Transcoder performance testing of Wowza Streaming Engine and server platform Supermicro MicroBlade

2016-04-03 13:36:00

PWI Ltd has completed the testing of new server platform Supermicro MicroBlade for evaluation of it's capabilities be a hardware for live streams transcoding with Wowza Streaming Engine.

When the task is to transcode a large number of video and audio streams OTT operator is faced not only with the problem of choosing a performance hardware platform, but also with the problem of a compact placement of many encoding and switching equipment in the rack and need to provide quick interchangeability of any transcoding server with a minimal time for their disconnection and connection. With a conventional server platform (even if it is 1RU - Rack Unit) the following problems will occur:

• Any 1RU server's case is evenly filled with the hardware components. This is due to the fact that it was originally designed as a universal tool that allows to install additional expansion cards. It usually takes a significant portion of rack space. The same time only computer CPU / GPU power is an important for transcoding tasks while other subsystems are used less.
• In the event of a server failure it is necessary to remove it from the rack, disconnect all the wires and cables. After repair it is necessary to connect back again. And it's not always convenient, and always time consuming. For transcoding in the data center operator is necessary to ensure the most rapid and convenient replacement conditions.

These two main problems are easily solved with the help of Blade solutions, rack server case with multiply main boards aggregated with power supply system, network connections, centralized control and monitoring system. In this enclosure are set blades - compact chassis with a minimum set of hardware components. For the task of video streams transcoding it requires only the major components of the server system.

• upermicro MicroBlade series of chassis, depending on the configuration, allows to set 14 (Series Supermicro MBE-314E 3RU) to 28 (series Supermicro MBE-628E 6RU) blade servers in the same chassis and server blade Supermicro MBI-6118D allow the use of technology Intel Quick Sync, for which no discrete graphics adapter is required (all processing is performed within the CPU, which greatly improves the computing density).

Typical OTT operator streams 100-200 TV channels. In order to understand what computing power will allow to conform the requirement and what place the hardware will occupy in the rack, it was necessary to test one of the blades. The test allow to estimate the required total capacity, the number of blades and chassis.

The following platform was used for the testing Supermicro MicroBlade:

• Blade server: Supermicro MBI-6118D-T4H
• CPU: Intel® Xeon® Processor E3-1285 v4 (3.5Ghz, 4 cores/8 threads)
• RAM : 32 GB
• Operating system: CentOS 7.1
• Java: Java 8 (64-bit)
• Graphical adapter: Intel IrisPro 6300
• Transcoder software - Wowza Streaming Engine

The methodic of testing is as follows: video stream encoded H.264 / AAC with two resolutions of 1280x720 and 1920x1080 was put to the input of transcoder for conversion of inbound streams to several streams at a lower resolution and different encoding bitrate (transrate) needed for multibitrate streaming (ABR). Gradually increasing the number of input streams, measure CPU utilization level, monitor transcoding error occurrence (skipped frames, not aligned) in the logs Wowza Streaming Engine and also visual verify video stream in the player. In case of errors and the degradation of the visual quality of the video you should stop testing and obtained in the previous step for the number of input streams considered acceptable.

Table 1. Testing 1280x720 H.264/AAC 4mbps

Input streams	Output streams	CPU encoding/decoding	QuickSync encoding/decoding
1 stream	1 stream 720p 1 stream 360p 1 stream 240p 1 stream 160p	5%	3%
2 stream	2 stream 720p 2 stream 360p 2 stream 240p 2 stream 160p	13%	5%
3 stream	3 stream 720p 3 stream 360p 3 stream 240p 3 stream 160p	20%	6%
4 stream	4 stream 720p 4 stream 360p 4 stream 240p 4 stream 160p	35%	12%
5 stream	5 stream 720p 5 stream 360p 5 stream 240p 5 stream 160p	35%	12%
6 stream	6 stream 720p 6 stream 360p 6 stream 240p 6 stream 160p	52%	15%
7 stream	7 stream 720p 7 stream 360p 7 stream 240p 7 stream 160p	64%	20%
8 stream	8 stream 720p 8 stream 360p 8 stream 240p 8 stream 160p		25%
9 stream	9 stream 720p 9 stream 360p 9 stream 240p 9 stream 160p		33%
10 stream	10 stream 720p 10 stream 360p 10 stream 240p 10 stream 160p		43%
11 stream	11 stream 720p 11 stream 360p 11 stream 240p 11 stream 160p		50%
12 stream	12 stream 720p 12 stream 360p 12 stream 240p 12 stream 160p		65%

Table 2. Testing 1920x1080 H.264/AAC 8mbps

Input streams	Output streams	CPU encoding/decoding	QuickSync encoding/decoding
1 stream	1 stream 720p 1 stream 360p 1 stream 240p 1 stream 160p	10%	15%
2 stream	2 stream 720p 2 stream 360p 2 stream 240p 2 stream 160p	20%	10%
3 stream	3 stream 720p 3 stream 360p 3 stream 240p 3 stream 160p	27%	18%
4 stream	4 stream 720p 4 stream 360p 4 stream 240p 4 stream 160p	43%	28%
5 stream	5 stream 720p 5 stream 360p 5 stream 240p 5 stream 160p	68%	39%
6 stream	6 stream 720p 6 stream 360p 6 stream 240p 6 stream 160p		50%
7 stream	7 stream 720p 7 stream 360p 7 stream 240p 7 stream 160p		69%
8 stream	8 stream 720p 8 stream 360p 8 stream 240p 8 stream 160p		25%
9 stream	9 stream 720p 9 stream 360p 9 stream 240p 9 stream 160p		33%
10 stream	10 stream 720p 10 stream 360p 10 stream 240p 10 stream 160p		43%
11 stream	11 stream 720p 11 stream 360p 11 stream 240p 11 stream 160p		50%
12 stream	12 stream 720p 12 stream 360p 12 stream 240p 12 stream 160p		65%

Conclusion:

With QuickSync technology transcoder performance and hence processing power per unit of rack capacity (RU) will primarily depend on the capabilities of the CPU. Based on the test results each blade allow processing up to 12 streams with 720p or 7 streams with 1080p.

Total for 3 RU chassis:	Total for 6 RU chassis:
12х14 = 168 streams	12х28 = 336 streams
7х14 = 98 streams	7х28 = 196 streams

The resulting density of transcoded channels per the RU unit is perfect for the organization of OTT operator, and allows us to recommend the platform Supermicro MicroBlade / MBI-6118D-T2H / MBI-6118D-T4H as hardware transcoding system based on Wowza Streaming Engine. The Word - HTML tool helps you convert Word documents, Excel, Google docs, PDF files and any other visual document to HTML.