Pydub - combine split_on_silence with minimum length / file size

Question

I have two scripts, one of them splits audio of a certain length, the other one splits audio on every time there is a silent passage. Would it be possible to split the audio on silence, but only after a certain time passed? I would need chunks of videos split on silence which are not shorter than 5 minutes.

Splitting script with ignores silence:

from pydub import AudioSegment
#from pydub.utils import mediainfo
from pydub.utils import make_chunks
import math

#lac_audio = AudioSegment.from_file("Kalimba.mp3", "mp3")
#flac_audio.export("audio.mp3", format="mp3")
myaudio = AudioSegment.from_file("Kalimba.mp3" , "mp3")
channel_count = myaudio.channels    #Get channels
sample_width = myaudio.sample_width #Get sample width
duration_in_sec = len(myaudio) / 1000#Length of audio in sec
sample_rate = myaudio.frame_rate

print "sample_width=", sample_width 
print "channel_count=", channel_count
print "duration_in_sec=", duration_in_sec 
print "frame_rate=", sample_rate
bit_rate =16  #assumption , you can extract from mediainfo("test.wav") dynamically


wav_file_size = (sample_rate * bit_rate * channel_count * duration_in_sec) / 8
print "wav_file_size = ",wav_file_size


file_split_size = 10000000  # 10Mb OR 10, 000, 000 bytes
total_chunks =  wav_file_size // file_split_size

#Get chunk size by following method #There are more than one ofcourse
#for  duration_in_sec (X) -->  wav_file_size (Y)
#So   whats duration in sec  (K) --> for file size of 10Mb
#  K = X * 10Mb / Y

chunk_length_in_sec = math.ceil((duration_in_sec * 10000000 ) /wav_file_size)   #in sec
chunk_length_ms = chunk_length_in_sec * 1000
chunks = make_chunks(myaudio, chunk_length_ms)

#Export all of the individual chunks as wav files

for i, chunk in enumerate(chunks):
    chunk_name = "chunk{0}.mp3".format(i)
    print "exporting", chunk_name
    chunk.export(chunk_name, format="mp3")

Splitting script which ignores length:

from pydub import AudioSegment
from pydub.silence import split_on_silence

sound = AudioSegment.from_mp3("my_file.mp3")
chunks = split_on_silence(sound, 
    # must be silent for at least half a second
    min_silence_len=500,

    # consider it silent if quieter than -16 dBFS
    silence_thresh=-16

 )

for i, chunk in enumerate(chunks):
    chunk.export("/path/to/ouput/dir/chunk{0}.wav".format(i), format="wav")

Answer 1

My advice is to use pydub.silence.split_on_silence() and then recombine the segments as needed so that you have files that are roughly the size you're targeting.

something like

from pydub import AudioSegment
from pydub.silence import split_on_silence

sound = AudioSegment.from_file("/path/to/file.mp3", format="mp3")
chunks = split_on_silence(
    sound,

    # split on silences longer than 1000ms (1 sec)
    min_silence_len=1000,

    # anything under -16 dBFS is considered silence
    silence_thresh=-16, 

    # keep 200 ms of leading/trailing silence
    keep_silence=200
)

# now recombine the chunks so that the parts are at least 90 sec long
target_length = 90 * 1000
output_chunks = [chunks[0]]
for chunk in chunks[1:]:
    if len(output_chunks[-1]) < target_length:
        output_chunks[-1] += chunk
    else:
        # if the last output chunk is longer than the target length,
        # we can start a new one
        output_chunks.append(chunk)

# now your have chunks that are bigger than 90 seconds (except, possibly the last one)

Alternatively, you can use pydub.silence.detect_nonsilent() to find the ranges and make your own decisions about where to slice the original audio

note: I also posted this on a similar/duplicate github issue

Answer 2

The solution is to use mp3splt instead: http://mp3splt.sourceforge.net/mp3splt_page/documentation/man.html

-t TIME[>MIN_TIME] Time mode. This option will create an indefinite number of smaller files with a fixed time length specified by TIME (which has the same format described above). It is useful to split long files into smaller (for example with the time length of a CD). Adjust option (-a) can be used to adjust splitpoints with silence detection. >MIN_TIME can be used to specify the theoretical minimum track length of the last segment; it allows avoiding to create very small files as the last segment. Make sure to quote the argument when using MIN_TIME - "TIME>MIN_TIME".

Then, it can be used in python like this:

import os
os.system("mp3splt inputfile.mp3")