Saturday, September 14, 2013

Experience casting tabs

The other day, I posted a note on my experience with the Chromecast radio. Today, I will talk about experience with video.

My Chromecast works well when showing video from a cast-enabled site like YouTube or casting a Chrome browser tab with still images in it, but poorly when casting a tab with streaming video. (Note that "to cast" is becoming a word, like "to google" or "podcast").

The first thing I tried was casting a tab in which I was surfing the Web and stepping through a Google Docs presentation. The TV image was shifted a little bit to the left, cutting off a few pixels; there was a noticeable, but sub-second, delay in updating the TV screen and data compression made small text difficult to read. The performance was imperfect, but generally satisfactory. (PDF documents do not work because they are handled outside the browser).

As you see below, the CPU load was seldom over 50% of capacity and usually less than 30%, but that was enough to turn the fan on. (My laptop was plugged in).


Next, I went to the CommonCraft Web site and watched a video that played in a 579 by 294 pixel widow. I picked Commoncraft because they make simple teaching videos with little movement on the screen. As you see below, the CPU load increased, but I was able to watch an entire video, which started at the arrow point:



For my final test, I watched a video of the Daily Show in a 512 by 288 pixel window. This is faster-changing video than Commoncraft's. At first, the video played satisfactorily, but CPU use quickly moved up to the vicinity of 100% and the the audio and video degraded severely. The audio went before the video, but the program was un-watchable.


It should be noted that I ran these test using a three-year old Dell Precision M4400 laptop with a 3.06 Ghz core duo CPU with 8 GB of memory running 64-bit Windows, connected to an old 802.11a/g Wifi network. The results would have been better with a newer, faster laptop or an 802.11n network.

The bottom line is that, given my computer and network, tab-casting is fine for PowerPoint presentations and Web surfing, but it is not up to streaming video in a window, much less streaming full-screen video. That is the bad news. The good news is that this is Chromecast version 1.0. Redesign and Moore's will take care of the performance problems soon enough.

For more on variables that can affect tab-casting quality, see this Google help page.

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Update 9/16/2013

+Zarthan South pointed out that my laptop lacks Google's minimum CPU for casting video tabs. With Windows 7, one should have a Core i3 or equivalent for standard quality video casting (http://bit.ly/17E3agi). My laptop is fast enough to cast stills like Web pages and slide presentations, which is quite useful. Note also that RAM utilization was around 3GB while running these tests.

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Update 10/22/2013

K. J. Kim has found that switching to the developer channel a Chromebook significantly improved video tab casting.  That shows that Google is continuing to improve the Chromebook.