Multi-Track Audio — 5.1 Surround, One Tone per Channel (MKV)
A 5.1 track with a different pitch in every channel: an A-major triad across L, R and C, a 60 Hz rumble in the LFE, and two higher tones in the surrounds. Channel order is the standard L, R, C, LFE, Ls, Rs. This makes channel-mapping bugs audible instead of theoretical. Downmix it to stereo and you should hear the triad plus the surrounds; if the centre and the LFE swap — a classic WAV-to-container ordering mistake — the result is unmistakable. Most 5.1 test files play the same content everywhere and cannot detect that at all.
Rendered preview of the mkv file (216.5 KB). Download above for the original.
Specifications
- Audio Tracks
- 1
- Channels
- 6
- Channel Layout
- 5.1
- Tone Map
- L 440 Hz · R 554 Hz · C 659 Hz · LFE 60 Hz · Ls 880 Hz · Rs 988 Hz
- Codec
- AAC LC 192 kbps 48 kHz
- Duration
- 8s
Testing contract
Expected to pass- Scenario
- Decode the audio and measure the dominant frequency in each of the six channels.
- Expected result
- 1 AAC LC track at 192 kbps 48 kHz with 6 channels in a 5.1 layout, each carrying a distinct tone: L 440 Hz, R 554 Hz, C 659 Hz, LFE 60 Hz, Ls 880 Hz, Rs 988 Hz. Because every channel differs, a downmix or a channel-order error is measurable rather than merely audible - swapped surrounds show up as swapped frequencies.
What is a .mkv file?
MKV (Matroska) is an open, codec-agnostic multimedia container that holds unlimited video, audio, subtitle, chapter, and attachment tracks in one file. Its structure is EBML, a binary tree of length-prefixed elements, and its attachments typically carry the fonts an ASS subtitle track needs. Because it constrains nothing about the streams inside, the extension says nothing about whether a player can decode them. Steve Lhomme started the project in 2002; WebM is the restricted profile of it that browsers accept.
How to use this file
Use an example MKV to test EBML parsing and multi-track demuxing, subtitle and chapter extraction, and remux pipelines, checking that per-track language and default flags survive, that font attachments are preserved, and that a remux to MP4 reports the tracks MP4 cannot carry instead of dropping them silently.
How to use this file for testing
“Multi-Track Audio — 5.1 Surround, One Tone per Channel (MKV)” is a deterministic Novus Examples fixture for Media accessibility, Video QA, Video codecs, Conversion testing. Containers carrying several subtitle and audio tracks at once, with real language tags and the default, forced, hearing-impaired and visual-impaired flags actually set, for testing track pickers, accessibility menus, and the flag handling that only shows up when more than one track exists.
Documented properties for this file: 6 ch · 8s. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such, expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Code examples
<video controls preload="metadata" width="640" src="mkv-surround-51.mkv"></video>Related files
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