Helpful hint from Merc

[Mercutio]

Yesterday I ran into a problem I found rather unusual.

A few weeks ago I sold a Home Theater PC to a college student whom I thought was reasonably "on the ball" as far as computers went.

She told me that videos played in windows media player didn't play back on her TV. She said they show up as black space. Which I thought was weird, because they always have worked for me.

So I stopped by her apartment yesterday to take a look.
Sure enough, we could watch AVI files on her PC but not her TV.

I thought about it for a minute and realized that I always work with MPEG files, not AVIs. So I dug around her PC, found an MPEG, and it played perfectly on both the TV and the PC.

Weird?

So I found the old 16-bit media player. With that one, both MPEG and AVI played.

After a moment I decided that for some reason windows was using video overlay to display AVIs. I'm not sure WHY it was doing that, why AVIs need that kind of treatment but MPEGs don't.

But the fix was to turn off all the graphics acceleration.
Once I did that, her movie files all played perfectly.

Just thought I'd share that. It's a weird problem but I can't think of a better solution. Hopefully with this being in the toolbox, it'll be easier to find than it it got stuck in the support or Computers forum.

 

[Handruin]

I have a similar issue with dual monitors. I can't drag an avi to my secondary monitor and continue watching, I get the same black box. I thought it was because of DirectX, but I didn't know how to get around it. That's good to know about the overlay.

 

[blakerwry]

Yup, your application/codec determines what kind of graphics acceleration to use. Using overlay greatly enhances the ability of the graphics card to process the video rather than your host processer. For example, I've seen near 100% CPU usage and dropped frames on an Athlon system when not using overlay. Going to overlay made the CPU usage drop to single digits with no dropepd frames.

The decision to use overlay or not and the affect it has on performance depends alot on the application/codec and hardware you have. With my matrox dual head g400 I could never get overaly to work on the secondary display. The fix was to disable overlay in my player. This was a big performance hit whether playing on the primary or secondary display. Because this was not a dedicated HTPC and instead was my desktop PC which I wanted to ado other things while playing video I decided to keep overlay enabled and simply use the primary display for video.

On my newer GeforceFX5600 dual head is no problem.. Overlay works properly on the primary or secondary display. On a readeon9000 with TV out I think I may of had to disable overlay or some advanced HW acceleration options for some codecs to display correctly on the TV (2nd display). Media player classic and bsplayer both have a good amount of options that allow you to have control over hardware acceleration modes allowing you to get around the hardware limitations of many cards.

 

[ddrueding]

I'd just like to throw in a thanks to Merc for this one...it made me look really good at a conference. When the powerpoint presentation's videos wern't being displayed on the projector