ogg2mp3

ogg2mp3

QQ Music's macOS app stores audio as Vorbis-in-Ogg (.ogg or .oggh) with the cover image hidden in the macOS Resource Fork as an ICNS resource — not in the Vorbis stream. ogg2mp3 reassembles audio + cover + metadata into a standard MP3 with id3v2.3 tags using ffmpeg, derez, and icnsutil.

When to use

• User has .ogg or .oggh files from QQ Music's Mac app and wants .mp3.
• User wants to inspect what's in a file before converting.
• User wants to verify the environment is ready for conversion.

When NOT to use

• .ogg files from other sources (web downloads, Bandcamp, etc.) — conversion will still produce a valid MP3 but cover_embedded will be false because the file has no ICNS in its Resource Fork.
• Non-OGG audio (MP3 / FLAC / WAV / M4A in / out): use ffmpeg directly.
• Audio editing (trim, mix, normalize, format other than MP3): use ffmpeg directly.

Prerequisites

1. The binary must be on PATH at ~/.local/bin/ogg2mp3. If command -v ogg2mp3 fails, the user has not installed it — instruct them to git clone https://github.com/HerbertGao/ogg2mp3 && bash ogg2mp3/scripts/install.sh.
2. Run ogg2mp3 doctor --json once per session before any convert / batch call. Parse .ok; if false, stop and surface each failing check's install_hint to the user.
3. Verify .binary_version from doctor is 2026.5.0 or higher. If the binary is newer and emits a different JSON shape, trust the binary over this document.

Tools

convert <input> — convert one file

ogg2mp3 convert <input> [-o <output>] [--no-cover] [--no-metadata] [--overwrite] [--yes] [--json]

Flag	Meaning
-o <path>	Output path. Default: <input> with extension swapped to .mp3, same directory.
--no-cover	Skip cover art extraction and embedding.
--no-metadata	Skip metadata copying.
--overwrite	Replace existing output without prompting.
--yes	Required for non-interactive callers. Skips all confirmation prompts.
--json	Emit a single JSON object to stdout.

JSON result (with --json):

{
  "ok": true,
  "input": "/path/to/song.ogg",
  "output": "/path/to/song.mp3",
  "cover_embedded": true,
  "metadata_fields": 3
}

Without --json, stdout is one line: the output path. Logs go to stderr.

Exit codes: 0 success · 1 conversion failed or output exists without --overwrite · 2 bad args · 3 missing dependency or running as root.

Agent rules:

• Always pass --yes. You are non-interactive; without it, an existing output blocks the run waiting for stdin.
• Always pass --json so you can parse the result.
• Do not pass --no-cover unless the user explicitly says they don't want cover art — cover embedding is the whole point of this tool over plain ffmpeg.
• A successful result with cover_embedded: false is not an error; it usually means the source had no ICNS in its Resource Fork (i.e. not actually from QQ Music). Surface this to the user as a note, don't retry.

batch <dir> — convert a directory

ogg2mp3 batch <dir> [-r|--recursive] [--skip-existing | --overwrite] [--no-cover] [--no-metadata] [--dry-run] [--yes] [--json]

Flag	Meaning
-r, --recursive	Recurse into subdirectories. Default: top level only.
--skip-existing	Skip files whose .mp3 already exists. Mutually exclusive with --overwrite.
--overwrite	Replace existing .mp3 files.
--dry-run	List planned conversions; do not execute.
--yes, --json, --no-cover, --no-metadata	Same semantics as convert.

Output format (--json mode → NDJSON, one object per line):

Outcome	Schema
Converted	{"ok": true, "input": "...", "output": "...", "cover_embedded": bool, "metadata_fields": int}
Skipped	{"ok": true, "skipped": true, "input": "...", "output": "..."}
Failed	{"ok": false, "input": "...", "output": "...", "error": "..."}
Dry-run preview	{"input": "...", "output": "...", "planned_action": "convert"|"skip"|"fail", "reason": null | "..."}

Plain mode emits OK\t<path> / SKIP\t<path> / FAIL\t<path>\t<reason> per line.

Exit codes: 0 all succeeded (or dry-run) · 1 at least one file failed · 2 bad args (including using --skip-existing and --overwrite together) · 3 missing dep or root.

Default flag combinations Agents should use:

User intent	Recommended flags
"Convert all songs in this folder"	-r --skip-existing --yes --json
"Reconvert everything"	-r --overwrite --yes --json
"Show me what this will do"	-r --dry-run --json

If .mp3 already exists and the user did not specify policy, default to --skip-existing and tell the user how many were skipped — do not silently overwrite.

inspect <input> — read-only probe

ogg2mp3 inspect <input> [--json]

Does not convert. Reports codec, duration, bitrate, all vorbis tags, and whether an ICNS cover is present in the Resource Fork.

JSON schema:

{
  "file": "/path/to/song.ogg",
  "codec": "vorbis",
  "duration_sec": 181.25,
  "bitrate": 314482,
  "metadata": { "TITLE": "...", "ARTIST": "...", "ALBUM": "..." },
  "cover": { "present": true, "size_bytes": 356845 }
}

Exit codes: 0 readable · 1 ffprobe could not parse the file.

Agent rules:

• Use this when the user asks "what's in this file?" without wanting conversion.
• Do not use inspect as a precondition for convert — convert already handles missing covers gracefully and is the canonical write path.

doctor — environment self-check

ogg2mp3 doctor [--json]

JSON schema:

{
  "ok": true,
  "binary_version": "2026.5.0",
  "checks": [
    {
      "name": "ffmpeg",
      "found": true,
      "path": "/opt/homebrew/bin/ffmpeg",
      "version": "8.1.1",
      "install_hint": "brew install ffmpeg"
    }
  ]
}

Checks all of: ffmpeg, ffprobe, derez, icnsutil, jq, xxd, grep, sed.

Exit codes: 0 all green · 3 any missing.

Agent rules:

• Call this once at the start of any session that will run convert or batch.
• If .ok is false, do not call convert or batch. Surface each failing check's install_hint to the user verbatim.
• Verify .binary_version is 2026.5.0 or higher (CalVer; major = year, minor = month). If the binary is newer and emits a JSON shape that disagrees with this document, trust the binary.

Capabilities NOT exposed to Agents

These exist for human terminal users and will hang or misbehave if an Agent invokes them:

Don't	Why
ogg2mp3 with no subcommand	Drops into an interactive menu prompt. Blocks on stdin in a TTY; in non-interactive agent contexts exits 0 or 1 without performing any action. Always pass an explicit subcommand.
convert or batch without --yes when output exists	Prompts y/N only in a TTY; in non-interactive agent contexts the binary exits 1 immediately rather than blocking. Always pass --yes.
--skip-existing together with --overwrite	Exit 2 (mutually exclusive).
Running under sudo / as root	Exit 3 (require_unprivileged guard). The binary refuses on purpose to avoid leaving root-owned files in the user's library.

Output contract recap

• stdout = data only: paths (plain mode) or JSON / NDJSON (--json).
• stderr = all human-readable logs (→, ✓, warning:, error:).
• Agents should redirect or ignore stderr when parsing; never parse stderr for data.

Failure modes Agents should handle

Symptom	Meaning	What to do
exit 3 from anything	Missing dependency or running as root	Run doctor --json; surface install_hints. Never retry the same call.
exit 1 from convert	Conversion failed	Read stderr (ffmpeg: lines) for the real cause. Don't silently retry.
cover_embedded: false on success	No ICNS in Resource Fork	Note it to the user (likely not a QQ Music file). MP3 is still valid.
metadata_fields: 0 on success	OGG had no Vorbis tags	Note it. MP3 is still valid, just untagged.
Batch exits 1 but most files are ok: true	Some files failed	Filter NDJSON for ok: false lines and report those to the user.