Poor image quality when opening capture device

[calande]

Hello,

I use a Magewell HDMI Capture USB interface to record TV programs on my computer in HD. I use ffmpeg and I have upmost quality. I also would like to watch TV live on my computer, and I tried opening the capture device in VLC, the audio is good, but the image quality is of poor quality, the type font outlines are fuzzy/pixelated, and the image is cropped. I tried all possible options in the context menu, but neither can I get the original source quality, nor the image to display in 16/9. Also, the image is either resized without keeping proportions, adding black vertical bars left and right, or the image uses all available screen space but is trimmed up and down. I have a full HD 1920×1080 monitor. If I resize the video bringing the right edge to the left, VLC keeps the black vertical bars on both sides and resizes the whole video. I wondered if the problem would come from the capture device or the set-top-box, but ffmpeg records the TV programs properly in full HD with clean type font outlines. The image quality doesn't come from DRM fallback limits, as I have an HDCP filter in-between, and ffmpeg records in upmost quality. Here are a few screenshots. Thank you for your advice.

Settings
Black vertical bars with option enabled to always fit content to window
Same problem, and with black bars also above as I resize
Fuzzy font outline
Pixelated outline of the TV channel logo
Black vertical bars with poor text outline quality
Image uses whole screen but is trimmed above and below

Thank you.

[Hitchhiker]

In the Preferences menu (Ctrl + P to open), opening Interface menu there's an option to have vlc resize the video according to its dimensions. It's called "Resize interface to video size", but it's checkmarked by default. But check anyway.

I can't load any of your screenshots because the site doesn't support SSL and my security software blocks non-http only sites.

Could you possibly upload them again to this site which we recommend here: https://postimages.org/
No need to create an account there and no ads. I usually use the Thumbnail link on the forum (appears below after you upload an image) since the image takes up less space and users can click them easily enough to enlarge. But up to you.

[calande]

Thank you. I tried checking/unchecking this option, but I didn't get rid of the vertical black bars...
Here are the screenshots:

[calande]

[calande]

If someone knows how to enhance the image quality and get rid of the vertical black bars, that would be nice
Thank you.

[Hitchhiker]

Try this.

1. Open vlc and hit Ctrl + P to open preferences and then click "All" at the bottom to open the Advanced menu.
2. In the left hand pane click "Video".
3. In the right hand pane scroll down to "Video cropping" and then type one of the available options i.e. 16:9, 16:10 etc.
4. Save, exit and restart vlc.

Here's a screenshot to save you looking for the setting.


(click to enlarge)

[calande]

Thank you. I added the video cropping value (16:9) and restarted VLC, but the video quality is the same.

[Hitchhiker]

To improve the video quality try a different Output module. The menu (open wih Ctrl + P again) is located in the standard option accessed by clicking the Video button at the top and then using the dropdown menu to select a different module. I use Direct3D11 myself, but you can try others. Save and exit as before if you find one that works otherwise they'll be lost after you exit vlc.

As regards the black bars you can experiment with the Aspect Ratio and Crop modules accessible by right clicking the video and then right clicking Video ---> Aspect Ratio, or Crop. You might succeed in eliminating the black bars, but the trade off will likely be that the faces of people and other shapes will appear elongated or otherwise out of shape.

[calande]

Thank you.

[Hitchhiker]

There's a possibility that you can download the TV programs to your own computer. You need Firefox for this so install that if you don't use it already.

Next step is to go to the Firefox addons site and install this addon: The Stream Detector
It adds a button to the browser toolbar which looks like a musical note.

Now go to the site where you would normally use capture. If the stream detector detects a URL it will display them above the toolbar button. Click that and it will show a number of links (usually). Click the "Copy all URLs" buttons and then open Notepad and post them in there initially.

It depends on how many URLs the addon detects, but if it's more than one, then you need the one with an m3u8 extension since that will be the one which links all the others together. Copy that the vlc's Network menu (Ctrl + N to open) and then click Play.

I tried it myself earlier this evening on a Dutch news site which usually has a number of videos available all of which use the JW Player. There aren't any links which can be copied on the site itself, but the addon found the links to them immediately. This is the one I used:
https://cdn.jwplayer.com/manifests/slZTdE4C.m3u8

Paste it into vlc and it'll play a video of some idiot in China setting fire to a car in a gas station. Fortunately, nobody was injured and the text overlays said the police caught him afterwards.

[calande]

Thanks. I installed the plugin in my browser and opened my TV subscription service online. The plugin apparently detected 2 streams, but they are not related, I think. No m3u8 file:

Code: Select all

https://dsh-m005.p-cdnlive-edge020206.scy.canalplus-cdn.net/sfr02-604c591252fb38ba4bcf9673c99b80fb-9b2f/live/disk/canalplusdecale-hd/dash-fhd/canalplusdecale-hd.mpd https://dsh-m005.p-cdnlive-edge020206.scy.canalplus-cdn.net/sfr02-604c591252fb38ba4bcf9673c99b80fb-9b2f/live/disk/canalplusdecale-hd/dash-fhddvr/canalplusdecale-hd.mpd

This TV subscription web site seems pretty hard to hack. The TV company says they provide full HD and UHD content only to DRM-capable browsers (only Edge at the moment, in theory, but it doesn't even work in HD or UHD). The DRM is Widevine L1. This is why I decided to use a regular NVIDIA Shield TV Android set-top-box (DRM compliant), connected to an HDCP filter, and finally to a capture interface. This way, I can have full HD content on my computer. If the TV company didn't throw a wrench in the gears, I could use VLC with a playlist of streams, one per TV channel, like I once did my my DVB-T board. Anyway

[Hitchhiker]

I think you've made the best choice. I tried connecting using the two stream links you provided, but it would appear that CanalPlus is restricted to France and I was trying to access it from the Netherlands.

But in any event I would still need an account with them and although it's theoretically possible to open one outside of France using a VPN and connecting to a French server I never learned the language when I was at school many moons ago and I'd be stumbling in the dark with both hands tied behind my back so to speak.

And so to the quality aspect: did you test other output modules and if so did any of them improve the playback quality?

[calande]

Yes, I tried a few of them, but I didn't notice any difference in terms of playback quality... For TV, I think I'll use Magewell's capture utility, and I'll use VLC to play video files and recordings.
Thank you

[Hitchhiker]

You might try using the Deinterlace menu options to see if they help. Here's the Wiki on the subject:
https://wiki.videolan.org/Deinterlacing/

[calande]

Thank you. Yes, I tried 6 several deinterlace modes to no avail.

[Hitchhiker]

Maybe try a Nightly version: https://nightlies.videolan.org/

[calande]

Thanks, will do