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Stuttering streaming video problems

by manwreck / September 12, 2009 11:33 AM PDT

Hi all,

I've been tearing my hair out testing this to the best of my ability.. But sometimes one just has to ask for help.

I am unable to watch any streaming video without it stuttering and glitching. Usually this occurs as a slowdown of the video signal, and dropouts on the audio.

I am having this problem with both Flash and Silverlight (Netflix specifically). I have tried the following things:

* Variable versions of Firefox (2.x, 3.0.x, 3.5.x)
* Safari 4.0.3
* Flash 9.x, Flash 10.x
* Silverlight (not sure what version, updated a month ago)

The thing that seems to make the most difference, oddly, is moving the video window to the Macbook's built-in monitor rather than using my Dell 22" external monitor. The video adapter is mini-DVI-to-DVI. But even with this done, I get some slowdowns and dropouts.

Here's my system info:

- Macbook 2ghz Core Duo
- OSX 10.6.1
- 2 GB RAM
- 250GB 7200 RPM HD

Thanks in advance for your help!


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by macnerd10 / September 12, 2009 1:22 PM PDT

Maybe your connection speed. I would get the speed with any speed test sites (Cnet provides a very good one), and then talk to the service provider. Maybe you need to upgrade to the faster service. I have this sometimes and I just pause until the bar below the video is full. Then it goes on well. It is rather strange to me that the monitor makes a difference. Maybe some connector issue as well.

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Re: bandwidth
by manwreck / September 12, 2009 1:28 PM PDT
In reply to: bandwidth

@macnerd10 --

Actually, my connection speed tests all say 5-6 Mbps downstream (which is good because it's what I pay for). I can download files very quickly even while the Flash problems occur.

Sorry I wasn't clear -- I will edit my earlier post describing the problem.


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by manwreck / September 12, 2009 1:33 PM PDT

I need to add some info to my previous post -- tried to edit, but could not.

1. Here are my speed test results per

- 5.24 Mb download
- .75 Mb upload
- 22 ms ping

2. I can download files very quickly (0.5-1 MB/s) pretty consistently, no matter what the Flash is doing

3. According to Activity Monitor, my CPU usage is ~130% when playing full screen streaming video.


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by Zuschlauer / September 13, 2009 10:42 AM PDT
In reply to: NEW INFO

When you are redirecting video out the port, you may be in a situation where you are bringing data in over your system bus, then sending it out again over the system bus. Normally your computer manages the data coming in from the internet and sends it to the video card where it goes directly to your screen. If you are instead redirecting it to the DVI out from the video circuitry, then it may be taking time on the bus, also. I would expect that laptops have less robust buses to save power.

The high cpu usage is from decoding the video data coming in before sending it to the video card. It is pretty intensive computing decoding the images real time.

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by manwreck / September 13, 2009 11:49 AM PDT
In reply to: I/O

Hi Zuschlauer,

that is all good info, thanks. However, it turns out the problem was overheating -- it took an hour on the phone with Apple for something unrelated to figure that one out.

I bought a cooling pad for the Macbook and hopefully that will continue to do the trick.


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