Performance - Video
Video editing is one of the most demanding activities that you can ask a computer to do. In order to make your editing experience efficient, you’ll want to examine your system for any bottlenecks. In this section we’ll examine the essential ingredients you’ll need to achieve proper system performance when editing video.
What’s your bottleneck?
Operating System (OS)
Central Processing Unit (CPU)
Random Access Memory (RAM)
Graphics Processing Unit (GPU)
Video I/O card/device
Configuring the Workstation
When considering performance, you should try to figure out which components are going to slow you down the most, and fix those first. There are lots of combinations of hardware, software, setup and workflow practice, so there is no single method to find the bottlenecks. But there are some issues that are pretty common performance barriers. Let’s look at a triage list, in order of importance.
- Nonlinear Editing (NLE) application: In order to take advantage of the optimum performance, you need to use a modern application that takes advantage of all of the tools below. The most recent version of your software should be the fastest.
- Editing Codec: You can either work with native footage in your NLE, or you can transcode the source files. Editing with native DSLR files puts a greater strain on your processor, since there is more work involved in decompressing the files. Transcoded footage has less compression applied, so it puts a higher demand on your storage system. If you are going to transcode footage, try to look for modern codecs (many of which have yet to be converted to 64-bit versions).
- 64 bit Operating System: This is the foundation of good performance. It requires both the OS as well as the application to support 64-bit architecture.
- Adequate RAM: In most cases, this should be as much as you can afford. It should be at least 8GB, or 2GB per processor, whichever is more. Add more if you can. RAM often needs to be loaded in matched pairs or even sets, so be sure to examine your system’s requirements.
- Adequate moderately fast data storage: To work in video, you’ll want at least two drives from which to work – one for your operating system and applications and another for your media. Each should be at least a 7200 RPM disk, with plenty of extra space. If possible, your editing disk should be a performance configuration such as a RAID 0 or SSD. Your performance can benefit from more and faster storage, but it might be diminishing returns, depending on the files you work with.
- Processor number and speed: Given a good platform for RAM and OS, the ability of the processor to handle the required calculations will probably be the next limiting factor. Newer processors and more cores is better.
- Accelerated GPU: If your application supports GPU acceleration, then a fast GPU can also make a lot of difference. If the program is not accelerated, then you may not see any difference at all.
- Really fast data storage: Fast data storage can help with ingestion and backup processes, and it’s important when rendering to tape. If you work with compressed in-camera originals then disk speed is less important for the bottleneck tasks. Consider stripped RAID, SSDs and dedicated scratch drives to boost performance to the fullest.
The CPU is the core element of a computer, and its design affects the speed that computations can occur. Because video files are very complex and require real-time playback, it is essential that you have a fast processor. You may have noticed that improvements in the clock speed (as measured in Gigahertz) of processors has leveled off. Instead, manufacturers are choosing to improve performance through the use of multiple cores, and other changes to the processor architecture.
All high-end computers are now sold with some variation of multiple processors, and/or multiple cores per processor. Each core can handle its own stream of calculations, which speeds up the work done by the computer. It is commonplace to find dual-core and quad-core processors in use for laptops. Desktop machines are currently available with up to 16 cores.
In order to achieve faster processing, computer programs have largely been re-written to take advantage of multiple processors and multiple cores on those processors (as well as 64-bit operating systems). Most professional video editing programs (like Adobe Premiere Pro, Apple Final Cut Pro, and Avid Media Composer) have been optimized for multiple/multi-core processors. On the other hand, many consumer-oriented editing applications have not been as well optimized for multiple processing.
Note that the speed boost you get from having multiple cores won’t be an exact multiple of the cores. It will depend on the design of the OS, design of the software and whether the task is one that can be split up easily. If you want to maximize performance, you’ll want to find up-to-date tests that measure performance of the software you care about most. Sometimes per-core speed is more important, sometimes the number of cores is the most important.
Most video editing software manufacturers have links to recommended hardware configurations lists on their websites. Some, like Avid and Adobe, make recommendations for multiple manufacturers.
RAM is where a computer temporarily stores data that it is currently working with. Typically, files are read off the hard disk and loaded into RAM. The processor does its work, and eventually the files are saved back to the hard drive. Since RAM is so much faster than a hard drive, all your computer work goes faster if entire files can be loaded into RAM while they are being worked on, as shown in Figure 1. If the entire file won’t fit into RAM, it has to be “swapped” back and forth to the disk, which slows everything down.
Figure 1 Files are loaded from the hard drive into RAM and the CPU does its work to them. Eventually, they are saved back to the hard drive.
In the early days of computing, RAM was small in capacity and very expensive. RAM is now one of the cheaper computer components, and with 64-bit processing, the amount of RAM that computers can use has become very large. For instance, 32-bit processors can address up to 4 GB of RAM, while 64-bit processors can address up to 16.8 million terabytes of RAM. While you’ll probably never reach a need for 16.8 million terabytes, a good rule of thumb is to have at least 2-3GB of RAM per processor core in your computer. Most current computers suitable for video editing support at least 8GB of RAM, and some support up to 64GB. We recommend you install as much as you can afford.
Most computers require RAM to be loaded in matched sets (typically sets of two or four chips). Use great caution when purchasing additional RAM and follow the recommendations of your computer’s manufacturer for type and quantity.
Video editing is heavily reliant upon RAM, which allows for rapid exchange of data in use by an application. The video editing application will typically recommend 4GB or more for just the one application. While editing video, you may be using a suite-based approach. In this workflow you may use related applications for graphics, audio enhancement, and video compression. Each of these applications will have their own needs. Pay attention to the allocation of RAM between programs, and which programs you use at the same time. If you can close other RAM-intensive programs while you are editing video, you will help your NLE performance.
While RAM chips have become increasingly reliable, there is an additional advantage to have ECC (error correction code) RAM to avoid data corruption. This RAM design uses internal error correction algorithms to detect and recover from small errors. It is more expensive and slightly slower than non-ECC RAM. Note that Apple desktop computers support ECC RAM, as do most high-end PC desktops. Apple laptop computers currently do not support ECC RAM, but some PC laptops do.
Graphics cards, also referred to as video cards or the GPU, are becoming increasingly important components for video editing workstations. GPUs have parallel processing capability which makes them more efficient at executing the complex algorithms used for intensive tasks like running filters and color grading.
The GPU is typically bundled with your computer at time of purchase. For some types of computers (especially towers) there are often a range of options presented at time of purchase. Towers can often be easily upgraded with third-party offerings at a later date. Currently, CUDA-accelerated cards provide the best performance boost.
All-in-one and laptop computers typically offer few if any options for the GPU. As such, it is critical that you examine your options closely at the time of purchase. A dedicated graphics card will typically offer better performance than one that is integrated into the circuit board of the computer.
You can think of a GPU as a multi-core processor that is designed specifically to render image files. It’s really good at breaking up image adjustments into multiple streams and working on them simultaneously, as shown in Figure 2.
Figure 2 A GPU is like a “mini-computer” that is specially designed to process image signals by breaking them up into lots of smaller streams. This helps video cards render images out to the screen in real time.
For this reason, programs such as Adobe Premiere Pro and Apple Final Cut Pro X depend on the GPU for internal signal processing tasks, as shown in Figure 3. The real-world implementation of GPU acceleration is, unfortunately, pretty spotty. For a program to make use of a GPU in signal processing, it needs to be able to hand data back and forth very quickly and without any errors. This is a complex operation.
In order to make use of GPU acceleration, you need to check with the manufacturer of your NLE application for a list of supported video cards. Unsupported cards won’t help you with this, no matter how fast or expensive they are. And even when an application can make use of a GPU, it can’t always do all functions using GPU acceleration. Adobe Premiere Pro 5.5 can make use of the GPU, but Adobe After Effects 5.5 does not.
This is an area of pretty rapid change, so you will want to consult current product literature before making a purchase decision.
Figure 3 Video editing applications may make use of the special capabilities of your GPU when processing an image.
Video-capable GPUs will frequently offer several different connection options for attaching displays. For example, you may be able to hook up two computer monitors using a DVI connection as well as a video monitor to a GPU’s HDMI port. While the use of the HDMI port (or DisplayPort with an adapter) is very popular, some users still attach dedicated video capture or display cards with professional monitor connections for higher-end workflows.
A video input/output card or device allows you to both capture and output a true video signal from a computer. These are considered a specialty item in use for many video workstations and may not be needed for all workflows. They are typically employed when a user needs to capture video from tape-based acquisition formats. They also allow the user to monitor or record the video signal with professional video hardware.
Figure 3 A video I/O device, like the AJA Io HD provides a connection to a video monitor. Photo courtesy AJA Video Systems.
If you are using a tower-based workstation, the use of an internal card is a viable solution. For laptops as well as towers (especially those that lack enough card slots) a standalone device can be used. The most common connection for standalone devices is currently FireWire. However both USB 3 and Thunderbolt are quickly gaining popularity.
The I/O devices can serve one or more of the following needs:
- They allow users to capture video tape by providing professional video connections that can be used with tape decks.
- They can also allow the output to professional tape decks for recording finished programs. Tape is still a standard delivery and archive format for many workflows.
- They allow for the connection of professional video monitors that support hardware calibration.
When choosing a video I/O card/device you need to consider three primary factors. First, what are the formats it supports? Video comes in several flavors and formats. For example, the requirements of a digital cinema workflow may demand a card or device capable of handling video at a 4K resolution. On the other hand, if your only need was to work with HD video, the cost and system requirements are much lower.
The second area to consider is how the card or device connects to your computer. Will it use a card slot in a tower or can it be connected using a FireWire cable (a necessity for most laptops and all-in-one computers). You may want to consider USB 3 or Thunderbolt, which are emerging as potential successors to FireWire.
Also, which video connection types are supported from the card or device to your professional video equipment? The simplest cards offer only a single connection type (such as HDMI, which is used by several consumer and prosumer video capture devices). Alternately there are specialty connection type like SDI (serial digital interface) that are in use by higher-end professional cameras and tape decks.
The most popular manufacturers for video I/O devices are:
- AJA Video Systems (www.aja.com)
- Blackmagic Design (www.blackmagic-design.com)
- Matrox (www.matrox.com/video)
A fast card reader is an essential device that will impact how quickly you can go from shoot to edit. Card readers are fairly ubiquitous these days. However, you should investigate adding a performance reader for video workflows as the amount of data you need to transfer is significantly greater. While there are many models to choose from, not all card readers are well-suited for video.
- Bus power: Consider purchasing for a reader that is bus powered. This allows for the card reader to run off the FireWire or USB port. It will give you greater flexibility when working with the reader in the field (especially with laptops).
- Transfer speed: While transferring video footage is largely dependent on card speed, even a fast card can be handicapped by a slow card reader. Options like FireWire 800, ExpressCard, and Thunderbolt are typically your best choice. The most essential thing when choosing a card reader is the connection type.
- Multiple slots: Many card readers offer two or even four slots, which are handy to load additional cards. Ingestion and backup often happen in short bursts on set. Being able to load a few cards and walk away from the machine lets you get back to shooting sooner.
Some computers are shipping with SD card readers built in. For some, this will be an adequate solution. But many DSLR cameras continue to use the Compact Flash card format which will continue to require a dedicated reader.
Once you have purchased all the hardware for your system, you still have a few configuration steps in order to maximize performance. The most important of these choices involve your storage allocation. By using each hard drive for a particular task, you can maximize the speed of your system. We’ll take a look at two different configurations below.
In each case, we’ll assume that you are using an OS and an application that is 64-bit, and that you have put in adequate RAM as described above.
Central Processing Unit (CPU)
Many video editing applications have strict minimum requirements for the CPU. This is because video editing is a high-performance task that requires several computational operations to occur simultaneously with precision. Additionally, most manufacturers offer recommended requirements or configurations. These system requirements should be strongly considered when purchasing or upgrading a computer.
We’ll start by examining a good configuration for a tower system, since this is the best system for your primary video editing. We’ll assume that this system has a 64-bit OS and plenty of RAM. We’ll want to have several drives in the system, each dedicated to a particular type of storage. We’ll also want to have some external storage for backup.
In most video workflows, you’ll probably need to run more than one program that can benefit from lots of available RAM. Photoshop, Premiere Pro, Final Cut Pro as well as color grading applications can all benefit from having a lot of RAM available. For a 64-bit workflow, the generally recommendation is to target 2-3 GB of RAM per processor core in your machine, as shown in Figure 5.
Figure 5 You can allocate specific amounts of RAM to your NLE application. Give it as much as you can, while reserving adequate RAM for other programs you run at the same time.
For storage, you will likely want to use multiple drives and even drive types to achieve best performance. If your computer has available slots, internal drives can be very affordable. If you’re out of space, external drives and arrays can be successfully used. Figure 6 diagrams a configuration scheme for tower data storage.
Boot/program drive: Keep your operating system and your applications on a dedicated drive. It is recommended that you regularly maintain a restoration copy of this drive to recover from data loss or drive failure.
Data drive: You’ll want to store the footage for your project on large, fast drives. Typically these drives will be striped together as a RAID 0 array that uses multiple drives for increased performance. This drive can hold both your original footage as well as any preview, transcoded, or render files that your editing system generates.
Near-term storage: Because video projects tend to be large, multiple hard drives can be consumed over time. For projects that are not actively being edited, the option of transferring from edit drive to more affordable storage drives works well.
Figure 6 In a tower system, you should split your data between several drives. The OS and applications can be on one drive, which could be an SSD. The project files can be on a second data drive, and the video source files can be on a third. Both the project and source files may be stored on a RAID to increase performance and redundancy.
A performance laptop configuration should strive to follow similar specifications as a tower. In order to achieve better performance, a second internal drive can be used. Some computers allow for this installation easily, while others choose to remove their optical drive to accommodate for more space.
Laptops typically have fewer slots for memory than a tower. For a video workflow, bump your system with as much as you can afford and the manufacturer supports.
For storage, you will likely want to use multiple drives and even drive types to achieve best performance. Laptops offer very limited expansion options. You will likely only have a single internal drive by default. It is often possible to replace the internal optical drive with an additional hard drive, which is a good upgrade for a video editing laptop.
It is a very good idea to have access to fast external storage disk arrays when editing with a laptop.
- Thunderbolt is the new fastest type of connected storage, but the hardware options are extremely limited at the moment.
- eSATA is a well-supported choice that provides very good speed with lots of hardware choices.
- FireWire 800 and USB 3 can also work, but provide less speed.
Figure 7 Here’s a configuration diagram for a laptop storage system for video editing. Add a second internal drive for added performance. Use an external storage device to maximize capacity and speed.