Bitrate vs Resolution? What about Bits Per Pixel? A Dive into Transcoding Expertise

tl;dr

Is it safe to put your faith in an online video provider that suggests 2 Mbps for 1080p streaming using H264 just because it's good at buying links to be the top 1 result in Google? The answer: Exercise caution and think twice.

In the realm of digital video streaming, the concepts of bit rate and video resolution are often in the spotlight when it comes to discussions about video quality. However, transcoding experts rely on a hidden gem known as "bits per pixel" (bpp) to strike the perfect balance between bit rate and resolution, ensuring an optimal viewing experience. In this article, we'll explore the significance of bits per pixel in the world of transcoding and how experts utilize it to optimize streaming quality while keeping bit rates and resolutions in check.

Understanding Bit Rate and Video Resolution

Before we delve into the nuances of bits per pixel, let's establish a foundational understanding of bit rate and video resolution.

Bit Rate: Bit rate refers to the rate at which data is processed or transmitted in a video stream. It's commonly measured in bits per second (bps) or kilobits per second (kbps). For those wondering, "What is bit rate?" or "What is bitrate used for?"—it's essentially the amount of data that flows through your screen every second. A higher bit rate usually translates to better video quality, but it also requires more bandwidth for seamless streaming.

Video Resolution: Video resolution signifies the number of pixels that form the width and height of a video frame. Common resolutions include 720p, 1080p, and 4K. A higher resolution yields sharper visuals, but it also demands greater data and processing power.

During my tenure at Envivio (now Ericsson Mediakind), a significant MPEG-4 supplier for Apple since the early 2000s, the transcoder supplier had the honor of being chosen by Apple as one of the two reference encoders (shootout to Alex!), although we were not directly involved in the inception of HLS. At that time, the question of which bitrate to apply for specific resolutions wasn't our main concern. We recognized that this isolated metric couldn't guarantee the utmost quality. Instead, our attention turned to a more holistic measurement—'bits per pixel.' By considering both resolution and bitrate, this approach seamlessly aligned with the evolving landscape of adaptive streaming. This perspective, one that I strongly advocate for, underlines the core principles of attaining unparalleled streaming excellence." - Sylvain Corvaisier

Bits Per Pixel: The Unseen Catalyst

Bits per pixel (bpp) is a pivotal metric that transcoding experts use to bridge the gap between bit rate and video resolution. Bpp quantifies the amount of data allocated to represent a single pixel in a video frame. It's the secret sauce that determines the level of detail each pixel holds in relation to the overall video quality.

How Transcoding Experts Utilize Bits Per Pixel

1. Quality Allocation: Think of bits per pixel as a quality controller. Transcoding experts assign a specific amount of data to each pixel based on the desired quality level. A higher bits per pixel value means that more data is dedicated to individual pixels, resulting in enhanced image detail and clarity. Conversely, lower values lead to reduced data allocation, making the video appear smoother but potentially sacrificing fine details.

2. Optimal Bit Rate and Resolution: The magic of bits per pixel comes to life when transcoding experts aim to optimize both bit rate and resolution. By setting a suitable bits per pixel target, these experts finely balance the relationship between resolution and bit rate. This practice prevents wasteful data usage for barely noticeable increases in quality and ensures that higher resolutions don't lead to disproportionately larger file sizes or bandwidth demands.

3. Adaptive Streaming: The concept of bits per pixel extends to adaptive streaming, a technique that adjusts video quality based on the viewer's available bandwidth. Through dynamic adjustments to bit rate and resolution, adaptive streaming maintains a consistent viewing experience. Transcoding experts harness bits per pixel to determine how much detail can be retained in lower-quality video versions without compromising the overall viewing enjoyment.

Bitrate vs Resolution? What about Bits Per Pixel?

Conclusion

In the intricate world of video transcoding, the interplay between bit rate, video resolution, and bits per pixel resembles a graceful dance. Transcoding experts rely on bits per pixel as a guiding star, allowing them to make informed decisions that result in the perfect equilibrium between bit rate and resolution. This approach ensures that viewers can indulge in high-quality streaming without putting undue strain on network resources. As technology advances, the prominence of bits per pixel in video optimization is destined to grow, shaping the future of digital content delivery.

Remember, whether you're pondering "What bitrate should I stream at?" or seeking insights into "1080p bitrate," the balance struck by transcoding experts using bits per pixel is the key to an unparalleled streaming experience.

Article written by
Sylvain Corvaisier