Streaming media

Video is one of the most complex forms of digital content to deliver. Raw, high-resolution video footage can reach bitrates of 1 Gbps or more. But most viewers aren’t accessing content in studio conditions; they’re watching on phones, laptops, or TVs with varying screen sizes and internet speeds.

To support all these devices and connections, we must create multiple versions (or renditions) of each video. Each rendition is optimized for a different set of viewing conditions, balancing quality with performance. Technologies like codecs, container formats, and adaptive streaming make this possible.

A codec (short for compressor/decompressor) is a software algorithm that reduces the size of video files for easier delivery and playback. Arc XP’s Video Center uses the AVC (H.264) codec, the most broadly supported option across modern devices.

Other codecs like HEVC, VP9, and AV1 offer advantages in specific contexts, but AVC remains our default due to its excellent compatibility and manageable licensing costs.

While codecs compress the video data, container formats package that data with the necessary information for playback. The most common format used in Video Center is MP4. You may also encounter formats like .aac or .mp3 for audio-only content.

When we change container formats without re-encoding the video itself, we’re performing a process knowing as transmuxing (or just muxing).

Adaptive Bitrate (ABR) streaming is what makes platforms like YouTube, Netflix, and Arc XP Video Center so flexible. Instead of delivering a single version of a video, we create a ladder of renditions at various resolutions and bitrates.

As a user begins watching, the player assesses their device capabilities and network conditions, then selects the most appropriate stream. If the connection changes mid-playback, the player can seamlessly switch to a better-match rendition, helping minimize buffering and interruptions.

Video Center uses HLS (HTTP Live Streaming) for ABR delivery, a widely supported standard. Other options, like CMAF and DASH, are also gaining popularity.

To enable ABR, videos are delivered in segments, usually just a few seconds long. This allows the player to quickly switch between renditions as needed.

Currently, Video Center uses MPEG-2 Transform Stream (.ts) segments. A newer format, Fragmented MP4 (fMP4), reduces segmented overhead and lowers bandwidth usage by 5-15%. While fMP4 offers clear advantages, transitioning to it requires re-encoding petabytes a content, which is a costly endeavor.

Before ABR became standard, many platforms used progressing downloads. This method downloads the full video file, allowing playback to begin while the download is in progress.

While simpler, progressive delivery doesn’t adapt to changing network conditions. As a result, it’s largely being phased out of Video Center in favor of ABR.

If a high-resolution video is delivered to a device on a slow connection, playback pauses as the player waits for more data. This is buffering.

To avoid this, ABR dynamically adjusts the video quality in real-time. While this might mean sacrificing some visual clarity, most users prefer continuous playback over occasional buffering interruptions.

A successful streaming experience depends on several integrated technologies:

Even when technologies are based on open standards, they still may be subject to licensing obligations. Codec usage, in particular, can trigger royalty obligations from patent tools like HEVC Advance, MPEG LA, and Velos Media. We recommend that you consult with a lawyer on your licensing and other intellectual property obligations. Open Comments PanelOpen Details Panel