distrokid-prep

name	distrokid-prep
description	Use when Daniel wants to prep raw audio tracks for DistroKid upload — convert to FLAC, EBU R128 normalize, and group under distrokid/to-upload/<release>/. Triggers on "distrokid prep", "prep for distrokid", "prep these tracks for upload", "normalize and FLAC for distrokid".

DistroKid Release Prep

Take a set of raw input tracks and produce upload-ready FLACs grouped into a release folder under distrokid/to-upload/<release-slug>/. Daniel will move the folder into a processed subfolder once he's confirmed the upload.

Inputs

• Raw tracks (any common format ffmpeg can read: WAV, MP3, M4A, FLAC, AIFF, etc.) provided by the user — usually a folder path or a list of files.
• A release slug (kebab-case, e.g. marc-mehlman). Ask if not given.

Output

• distrokid/to-upload/<release-slug>/ containing one FLAC per input track.
• Filenames preserve track order — if inputs aren't already numbered, prefix with 01_, 02_, etc. in the order given.

Processing

For each input track:

1. Two-pass loudness normalization to -14 LUFS integrated, -1 dBTP, 11 LU LRA (music streaming target — DistroKid distributes to Spotify/Apple/etc. which apply their own normalization, but -14 LUFS is the safe master target).
2. Encode to FLAC at the source sample rate, 16-bit unless source is 24-bit (then keep 24-bit).
3. Strip any embedded artwork unless the user says otherwise — DistroKid handles artwork separately.

ffmpeg pattern (two-pass loudnorm)

Pass 1 — measure:

ffmpeg -i "$IN" -af loudnorm=I=-14:TP=-1:LRA=11:print_format=json -f null - 2> /tmp/ln.log

Parse input_i, input_tp, input_lra, input_thresh, target_offset from the JSON block at the end of the log.

Pass 2 — apply with measured values:

ffmpeg -i "$IN" -af loudnorm=I=-14:TP=-1:LRA=11:measured_I=$mi:measured_TP=$mtp:measured_LRA=$mlra:measured_thresh=$mth:offset=$off:linear=true:print_format=summary -ar 44100 -map_metadata -1 "$OUT.flac"

Use -ar 44100 only if source is 44.1k or below; otherwise preserve source rate.

Verify ffmpeg is installed before starting. If not, tell the user.

After processing

• Print a short table: input filename → output filename → measured input LUFS → final LUFS.
• Remind Daniel the folder is at distrokid/to-upload/<release-slug>/ and he should move it into a processed/ subfolder once uploaded.
• Do not delete or modify the original raw inputs.