How HandBrake Encodes MKV Files
HandBrake is a popular open-source video transcoder that handles MKV (Matroska) files with high efficiency, allowing users to both import MKV files for conversion and output new videos in the MKV container. This article explains how HandBrake processes MKV files, including its support for modern video and audio codecs, its capability to preserve multiple audio tracks and subtitles, and how it manages chapter markers during the encoding process.
MKV as a Container, Not a Codec
To understand how HandBrake handles MKV files, it is important to recognize that MKV is a container format, not a video codec. HandBrake treats the MKV container as a shell that packages video, audio, subtitle, and chapter streams together.
When you select MKV as your output format in HandBrake, the software
packages the transcoded streams into a .mkv file. Because
MKV is highly flexible, HandBrake allows you to pair it with a wide
variety of video and audio codecs that are not always supported by other
containers like MP4.
Video Encoding Options for MKV
HandBrake utilizes several library encoders to process video inside the MKV container. Depending on your quality and compatibility needs, HandBrake can encode MKV files using the following video codecs:
- H.264 (x264): The most widely compatible video codec, offering a great balance between compression and playback compatibility across older devices.
- H.265 / HEVC (x265): Provides superior compression compared to H.264, making it ideal for 4K video and reducing file sizes significantly without losing quality.
- AV1 (SVT-AV1): A modern, royalty-free codec that offers even better compression efficiency than H.265, though it requires more processing power to encode.
- VP8 and VP9: Open formats developed by Google, primarily used for web-friendly video delivery.
HandBrake also supports hardware-accelerated encoders (such as Intel Quick Sync, NVIDIA NVENC, and AMD VCE) to speed up the MKV encoding process by utilizing your computer’s graphics card.
Audio and Subtitle Preservation (Passthrough)
One of the primary advantages of encoding to MKV in HandBrake is the container’s ability to handle complex audio and subtitle layouts.
Audio Passthrough
If you do not want to re-encode your audio, HandBrake allows “audio passthrough.” This feature copies the original audio track (such as 5.1 or 7.1 Dolby Digital, DTS, or TrueHD) directly into the new MKV file without modification, preserving the exact original audio quality. Alternatively, HandBrake can transcode audio to formats like AAC, MP3, or FLAC.
Subtitles
MKV is highly regarded for its robust subtitle support. HandBrake can handle multiple subtitle tracks within an MKV file in two ways: * Soft Subtitles: HandBrake can pass through subtitles (like SRT, SSA, or PGS) as separate, selectable tracks inside the MKV file. This allows viewers to turn them on or off during playback. * Hard Burn-in: HandBrake can permanently render the subtitles directly onto the video frames.
Chapter Markers and Metadata
HandBrake automatically detects chapter markers in source files and can preserve them in the output MKV file. This ensures that you can still skip to specific scenes when playing the encoded file on compatible media players. Additionally, HandBrake retains basic metadata, though advanced tagging is usually best handled by external metadata editors after the encoding process is complete.