X264 Workload Briefs

We evaluate x264 using “vbench: a Benchmark for Video Transcoding in the Cloud, a benchmark for the emerging video-as-a-service workload”, available here. Vbench’s 15 input videos were algorithmically selected to represent a large commercial corpus of millions of videos based on resolution, framerate, and complexity. We use the "Upload" and "Video on Demand" configurations to evaluate performance and power usage. Upload uses a single pass transcoding without degrading the input video quality which represents the initial upload encoding to a video service, requiring speed and quality. The Video on Demand (VoD) configuration uses a 2 pass transcoding that requires speed and improved compression without degrading video quality. The VoD first pass collects statistics used in the second pass to allocate more bits when encoding complex vs. simple frames.

To maximize ffmpeg throughput, we run multiple ffmpeg instances equal to the number of CPU cores available on the socket, using one ffmpeg thread per instance. All ffmpeg instances are run on one socket with a dedicated CPU core using numactl to set affinity. We report the average time to transocde the 15 vbench input files for each ffmpeg process and the socket level power usage. To minimize OS overhead, the ffmpeg binary, and all input and output files are stored on a ramdisk. We compare Ampere Altra Max M128- 30 processor to Intel® Xeon® Platinum 8380 (Ice Lake) and AMD EPYC™ 7763 (Milan) running CentOS 8.4 with 4.18 kernel. We built the latest available versions of ffmpeg version and libx264 with gcc 11 on all platforms. See Additional Benchmarking Details description below for additional details including the ffmpeg commands run.

Ampere Altra Max has the best transcode performance running ffmpeg using x264 compared to Intel Xeon 8380 and AMD EPYC 7763. In Figure 1, we plot the average transcoding time for each ffmpeg process showing Ampere Altra Max is 2.09x and 1.79x faster than Intel Xeon Platinum 8380 for the Upload and VoD configurations, respectively. Ampere Altra Max is 1.15x and 1.05x faster than AMD EPYC 7763 (Milan) for Upload and VoD.

In addition to the best transcoding performance, Ampere Altra Max is the most power efficient processor, reducing the carbon footprint of video transocding. In Figure 2, we plot the socket level power usage showing Ampere Altra Max is 1.17x more power efficient compared to Intel® Xeon® Platinum 8380 Processor (Ice Lake) and 1.24x vs. AMD EPYC™ 7763 (Milan) for the Upload configuration. For VoD, Ampere Altra Max is 1.22x more power efficient vs. Intel® Xeon® Platinum 8380 Processor (Ice Lake) and 1.29x vs. AMD EPYC™ 7763 (Milan).

Ampere Altra Max processors are a complete System On Chip (SOC) solution built for cloud native workloads, designed to deliver exceptional performance and energy efficiency for applications like video transcoding using x264. Ampere Altra Max delivers both industry leading performance and power efficiency running x264 with up to 2.09x faster performance compared to Intel Xeon 8380 and is up to 1.22x more power efficient. Compared to AMD EPYC 7763, Ampere Altra Max is up to 1.15x faster and up to 1.29x more power efficient. In additional to providing the fastest video transcoding, Ampere Altra Max innovative architecture that delivers predictable high performance with it’s highly energy efficient design and reduces the carbon footprint of video transcoding.

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System configurations, components, software versions, and testing environments that differ from those used in Ampere’s tests may result in different measurements than those obtained by Ampere.

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