Author Topic: Video Quality & Sound with Intel Drivers  (Read 1112 times)

cafedumonde

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Video Quality & Sound with Intel Drivers
« on: August 08, 2016, 12:41:09 am »

I have just gotten my new 14.04 installation to drive my Sony CRT television at 1080i but still have a few issues.

LMCE is working fine. I ran the AVWizard to resize the UI and specified sound over HDMI. The UI comes up and seems just as it should.

I think I have problems at a few levels:

1. Video Content is Dark: Is there a gamma or brightness adjustment in Xine, Xwindows, or perhaps in the Intel driver? I just need to brighten things up a bit. Cranking the brightness on the TV adds detail to the dark areas but washes out the brighter ones.

2. Video Tearing: Tearing is apparent when the video content changes quickly. I expect this is a driver issue, though I specified the intel driver in my xorg.conf. I will try switching back to the "fbdev" driver. Does anyone know the difference? Any other ideas? My old system, with the GeForce 6200 looked way better.

3. Horizontal Distortion: There is a slight horizontal wiggle in the CRT scan that happens when bright content transitions through a few lines of video. One possibility is that I may need to tweak my modeline. I used the ATSC timings as a start but there seem to be many variations for 1080i. Another possibility is that my attempt to pass sound over HDMI is somehow screwing up the video.

4. Sound Not Working: Sound is not coming over HDMI. Just a loud static. Sound works great on the HDMI output of my cable box and I run it into the TV exactly the same way. I said "yes" to DTS in the AVWizard. Any links or tips on this?

Once again, any input would be appreciated.

Thanks,

CDM

phenigma

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Re: Video Quality & Sound with Intel Drivers
« Reply #1 on: August 08, 2016, 01:28:08 am »
I believe newer Intel stuff needs fbdev and vaapi for acceleration.

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cafedumonde

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Re: Video Quality & Sound with Intel Drivers
« Reply #2 on: August 08, 2016, 01:36:32 am »

Thanks Phengma for the quick reply. 

The tearing problem is solved. I added the following to the "Device" section of xorg.conf:

Option "TearFree" "true"

Apparently this is an special option for the Intel driver. It is puzzling to wonder why someone would want tearing.

What is fbdev? Why would it be a better choice than the proprietary driver?

CDM

phenigma

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Re: Video Quality & Sound with Intel Drivers
« Reply #3 on: August 08, 2016, 08:14:12 pm »
Since I'm not actually running any newer Intel video I'm only relating what I've heard.  fbdev is a video driver, like Intel or nvidia.  va-api is the acceleration mechanism that Intel uses, like vdpau on Nvidia.  Tearing is related to vsync and must movies are not recorded in the same refresh rate your monitor/card regularly uses.  This option likely adjusts the monitor vsync to equal the film's frame rate, which eliminates tearing.  This is not desirable for most other day to day tasks, or gaming, which wasn't the highest possible refresh rate.  I know the Intel driver is fubar in 1604 and tschak uses frame buffer on his NUCs with newer Intel video built in.

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cafedumonde

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Re: Video Quality & Sound with Intel Drivers
« Reply #4 on: August 12, 2016, 03:11:48 am »

All issues resolved:

1: Darkness was not specific to LMCE. I just adjusted the display controls.

2: Video tearing fixed by passing the TearFree option to the Intel driver as described in the thread.

3: The subtle distortion was indeed a function of the modeline timings. The standard ATSC timings caused the distortion. I switched to one known to work with Sony TVs.

4. Sound is working fine. My receiver was not setup correctly.

Thanks again for the feedback. System is working great for basic playback...now on to the next set of issues...

CDM

phenigma

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Re: Video Quality & Sound with Intel Drivers
« Reply #5 on: August 13, 2016, 10:36:28 pm »
Glad to here it!  Have fun!

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