X Codec Inspector 1.0
If you have ever installed a codec pack and watched your media player suddenly refuse to play files it handled fine the day before, the cause is almost always a DirectShow filter conflict.
Two decoders are registered for the same media type and the wrong one is winning.
Until now, diagnosing that required either a costly commercial tool or manually digging through the Windows registry.
X Codec Inspector solves that with a free, portable EXE that maps your entire DirectShow and Media Foundation environment in seconds.
Something new just entered the pipeline - X Codec Pack 3 is coming soon.
What X Codec Inspector does
X Codec Inspector scans the Windows registry and loads every registered DirectShow filter and every Media Foundation Transform (MFT) on your system.
For each filter it shows the CLSID, the DLL path, the file version, the company name, the merit value, and all supported media types and pin directions.
Both 32-bit and 64-bit filters are listed in separate views. There is no installation required - download the EXE, run it, and everything is visible immediately.
The tool covers two distinct layers of the Windows media pipeline. DirectShow is the legacy pipeline used by players like MPC-HC, Windows Media Player, and most third-party decoders including LAV Filters.
The Media Foundation tab covers the modern pipeline used by Windows 8 and later, which handles hardware-accelerated decoding for H.264, HEVC, and AV1 through Intel Quick Sync, NVDEC, and DXVA.
Where it fits in your codec workflow
X Codec Inspector is most useful at the diagnostic stage - after something has gone wrong or before you make changes you may need to reverse. The three-step workflow the tool is designed around reflects this:
Step 1 - Baseline snapshot.
Before installing a new codec pack such as K-Lite Mega Codec Pack or a standalone DirectShow FilterPack, click Snapshot to capture your current filter state. This takes a moment and records every registered filter and MFT.
Step 2 - Install, then compare.
After installing your codec pack or filter update, click Reload and then Compare Snapshot. The comparison window highlights every filter that was added (green) and every filter that was removed (red). You see exactly what the installer did to your system, with no guesswork.
Step 3 - Resolve conflicts.
Click Detect to open the Codec Conflict Detector. This lists every media type that is handled by more than one filter, ranked by severity.
For each conflict you can use Edit Merit to lower the priority of the filter you want to demote - setting it to DO_NOT_USE or UNLIKELY - without uninstalling it. DirectShow then routes playback through the preferred decoder. This is safer than unregistering filters because the merit change is fully reversible.
Merit values explained
Merit is the mechanism DirectShow uses to decide which filter wins when multiple decoders compete for the same media type. The values follow a hierarchy: PREFERRED (0x800000) takes priority over NORMAL (0x600000), which beats UNLIKELY (0x400000), which beats DO_NOT_USE (0x200000).
If FFDShow and LAV Filters are both registered for H.264 and FFDShow has a higher merit, it will be chosen even if LAV Video is the better decoder. Editing the merit of FFDShow down to UNLIKELY in X Codec Inspector immediately resolves that without touching the registry manually or uninstalling either filter.
This is especially useful when following a setup guide like Transform Your Media Player with LAV Filters, where filter priority is the difference between smooth hardware-accelerated playback and a black screen.
The Health Check and DLL scanner
A secondary but genuinely useful feature is the Health Check, which scans every registered filter and highlights in red any entry whose DLL file is missing from disk.
Broken registrations like these are a common source of playback errors and crash-on-open behavior.
They accumulate over time as codec packs are updated, uninstalled improperly, or overwritten. X Codec Inspector makes them visible in one pass.
When you need it most
The typical scenarios where X Codec Inspector saves real time are: after installing or updating K-Lite Codec Pack when a format that previously worked stops playing; after a Windows update that adds or modifies Media Foundation components and disrupts your hardware decoding path; when setting up HEVC playback on a fresh system (the guide on playing HEVC files with LAV Filters covers the codec side, and X Codec Inspector lets you verify the filter registration is correct); and when a DTS/AC3/DD+ Source Filter installation conflicts with an existing audio decoder.
For broader context on which codec tools work well together on Windows, the Best Codec Packs guide covers the current landscape including K-Lite, LAV Filters standalone, and lighter alternatives.
System requirements and availability
X Codec Inspector runs on Windows 7, 8, 8.1, 10, and 11 in both 32-bit and 64-bit editions. Admin rights are not required for browsing, searching, exporting, or taking snapshots.
UAC elevation is only triggered when you use the Register DLL, Unregister DLL, or Edit Merit actions - Windows prompts automatically at that point.
The export function supports HTML, CSV, and JSON, making it straightforward to document your filter state or share a configuration for support purposes.
The tool is a free portable EXE from the same team behind X Codec Pack and requires no installation.
