ffmpeg-normalize: Progress is not working correctly

Hi there,

Thanks for the script. It is working great, except for one thing. The progress bar (–progress) does not update. It shows the following for a while:

File:   0%|                                                  | 0/1 [00:00<?, ?it/s]
Stream 1/1:   0%|                                            | 0/100 [00:00<?, ?it/s]

And then the script is done.

What could be wrong? ffmpeg version? I installed from linuxbrew.

• Operating system: Ubuntu 17.10

• Python version / distribution: Python 2.7.15 in a venv

• ffmpeg:

    ffmpeg version 4.0 Copyright (c) 2000-2018 the FFmpeg developers
    built with gcc 5.4.1 (Ubuntu 5.5.0-1ubuntu2) 20171010
    configuration: --prefix=/home/paul/.linuxbrew/Cellar/ffmpeg/4.0 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=gcc-5 --host-cflags= --host-ldflags= --enable-gpl --enable-libfdk-aac --enable-libmp3lame --enable-libx264 --enable-libxvid --disable-lzma --enable-nonfree
  

• Command:

    ffmpeg-normalize movie.mp4 -v -pr -c:a libfdk_aac -b:a 192k --extension mp4