u/Himankan

Even with HEVC extension installed for windows, 4K 60fps videos from iPhones stutter on VLC. (system: Corei7 6700HQ with GTX950m, SATA SSD and 16gb ram).

I found a temporary workaround in other subreddits as shown below. Meanwhile I request the videolan team to look into this.

• STEP 1
  • Open VLC media player and click on Tool > Preference.
  • Go to Show settings option in the lower-left corner and click on All.
  • Go under Input/codecs and click on the arrow in front of Video Codecs .
  • Click on FFmpeg under Video Codecs to find Decoding box on the right side, change Threads from 0 to 2.
  • Remember to save the change and restart VLC.
•   Adjusting FFmpeg decoding threads in VLC can fix 4K lag or stuttering by offloading more processing work to your CPU.   
• STEP 2
  • Open Tools > Preferences Select “All” wherever it says “show settings”.
  • In Advanced settings, click the Input/Codecs option.
  • Scroll down to Advanced in the Input/Codecs bit. Change File caching (ms) from 300 to something like 1000, 2000 or 2500
•   From <https://www.reddit.com/r/VLC/comments/lp7cb1/vlc_lags_on_big_4k_files_is_there_a_way_to_fix/>  
• STEP 3 Hardware decoding issues are the most common culprit for stuttering.
  • Open VLC, go to Tools > Preferences.
  • Select the Input / Codecs tab.
  • Find Hardware-accelerated decoding.
  • Try changing it to Automatic (to let your GPU take over only when necessary). Click Save and restart VLC.
• STEP 4
  • Go to Tools > Preferences.
  • Click the Video tab.
  • Under Display, change the Output setting from Automatic to OpenGL video output for Windows. Click Save and restart.
•   If VLC continues to lag despite these changes, try playing the video using K-Lite Codec Pack (full) with MPC-HC.