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bug fix and adjustment of LUFS to -18 for better dynamic range

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pat-e
2025-09-22 08:56:04 +02:00
parent d42d786eb9
commit 8d8d8b0df7
2 changed files with 39 additions and 9 deletions
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26
MkvOpusEnc.py
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@@ -83,17 +83,33 @@ def convert_audio_track(stream_index, channels, temp_dir, source_file, should_do
# First pass: Analyze the audio to get loudnorm stats
print(" - Pass 1: Analyzing...")
result = subprocess.run(
["ffmpeg", "-v", "info", "-i", str(temp_extracted), "-af", "loudnorm=I=-14:LRA=7:tp=-1:print_format=json", "-f", "null", "-"],
["ffmpeg", "-v", "info", "-i", str(temp_extracted), "-af", "loudnorm=I=-18:LRA=7:tp=-1:print_format=json", "-f", "null", "-"],
capture_output=True, text=True, check=True)
stats_lines = result.stderr.strip().split('\n')
stats_json_str = "".join(stats_lines[-12:]) # The JSON block is the last 12 lines
stats = json.loads(stats_json_str)
# Find the start and end of the JSON block to avoid parsing extra data.
stderr_output = result.stderr
json_start_index = stderr_output.find('{')
if json_start_index == -1:
raise ValueError("Could not find start of JSON block in ffmpeg output for loudnorm analysis.")
brace_level = 0
json_end_index = -1
for i, char in enumerate(stderr_output[json_start_index:]):
if char == '{':
brace_level += 1
elif char == '}':
brace_level -= 1
if brace_level == 0:
json_end_index = json_start_index + i + 1
break
stats = json.loads(stderr_output[json_start_index:json_end_index])
# Second pass: Apply the normalization using the stats from the first pass
print(" - Pass 2: Applying normalization...")
run_cmd([
"ffmpeg", "-v", "quiet", "-stats", "-y", "-i", str(temp_extracted), "-af",
f"loudnorm=I=-14:LRA=7:tp=-1:measured_i={stats['input_i']}:measured_lra={stats['input_lra']}:measured_tp={stats['input_tp']}:measured_thresh={stats['input_thresh']}:offset={stats['target_offset']}",
f"loudnorm=I=-18:LRA=7:tp=-1:measured_i={stats['input_i']}:measured_lra={stats['input_lra']}:measured_tp={stats['input_tp']}:measured_thresh={stats['input_thresh']}:offset={stats['target_offset']}",
"-c:a", "flac", str(temp_normalized)
])

22
av1_opus_encoder.py
View File

@@ -72,21 +72,35 @@ def convert_audio_track(index, ch, lang, audio_temp_dir, source_file, should_dow
# The stats are printed to stderr, so we must use subprocess.run directly to capture it.
print(" - Pass 1: Analyzing...")
result = subprocess.run(
["ffmpeg", "-v", "info", "-i", str(temp_extracted), "-af", "loudnorm=I=-14:LRA=7:tp=-1:print_format=json", "-f", "null", "-"],
["ffmpeg", "-v", "info", "-i", str(temp_extracted), "-af", "loudnorm=I=-18:LRA=7:tp=-1:print_format=json", "-f", "null", "-"],
capture_output=True, text=True, check=True)
# Find the start of the JSON block in stderr and parse it.
# This is more robust than slicing the last N lines.
# We find the start and end of the JSON block to avoid parsing extra data.
stderr_output = result.stderr
json_start_index = stderr_output.find('{')
stats_json_str = stderr_output[json_start_index:]
stats = json.loads(stats_json_str)
if json_start_index == -1:
raise ValueError("Could not find start of JSON block in ffmpeg output for loudnorm analysis.")
brace_level = 0
json_end_index = -1
for i, char in enumerate(stderr_output[json_start_index:]):
if char == '{':
brace_level += 1
elif char == '}':
brace_level -= 1
if brace_level == 0:
json_end_index = json_start_index + i + 1
break
stats = json.loads(stderr_output[json_start_index:json_end_index])
# Second pass: Apply the normalization using the stats from the first pass
print(" - Pass 2: Applying normalization...")
run_cmd([
"ffmpeg", "-v", "quiet", "-stats", "-y", "-i", str(temp_extracted), "-af",
f"loudnorm=I=-14:LRA=7:tp=-1:measured_i={stats['input_i']}:measured_lra={stats['input_lra']}:measured_tp={stats['input_tp']}:measured_thresh={stats['input_thresh']}:offset={stats['target_offset']}",
f"loudnorm=I=-18:LRA=7:tp=-1:measured_i={stats['input_i']}:measured_lra={stats['input_lra']}:measured_tp={stats['input_tp']}:measured_thresh={stats['input_thresh']}:offset={stats['target_offset']}",
"-c:a", "flac", str(temp_normalized)
])