Best way to re-encode video to smaller file size (keep quality)?

I want to upload a torrent of IBA BK with Yoel Romero, but the file size is like 15 gb and would like it to be lower.'

Ive been trying Handbreak but seems it takes way too long

Any alternatives or tips?

The best balance of speed, smaller file size, and minimal quality loss for re-encoding a big MP4 is using FFmpeg with hardware-accelerated H.265/HEVC (or AV1 on newer hardware).
This is far superior to basic online compressors or simple bitrate reduction.


Recommended Approach: FFmpeg (Free, Powerful, Fastest with Hardware)

FFmpeg is the gold standard, it's what powers most GUI tools under the hood. HandBrake is a good user-friendly alternative with a GUI if you prefer that.


1. Fastest Option: Hardware Acceleration (NVENC, Quick Sync, etc.)

Use your GPU/CPU's dedicated encoder for 5-10x faster speeds than pure CPU encoding, with very good quality.

NVIDIA GPU (RTX 20xx or newer recommended): hevc_nvenc (H.265)
Intel CPU (recent integrated graphics): hevc_qsv
AMD: hevc_amf

Best fast command for minimal quality loss (H.265 NVENC example):

-cq 24: Quality-based (lower = better quality/larger file; 20-28 range is good "visually near-lossless" for most content). Adjust based on your source.
-preset p5 or p4-p7: Balances speed/quality (higher = slower/better compression).
-c:a aac -b:a 128k: Compresses audio lightly (or use -c:a copy to keep original if it's already good).
-movflags +faststart: Makes the video streamable (web-friendly).

For even better quality/size (still fast on good hardware): Try AV1 with av1_nvenc (RTX 40-series+) if your playback devices support it—~20-30% smaller files than HEVC at similar quality.


2. Highest Quality/Smallest Size (Slower CPU Encoding)

If you can wait longer for better compression:



-crf 24-28: Constant Rate Factor (quality mode). ~18-23 for near-visually-lossless, higher for more compression. H.265 CRF values are typically 4-6 higher than H.264 equivalents.
-preset medium (or slow/veryslow for even smaller files, much slower).

H.264 fallback (better compatibility, larger files):

Code:
ffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output.mp4

Expected Results

Size reduction: 40-70%+ smaller depending on original bitrate, resolution, and settings (HEVC/AV1 shine here vs. H.264).
Quality: CRF mode keeps it "visually lossless" or very close, test on your videofile.
Speed: Hardware = minutes for a big file; pure CPU slow preset = hours.

Other Tips for Better/Faster Results

Downscale if possible: Add -vf scale=1920:-2 (for 1080p) or similar—biggest size saver with little perceived loss on smaller screens.
Test first: Run on a short clip: ffmpeg -i input.mp4 -ss 00:05:00 -t 60 ... (skip to 5 min, encode 60 sec).
Two-pass for precise bitrate control (less common now with CRF).
GUI alternative: HandBrake — select H.265 (NVENC/Quick Sync if available), CRF ~24-28, medium/slow preset. Very similar results.
Online tools (e.g., VideoCompress, Cloudinary-based): Convenient for quick jobs but less control, potential quality hits, and privacy/upload limits. Not ideal for "big" files.

Quick Start

Download FFmpeg (static build from official site or winget install ffmpeg on Windows).
Run the command in terminal/cmd.
Compare original vs. output with VLC (side-by-side) and file sizes.

Hardware makes the biggest difference for speed. If you share your GPU/CPU, input resolution/bitrate (run ffmpeg -i input.mp4), I can refine the exact command.
AV1 is the future for ultimate efficiency if supported.

Just a tip for all the people that would like to gain some extra ratio. Downloading releases that are big and re-encoding them to a smaller size in good quality, allows you to re-upload them as a new torrent

Quick Guide: Using Command Line on Windows and Mac

1. Opening the Command Line

Windows

Command Prompt (CMD): Press Win + R, type cmd, and press Enter.
PowerShell (recommended modern replacement): Press Win + X → "Windows PowerShell" or "Terminal", or search for "PowerShell".
Windows Terminal (best option): Search for "Terminal" in Start menu (available in Windows 10/11).

Mac

Open Terminal:
Spotlight: Press Cmd + Space, type "Terminal", press Enter.
Or go to Applications → Utilities → Terminal.

2. Basic Navigation & Commands


Action


Windows CMD / PowerShell

Current directory: cd
List files: dir
List with details: dir
Change directory: cd foldername or cd ..
Create directory: mkdir foldername
Delete file: del filename
Delete folder: rmdir /s foldername
Copy file: copy source dest
Move/Rename: move source dest or ren
Clear screen: cls
Show IP address: ipconfig
Ping: ping google.com

macOS Terminal (bash/zsh)

Current directory: pwd
List files: ls
List with details: ls -la
Change directory: cd foldername or cd ..
Create directory: mkdir foldername
Delete file: rm filename
Delete folder: rm -r foldername
Copy file: cp source dest
Move/Rename: mv source dest
Clear screen: cls clear or Cmd + K
Show IP address: ifconfig or ip addr
Ping: ping google.com

3. Essential Commands

Windows CMD / PowerShell

whoami → Shows current user
systeminfo → System information
tasklist → List running processes
taskkill /PID 1234 /F → Kill a process
chkdsk → Check disk
sfc /scannow → System file checker

macOS Terminal

whoami → Current user
top → Live processes (press q to quit)
ps aux → List processes
kill 1234 or kill -9 1234 → Kill process
diskutil list → Disk information
softwareupdate -l → Check for updates

4. Useful Shortcuts

Windows

↑ / ↓ → Previous/next command
Tab → Auto-complete filenames/commands
Ctrl + C → Cancel current command
Ctrl + V → Paste (in modern Terminal/PowerShell)
Right-click title bar → Properties → Enable "Use Ctrl+Shift+C/V as Copy/Paste"

Mac

↑ / ↓ → History
Tab → Auto-complete
Ctrl + C → Cancel
Cmd + C / Cmd + V → Copy/Paste
Cmd + K → Clear screen

5. Quick Tips

Windows:

CMD is old-school. Use PowerShell or Windows Terminal for better features (tab support, better colors, etc.).
To run as Administrator: Right-click → "Run as administrator".
Drag & drop a folder into the command window to auto-type its path.

Mac:

Default shell is now zsh (newer than bash). You can check with echo $SHELL.
Install Homebrew (package manager): /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homeb ... install.sh)"
Use nano filename or install vim/nano for quick editing.

Cross-platform:

Learn Git Bash (on Windows) or use WSL (Windows Subsystem for Linux) for a full Linux environment inside Windows.
Many commands are the same in PowerShell and Terminal (e.g., cd, mkdir).

Bonus: Common Everyday Commands

Update everything on Mac: brew update && brew upgrade (after installing Homebrew)
Find a file: Windows dir /s filename, Mac find . -name "filename"
Open current folder in Explorer/Finder: Windows explorer ., Mac open .

Start practicing with simple navigation (cd, ls/dir, pwd). The command line is extremely powerful once you get comfortable!

Thanks for the in-depth response! it will take me a minute to understand the commands, but if it better/faster than Handbreak I will be happy

Took me almost 3 hours to reduce the IBA BK file I have

Lets hope that you can do it faster in the future Thanks for your hard work!