If you’re thinking about streaming media, you probably fall into one of camps: Either you already know something about transcoding, otherwise you’re wondering why you keep hearing about it. Should you aren’t certain you need it, bear with me for a few paragraphs. I’ll clarify what transcoding is (and isn’t), and why it is likely to be critical to your streaming success — especially if you want to deliver adaptive streams to any device.
So, What Is Transcoding?
First, the word transcoding is commonly used as an umbrella term that covers a number of digital media tasks:
Transcoding, at a high level, is taking already-compressed (or encoded) content material; decompressing (decoding) it; and then someway altering and recompressing it. For instance, you would possibly change the audio and/or video format (codec) from one to a different, corresponding to converting from an MPEG2 source (commonly used in broadsolid television) to H.264 video and AAC audio (the most well-liked codecs for streaming). Different basic tasks could include adding watermarks, logos, or other graphics to your video.
Transrating refers specifically to altering bitrates, reminiscent of taking a 4K video input stream at 13 Mbps and converting it into one or more lower-bitrate streams (also known as renditions): HD at 6Mbps, or other renditions at three Mbps, 1.eight Mbps, 1 Mbps, 600 kbps, etc.
Transsizing refers specifically to resizing the video frame; say, from a decision of 3840×2160 (4K UHD) down to 1920×1080 (1080p) or 1280×720 (720p).
So, while you say “transcoding,” you is likely to be referring to any combination of the above tasks — and typically are. Video conversion is computationally intensive, so transcoding normally requires more highly effective hardware resources, together with faster CPUs or graphics acceleration capabilities.
What Transcoding Is Not
Transcoding should not be confused with transmuxing, which may also be referred to as repackaging, packetizing or rewrapping. Transmuxing is whenever you take compressed audio and video and — without changing the precise audio or video content — (re)package it into completely different delivery formats.
For example, you might have H.264/AAC content, and by altering the container it’s packaged in, you’ll be able to deliver it as HTTP Live Streaming (HLS), Clean Streaming, HTTP Dynamic Streaming (HDS) or Dynamic Adaptive Streaming over HTTP (DASH). The computational overhead for transmuxing is way smaller than for transcoding.
When Is Transcoding Critical?
Simply put: Transcoding is critical while you want your content to achieve more end users.
For instance, let’s say you need to do a live broadcast utilizing a camera and encoder. You is perhaps compressing your content material with a RTMP encoder, and choose the H.264 video codec at 1080p.
This needs to be delivered to online viewers. However should you try to stream it directly, you will have just a few problems. First, viewers without enough bandwidth aren’t going to be able to view the stream. Their players will be buffering continuously as they wait for packets of that 1080p video to arrive. Secondly, the RTMP protocol is now not widely supported for playback. Apple’s HLS is far more widely used. Without transcoding and transmuxing the video, you will exclude almost anyone with slower data speeds, tablets, mobile phones, and related TV devices.
Using a transcoding software or service, you may simultaneously create a set of time-aligned video streams, every with a different bitrate and frame measurement, while changing the codecs and protocols to reach additional viewers. This set of internet-friendly streams can then be packaged into several adaptive streaming formats (e.g., HLS), allowing playback on virtually any screen on the planet.
Another widespread example is broadcasting live streams using an IP camera, as can be the case with surveillance cameras and visitors cams. Once more, to succeed in the largest number of viewers with the absolute best quality allowed by their bandwidth and devices, you’d need to assist adaptive streaming. You’d deliver one HD H.264/AAC stream to your transcoder (typically positioned on a server image within the cloud), which in flip would create multiple H.264/AAC renditions at different bitrates and resolutions. Then you definately’d have your media server (which is likely to be the identical server as your transcoder) package those renditions into one or more adaptive streaming formats earlier than delivering them to end users.
If you have any queries with regards to in which and how to use Traffic Cameras on the Web and Mobile, you can speak to us at the page.
