Telestream Wirecast Gear
96 STREAMING MEDIA June 2017
dropped so many frames that the streams would
have been unusable.
I also tested streaming at 1080p with various
combinations of recording and ISO recording
with the results shown in Figure 5 on page 95.
Here, broadcasting two 1080p streams barely
taxed the system, and I was able to record three
ISOs without breaking a sweat. Four ISOs (on
top of all other activities) finally pushed utilization into the 80%+ range, which bodes poorly
for overall stability.
As sort of a valedictory trial, I ran a 40-minute
test in which I streamed 720p Quick Sync videos
to You Tube and Ustream while recording the
output at 1080p Quick Sync and four ISOs using the Good setting. CPU utilization remained
very stable and close to the 60% mark.
Overall, as long as you’re using Quick Sync
rather than x264, you should be able to deploy a
range of streaming and recording options without bumping into either CPU or hard disk limitations. Of course, this begs the question as to
whether the Intel Quick Sync codec delivers
significantly lower quality than x264. Anyone
who remembers the earliest versions of Intel’s
hardware-based codec has to be concerned
about this issue, but my tests found that Intel
has come a long way toward achieving parity
with x264, particularly in the relatively generous data rates used for streaming.
Whither Quick Sync?
Specifically, to test Quick Sync against x264,
I captured a 1080p stream at 6 Mbps with each
codec. Then I tested the two captured streams
using the Moscow University Video Quality
Measurement Tool and the metrics shown in
Table 1. As you can see, Quick Sync held its own,
Then I loaded both captured clips into Pre-
miere Pro and aligned them vertically on the
same timeline, so I could enable or disable view-
ing of the top video and compare the frames
that way. At 100% resolution, the two videos
were very close in terms of quality, with very lit-
tle noticeable difference beyond a slight edge in
sharpness for x264. At 400% viewing, you could
see that this additional detail occasionally re-
sulted in blocks that swung the Blocking Metric
in Quick Sync’s favor.
In any event, at this encoding configuration,
the differences wouldn’t be noticeable in side-by-side videos. Since Quick Sync is clearly more
efficient CPU-wise, this makes the Intel codec
the obvious choice for streaming and non-ISO
Overall, the value proposition for Telestream
Gear is clear. You’re paying a premium of about
$2,500 for a system that’s configured and tuned
by Telestream and clearly powerful enough for
most productions. Given the mission-critical nature of most live event productions, it seems like
a pretty good deal to me.
Jan Ozer ( firstname.lastname@example.org) is a streaming
media producer and consultant, a frequent contributor to industry
magazines and websites on streaming-related topics, and the
author of Video Encoding by the Numbers. He blogs frequently at
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