Review: Videon’s Shavano 4K HEVC Video Encoder

Encoder Settings

After you’ve updated the Shavano’s firmware, you can navigate to the Encoder Control page again and click the Configure button under Encoding Settings. Here, you can select the output resolution, encoding mode (constant/variable bitrate), keyframe interval, video codec/profile, video bitrate, audio codec, and audio bitrate (Figure 6, below).

Figure 6. Encoder settings

Note that the only audio codec available is AAC-LC, which is the low-complexity (LC) version of Advanced Audio Coding. A new option in later firmwaren updates is the Quality/Latency setting. You may see better video quality if you set the Quality/Latency to High, at the expense of longer (higher) latency as the video buffer time is increased. For lower latency, you can set chose settings below Normal, but your video quality will likely decrease for a given video bitrate.

Output Settings

From the Encoder Control page, you can also set one or more streaming/recording destinations. You can use a wide variety of network protocols, as shown in Figure 7 (below).

Figure 7. RTMP and other network/format options for output

For H.264 streams, you can use any of the destination tabs, but HEVC cannot be delivered over RTMP streams. In my workflow, I use the Unicast option (Figure 8, below) to stream over UDP to a custom port on a Wowza Streaming Engine instance. The Wowza configuration uses a .stream file that listens to the same port specified on the Shavano.

Figure 8. Unicast options for live streaming

Compression Quality Analysis

Using the same technique I created for an earlier H.264 hardware encoder review (see go2sm.com/sub2000), I recorded live streams from the Shavano with these encoder settings for 1280x720 29.97p, all using Constant Bitrate, 2-second Keyframe Interval, and Normal Quality/Latency:

• H.264 High Profile at 500Kbps
• H.264 High Profile at 1000Kbps
• HEVC Main Profile at 500Kbps
• HEVC Main Profile at 1000Kbps

The H.264 Video Quality Metric (VQM) scores for the 500Kbps and 1000Kbps streams were 5.30368 and 5.02939 respectively, which would have ranked it better than the Teradek Cube 655 and AJA HELO scores in that previous review. For HEVC, both 500Kbps and 1000Kbps bitrates scored much better than any equivalent H.264 bitrate, at 2.70350 and 2.60434 respectively. A sample “bad” frame returned by MSU Visual Quality Measurement Tool for the H.264 tests is shown in Figure 9 (below), with VQM scores of 19.0507 and 19.112 respectively. The same frame for the HEVC tests is shown in Figure 9, with VQM scores of 2.18779 and 0.95568—a remarkable difference in score. Both H.264 and HEVC 500Kbps streams showed keyframe flashing (or pulsing) every 2 seconds due to inadequate available bitrate for the resolution and frame rate.

Figure 9. Clockwise from top left: Shavano’s H.264 output at 500Kbps, Shavano’s H.264 output at 1000Kbps, Shavano’s HEVC output at 500Kbps, Shavano’s HEVC output at 500Kbps. Click the image to see it at full size.

Final Thoughts

The Videon Shavano has been on the market for just over a year and was initially released with fewer features than the current firmware has now. As Videon has added features to the compression and destination settings, I’ve been able to successfully integrate this compact and high-quality H.264 and HEVC encoder into my webcasting workflow. If you’re looking to add the capabilities of HEVC to your live streams, I recommend giving the Shavano a test drive.