Render file & Updated config & Updated Libraries

src/amplify/cli.py

@@ -1,6 +1,7 @@
 import typer
 from pathlib import Path
 from amplify.config import load_cfg, save_cfg, ensure_cfg
+from amplify.render import export as render_export
 
 app = typer.Typer(add_completion=False)
 
@@ -85,7 +86,8 @@ def export(cfg: str, out: str):
     data = load_cfg(cfg)
     data["export"]["path"] = out
     save_cfg(cfg, data)
-    typer.echo(f"Would export to {out} (render engine not connected).")
+    render_export(data)
+    typer.echo(f"Exported to {out}")
 
 def main():
     app()

src/amplify/pyproject.toml

@@ -0,0 +1,25 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "amplify"
+version = "0.1.0"
+description = "CLI audio manipulation tool"
+requires-python = ">=3.10"
+dependencies = [
+    "typer>=0.12",
+    "pyyaml>=6.0",
+    "pydub>=0.25.1",
+    "librosa>=0.10.1",
+    "soundfile>=0.12.1"
+]
+
+[project.scripts]
+amplify = "amplify.cli:main"
+
+[tool.setuptools]
+package-dir = {"" = "src"}
+
+[tool.setuptools.packages.find]
+where = ["src"]

src/amplify/render.py

@@ -0,0 +1,60 @@
+import numpy as np
+import librosa
+import soundfile as sf
+from pathlib import Path
+
+def apply_scale(audio, sr, factor, preserve_pitch):
+    """
+    Time-scale audio
+    Scale factor > 1.0 = faster audio
+    Scale factor < 1.0 = slower audio
+    """
+
+    # if preserving pitch, change duration but keep pitch the same
+    if preserve_pitch:
+        return librosa.effects.time_stretch(audio, rate=factor)
+
+    # if not preserving pitch, change sample rate by  a factor
+    else:
+        new_sr = int(sr * factor)
+        return librosa.resample(audio, orig_sr = sr, target_sr = new_sr)
+
+def render(cfg_data):
+
+    # stores tracks
+    mix_buffer = []
+
+    # stores sample rate, set with first audio file in track
+    sample_rate = None
+
+    for item in cfg_data["timeline"]:
+        # get asset id of current item
+        asset_id = item["asset"]
+
+        # finds next asset matching id
+        asset = next(a for a in cfg_data["assets"] if a["id"] == asset_id)
+        audio, file_sr = librosa.load(asset["path"], sr = None)
+
+        if sample_rate is None:
+            sample_rate = file_sr
+
+        for op in item["ops"]:
+            if op["type"] == "scale":
+                audio = apply_scale(audio, file_sr, op["factor"], op["preserve_pitch"])
+            elif op["type"] == "loop":
+                if op["count"]:
+                    audio = np.tile(audio, op["count"])
+        mix_buffer.append(audio)
+    output = np.sum(mix_buffer, axis = 0)
+
+    if cfg_data["mix"]["normalize"]:
+        peak = np.max(np.abs(output))
+        if peak > 0:
+            output = output / peak
+
+    return output, sample_rate
+
+def export(cfg_data):
+    audio, sr = render(cfg_data)
+    out_path = Path(cfg_data["export"]["path"])
+    sf.write(out_path, audio, sr)