Backscreen cloud transcoding service streamlines the transcoding workflow for the largest VOD service in Nordics

Norberts Osītis
CEO 

Introduction

Telia Play is the leading digital TV and streaming service provider in the Nordics and Baltics with more than 3 million subscribers, providing over 100 TV channels and tens of thousands of video-on-demand (VOD) titles. Since the mid-2020 Telia Play is available as a standalone service for subscribers outside of the Telia network which adds an additional challenge to deliver the quality service over uncontrolled networks. The subscribers watch the content over cable and mobile networks of different speed and quality, using various devices like set-top-boxes, computers, mobile phones and tablets, smart TVs, and game consoles.

Before the video can be streamed to the viewers it needs to be prepared for streaming formats suitable for the delivery systems like streamers and packagers. Also, the video and audio are converted into compressed formats of different qualities, called renditions having different resolutions, bitrates, and other technical characteristics in a process called transcoding. As a result, to deliver the best possible uninterrupted viewing experience the viewer device adapts to the most suitable video and audio quality based on network conditions, device screen size and other logic. 

Challenges

Telia Play receives the content in different formats from numerous content providers like Discovery, Disney, History Channel, Viacom, Paramount, C More, and needs to prepare it for IPTV and online streaming services with each requiring its own formats of video, audio, subtitles, and supplementary files. The whole process should be streamlined to work automatically starting with ingest from the content provider and up to publishing to the streaming service portals and applications.

The videos often come in a regular flow from the content providers. Sometimes, when a larger content deal is signed, a large batch or the whole back-catalogue needs to be processed. As the transcoding is a compute intensive task requiring substantial amount of computing resources to process, it is not possible to constantly utilize dedicated resources. Quite often these would be underutilized when there are just regular content inflows or struggling to do the job in reasonable time period when there is much more content coming in.

The main question was whether to invest into dedicated transcoding hardware or rely on cloud service with scalable costs. 

Solution

At the time when colleagues from Telia Play were looking for the transcoding solution, we at Backscreen had already created and launched the cloud video file transcoding service able to transcode the videos at any scale, aimed at broadcasters, media houses, VOD providers, IPTV, and cable TV companies. 

The service uses Backscreen Virtual Cloud Servers and Backscreen Object Storage for underlying infrastructure, which are scalable services using regular computing and storage resources suitable for almost any workload. Thus, the infrastructure utilization is optimal and can be scaled according to the actual need. 

Backscreen Stream Video File Transcoding service met Telia Play requirements to provide a consistent media ingest, transcoding and delivery workflow as a service in the cloud. Initial proof-of-concept stage was initiated in the autumn of 2019 and first production videos were transcoded and delivered to Telia Play systems in December of the same year. 
The whole process can be split into several steps – ingest, validation, transcoding, muxing, subtitle conversion, manifest generation, and upload into the storage of streaming systems. The Backscreen Stream Video Cloud media asset management portal is used as the orchestrator of all processes. 

- Separate isolated locations for file ingest are provided for each content provider with upload to FTP folder or S3 storage bucket as possible options. One or more file naming patterns, content grouping and ingest logic are defined separately for each provider. As a result of ingest process all files of the asset – video, audio, subtitles, metadata files and related images are grouped and processed together. 

- Validation process ensures the asset integrity and readiness for transcoding. 
- Transcoding process creates all necessary video and audio renditions. Multiple transcoding presets (configurations) are defined to perform the process on the content from different providers. 
 
- Muxing process merges video, audio and for some formats also subtitle tracks into the specified container files. Telia Play uses MP4 with SRT subtitles and TS containers with muxed-in DVB subtitle tracks for different services. 

- Subtitle conversion creates specified text-based subtitle files or muxes DVB format subtitles into the containers. 

- Manifest generation creates manifests necessary for streamers and packagers, which define the layout of video and audio tracks, e.g., for Elemental Delta packager. Page 1 of 2 “ The flexibility and performance with Backscreens platform helps us meet the requirements that we have with today’s and tomorrow’s workflows. Our goal is to exceed expectations and to continuously strive to deliver a great quality of experience. With the scalable and cost-effective solution Backscreen provides we can keep our focus and attention on delivering the best streaming experience possible to our viewers. Andreas Backlund Telia Play 
 
- Upload process delivers the files to the specified FTP or S3 locations for streaming. 
 
- The portal provides the full control with monitoring of the process, error detection and resolution, configuration of the process and transcoding settings, and reports of the process steps and other metrics. 

- Prioritization between the content categories and providers is done to separate regular workflows which need to be delivered in short time versus the back-catalogue transcodings which can take days and even weeks to process.

As a result, the whole process is automated, and content is ingested and delivered without any user interaction. Of course, errors sometimes appear because of different factors but typically these are not frequent and happen because of incompletely delivered content or non-standard situations. 

Results 

More than 32 000 videos of average length of around 50 minutes were transcoded during the first 24 months of operation with more than 300 TB of transcoded files delivered to Telia Play systems. During the peaks more than 500 videos per day were transcoded. Backscreen constantly adds new features to the service to support new requirements by Telia Play. For large back-catalogue transcoding additional dedicated resources were added temporarily to the service for guaranteed performance. 

 
Our goal is to exceed expectations and to continuously strive to deliver a great quality of experience. With the scalable and cost-effective solution Backscreen provides we can keep our focus and attention on delivering the best streaming experience possible to our viewers.