Master Remux Tool | Zero-Loss Batch Media Remuxer

What is Master Remux Tool?

Master Remux Tool is a production-grade Windows command-line automation suite designed to change multimedia file containers (e.g., convert MKV to MP4, or extract audio tracks into FLAC/M4A) at maximum drive speed without re-encoding video or audio streams.

Unlike traditional transcoding software that degrades quality and takes hours, Master Remux executes stream copy operations (-c copy) in seconds while preserving full metadata, retaining folder hierarchies, and handling bad tags using smart fallback logic.

Key Capabilities

Zero-Quality-Loss Stream Copy: Changes containers instantaneously by copying bitstream data directly without touching video/audio codec matrices.
Smart Auto-Codec Detection: Probes source files with FFprobe to identify original elementary audio stream codecs and extracts them to matching target containers automatically.
Two-Pass Automated Failover: If container constraints reject video cover art or secondary data streams during Pass 1, the engine automatically strips invalid streams and retries audio-only remuxing in Pass 2.
Dynamic Drag-and-Drop Queue: Drag individual files or entire directory trees directly onto the script icon. Subfolder structures are recursively mapped and duplicated inside the output folder.
Bitexact & Clean Metadata Tags: Strips redundant encoder signatures (-fflags +bitexact) while mapping global metadata, video/audio stream tags, and iTunes/ID3v2 parameters.
Observability & Live Reporting: Real-time console metrics displaying precise process start/end times, execution duration, total files queued, success rate percentages, and file-based debug logging (remux_log.txt).

Complete Guide: Setting Up FFmpeg on Windows

On a fresh Windows installation, Windows does not know what ffmpeg or ffprobe means until you set them up. Follow these simple steps to configure your environment:

STEP 1 Download FFmpeg for Windows

1. Go to the official builds website: Gyan.dev FFmpeg Builds →

2. Scroll down to the git master builds or release builds section and click on ffmpeg-git-full.7z or ffmpeg-release-full.7z to download the compressed archive file.

3. If you don't have an extractor to open .7z files, download 7-Zip (Free).

STEP 2 Extract FFmpeg to Your Computer

1. Open the downloaded .7z archive file.

2. Open your Local Disk (C:) drive in Windows File Explorer.

3. Extract the folder into C:\ and rename it to ffmpeg. Your path should look like this:

C:\ffmpeg\bin\ffmpeg.exe
C:\ffmpeg\bin\ffprobe.exe

STEP 3 Add FFmpeg to Windows System PATH (Recommended)

Adding FFmpeg to your PATH allows Windows to run ffmpeg and ffprobe from any location on your PC:

Press the Windows Key on your keyboard, type env, and select "Edit the system environment variables".
In the window that appears, click the "Environment Variables..." button near the bottom right.
Under the "User variables for [YourName]" section (top box), click on Path and then click Edit....
Click New on the right side and type: C:\ffmpeg\bin
Click OK on all open windows to save the changes.

ALTERNATIVE The Quick Local Folder Method

If you do not want to configure system environment variables, you can extract the binaries directly to your working folder:

Open the downloaded ffmpeg-release-full.7z (or git-full.7z) archive file using 7-Zip.
Navigate into the internal bin\ folder inside the archive.
Extract both ffmpeg.exe and ffprobe.exe directly into the exact same folder where MasterRemux.bat is saved.

Your local folder structure should look like this:

📁 MyRemuxTool/
   ├── 📄 MasterRemux.bat
   ├── ⚙️ ffmpeg.exe
   └── ⚙️ ffprobe.exe

How to Use Master Remux

Download & Extract: Download MasterRemux.zip and extract MasterRemux.bat into your desired folder.
Select Media Files or Directories: Highlight one or multiple audio/video files (or entire folders).
Drag and Drop: Drag your selected items and drop them directly onto the MasterRemux.bat file icon.
Select Target Container: Choose option 0 for auto-extracting native audio codecs, or pick a specific video/audio container from the interactive menu (Options 1–14).
Review Results: Remuxed files are neatly placed into the Converted\ directory (preserving subfolder structure), and a session log is saved to Converted\remux_log.txt.

Supported Output Formats

Master Remux Tool supports 15 interactive output container selection modes:

0. AUTO-DETECT 1. Dolby Digital (.ac3) 2. FLAC (.flac) 3. Matroska Audio (.mka) 4. MP3 Audio (.mp3) 5. MPEG-4 Audio (.m4a) 6. Ogg Audio (.ogg) 7. Opus Audio (.opus) 8. WAV Audio (.wav) 9. AVI Video (.avi) 10. Matroska Video (.mkv) 11. MPEG-4 Video (.mp4) 12. QuickTime (.mov) 13. WebM (.webm) 14. Custom (.ts, etc.)

[0]

Auto-Detect Audio Codec

Queries stream 0 audio codec with FFprobe. Automatically maps AAC/ALAC → .m4a, Vorbis → .ogg, PCM → .wav, FLAC → .flac, AC3 → .ac3.

[1-8]

Audio Container Extraction

Extracts elementary audio streams into standalone lossy or lossless audio containers without touching original audio samples.

[9-13]

Video Remuxing & Transmuxing

Swaps video containers (e.g. MKV to MP4 or MOV to MKV) while applying MP4/MOV metadata tags (-movflags use_metadata_tags).

[14]

Custom Container Extension

Allows power users to manually specify any custom multiplexer target container extension (e.g., ts, m2ts, nut).