Processing Podcasts

Ahuka's recent episodes about pre processing podcasts with audacity reminded me that I have been wanting to do an episode about pre-processing podcasts with sox.

I no longer need to use sox to change the podcast tempo since now, I use Antena Pod on my phone

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When I started listening to podcasts the only playback options were either a PC or a mp3 player. I started out just downloading the podcasts to my PC from the podcast's web page.

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My first podcast automation was using bashpodder. bashpodder was simple to set up and run via cron. It would: - read a file to get a list of RSS feeds - Track previous downloads in a log - Download new episodes

https://lincgeek.org/bashpodder/

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A few of the podcasts I listened to were panels of a few hosts that were recorded live and released later as a podcast. Some of those shows were unedited and had some dead air that I wanted to remove. It took me a few tries, but I eventually figured out how to truncate silence with sox

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Many of the podcast players I used did not have the ability to alter the playback speed. So I also figured out how to change the tempo using sox.

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I stuck to using dedicated mp3 players for several years. Before the sansa clips came out, my favorite was the sansa e200 series https://en.wikipedia.org/wiki/Sansa_e200_series They could run the alternative firmware, rockbox. https://www.rockbox.org/ I remember wasting hours playing frozen bubble on my mp3 player.

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The sansa clips were a big innovation. Small, light, and cheap. They were my preferred player until I eventually switched to phones.

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I had a workflow set up - cron bashpodder - script to process with sox - script to reload podcast - mount - move from player to archive - move new files to player - unmount

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I did a HPR episode a few months ago about my first tech job. When I started there, I was given in iPhone. It was my first smart phone. While there, I had started taking walks on by lunch break. And I would get to listen to podcast while out.

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There were a few times where I would run out of episodes to listen to. So I decided to add some podcasts to my work iPhone. For most of the time I worked there, I would take my sansa with me and listen to every thing on it. Then if I ran out, I had my phone with me, so I would listen to podcasts on it.

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This process meant I had 2 sets of podcasts - provided by mashpodder - iPhone app.

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I kept this practice of having 2 podcast sources for a few years, but I eventual stopped using the sansa. Phones were getting better, and the sansa devices were getting harder to find.

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I wanted to start listening to my bashpodder podcasts on my phone. I looked for a few file transfer solutions, but eventually settled on making my own RSS feed of files I had downloaded.

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I found a python script that would take a directory listing of mp3s and build a RSS feed. Now I had a cron job that would - download - process with sox - create the RSS feed - rsync RSS XML file on podcast files to a VPS

https://genrss.readthedocs.io/en/latest/

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I used a VPS so I could download new episodes to my phone from anywhere. After a while, I experimented with using a AWS S3 to host the files. I stopped using S3 when the free tier ran out, and I started getting charged for storage and bandwidth.

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Eventually, when I started working at home I no longer needed the RSS feed to be available from anywhere. So I just started using a http server in my home lab to host my RSS feed and files. I can update my phone with the files I download and process as long as I am on my home network

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Also, one other change I made at some point was switching from bashpodder to mashpodder. There were a few podcast that bashpodder was not able to parse.

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Today, I listen to podcasts via antenna pod Most of of the podcasts I searched for and subscribed to via the app. There are still a few podcasts that I get via mashpodder and pre-process with sox. Since the phone app is good at altering the tempo (I like 2x), I no longer have to use sox for speeding up. But I still use sox for leveling the audio and truncating silence.

My tendency is to have the podcasts that are produced by studios/companies via the app and podcasts produced by enthusiasts via mashpodder/sox

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set -euo pipefail
IFS=$'nt'
SOX="/usr/local/bin/sox"
cd /mashpodder/podcasts/files
if [ -z "$(ls -A )" ]; then
   echo "Empty"
   exit 0
else
   echo "Not Empty"
fi
for i in *
    do
    $SOX  -v 0.5 $i "/mashpodder/podcasts/faster/$i.mp3" compand 0.3,1 6:-70,-60,-20 -5 -90  remix - silence 1 0.1 1% -1 0.1 1%  stat
    mv -v $i ../archive/
done

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• Delete old file from the Archive
• Generate a RSS feed of the faster directlry

find  /mashpodder/podcasts/archive/ -name "*mp3" -mtime +30 -delete
cd /mashpodder/podcasts
  && python2.7 ../genRSS/genRSS.py
  -v
  -e mp3
  -i 'faster/faster.gif'
  -t Faster
  -p "Faster Podcasts"
  -d faster
  -H http://address.of.web.host
  --sort-creation
  -o faster/faster.xml