Parallel Processing for Longer Texts

[shikharmay7]

Hi everyone,
I'm trying to synthesise parallely doing something like below to reduce total time for a TTS for longer texts.

from moviepy.editor import AudioFileClip, concatenate_audioclips
from fam.llm.fast_inference import TTS
from concurrent.futures import ThreadPoolExecutor, as_completed
tts = TTS()

speaker_path = "<path to speaker src>"
output_dir = "<save path>"
silentPath = "<silent audio path>"

def process_sentence(i, sentence):
    print(f"Synthesising utterance for sentence {i}...{sentence}")
    wav_file = tts.synthesise(
      text=sentence,
      spk_ref_path=speaker_path
    )
    audioPath = wav_file
    audio = AudioFileClip(audioPath)
    
    return i, audio

script = "<some long script>"
sentences = script.split('.')  # contains sentences with chars<200
audioClips = []
threads = 4

with ThreadPoolExecutor(max_workers=threads) as executor: 
    futures = {executor.submit(process_sentence, i, sentences[i]): i for i in range(len(sentences))}

    for future in as_completed(futures):
        i, modAudio = future.result()
        audioClips.append((i, modAudio))

# Sorting the audio clips by sentence order
audioClips.sort(key=lambda x: x[0])
audioClips = [clip for i, clip in audioClips]

# Insert pauses between sentences
finalClips = []
for i, clip in enumerate(audioClips):
    finalClips.append(clip)
    if i < len(sentences) - 1:
        pauseClip = AudioFileClip(silentPath)
        finalClips.append(pauseClip)

# Concatenate all audio clips
concatenated_audio = concatenate_audioclips(finalClips)
concatenated_audio.write_audiofile(f'{output_dir}/complete.mp3')

It runs normally with threads=1 but not for any value >1. It throws errors like

unknown:0: unknown: block: [0,0,0], thread: [64,0,0] Assertion index out of bounds: 0 <= tmp12 < 2048 failed.
unknown:0: unknown: block: [0,0,0], thread: [65,0,0] Assertion index out of bounds: 0 <= tmp12 < 2048 failed.
unknown:0: unknown: block: [0,0,0], thread: [66,0,0] Assertion index out of bounds: 0 <= tmp12 < 2048 failed.
unknown:0: unknown: block: [0,0,0], thread: [67,0,0] Assertion index out of bounds: 0 <= tmp12 < 2048 failed.
.
.
...

IMO, it's due to the assert in the decode_one_token method. Can someone please help me with this?