improve example subrip to mp3 perf

examples/02_subrip_to_mp3.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 import asyncio
+import os
 import shutil
 import subprocess
 import sys
@@ -14,7 +15,7 @@ if shutil.which("ffmpeg") is None:
 
 
 def parse_srt(srt_file):
-    with open(srt_file, "r") as f:
+    with open(srt_file, "r", encoding="utf-8") as f:
         data = f.read().strip().split("\n\n")
     data = [i.strip() for i in data]
     data = [(*i.split("\n")[:2], " ".join(i.split("\n")[2:])) for i in data]
@@ -86,48 +87,71 @@ async def _main(srt_data, voice_name, out_file):
             stderr=subprocess.DEVNULL,
         )
 
+        input_files = []
+        input_files_start = {}
+
+        with tempfile.TemporaryDirectory() as temp_dir:
             for i in srt_data:
+                print(f"Processing {i[0]}...")
+
+                fname = os.path.join(temp_dir, f"{i[0]}.mp3")
+                input_files.append(fname)
+
                 duration = i[1].replace(",", ".")
                 duration = duration.split("-->")
 
                 start = duration[0].split(":")
                 start = int(start[0]) * 3600 + int(start[1]) * 60 + float(start[2])
+                input_files_start[fname] = start
 
                 end = duration[1].split(":")
                 end = int(end[0]) * 3600 + int(end[1]) * 60 + float(end[2])
 
                 duration = end - start
-            with tempfile.NamedTemporaryFile(suffix=".mp3") as temporary_file:
+                with open(fname, "wb") as f:
                     async for j in communicate.run(
                         i[2], codec="audio-24khz-48kbitrate-mono-mp3", voice=voice_name
                     ):
                         if j[2] is not None:
-                        temporary_file.write(j[2])
+                            f.write(j[2])
 
-                temporary_file2 = tempfile.NamedTemporaryFile(suffix=".mp3", delete=False)
+                    temporary_file = tempfile.NamedTemporaryFile(
-                try:
+                        suffix=".mp3", delete=False
-                    ensure_audio_length(
-                        temporary_file.name, temporary_file2.name, duration
                     )
+                    try:
+                        ensure_audio_length(fname, temporary_file.name, duration)
                     finally:
-                    shutil.move(temporary_file2.name, temporary_file.name)
+                        shutil.move(temporary_file.name, fname)
+
+            ffmpeg_opts = []
+            for i in range(len(input_files)):
+                ffmpeg_opts.append("-i")
+                ffmpeg_opts.append(input_files[i])
+
+            filter_complex = ""
+            for i in range(len(input_files)):
+                filter_complex += (
+                    f"aevalsrc=0:d={input_files_start[input_files[i]]}[s{i+1}];"
+                )
+                filter_complex += f"[s{i+1}][{i+1}:a]concat=n=2:v=0:a=1[ac{i+1}];"
+
+            filter_complex += f"[0:a]"
+            for i in range(len(input_files)):
+                filter_complex += f"[ac{i+1}]"
+            filter_complex += f"amix={len(input_files)+1}[aout]"
+
+            ffmpeg_opts.append("-filter_complex")
+            ffmpeg_opts.append(filter_complex)
+            ffmpeg_opts.append("-map")
+            ffmpeg_opts.append("[aout]")
 
             temporary_file2 = tempfile.NamedTemporaryFile(suffix=".mp3", delete=False)
             try:
+                print("Concatenating...")
                 subprocess.call(
-                        [
+                    ["ffmpeg", "-y", "-i", mother_temp_file.name]
-                            "ffmpeg",
+                    + ffmpeg_opts
-                            "-y",
+                    + [temporary_file2.name],
-                            "-i",
-                            mother_temp_file.name,
-                            "-i",
-                            temporary_file.name,
-                            "-filter_complex",
-                            f"aevalsrc=0:d={start}[s1];[s1][1:a]concat=n=2:v=0:a=1[ac1];[0:a][ac1]amix=2[aout]",
-                            "-map",
-                            "[aout]",
-                            temporary_file2.name,
-                        ],
                     stdout=subprocess.DEVNULL,
                     stderr=subprocess.DEVNULL,
                 )
@@ -135,6 +159,7 @@ async def _main(srt_data, voice_name, out_file):
                 shutil.move(temporary_file2.name, mother_temp_file.name)
     finally:
         shutil.move(mother_temp_file.name, out_file)
+    print("Done")
 
 
 def main():

lint.sh

@@ -1,2 +1,2 @@
-find src -name '*.py' | xargs black
+find src examples -name '*.py' | xargs black
-find src -name '*.py' | xargs isort
+find src examples -name '*.py' | xargs isort