Lossless MKV to MP4 Conversion
Master the fastest lossless MKV to MP4 conversion method without any quality loss. Learn when and how to use the -c copy method for lightning-fast MKV to MP4 remux.
What is Lossless Remux?
Lossless MKV to MP4 remux is the process of changing a video's container format (from MKV to MP4) without re-encoding the video or audio streams. This lossless conversion method means:
- Zero quality loss — Original video and audio remain untouched
- Lightning fast — No re-encoding, just container rewrapping
- Small file size — No additional compression artifacts
- Perfect for compatible codecs — When MKV contains H.264/H.265 + AAC
Key Point
Lossless MKV to MP4 remux only changes the "container" (the wrapper), not the actual video/audio data inside. Think of it like moving files from a ZIP folder to a RAR folder — the files inside remain identical.
When to Use Lossless Remux
Perfect For
- H.264 or H.265 video with AAC audio
- Device compatibility — Making MKV to MP4 conversion for phones/TVs
- Streaming platforms — Many prefer MP4 format
- Speed priority — Need fast conversion
Not Recommended For
- Incompatible codecs — AV1, VP9, or FLAC audio
- File size reduction — Won't compress the file
- Quality adjustments — Can't change resolution/bitrate
- Multiple subtitles — May lose some subtitle tracks
Step-by-Step: Lossless MKV to MP4
Select Your MKV File
Start by choosing your MKV file in our lossless MKV to MP4 converter tool. The tool will automatically detect the video and audio codecs to determine if lossless remux conversion is possible.
Look for files with H.264 (AVC) or H.265 (HEVC) video and AAC audio for best remux compatibility.
Choose Lossless Remux Option
In the MKV to MP4 conversion options, select "Lossless Remux" or"Copy Streams". This tells the converter to use the-c copy method for lossless conversion.
The -c copy flag tells FFmpeg to copy the streams directly without transcoding, resulting in identical quality and much faster MKV to MP4 processing.
Convert and Download
Click convert and watch the magic happen! Lossless MKV to MP4 remux is typically 10-50x fasterthan re-encoding, often completing MKV to MP4 conversion in seconds rather than minutes.
1GB MKV: ~30 seconds remux vs 15+ minutes re-encode
100% identical to original — bit-for-bit copy
Technical Deep Dive
Performance Comparison
Lossless MKV to MP4 Remux (-c copy)
- Speed: Ultra fast (seconds)
- Quality: 100% identical
- Size: Same as original
- CPU Usage: Minimal
Re-encoding
- Speed: Slower (minutes/hours)
- Quality: Slight loss possible
- Size: Can be reduced
- CPU Usage: High
When to Choose Each Method
Choose Remux when: You need speed, have compatible codecs, and want perfect quality
Choose Re-encoding when: You need smaller files, different codecs, or device compatibility
Frequently Asked Questions
Ready to Try Lossless Conversion?
Experience the speed and quality of lossless remux with our free online converter. Perfect for compatible MKV files — no upload required, complete privacy protection.
100% browser-based • Lossless quality • Lightning fast • Completely free