What Is Transcoding And Transcoding Working

what is transcoding


Generally in Digital Headend we converts analog signal into the digital signal then it is know as encoding and the device which performs this action is called the encoder. But transcoding is much different from encoding.  Transcoding is digital to digital conversion of one encoding to another.

When the things comes in terms of playing TV services in Mobile , Laptop and Tablet then transcoding is implemented. It enable users to watch television services in their Computer,mobile,tablet and laptop.

What Is Transcoding

Transcoding creates adaptive platform for theirs users to watch tv services on different playback devices like mobile , tablet and laptop. This function is performed by Tanscoder. A transcoder translate the source format into raw intermediate format and then re-translate it into the format which is capable for playing in different users devices. A transcoder need high CPUs power to perform this function.

When we talks about transcoding then there are two more terms which takes place in trancoding these terms are Trans-rating and Trans-sizing. So Transrating and Trans-sizing these two functions are also performed with transcoding. Transcoding takes high processing power.


In this function a video is transrated at different bitrate. For example ,

If we are having a source of  HD video stream at 6 Mbps bitrate as input. Then it will convert the stream bitrate at 3 Mbps , 1 Mbps and 600 kbps. It is known as ABR (Adaptive Bitrate Streaming) streaming.

In other words ABR streaming is the streaming which is adaptive to user’s requirement. ABR streaming is denoted by users CPU power and connection bandwidth in real time.


The function of Trans-sizing is to change the resolution of the video. For example,

If we are having a stream at 1920 x 1080 @ 1080p then it will convert down the resoultion at 1280 x 720 @ 720p. Trans-sizing is performed with Trans-rating to enable users to watch services without buffering.

Transcoding Working And Transcoding Architecture

transcoding architecture

As shown above in the figure a transcoder is having source, stream input from the encoder. It can also have source from directly camera device. So after getting input transport stream a transcoder performs its all functions like transcoding , trans-rating and trans-sizing. It downgraded the 1080p@3 Mbps into,

720p@ 2Mbps

480p@ 1Mbps

360p@ 900 Kbps

240p@400 Kbps

These different streaming format depends upon the CPU power and bandwidth of the user. The user who have low bandwith internet connection with low CPU power can go for 240p@400 Kbps. While on the other if the user is having good CPU power with high internet connection bandwidth can go for 1080p@ 3Mbps.

Thus it enable to all users to watch tv services in different devices.


Transcoding is a technique which enable users to watch tv services on their computer , laptop , tablet and smartphones by using the trancoder. Transcoder can be called as logical device which stream the data as per user’s device requirement.

If you do not want to use transcoder then you need to use multiple encoders. which gives different resolution at different bitrate. Also it increases bandwidth consumption. To avoid theses kinds of problems we need to use transcoder. It reduces the cost of multiple encoders and its complexity.

Know More About DVB-H For Mobile TV

headend info



  1. KAMAL BERA says:

    more update sir
    for digital headend engineer