Jagged edges on HD HTML5 videos

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Jagged edges on HD HTML5 videos

Post by sabrefresco on Sat Aug 02, 2014 8:52 pm

For some reason, videos which have higher resolution than my monitor end up having jagged edges on HTML5 videos (on Vimeo, YouTube etc.). This does not seem to occur if the video is being played through flash player or if the video is being played on my media player (MPC-HC). This happens on both IE11 and Google Chrome (version 36.0.1985.125 m).

Take a look at this two images for clarification:

If you view both images at full resolution, you can notice the edges being too sharp.

Interestingly, this seems to be a problem with what codec a video is being played on. I tried the two following videos which played through two different encoders: Image 1, Image 2. The problem occurs in the first one and not the second. According to the encoding options here, I have a problem playing H.264/AVC videos (which has an itag of 248; mp4) and no problem playing VP8 videos (which has an itag of 137; WebM) through the YouTube HTML5 player.

I have a feeling this has to do with K-Lite Codec Pack, I tried playing H.264/AVC videos on Windows 8 through a VM without the codec pack, and there were no jagged edges. How do I disable the codec pack from being active when playing videos on my browsers?

The reason I play a higher than required resolution video is because my monitor is at 1600x900, so 720p videos look slightly out of focus or not that detailed compared to 1080p videos.

My relevant PC specs FYI: Intel Core i7 3615QM, Intel HD4000/Nvidia GeForce GT640M, Windows 8.1 Pro 64-bit.

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Re: Jagged edges on HD HTML5 videos

Post by Admin on Sun Aug 03, 2014 12:06 am

This is NOT the fault of the codec pack. Chrome does not use any of the codecs on your system, contrary to MPC-HC. Chrome uses its own private decoders.

Since it happens with H.264 and not with VP8. It might be related to hardware accelerated decoding, usually due to a graphics driver bug. It could also be because of bad post-processing done by the Intel driver.

1) Update the Intel graphics driver
2) In the Intel driver control panel find the option called "Contrast Enhancement" and disable it. (Media > Image Enhancement > Adaptive Contrast Enhancement )

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Re: Jagged edges on HD HTML5 videos

Post by sabrefresco on Sun Aug 03, 2014 2:16 am

Admin wrote:This is NOT the fault of the codec pack. Chrome does not use any of the codecs on your system, contrary to MPC-HC. Chrome uses its own private decoders.

Since it happens with H.264 and not with VP8. It might be related to hardware accelerated decoding, usually due to a graphics driver bug. It could also be because of bad post-processing done by the Intel driver.

1) Update the Intel graphics driver
2) In the Intel driver control panel find the option called https://www.youtube.com/watch?v=gIx0JFEyLuQ and disable it. (Media > Image Enhancement > Adaptive Contrast Enhancement )

My drivers are up-to-date. And I just switched off "Contrast Enhancement", but that did not help. It seems more of a scaling issue with the H.264/AVC video format. I've tried putting this up on superuser with no responses so far. I am going to try and force run Google Chrome on my Nvidia GPU to see the results. As I have mentioned this is not isolated to Chrome, but is present on every browser on my PC. Might be the GPU or a problem with how YouTube scales videos on its H.264/AVC formats.

Thanks a lot for your help!  Wink 

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Re: Jagged edges on HD HTML5 videos

Post by Admin on Mon Aug 04, 2014 2:17 am

Yes, it really looks like it is using a very poor scaling algorithm in your screenshot. Does it also look bad in "Theater mode" instead of fullscreen (button to the left of fullscreen button)?

I tried that exact same video in Firefox with the YouTube html5 player and it looked much better here.

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Re: Jagged edges on HD HTML5 videos

Post by sabrefresco on Mon Aug 04, 2014 3:25 am

Admin wrote:Yes, it really looks like it is using a very poor scaling algorithm in your screenshot. Does it also look bad in "Theater mode" instead of fullscreen (button to the left of fullscreen button)?

I tried that exact same video in Firefox with the YouTube html5 player and it looked much better here.

Yes it does. I know this is not a YouTube support forum, but thanks for bearing with me. Here are a few more screenshots to show you the results across different browsers. I used this video for testing purpose.

  • So on my PC's Chrome browser it was jagged as usual since the format was avc. Here's the screenshot.
  • I switched to IE11, and it did not have the scaling issue. Here's the screenshot. I could've sworn I remember seeing jagged edges before.
  • I tried it on Firefox, it played on the Flash player, so I didn't bother to force HTML5 player, no jagged edges, no screeny!
  • So I fired up my VM, and tried the video on Chrome on Windows 8.1 running through vmware, and it has no jagged edges. Here's the screenshot.
  • I have a ton of extensions on Chrome on my PC, so I tried Incognito mode, after making sure none of the extensions are enabled. Here's the screenshot.

So that rules out the extensions I use. Next up, I will try reinstalling Chrome after removing all Caches, Settings etc. and give it another go. Might have to switch browsers if this persists.  Mad

UPDATE: Uninstalling did not help, I am switching to Firefox from now on.


Last edited by sabrefresco on Tue Aug 05, 2014 6:08 am; edited 1 time in total (Reason for editing : Update.)

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Re: Jagged edges on HD HTML5 videos

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