Recently, I started watching movies in 4K HDR format more frequently. However, they often appear too dark on both my display and TV. I use the VLC player in both cases. This issue occurs because 4K HDR (High Dynamic Range) movies can look too dark on displays or players that do not fully support HDR. This happens due to the way HDR content is encoded and processed.
I’ve decided to investigate why this happens and explore how I can fix it.
1. HDR Content Is Optimized for HDR Displays
HDR content is created with a specific emphasis on a wider range of brightness levels (dynamic range) and colors compared to standard dynamic range (SDR) content.
HDR uses metadata to provide instructions to HDR-compatible displays about how to render the brightest highlights, darkest shadows, and vibrant colors.
When viewed on an HDR-capable display, this content is mapped correctly to take advantage of the screen’s expanded capabilities, resulting in a more vivid and realistic image.
2. Tone Mapping Issues
When HDR content is played on a non-HDR display or device, there needs to be a process called tone mapping to adjust the HDR signal down to the SDR display's capabilities.
Without proper tone mapping, the content may appear too dark because the non-HDR device cannot interpret the HDR metadata correctly or handle the extended brightness and color ranges.
Some non-HDR devices simply display the content as-is, without any adjustments, resulting in a visually dark and unsatisfactory image.
3. Different Brightness Standards
HDR content is typically mastered for peak brightness levels far above what SDR displays can handle. For example:
SDR content is usually mastered for a maximum brightness of 100 nits.
HDR content can be mastered for 1,000 nits or more.
When played back on an SDR display without proper down-conversion, the higher brightness levels may not translate properly, causing the image to appear too dim.
4. Limited Support on Players or Displays
Older or low-end players and displays may lack the ability to properly decode or down-convert HDR content, leading to a poor viewing experience.
Some players or displays might not have accurate tone mapping algorithms, resulting in crushed shadows (loss of detail in dark areas) or reduced overall brightness.
5. Color Space Mismatch
HDR content often uses a wider color gamut (like Rec. 2020) that SDR displays cannot fully reproduce.
Without proper conversion, colors can appear muted or dark because the display cannot interpret the wider range of colors correctly.
6. Incorrect Settings
Sometimes, the issue can stem from misconfigured settings on the player or display. For example:
If an HDR signal is sent to an SDR display without proper conversion.
If the player or display settings are not optimized for the content being played.
There can be multiple ways to fix it, but what first worked for me is:
I used PotPlayer instead of VLC, and on my TV, it immediately improved the output because my TV supports some (or most) HDR formats. However, it didn’t improve playback on my PC display since it doesn’t support HDR at all.
To resolve this, I started using the madVR video renderer (Madshi Video Renderer) and was able to fix the issue completely.
2) Get Madvr, unpack it somewhere (it will have to stay there), run install.bat under administrator. It will register itself in your system as an available video renderer.
3) Open PotPlayer and navigate to Video → Video Processing Settings. Set the Video Renderer to Madshi Video Renderer, then click the [...] button next to the Video Renderer dropdown to access additional settings.
4) In the dialog window that opens, select Edit Settings.
5) Navigate to Devices → [Your Display] → HDR.
6) For any display, or for displays that don’t support HDR, select "Tone map HDR using pixel shaders" and set the Target Peak Nits to a low value (100 is the lowest, which will increase brightness the most). You can adjust this value to achieve the desired result.
7) Alternatively, for displays that support HDR, you can select "Passthrough HDR to display" and enable "Send HDR metadata to the display".
8) That's it, your 4K HDR movies should look much better now, enjoy!
As much as I love my UGREEN NAS, it doesn't come with a built-in app for backups. There's one, actually, but it only allows backups between different NASes or between your NAS and your PC. While I needed to set up a backup from one drive on my NAS to another drive on the same NAS. I tried a few Docker containers with web UI, but I wasn't able to make them work, or they didn't work as I wanted (for example one app encrypted the backups, and I wasn't able to change this. And I didn't want my files encrypted, I just needed a simple copy). So in the end, I decided to go with creating a script that runs rsync for a backup and schedule it with cron. I just needed to back up my music folder from one drive to another. Here's how I did this: 1) Log in to your NAS via SSH . 2) Run: sudo nano /usr/local/bin/backup_music.sh 3) The Nano editor will open, paste this there (update the script to use your paths) SOURCE="/volume1/4TB_NVME/Music/" DEST="/m...
A very clear and interesting video about the different types of program interfaces and what they definitely shouldn't be like: Switching To A Secure Frequency
Thank you!
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