How Much Video Processing Performance Boost Do the Latest PC Processors Deliver?

Encoding for Streaming

In my streaming encoding trials, I tested three programs; Adobe Media Encoder, ProMedia Carbon, and Sorenson Squeeze. You can see the results in Table 2 (below), which uses the same color-coding as Table 1. That is, green if the benefit is greater than 30%, yellow if between 0% and 30%, and red if less than 0%. As you can see, the Z820 delivered significant time savings in all programs.

Table 2. Comparative results from streaming encoding programs.

All tests involved rendering one or more files to one or more streaming formats. By design, the tests varied by program, using different quantities of source files and different output presets. So you should not draw any conclusions about comparative performance from these results, only how each program performs on a more capable computer.

Note that all three tests were one-to-many trials where I encoded multiple source files to multiple outputs. If you’re encoding a single file to a single output, don’t expect the same benefit; more on this in the sidebar.

Since the tests varied by program, I’ll describe them individually. With Adobe Media Encoder, I encoded six 3-4 minute 720p source files to six canned presets supplied by Adobe, which simplified producing the identical test on both computers. Perhaps one of the best-kept secrets about Adobe Media Encoder is that when you assign multiple H.264 presets to a single file, it encodes them in parallel, which obviously makes good use of the additional cores (Figure 4, below).

Figure 4. Adobe Media Encoder rendering six outputs from a single test input. Click the image to see it at full size.

Let me take a moment to distinguish this set of tests from those reported above. In the editing-related output tests, I rendered sequences from various Premiere Pro projects in Adobe Media Encoder to a single-output preset. Accordingly, a substantial portion of the encoding time related to rendering the project, then transcoding to the selected preset. In these tests, I input multiple disk-based files, not projects, so all encoding time related solely to transcoding that file to the selected presets.

Our next test involves ProMedia Carbon, is a $5,000 batch-encoding program from Harmonic that has proven itself one of the most efficient consumers of multiple cores that I’ve ever seen, essentially redlining CPU utilization on every computer that I’ve ever tested. In these tests, I encoded six 3-4 minute 720p files to 11 presets that bore no relation to those used in Adobe Media Encoder or Squeeze. Not surprisingly, Carbon efficiently leveraged the Z820 to a 42% reduction in encoding time; if you’re running Carbon on an older computer and need more throughput, don’t buy another copy of Carbon (sorry, Harmonic); buy a computer with additional cores.

Sorenson Squeeze is a $749 desktop encoding product from Sorenson Media, and to test Squeeze, I rendered six 3-4 minute 720p files to 9 different encoding presets. One little-known feature of Sorenson Squeeze is that you can open multiple instances of the program to improve encoding efficiency on multicore computers. On Windows computers, the procedure is simple: You start the program as you normally would, either via the Start menu or an icon on your desktop, and then do the same to open another instance. On the Mac it’s a bit more challenging, but you can learn about the procedure in an article on StreamingLearningCenter.com.

To produce the results shown in Table 2, I opened three instances of Squeeze, each encoding two source files to eight outputs. In this mode of operation, Squeeze definitely put the additional resources to good use.

How should these results affect your CPU selection? I’ll discuss that after the next section.