> ## Documentation Index > Fetch the complete documentation index at: https://chart-spec.enchor.us/llms.txt > Use this file to discover all available pages before exploring further. # BTrack 20240320 (obsolete) > The older BTrack format and TrackHash that Clone Hero 1.1 calculates. This version is obsolete. New programs write [version 20260801](/hashes/btrack). This page is for checking the hashes Clone Hero 1.1 calculated. Clone Hero 1.1 writes each track as a BTrack of version 20240320, and its legacy TrackHash is a hash of that whole file. Its leaderboards hold every score played on Clone Hero 1.1 by these hashes, and each song by a [SongHash of version 20251010](/hashes/songhash#version-20251010), which holds them. Clone Hero 1.1's code is the reference for this version. This `.chart` file has one track, Expert guitar: ```text theme={null} [Song] { Resolution = 192 } [SyncTrack] { 0 = TS 4 0 = B 120000 } [Events] { } [ExpertSingle] { 0 = N 0 0 0 = S 2 192 192 = N 1 96 } ``` Its BTrack is these 136 bytes: ```text theme={null} 43 48 4e 46 identifier, CHNF c0 d7 34 01 version 20240320 c0 00 00 00 resolution 192 01 00 00 00 1 tempo: 00 00 00 00 00 00 00 00 tick 0 00 00 00 00 00 00 5e 40 120 BPM 01 00 00 00 1 time signature: 00 00 00 00 00 00 00 00 tick 0 04 00 00 00 04 00 00 00 4/4 01 00 00 00 1 star power phrase: 00 00 00 00 00 00 00 00 tick 0 c0 00 00 00 00 00 00 00 length 192 00 00 00 00 0 solos 00 00 00 00 0 lanes 00 00 00 00 0 drum fills 02 00 00 00 2 notes: 00 00 00 00 00 00 00 00 tick 0 00 00 00 00 00 00 00 00 length 0 02 00 00 00 01 00 00 00 green, strum c0 00 00 00 00 00 00 00 tick 192 60 00 00 00 00 00 00 00 length 96 03 00 00 00 01 00 00 00 red, strum ``` Its legacy TrackHash is `bLRupqmuemBT2XL2bPISQI0F5cZgPLY_BzEpxiKRzDc`. The TrackHash of version 20260801 for the same track is `ewVfnLFazT8nsQyO09qat4CgKichUepV8yw1mxypxSA`. ## The file Every number is little-endian. | Field | Holds | | - | - | | Identifier | `43 48 4E 46`, the text `CHNF` | | Version | `20240320`, as an unsigned 32-bit number | | Resolution | The chart's resolution, as an unsigned 32-bit number | | Tempo | A count, then each tempo: tick, and tempo in BPM | | Time signature | A count, then each time signature: tick, numerator and denominator | | Star power | A count, then each phrase: tick and length | | Solo | A count, then each solo: tick and length | | Lane | A count, then each lane: tick, length, and 1 for a double lane or 0 for a single lane | | Drum fill | A count, then each fill: tick, length, and 1 at or after the coda or 0 before it | | Note | A count, then each note: tick, length, note type and flags | * Each count is an unsigned 32-bit number, and is written even when it's 0. Nothing follows the notes. * The records are those of [version 20260801](/hashes/btrack#sections), with the same [note types and flags](/hashes/btrack#note-types-and-flags). * There's no list of range shifts. * A file is `40 + 16 × (tempos + time signatures + star power phrases + solos) + 17 × (lanes + drum fills) + 24 × notes` bytes long. ## The legacy TrackHash The legacy TrackHash is the BLAKE3 hash of the whole file, from its identifier to its last note: 32 bytes, written in base64url without padding as 43 characters. The tempos are hashed exactly as the file holds them, without rounding. **Edge case: scan-chart 8.** scan-chart 8.0.1 and earlier write the legacy TrackHash with padding, as 44 characters that end in `=`. Without the `=`, it's the TrackHash. ## What Clone Hero 1.1 writes Clone Hero 1.1 fills the lists as [version 20260801](/hashes/btrack#from-a-chart-to-a-btrack) says, from the chart as it reads it. It reads some charts differently from the format pages: | Chart | Clone Hero 1.1 | The format pages | | - | - | - | | A `.mid` tap modifier | Doesn't cover the note on its end tick. Nor does any other modifier with a length | [Covers](/mid/modifiers#taps) the note on its end tick | | A `.chart` `TS 4 ` with a space at its end | 4/1 | 4/4 | | A `dnoflip` while a `d` disco flip is on | The flip stays on until the next off event | The later event counts: see [Disco flip](/chart/drums#disco-flip) | | `.chart` instrument text in quotation marks, such as `E "solo"` | Not read | Read as without them | | A `.mid` tom marker that covers no note | Makes the chart pro | [Doesn't](/mid/drums#drum-types) | | A `.mid` kick at the velocity of an accent or ghost | An accented or ghost kick | A kick | | `.chart` `N 109` | Ignored | A [flam](/chart/drums#flams) | | Tracks | Every recognized `.chart` section, and in a `.mid` file each instrument's Expert and each difficulty a modifier gives, even without notes | Only tracks with a note | | Two notes of one type at one tick | The longer, or the first of equal length, with the other's flags added. So a kick and a double kick are a double kick, and a note can be both ghost and accent | The [longer](/chart/note-resolution#remove-duplicate-notes) | | A lane whose notes are all on its end tick | Left out | [Kept](/chart/phrases#lanes): a lane covers its end tick | | A note that `chord_snap_threshold` moves onto a note of its fret | The chord's type, and the next note's HOPO, come from the tick it moves to | They come from the [written ticks](/chart/note-resolution#snap-close-notes-into-chords) | | A `.chart` file without `[Song]` | Resolution 192, with no HOPO threshold and no sustain cutoff, so no natural HOPOs | Read as `Resolution = 192` | | A `[Song]` without `Resolution` | The file isn't loaded | Resolution 192 | | `notes.chart` and `notes.mid` in one folder | The last of the two that the folder's listing gives | [`notes.mid`](/song-folders#the-chart) | | `pro_drum` and `star_power_note` in `song.ini` | Not read | [Older names](/ini/settings#deprecated) of `pro_drums` and `multiplier_note` | **Edge case: scan-chart's `frozenLegacy6142`.** scan-chart calculates legacy TrackHashes with its `frozenLegacy6142` profile, which agrees with Clone Hero 1.1 for almost every track. It reads some charts differently: a `TS` with a space at its end, a `dnoflip` during a `d` flip, quoted text, a tom marker that covers no note, two notes of one type at one tick, snapped chords, and a `.chart` file without `[Song]`, which it doesn't load. It also applies an `[ENABLE_CHART_DYNAMICS]` event to every note of a later difficulty, writes no empty `.mid` difficulty but Expert, and reads every `.mid` track of an instrument. To check a legacy TrackHash, use Clone Hero 1.1. ## Telling the versions apart Both versions start with `CHNF`, so the 4 bytes of the version tell them apart: `C0 D7 34 01` for 20240320, and `C1 27 35 01` for 20260801. A reader that reads both chooses by them, and rejects any other version. The next 4 bytes are the resolution in version 20240320 and the section count in version 20260801, and either can be a small number, so they can't tell the versions apart. A legacy TrackHash and a TrackHash of version 20260801 are both 43 characters, so a hash alone doesn't say which it is. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.