A bloated script for time-scheduled audio stream recordings

A bloated script for time-scheduled audio stream recordings

Posted May 18, 2006 12:15 UTC (Thu) by scheck (subscriber, #4447)
Parent article: The Grumpy Editor's guide to audio stream grabbers

I wrote a small script for time-scheduled stream recordings and bloated it by extensive use of comments and a small "station database", which holds my favourite German radio stations.

A mere echo 'srec myrockstation 60 "Iron Maiden Live in Lederhosen"' | at 22:00 Sat would take care of your desired one-hour-show on coming Saturday at 10pm while you go out with friends who listen to Madonna... ;-)

BTW: if you adapt the mplayer command and the assignment of extensions, the script might also work with videos...

#!/bin/sh
#
# srec - stream recording
# v0.01 2006-03-21 torsten.scheck@gmx.de
#
# Copyright is hereby assigned to the Public Domain.
#
# This script relies on wget or mplayer, depending on
# the stream format.

# parameter defaults
station=${1:-"NoStation"}
length=$((${2:-60} * 60))
name=${3:-"Unnamed"}

# time period in seconds, after which the dumping process is checked
checktime=10

# choose station from database and build station list
url=''
list=''
add() {
  list="$list"$(printf "%-8s %-3s %-25s %s" "$list_station" "$list_ext" \
               "$list_info" "$list_name")"\n"
  if [ "$station" == "$list_station" ]; then
    ext=$list_ext
    info=$list_info
    url=$list_url
  fi
}
############################################################
list_station="dlf"
list_ext="ogg"
list_name="Deutschlandfunk"
list_info="96 kbps, variable, stereo"
list_url="http://dradio-live.ogg.t-bn.de/dlf_high.ogg"
add
list_station="dlfmp3"
list_ext="mp3"
list_name="Deutschlandfunk"
list_info="48 kbps, constant, mono"
list_url="http://dradio-live.mp3.t-bn.de/dlf_live"
add
list_station="dlfwma"
list_ext="wma"
list_name="Deutschlandfunk"
list_info="48 kbps, constant, stereo"
list_url="mms://dradio-live.wm.t-bn.de/live/dlf/dlf"
add
list_station="dlrk"
list_ext="ogg"
list_name="Deutschlandradio Kultur"
list_info="96 kbps, variable, stereo"
list_url="http://dradio-live.ogg.t-bn.de/dkultur_high.ogg"
add
list_station="contra"
list_ext="ra"
list_name="SWR Cont.Ra"
list_info="44 kbps, stereo"
list_url="rtsp://213.254.239.61/farm/*/encoder/swr/contra/livestream.rm"
add
############################################################

filename="${name}_${station}_$(date +%Y%m%d_%H%M).${ext}"
logname="${filename%.*}.log"

# display help when station name is not found or wasn't provided
if [ -z "$url" ]; then
  echo "Usage: $0 STATION [LENGTH in minutes] [NAME]
Saves an audio stream of a given internet radio STATION to a file in 
the current working directory. 

LENGTH defaults to 60 minutes and NAME defaults to 'Unnamed', so the 
resulting file name looks like this: ${filename}xxx
The download process is logged to a separate file using the suffix 'log'.

This script is best used with the Unix tool 'at' for time-controlled
recordings. For example, try this to record the 55-minutes-show 
'Querkoepfe' on the station 'Deutschlandfunk' next Wednesday at 21:05
including some 'safety minutes' before and after the show:
> echo 'srec dlf 60 Querkoepfe' | at 21:03 Wed
Mind your time zone and get the list of your locale's supported 
abbreviations for the time specification with:
> locale -c LC_TIME

Available stations:" >&2
  echo -ne "$list" | sort >&2
  exit 1
fi

# use 'wget' as default tool and 'mplayer' for special streaming formats
case "$ext" in
  ra|wma) util="mplayer";;
  *) util="wget"
esac
# quit if needed tool is not installed
type "$util" >/dev/null 2>&1 || { echo "Please install '$util'."; exit 1; }

# all output is redirected to logfile for easier 'at' usage
exec >> "$logname"
exec 2>> "$logname"

until
  # start background process to dump stream to file 
  if [ "$util" == "mplayer" ]; then
    mplayer -vo null -vc dummy -dumpstream -dumpfile "$filename" "$url" &
  else
    wget -nv -O "$filename" "$url" &
  fi
  # keep process id of bg process
  mypid=$!
  # in case of SIGINT and SIGTERM: kill bg process before exit
  trap 'kill $mypid; exit;' 2 15
  # wait until bg process figured out if stream is available
  # e.g. "ERROR 504: Server Full" ends the bg process
  sleep $checktime
  # check if process is still here, i.e. the stream is being downloaded,
  # or if the recording length is reached 
  kill -0 $mypid >/dev/null 2>&1 || [ $length -le 0 ]
do
  echo "Server problem, another try: $(date '+%Y%m%d %H%M%S')" 
  # decrease recording length by checktime; in the case of a transient
  # problem the remaining length of the stream will be saved
  length=$((length - checktime))
  # retry download with another until loop
done

if [ $length -gt 0 ]; then 
  # wait recording length
  sleep $length
  # kill bg process and wait for its termination
  kill $mypid 
  wait 
else
  # the recording length had been reached by trying just to get 
  # the download started
  # an unrecoverable problem prevented the desired download
  echo "Aborted." 
fi
echo "$filename END: $(date '+%Y%m%d %H%M%S')" 

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