#!/bin/bash

# Determine the bitrate of a media file, playing it to wav to determine its length.
#
# mplayer's AUDIO lines look like this:
# AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400)

for file; do
	
	{ ls -l "$file" | awk '{ print "FILESIZE:",$5 }'
	  mplayer -vo null -vc dummy -ao pcm:waveheader:file=>(
			wc -c |sed 's/^/WAVESIZE: /'
		) "$file" </dev/null
	} 2>&1 |
	{ awk '/^AUDIO: [0-9]+ Hz/ {
			rate=$2
			channels=$4;
			bitspersample=gensub("[^0-9]","","g",$6);  }
	     /^FILESIZE: [0-9]+/ { filesize=$2 }
	     /^WAVESIZE: [0-9]+/ { wavesize=$2 }
	     END {
			OFMT="%f"
			print filesize * rate * channels * bitspersample / wavesize }'
	  echo "$file";
	} | paste - -
done