Add gitignore

.gitignore

@@ -0,0 +1,6 @@
+.DS_Store
+.idea
+*.log
+tmp/
+
+

main.py

@@ -10,6 +10,9 @@ import argparse
 # executing some commands
 import subprocess
 
+# parsing json output of loudnorm
+import json
+
 """
 parser = argparse.ArgumentParser(description="")
 
@@ -31,10 +34,11 @@ ffmpeg -i $FILE -c:v libx264 -b:v 4000k -pass 2 -filter:a loudnorm=linear=true:m
 inputfile = (
     '/home/marc/Downloads/FalKKonE - 01 Aria (From "Berserk: The Golden Age Arc").flac'
 )
-inputfile = "/home/marc/Downloads/test441.opus"
+# inputfile = "/home/marc/Downloads/test441.opus"
+outputfile = "/home/marc/Downloads/test441_out.opus"
 
 
-def get_format(inputfile):
+def get_format(inputfile) -> str:
     # get codec format
     # https://stackoverflow.com/a/29610897
     # this shows the codecs of all audio streams present in the file, which shouldn't matter unless you have more than one stream
@@ -62,7 +66,7 @@ def get_format(inputfile):
     return format
 
 
-def loudness_info(inputfile):
+def loudness_info(inputfile) -> dict[str, str]:
     # get format from file
     # inputformat = get_format(inputfile)
     # NOTE format is actually unnecessary here
@@ -72,13 +76,52 @@ def loudness_info(inputfile):
         global_options=("-y"),
     )
 
+    # print(ff.cmd)
+    proc = subprocess.Popen(
+        ff.cmd, shell=True, stderr=subprocess.STDOUT, stdout=subprocess.PIPE
+    )
+    # NOTE get loudness info from subprocess
+    # rstrip: remove trailing newline
+    # decode: convert from binary string to utf8
+    # splitlines: list of lines (only 12 last ones, length of the output json)
+    # join: reassembles the list of lines and separates with "\n"
+    loudness_json: str = "\n".join(
+        proc.stdout.read().rstrip().decode("utf8").splitlines()[-12:]
+    )
+    # decode json to dict
+    loudness: dict[str, str] = json.loads(loudness_json)
+    # print(loudness_json)
+    return loudness
+
+
+def convert(inputfile, outputfile, loudness):
+    ff = ffmpy.FFmpeg(
+        inputs={inputfile: None},
+        outputs={
+            outputfile: "-pass 2"
+            " "
+            "-filter:a"
+            " "
+            "loudnorm=I=-30.0:"
+            "measured_I={input_i}:"
+            "measured_LRA={input_lra}:"
+            "measured_tp={input_tp}:measured_thresh={input_thresh}:"
+            "print_format=json"
+            " "
+            "-c:a libopus"
+            " "
+            "-b:a 320k".format(
+                input_i=loudness["input_i"],
+                input_lra=loudness["input_lra"],
+                input_tp=loudness["input_tp"],
+                input_thresh=loudness["input_thresh"],
+            )
+        },
+    )
     print(ff.cmd)
-
-
-def convert():
-    # ff = ffmpy.FFmpeg()
-    pass
+    ff.run()
 
 
 if __name__ == "__main__":
-    loudness_info(inputfile)
+    loudness = loudness_info(inputfile=inputfile)
+    convert(inputfile=inputfile, outputfile=outputfile, loudness=loudness)