When we think of transcoding and encoding, naturally we think of transforming the video essence of files into the myriad versions required in today’s complex delivery ecosystem. Taking a mezzanine master file and turning it into an Adaptive Bit Rate (ABR) ladder of files for streaming is a well-established process these days. A bigger part of the transcoding and encoding process, and arguably a more complex endeavor, comes in dealing with all the non-video essence and metadata that goes with those video files.
Each content creator, broadcaster, or service provider is unique in terms of what is required to support their media supply chain when delivering content that has true business value. Merely encoding the video and hitting a set video specification is easy to do with today’s tools. The real complexities arrive when adding captions, subtitles, and audio to the mix and making it conform to a precise delivery specification. Get just one thing wrong and the whole package is going to get rejected by distribution companies with their reputation for quality at stake, or for whomever the program is ultimately destined.
ADDING AUDIO TO THE MIX
At first glance, audio files—being much smaller than video files, even with a bevy of surround channels—might become just an afterthought. In truth, audio is frequently harder to deal with because of the number of regulations and formats, both legacy and advanced, that need to be catered for. Each content creator or distributor tends to have a specific and individual way in which they need to route, process, package, and play out audio files, and there can be many points of failure.
Take Dolby E, for example. It’s still a popular way for people to use legacy systems to route more PCM or uncompressed audio channels over a conventional analog stereo channel. Where it gets complicated is in maintaining compatibility through modern delivery pipelines while also supporting newer audio formats and layouts. To meet delivery specs, it might specify a unique combination of certain channels. Channels are frequently routed to multiple stereo pairs in a certain way for a downstream playout system to create separate music and effects that play under different languages. It’s rare that any two workflows are exactly the same. The task of automating non-creative processes like this takes a lot of delicate handling and flexibility that not all systems can support, particularly when doing it either on-prem and/or in the cloud.
THE CHALLENGES OF METADATA (CAPTION, SUBTITLES, AND AD SIGNALING)
When it comes to managing and converting captions and subtitles, it can be a dark art, making the audio variations discussed above look trivial. With all the various formats of captions and subtitles, there are few systems that can accurately process every variation with the challenges of accurately standards-converting, re-formatting, re-timing, and attaching them to the video or MXF file in a way that makes sense. It’s not embarrassing to say that it is complete rocket science for many of us. And it’s not simply a nice-to-have feature, since in many countries it’s the law that this content be there. The old UK Teletext system is an example of an ancient standard that, while in decline, is still used to this day to generate subtitles in a few countries. Until this system is no longer in use, it remains important for creating video overlays and bitmap subtitles for each language, changing the frame rate to match the video and audio, then laying everything out so that the Teletext subtitles come out on
the correct Teletext page in the correct place with the right language label on them.
A surprising amount of handling happens behind the scenes to ensure accurate captions and subtitling across all delivery methods. Routing subtitles and combining multiple incoming streams into outgoing streams and mapping them to the right PIDs (Packet identifiers) are not for the faint of heart. We tend to assume that every system can do this well, but there have been many instances when content has had to be rescued when captions have been malformed by a system, and by well-meaning engineers who got in over their heads.
Throwing in ad-signaling metadata further complicates the process. Improper transcoding and other processing can corrupt the timing of the messages by failing to consider the decoding and encoding delay, for example. Since ad markers are directly tied to revenue, there is simply no room for error.
QC MEDIA WHERE IT RESIDES
With all this media transformation and processing, QC becomes a critical part of the workflow. Depending on where the media resides or is destined to reside, performing QC checks after any mediaprocessing is not only necessary, but also should be done without physically moving the media. That means the same QC processes need to be deployable either in the cloud or on-premises.
The QC process also needs to be all-inclusive for every type of output and delivery. Checking a master video file is certainly important, but it’s equally important to ensure that the entire deliverable—including all audio and metadata, and alternative versions that might exist in an IMF, DPP, or AS-11 variant package—conforms to the output profile specifications or manifest as outlined by the recipient. A final check of the deliverable package to confirm all regulations and specifications were satisfied can avoid an embarrassing or costly rework of an asset.
ADVANCED TRANSCODING AND ENCODING GOING FORWARD
As formats and standards continue to evolve, the need to transform media into the next generation of codecs and container formats increases exponentially when multiplied by the myriad of devices and program versions required. Supporting legacy formats is also a
necessary evil, as it takes a long time for entrenched formats to die out. With all this complexity, it’s crucial to automate as many mundane, repetitive processes as possible. Some processes will be best handled on the ground, while others will benefit from running in the cloud. For many companies, there won’t be a hard cut-over for every media pipeline they’ve developed. For that reason, hybrid approaches will work best for most organizations as they seek to maximize efficiency.
In the future, it’s easy to imagine even more orchestration and even auto-assembly of programs being done entirely in the cloud. Sophisticated business rules coupled with rich metadata are already enabling more intelligent automation of media processing by helping to pick the right processing path without human intervention. The more we can off load these complex processes, the more money we can save through accelerated content creation and distribution, along with a meaningful reduction in errors.
Cloud native services from Telestream incorporate a suite of media processing services that can perform all these processes in the cloud. These services are underpinned by the Telestream Media Framework, the same core platform that powers countless Vantage on-prem workflows in use around the globe. Knowing how to ingest, parse, transform, package, and QC the video, audio, and complex metadata isn’t easy, but after 25 years of continuous innovation, it’s why Telestream is relied on by top-tier media and
entertainment businesses everywhere.
Telestream’s ability to meet customers on their journey to the cloud at any point where they find themselves is a key part of the company’s unique value. Future proof your media processing and start your cloud journey with cloud native services from Telestream.
Find out how at go2sm.com/telestreamcloud.
Telestream® specializes in products that make it possible to get video content to any audience regardless of how it is created, distributed, or viewed. Throughout the entire digital media lifecycle, from capture to viewing, for consumers through high-end professionals, Telestream products range from desktop components and cross-platform applications to fully-automated, enterprise-class digital media transcoding and workflow systems. Telestream enables users in a broad range of business environments to leverage the value of their video content.
Telestream customers include the world’s leading media and entertainment companies: content owners, creators, and distributors. In addition, a growing number of companies supplying and servicing much larger markets such as ad agencies, corporations, healthcare providers, government and educational facilities, as well as video prosumers and consumers, are turning to Telestream to simplify the access, creation, and exchange of digital media.
Founded in 1998, Telestream corporate headquarters are located in Nevada City. The company is privately held.
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