Streaming media is booming, and the demand is growing with no limits in sight. A report by Cisco predicted that the video data consumption just on mobiles devices is going to see rapid boom, stating; “The next 5 years are projected to provide unabated mobile video adoption.” As mobile network speeds are increasing drastically the video consumption grows as well, compared to just 59% in 2017, nearly four-fifths (79%) of the world’s mobile data traffic will be video by 2022. The number of streaming platforms is growing and new options come availble seemingly every month.
You might have heard about transcoding if you’re engaged with streaming media or video production, or you don’t have any clue of what this thing is and why would you ever need it anyway. We’re here to get you familiar with the concept and how critical it is for you to use.
Digital storage is - in digital format and analog media needs to be converted to digital first for storing. The initial digital output format is raw file, and for it to be distributed efficiently across a multitude of devices it needs to be compressed in the digital format compatible for all. This video compression of files is called encoding. Yes, you’re right - we are here for understanding transcoding, both terms, encoding and transcoding are at times used interchangeably, though the use-case is different for both.
The big difference between video transcoding and video encoding
Video Encoding deals with converting uncompressed data to a specific format or codec and is a lossy process. While transcoding at a higher level is taking encoded or already compressed media content and decoding (decompressing) it to an uncompressed format, and then altering the content in any way possible and recompressing it. For example, you are adding watermarks, graphics or logos into the video. Or in other words re-encoding an existing video (or ongoing stream video) file from one digital video encoding format to another with a different codec or settings and involves translation of all three elements of a video file.
Video files are large and contain a lot of data, consuming a lot of storage and bandwidth during transmission, while some files also have limitations in terms of compatibility issues with the ever-growing number of appliances consuming video content. To address these problems, there’s a technology known as “codecs” to compress video files, removing extraneous data from the video to reduce the size (i.e. from WMA to MP4) and resolving compatibility concerns while maintaining the high-quality content.
The burgeoning variety of technologies day by day with different generations of equipment, low to high-speed networks and over-the-top (OTT) services are creating different demands for video formats and qualities to maintain interoperability across the plethora of devices, making sure of a high video quality experience for the end-user. Transcoders offer audio conversion, packaging and metadata transfer, caption conversion, etc. enabling the provider to provide several audio formats along with multiple video technology formats, i.e. H.264, MPEG-4.
Most of the OTT service providers, like Netflix, employ real-time transcoders and whenever a request is made to view a video the transcoders process the request and transcode video depending on the capability and type of requesting user’s device. The transcoder can repackage into adaptive bitrate like Flash HDS, MSS, HTTP Live Streaming (HLS) and the client device can select the optimal stream depending on bandwidth available.
Transcoding is widely an umbrella term that covers multiple digital media tasks like transmuxing, trans-sizing and trans-rating.
- Trans-rating – refers to changing bitrate ABR, using the same file format and converting to a different bitrate. Like taking a 4K video stream and converting it into one or several lower bitrate streams, this is also known as rendition.
- Trans-sizing – refers to resizing the video frame, e.g. from a resolution 4K UHD of 3840 pixels x 2160 below to 1920x1080 or 1080p.
So, while referring to transcoding, you might be indicating any combination of these activities. Another essential thing, video conversion (encoding) is a computationally intensive task and requires powerhouse hardware resources equipped with graphics acceleration capabilities.
What Transcoding Is Not
Transcoding software should not be mixed with transmuxing, as it refers to repackaging, rewrapping, or packetizing – conversion to a different container format without changing the file itself. It is like when you take compressed video and audio and without altering the actual content – repackage it into distinctive delivery format. For example, changing the h.264/AAC content container to send it as HTTP Live Streaming (HLS), HTTP Dynamic Streaming (HDS), etc. The content remains the same, unaltered so the computational overhead is much smaller than for transcoding.
Codec: Encoding and Decoding
The term Codec comes from the nexus of the two terms encoding and decoding. Therefore, a codec is any software/device that compresses and/or decompresses a compressed digital file. The device/software that only compresses an analog file is known as encoder, while the device/software that only decompresses is known as decoder.
The way codec works is it needs to compress frames. There are two ways to frame compression – inter-frame and intra-frame compression.
Inter-frame compression identifies redundancies across frames to compress the videos. While the intra-frame compression is essentially image compression or image scaling as it compresses each frame independently. That’s why inter-frame compression is more efficient and used by most codecs. (I won't be discussing variables of frame rates in this post)
Well-known codecs are:
- MPED (Motion Picture Experts Group)
- H.264
- VP9
- Theora
While the well-known containers are:
- QuickTime File Format
- MP4
- FLV
- WebM
- Ogg
- Advanced Systems Format (ASF)
3 Big Reasons to Transcode Video Files
Bridging the gap – Creating Multiple Video Formats
With diverse proprietary file formats and codec supports, the need for media exchange between a plethora of systems is clear. Transcoding enables to you to re-encode a video stream into multiple formats like MPEG or HLS – to offer streaming to a range of appliances that only support certain formats. Production, post-production, distribution, and archiving are all distinct and operate on their own standards, requirements, and practices. Transcoding bridges the gaps among them, enables media exchange between disparate systems and makes the vast range of uses to which digital media are now possible.
Boosting QoE (Quality of Experience)
Live streaming and media service providers like Netflix are the top tier users of transcoding software allowing them to serve their user base much more fittingly and efficiently. With video transcoding, live stream video broadcasters are able to accommodate the bitrate of your video stream based on certain factors i.e. the device your using, bandwidth available, and the codec supported. For example, using HLS allows dynamic switching between video sources i.e. 1080p and 720p versions of stream, depending on the network speed and device.
If a user regularly experiences lagging, buffering, slow video startup or frequent failures to play the content altogether, the QoE goes down and with that the customer’s video quality. Maximizing the QoE is crucial for any media broadcaster and transcoding can help. Rarely are these problems ever the fault of the media player, it's more likely to be the content delivery network.
Reducing customer storage
The source files on which transcoding is performed are much larger than the asset files produced after the tweaking and brushing are done. It takes the burden off the user system storage.
Custom requirements
Video content creators might have their specialized design and implementation requirements. Such as special formats, multi-lingual audio streams, clipping and trimming, etc. to be applied on the video stream before delivering to the user system.
Numerous factors go into video transcoding and makes an essential part of getting your content ready to be delivered for best user experience and efficacy.
Worried about your video storage space?
Regarding storage? To work with the large data sets of video files starting with raw, you’ll of course need ample storage. Better yet, you’ll probably be better off not worrying about storage AT ALL. That’s where ProMAX Platform comes in for the heroic rescue. Stop paying the unfair “storage tax” ( a phrase that we’ve lovingly coined in the industry). We all know that purchasing additional storage should not gouge customers, but unfortunately, those who are in the wrong so-called “golden handcuffs” attached to a proprietary shared storage platform are obliged to pay.
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