What is the Role of Transcoding in Telecom Business

The telecommunications industry has changed dramatically in a decade and no one knows how it will change in the future.

Although we are using transcoding at the current time, we hardly think about its underlying functionality. Unlike the normal definition, transcoding is a little different in VoIP calling. To put it simply, it is the transformation from one voice type or codec to another. 

We will discuss the role of transcoding in the telecommunication business. Along with that, we will give you a total overview, including the work process of transcoding, its types, and many more. 

The Definition of Transcoding

In order to increase the compatibility of a media file for a number of target devices, a process is needed to convert a video or audio file from an encoding format to another. This process is called transcoding.  

Key Facts

• Due to misconception, people interchange transcoding with encoding. We should know – if transcoding is the process of reformatting, decoding, and re-encoding the encoding file, encoding is the actual compression of data.
• The best method of converting big, archived media files is lossless-to-lossless transcoding.
• The best method of delivering compatible content for portable devices is lossless-to-lossy transcoding. We will discuss more of this in the “Type of transcoding” section in this article.

The Work Process of Transcoding 

Just like the transmuxing process, FFmpeg can be used for transcoding. FFmpeg is an open-source platform for handling both audio, video formats. With a simple command like below, a media file can be converted to a standard H.264 mp4 format.

ffmpeg -i "sourceVid.mov" "transcodedVid.mp4"

Although setting up a specific resolution using the FFmpeg requires complete knowledge of the software, the following command is enough to do the task – 

ffmpeg -i rtmp://server.ip/app/1080 -vcodec libx264 -preset veryfast -x264opts nal-hrd=cbr:force-cfr=1:keyint=60 -b:v 3000k -maxrate 3000k -bufsize 3000k -s 1280720 -sws_flags spline -r 30 -acodec copy -f flv rtmp://server.ip/app/720

Command

The above command includes several factors like buffer, bitrate, resolution, and framerate in the output. The command uses the x264, an H.264 encoder, and takes an RTMP stream. The final output of the file remains in an FLV format.      

Examples of Transcoding

Large streaming organizations like Twitch use both FFmpeg and their own TwitchTranscoder to stream audio and videos. This is a great example of transcoding.     

On the other hand, YouTube uses transcoding to make videos available in more than 5 formats and qualities. And you will be surprised to know – 

-Uploads of more than 300 hours are received within one minute by Youtube   

YouTube will start the encoding and transcoding process immediately after the original video is uploaded. It means, more than 20 versions can be transcoded after the original content is uploaded. That’s why users first get low-resolution videos until the high-resolution videos are transcoded.

The Role of Transcoding in Telecom Business

Transcoding in the telecommunications industry is the process of converting a media stream from one codec to another. This is done to overcome the difference in the ability of the telecommunications system to support the caller and the receiver. 

In telecommunication services, there are situations where transcoding is very difficult. When the two endpoints in the call share different codecs remaining in their codec sets, this type of situation can occur.

In addition, if the end-party only supports the G.723 codec and the originating end supports the G.729 codec, the call audio will no longer work in a direction unless the VoIP provider transcodes between these codecs. 

Session Border Controller (SBC) is a commonplace to perform transcoding. But be aware of choosing a valid or invalid SBC because transcoding is not supported by all SBCs.

Types of Transcoding

Transcoding deals with the data that are already encoded. While encoding is a natural lossy process where a certain amount of data will be lost ultimately affecting the quality of the audio and video. Lossless compression can be used for encoding, but this leads to lower compression ratios and larger media formats. 

Mainly three types of transcoding are used in the telecom business –

• Lossy-to-lossy: This means that you already have a lower quality file, and this type of transcoding will cause further degradation in quality. It is the least standard form of transcoding. To make files compatible with portable players, this type of transcoding is needed to reduce the bitrate and saves more space.  

• Lossless-to-lossless: Through improved compression and hardware support, files can be compressed via this type of transcoding. It is very convenient for converting a new format without losing quality. But the resulting files are not suitable for portable devices as the files are being too large.

• Lossless-to-lossy: Unlike Lossy-to-Lossy, this type of transcoding does not significantly reduce the quality of the file. On top of that, the file size is small enough for portable devices. You need to manage lossless archive files to truly take the advantage of this transcoding method.

Lost data and quality can’t be recovered during the transcoding or encoding process as there is no such thing as lossy-to-lossless transcoding. 

Transcoding and Session Border Controller

The Session Border Controller or SBC is a dedicated network element on SIP-based VoIP infrastructure. It mainly helps to manage real-time communication sessions. SBC not only provides complete control over the session but also hides the internal network from the outside world. Although the focus is on the software version, SBC can be found in both hardware and software forms.  

For telecom business, WD Telecom offers decent functions to handle multiple codecs and perform automatic transcoding when required. AMR, G711, G729 are the most popular codecs in IP  telecommunication. And WD Telecom has the built-in functionality that perfectly supports them.

Overview

The role of transcoding in the telecom business can lead to both success and failure unless you fail to determine the correct SBC. There are many codecs iLBC, G.711, G.726, G.722, G.723.1, AMR, etc. But not all are supported to be transcoded with SBC. 

We have already mentioned in this article, to pay attention to choose a suitable SBC as not all are competent for transcoding. And you may never know the number of compatible SBCs by asking. Rather, it is better to make a list of codecs that works flawlessly with SBC.