How to Convert WMV to MP4 Without Losing Quality

Why WMV Does Not Work Outside Windows

Windows Media Video (WMV) was Microsoft's proprietary video format, developed as part of the Windows Media framework in the late 1990s. For over a decade, it was the default output format for Windows Movie Maker, webcam recordings, and enterprise video systems running on Windows Server.

The problem? WMV is a Windows-centric format that struggles everywhere else. macOS can play some WMV files through third-party codecs, but with unreliable results. iPhones and iPads will not open them at all. Android support is inconsistent across manufacturers. Linux requires installing extra codecs. And no modern web browser supports WMV playback natively.

If you have WMV files from the Windows XP/Vista/7 era — corporate training videos, old home movies, webcam recordings, or screen captures — converting them to MP4 is the only practical way to ensure they play on every device and platform in 2026.

WMV Technical Overview

WMV files typically contain video encoded with Windows Media Video 7, 8, 9, or WMV Advanced Profile (VC-1), paired with Windows Media Audio (WMA). Understanding these codecs helps you choose the right conversion settings.

None of these codecs are natively compatible with the MP4 container, which means every WMV-to-MP4 conversion requires full re-encoding. Unlike converting MKV to MP4 where remuxing is often possible, WMV files always need their video and audio streams decoded and re-encoded.

Method 1: Convert WMV to MP4 Online

The fastest way to convert a WMV file is using an online tool. Our video converter supports all WMV versions and produces optimized MP4 output.

Steps:

1. Open the MP4 converter page.
2. Upload your WMV file — drag and drop works, or click to browse your files.
3. The converter automatically detects the optimal settings for your file.
4. Click Convert and download the MP4.

No software to install, no codecs to configure. The conversion runs on our servers, so it works on any device — even a Mac or Chromebook that cannot play the original WMV file.

If the WMV file is larger than you need, run it through our video compressor to reduce the file size. Need to trim out sections? The video trimmer lets you cut before or after conversion.

Method 2: Convert WMV to MP4 with FFmpeg

For full control over the conversion process, FFmpeg is the professional's choice. It handles every WMV variant, including DRM-free files with unusual configurations.

Standard High-Quality Conversion

ffmpeg -i input.wmv -c:v libx264 -crf 18 -preset slow \
  -c:a aac -b:a 192k -movflags +faststart output.mp4

Conversion Matching Source Resolution

Some WMV files use non-standard resolutions (like 640x352 or 720x404). To ensure compatibility while maintaining the original aspect ratio:

ffmpeg -i input.wmv -c:v libx264 -crf 18 -preset slow \
  -vf "scale='min(1920,iw)':'min(1080,ih)':force_original_aspect_ratio=decrease,pad=ceil(iw/2)*2:ceil(ih/2)*2" \
  -c:a aac -b:a 192k -movflags +faststart output.mp4

This ensures the output dimensions are even numbers (required by H.264) while preserving the original size when it is already within bounds.

Convert with Deinterlacing

Many WMV files from the DVD era are interlaced (you will see horizontal lines during motion). Deinterlace during conversion:

ffmpeg -i input.wmv -c:v libx264 -crf 18 -preset slow \
  -vf yadif=1 -c:a aac -b:a 192k -movflags +faststart output.mp4

The yadif filter is FFmpeg's best deinterlacer. The =1 parameter outputs one frame per field, effectively doubling the frame rate for smoother motion.

Method 3: Convert WMV to MP4 with VLC

VLC Media Player is already installed on many computers and includes conversion capabilities:

1. Open VLC and go to Media > Convert / Save (or press Ctrl+R).
2. Click Add and select your WMV file.
3. Click Convert / Save at the bottom.
4. Under Profile, select Video - H.264 + MP3 (MP4).
5. Choose the destination file and click Start.

VLC's conversion quality is decent but does not offer the fine-grained control of FFmpeg. For critical conversions, FFmpeg or our online converter will produce better results.

Choosing the Right Encoding Settings

The optimal settings depend on what you plan to do with the converted MP4:

For YouTube-specific settings, see our best video settings for YouTube guide. If you are sharing on social media, our best video format for social media article covers platform-specific requirements.

Handling DRM-Protected WMV Files

Some WMV files downloaded from services like Windows Media DRM (also called PlayReady) are encrypted and cannot be converted directly. FFmpeg will report an error like "This file is DRM protected."

Important points about DRM-protected WMV:

• You cannot directly decrypt and convert DRM WMV files with standard tools.
• If you purchased the content, contact the original provider for a DRM-free version or an alternative format.
• Some older DRM licenses have expired and may no longer validate, making the files permanently inaccessible.
• If you own the original source material, re-export it from the original project.

For more on privacy and security considerations during file conversion, see our guide on data privacy in file conversion.

Batch Converting WMV Files

If you have a folder full of old WMV files, batch conversion is the way to go:

Bash (macOS/Linux)

for f in *.wmv; do
  ffmpeg -i "$f" -c:v libx264 -crf 18 -preset medium \
    -c:a aac -b:a 192k -movflags +faststart \
    "${f%.wmv}.mp4"
done

PowerShell (Windows)

Get-ChildItem *.wmv | ForEach-Object {
  $output = $_.BaseName + ".mp4"
  ffmpeg -i $_.FullName -c:v libx264 -crf 18 -preset medium `
    -c:a aac -b:a 192k -movflags +faststart $output
}

Recursive Batch (All Subdirectories)

find /path/to/videos -name "*.wmv" -exec sh -c '
  ffmpeg -i "$1" -c:v libx264 -crf 18 -preset medium \
    -c:a aac -b:a 192k -movflags +faststart "${1%.wmv}.mp4"
' _ {} \;

For a complete guide on batch workflows, read our how to batch convert files article.

Common WMV Conversion Problems

Problem: Audio/Video Desync

Old WMV files sometimes have drift between audio and video. Fix it with:

ffmpeg -i input.wmv -async 1 -c:v libx264 -crf 18 \
  -c:a aac -b:a 192k output.mp4

Problem: Green or Corrupted Frames

If the WMV file has corruption, skip damaged packets:

ffmpeg -err_detect ignore_err -i input.wmv \
  -c:v libx264 -crf 18 -c:a aac -b:a 192k output.mp4

Problem: Aspect Ratio Looks Wrong

Some WMV files have incorrect display aspect ratio metadata. Force the correct ratio:

ffmpeg -i input.wmv -c:v libx264 -crf 18 \
  -aspect 16:9 -c:a aac -b:a 192k output.mp4

Problem: "Discarded Too Many Packets"

Very old WMV files with variable bitrate can trigger this warning. Increase the analysis duration:

ffmpeg -analyzeduration 100M -probesize 100M \
  -i input.wmv -c:v libx264 -crf 18 -c:a aac -b:a 192k output.mp4

Extracting Audio from WMV

If you only need the audio track from a WMV file, you can extract it and convert to MP3 or AAC using our audio converter:

# Extract as MP3
ffmpeg -i input.wmv -vn -c:a libmp3lame -b:a 192k output.mp3

# Extract as AAC
ffmpeg -i input.wmv -vn -c:a aac -b:a 192k output.m4a

For more on audio extraction methods, see how to convert video to audio.

WMV vs MP4: Feature Comparison

Understanding the differences helps explain why MP4 is the right destination format:

• Compatibility: MP4 plays on 99% of devices worldwide. WMV works reliably only on Windows.
• Codec efficiency: MP4 supports H.264, H.265, and AV1 — all more efficient than WMV9 or VC-1. See video codecs explained for details.
• Web support: Every browser plays MP4. No browser plays WMV.
• Mobile: All phones play MP4 natively. WMV requires third-party apps on iOS and may or may not work on Android.
• Editing: Every video editor imports MP4. WMV support in editors on macOS and Linux is often incomplete.

Future-Proofing Your Converted Files

Once converted, consider using modern codecs for long-term storage:

• H.265/HEVC: 50% smaller files than H.264 at equivalent quality. See our H.265 vs H.264 vs AV1 comparison.
• AV1: The newest codec with even better compression, but slower encoding. Best for archival.

# Convert WMV to MP4 with H.265 for 50% smaller files
ffmpeg -i input.wmv -c:v libx265 -crf 22 -preset slow \
  -c:a aac -b:a 192k -tag:v hvc1 -movflags +faststart output.mp4

The -tag:v hvc1 flag ensures compatibility with Apple devices.

Summary

Converting WMV to MP4 is a one-way upgrade. You gain universal compatibility, better compression efficiency, and a format that will remain supported for decades. Whether you use our online video converter for quick single-file conversions or FFmpeg for batch processing an entire WMV archive, the conversion process is straightforward.

The key decision is your CRF value: use 16-18 for archival quality, 20 for general viewing, and 22-24 for space-efficient conversions. Every WMV file requires full re-encoding (remuxing is not possible), so allow extra time for large collections — but the result is worth it.