opus, which is a great audio codec, although the video streaming platform still falls back to AAC. Dolby Audio or AC3 is sometimes used for surround sound because certain surround sound systems from the past fail to support AAC.
This codec is also referred to as HEVC or High-Efficiency Video Encoding. It is a standard developed by ITU -T VCEG and MPEG. This codec was made standard in 2013. It was then expanded upon from 2014 to 2016. H.265 aims to increase the compression rate by 50% over H.264 while maintaining an identical quality.
A Netflix study found that H.265 had a 35 to 53% improvement in performance compared to H.264, and a 17-21% increase compared to VP9.
It’s, however, worth keeping in mind that the type of content, the encoder, and other factors can also have a significant impact on such types of comparisons.
The improvements were made possible by optimizing the techniques that were already present in H.264. H.265 compresses video content into smaller files than H.264, which reduces the bandwidth required to play video content. Despite this being impressive, H.265 still gets very little use. And why is that? That’s because there is uncertainty surrounding licensing and royalties linked to H.265.
Also known as MPEG-4 AVC or Advanced Video Coding/AVC, H.264 was made standard in 2003. As part of a partnership called Joint Video Team or JVT, ITU-T VCEG and MPEG together created this codec with wide-ranging compatibility. It can be used almost anywhere, on any device despite its amazing video streams. In fact, it is considered a benchmark for other codecs.
This codec was created by Google’s On2Technologies. VP9 was made standard in 2013 and was launched to succeed VP8. This codec is very similar to HEVC but no royalties are required. VP9 can be problematic for industry professionals because, although it is supported across all android devices and important browsers, it is not supported on any Apple device. Apple instead supports H.265 or H.264.
The Alliance for Open Media (AOMedia), was founded in 2015. During that time, Mozilla (Xiph) was working on Daala, and Google on VP10. Cisco, on the other hand, was working on Thor. However, it so happened that they decided to create AV1 with their combined effort. Their goal was to achieve 30% more efficiency than VP9 and remain royalty-free.
Although the AV1 codec has been finalized, much work remains. This codec is being adopted by large industry players and it may be expected that it will receive more acceptance as time passes.
Video Container Formats: What are they?
After compression, each component of a stream is placed in a wrapper. This includes the video codecs and audio codec as well as any metadata and closed captioning. As far as popularity is concerned, .wmv, .mov.ts, and .mp4 top the list.
Usually, numerous codecs are supported by a single container. However, not all containers and codecs are supported by all playback devices. And that is why streaming on multiple devices requires multi-format encryption.
An interesting thing to note here is that while a .wmv and a .mov file might contain the same data and codecs, they are not identically supported across devices and video players. While the .mov file is intended for playback on QuickTime in Macbook, the Windows Media Player on a Windows PC would play .wmv files.
Codecs Vs Containers
The codec works on the video at both the source to compress it, and before it is played back to decompress it. The codec uses lossy compression to shrink the video. Any unnecessary data is then removed. Lossy compression makes large data sets smaller to transport to your screen.
A video container, on the other hand, stores the audio codec, the video codec, and the metadata. The container keeps all components together and determines which programs will be able to accept the stream.
Encoding Vs Transcoding
While transcoding and encoding are sometimes used interchangeably, they have slightly differing meanings.
Encoding refers to the process of compressing raw video footage. It is often done to make a file smaller, so it can be used across devices. Transcoding is the process of taking a compressed video source and changing it to a new format.
The relation between encoding, transcoding and codecs
Codecs are needed to complete all encoding and transcoding tasks. They are responsible for compressing and decompressing video files. Codecs, as discussed above, use algorithms that compress or convert a video to a format compatible with a device on which it is going to be played.
Mogi’s Proprietary Video Tech
Mogi’s Video Tech solutions are available end-to-end (Video Transcoding + Video Player + Mogi Streaming Engine (Multi-CDN delivery) + DRM + Video Analytics) or you can use individual products from the entire suite like just the Video Transcoding. Mogi also provides white-label end-to-end plug n play solutions for OTT and Edtech Platforms, with Web, Android, and iOS apps as well as a dedicated CMS for OTT and LMS for EdTech.
One of the best individual products we have is our Transcoding Architecture, which is a unique cluster-based process, does the transcoding within 30% of the content length. The transcoding architecture’s result includes a highly compressed video of up to 50% with no loss in quality, and if you choose quality enhancement, a 40% compression with the enhanced video quality.
The pricing for Transcoding is very competitive as well, and along with it, you get a highly compressed output with the same or higher quality. This means not only is your contractual pricing is low due to competitive pricing, but your bandwidth consumption also reduces, and user experiences increase multifold. It’s a win-win for all of us (Users, Clients, Mogi).
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