GPUs vs VPUs: What’s Best for Video Processing

October 4, 2024
10 Min
Video Education
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The term "Graphics Processing Unit" (GPU) was introduced by NVIDIA in 1999 with the launch of the GeForce 256. This card was marketed as the first true GPU, capable of handling both graphics rendering and complex calculations related to graphics processing, including hardware transformation and lighting.

Video processing has advanced quickly, driven by the increasing demand for high-quality content and the need for efficient systems. As the focus shifts toward higher resolutions and more complex visual effects, GPUs and VPUs have become essential tools for developers and content creators.

What are GPUs?

GPUs are built to handle tasks like image and video rendering, improving performance for graphics-heavy activities like gaming, design, or machine learning. They excel at managing many tasks at once by breaking them into smaller parts and running them in parallel. This makes them perfect for graphics rendering, video encoding, and processing large amounts of data quickly.

On the other hand, CPUs are great for tasks that require a step-by-step approach, like running operating systems and general apps. They focus on sequential tasks, making them versatile for day-to-day computing. While GPUs handle heavy lifting in graphics and data, CPUs keep things running smoothly behind the scenes.

Why use GPUs instead of CPUs for video processing?

GPUs are much better at parallel processing than CPUs, especially for repetitive tasks like audio and video encoding and decoding. While CPUs focus on sequential processing and can handle only a few tasks simultaneously, GPUs can manage thousands of threads simultaneously.

GPUs are great for video and audio tasks because they spread repetitive calculations across multiple cores. For example, when encoding a video, GPUs can process many frames at the same time, resulting in faster render times and smoother playback.

GPU architecture

At the heart of a GPU are individual processing units called cores. These cores are much smaller and more specialized than CPU cores, which focus on handling more complex tasks one at a time.  

GPU cores, on the other hand, are designed to execute many simpler tasks all at once. This allows GPUs to perform thousands of operations, making them ideal for parallel processing tasks like rendering graphics or video processing.

By using a model called Single Instruction Multiple Threads (SIMT), each core can execute the same instruction while working on different pieces of data. This design helps reduce delays and increase processing speed, allowing for quick data handling.

 

Why use GPUs instead of CPUs for video processing?

How do GPUs achieve parallelism?

To understand how GPUs handle large tasks, it’s important to look at how they manage parallel work. A key part of this is the Streaming Multiprocessors (SMs), which split up tasks into smaller pieces and assign them to thousands of threads that can run at the same time.  

SMs make sure everything is handled efficiently by managing both the processing and memory, allowing the GPU to easily take on complex tasks like video processing or machine learning.  

  • Threads are the smallest units of work in a GPU, each responsible for executing a specific task, such as performing calculations on a single pixel in video processing. A GPU can manage thousands of threads simultaneously, which allows it to perform many small operations in parallel.
  • Blocks are groups of threads. When a task is executed, it’s broken down into multiple threads organized into blocks. Each block operates independently and can share data through shared memory, which is accessible by all threads within the block. This setup is particularly efficient for tasks that require threads to collaborate, like applying filters or processing parts of a video frame.
GPU architecture

Memory hierarchy in a GPU

  1. Global memory: Global memory is shared across all cores and acts as the primary storage area for all the data the GPU handles. It’s like a vast library to hold video files, textures, and other essential assets. Global memory is accessible by all threads in a GPU, but it is slower compared to other types, which can create some latency.

    In video processing, global memory is where raw video streams and intermediate frames are stored. To keep things running smoothly, GPUs try to limit how much data is sent to and from global memory by utilizing faster memory types during demanding tasks.
  1. Shared memory: Shared memory is a smaller, faster memory space shared by threads within the same block. It helps threads communicate and synchronize more effectively. This memory is used for sharing data that multiple threads need, reducing delays and speeding up processing.
  1. Registers: Finally, there are registers, which are the fastest type of memory. Each thread in a GPU has access to a limited number of registers that store local variables and intermediate results.

    In video processing, registers are important for speeding up shader and pixel processing. During shader operations, registers temporarily hold pixel data, such as color values and texture coordinates, needed for rendering frames. This setup enables GPUs to execute quick calculations and transformations, resulting in a smooth and efficient rendering process.

What are VPUs?

A close-up of a computer partDescription automatically generated

VPUs (Video Processing Units) are designed to handle tasks like video decoding, encoding, and image processing. By offloading these jobs from the CPU, VPUs help videos run smoothly while using less power. They’re built to make video-related tasks more efficient, which is handy for streaming or media-heavy apps.

VPUs are a type of ASIC (Application-Specific Integrated Circuit), meaning they’re made for specific tasks. Unlike CPUs or GPUs that handle many tasks, ASICs focus on one area. You’ll find ASICs in everything from phones to cars and even cryptocurrency mining, where their specialized design speeds up certain processes.  

VPU architecture

A VPU is built with dedicated processing cores specifically for video tasks. These cores can handle multiple operations at once, making processes like rendering, decoding, and encoding faster. This parallel processing is what gives VPUs their edge in video-related work.

The VPU’s design tackles challenges like handling motion in video, applying real-time effects, and keeping things running smoothly even with high-resolution video or heavy workloads. It’s what makes VPUs ideal for demanding tasks like streaming or live video editing without losing performance.

Memory hierarchy in a VPU

VPUs, like GPUs, use a layered memory system with fast local memory (on-chip or cache) and external memory like DRAM. Cache memory offers quick access to frequently used data, reducing delays during processing tasks. Meanwhile, DRAM handles larger video files and assets but works slower than cache memory.  

VPUs have specialized buffers called frame buffers. These buffers temporarily hold the pixel data that will be displayed on the screen, allowing the GPU to render images while keeping the frame rate consistent. VPUs store this data in a buffer until it's ready for the next screen refresh, which prevents tearing or visual glitches during transitions.  

These buffers work on the FIFO (First In, First Out) principle. FIFO ensures that the data stream is processed in the correct order, handling video streams and sequential tasks to avoid bottlenecks or skipped frames.

What are image signal processors?

Image Signal Processors (ISPs) are hardware chips within VPUs designed to improve image quality. They implement various algorithms for tasks like noise reduction and color correction, which improve the overall visual output of video data.  (this whole sentence)

ISPs also have built-in support for specific codecs and video formats, which helps them handle real-time encoding and decoding smoothly. This support reduces the workload on the main CPU, allowing for better management of high-resolution video streams in applications like video conferencing, live streaming, and video editing.

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How cost-efficient are GPUs and VPUs?

When looking at GPUs and VPUs, a key comparison is their performance in FLOPS (Floating Point Operations Per Second), which shows how powerful the processor is. Another simple but useful metric is FLOPS per dollar, telling you how much performance you get for the money. This makes it easier to compare cost efficiency between different processors.

Modern GPUs are incredibly powerful, often reaching over 30 teraflops (trillions of operations per second). This makes them great for tasks like AI training, data processing, and high-performance computing while offering good performance for the cost.

VPUs typically have fewer FLOPS compared to high-end GPUs because they’re designed more for tasks like video encoding and decoding. However, they often deliver better value in video-focused applications, as they are optimized for those specific tasks. When looking at FLOPS per dollar, VPUs can offer solid performance for videos despite having lower overall FLOPS compared to GPUs.

FLOP per dollar for GPUs and VPUs

The table compares the FLOP per dollar for various GPUs and VPUs, calculated on their performance in single precision 32-bit floating point (FP32) operations.

Hardware FLOP rating (TFLOPS) Cost in USD FLOP per dollar (TFLOPS/USD)
NVIDIA A100 (GPU) 312 $10,000 0.0312
AMD Instinct MI250X (GPU) 383 $11,300 0.0339
Hailo-8 AI Processor (VPU) 26 $499 0.0521
Mythic M1076 Analog Matrix Processor (VPU) 4.8 $199 0.0241

Should you choose GPU or VPU?

Deciding between a GPU and a VPU comes down to what you need for your specific tasks. Each has its benefits that can affect performance, power use, and costs. Taking the time to assess your requirements can help you make a choice that fits your project best.

1. VPUs consume less power:

VPUs are designed specifically for video processing tasks, which allows them to operate with much lower power consumption compared to traditional GPUs. At the same time, a high-performance GPU may consume around 400 watts or more during intensive workloads.  

VPUs can achieve similar or even superior performance in video encoding and decoding, with power usage often below 100 watts. This efficiency leads to significant savings in operational costs, especially in large-scale setups with many units running at once.

2. GPUs have high performance in various applications:

GPUs are designed for high performance in tasks like gaming, machine learning, and data analysis. With thousands of processing cores, they excel in handling demanding computations efficiently.  

This makes them a strong choice for various applications beyond video processing. High-end GPUs like the NVIDIA A100 can achieve over 300 teraflops, making them ideal for demanding workloads.

3. VPUs can transcode high-quality:

Regarding transcoding capabilities, VPUs excel by handling a higher number of concurrent streams per server than GPUs.  

A single VPU can manage dozens of 4K streams simultaneously, while a GPU might be limited to fewer concurrent streams due to its higher power draw and thermal constraints.  

VPUs can maximize performance without significantly increasing power usage, making them appealing for video delivery services and streaming platforms.

4. GPUs are costly and not easily scalable:

GPUs usually have a higher upfront cost, especially the high-performance ones. While they deliver excellent power for various tasks, this investment might not make sense if your focus is solely on video processing.  

In comparison, VPUs are generally more budget-friendly and built for scalability. They work well in large-scale video processing environments, like streaming services, where multiple units can be efficiently deployed.  

With lower costs, VPUs help in better resource allocation and budget management, particularly when dealing with many simultaneous streams.

Why we chose VPUs for our video API

At FastPix, we saw the need for a more focused solution for video encoding as our video API services grew. Initially, we used GPUs, which handled a range of tasks well. However, as our demand for high-quality streaming increased, we found that switching to VPUs made more sense. VPUs are specifically built for video workloads, allowing us to optimize encoding and decoding while cutting down on power consumption.

The shift to VPUs let us manage more streams without losing quality and helped reduce operational costs. With this shift, we’ve been able to focus on delivering better performance and meet the increasing demands of our clients.

Summing up

At FastPix, our video API helps you fine-tune your video delivery with features like multi-CDN delivery and adaptive bitrate control. These features ensure your videos play smoothly, even when the network isn’t stable. By using VPUs for video encoding, our API handles high-demand streams more efficiently, saving resources while keeping quality high.

FastPix’s API is easy to integrate into different applications, letting developers focus on content creation instead of worrying about video performance. Want to simplify your video workflows? We’ve got you covered for reliable, high-quality streaming at scale.

Sign up today and see how FastPix can simplify your video workflows!

Frequently asked questions

What are the main differences between GPUs and VPUs?

GPUs (Graphics Processing Units) are designed for parallel processing, making them ideal for rendering graphics and performing complex calculations in tasks like video editing. VPUs (Vision Processing Units), on the other hand, are specialized for processing visual data efficiently, particularly in mobile applications. They excel in power efficiency and compact design compared to GPUs.

When should I use a GPU instead of a VPU?

GPUs are preferable for high-performance tasks requiring significant computational power, such as deep learning and complex video rendering. They have thousands of cores that allow for fast processing of large data sets. VPUs are better suited for lightweight applications where power consumption and size are critical, such as in mobile devices or embedded systems.

Can I use GPUs for real-time video processing?

Yes, GPUs are highly effective for real-time video processing due to their parallel architecture, which enables the rapid handling of multiple streams of data simultaneously. This capability is crucial for tasks like live streaming and interactive graphics rendering.

What are the power consumption differences between GPUs and VPUs?

GPUs typically consume more power than VPUs due to their higher processing capabilities. For example, high-end GPUs can require over 200 watts, while VPUs are designed for efficiency and may consume as little as 15 watts. This makes VPUs more suitable for battery-operated devices.

What is the future of VPUs in video processing?

Answer – VPUs are gaining popularity in applications like autonomous vehicles and smart cameras due to their efficiency and capability to process visual data in real-time. As demand for mobile and edge computing grows, VPUs are likely to become increasingly important in the video processing landscape.

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