Commands tagged audio (65)

  • This command creates and burns a gapless audio CD with 99 tracks. Each track is a 30 second sine wave, the first is 1 Hz, the second 2 Hz, and so on, up to 99 Hz. This is useful for testing audio systems (how low can your bass go?) and for creating the constant vibrations needed to make non-Newtonian fluids (like cornstarch and water) crawl around. Note, this temporarily creates 500MB of .cdda files in the current directory. If you don't use the "rm" at the end of the command, you can burn more disks using cdrdao write cdrdao.toc Prerequisites: a blank CD-R in /dev/cdrw, sox (http://sox.sourceforge.net/), and cdrdao (http://cdrdao.sourceforge.net/). I'm also assuming a recent version of bash for the brace expansion (which just looks nicer than using seq(1), but isn't necessary). Show Sample Output


    23
    (echo CD_DA; for f in {01..99}; do echo "$f Hz">&2; sox -nt cdda -r44100 -c2 $f.cdda synth 30 sine $f; echo TRACK AUDIO; echo FILE \"$f.cdda\" 0; done) > cdrdao.toc && cdrdao write cdrdao.toc && rm ??.cdda cdrdao.toc
    hackerb9 · 2009-11-17 06:23:42 3
  • This one uses dictionary.com


    13
    pronounce(){ wget -qO- $(wget -qO- "http://dictionary.reference.com/browse/$@" | grep 'soundUrl' | head -n 1 | sed 's|.*soundUrl=\([^&]*\)&.*|\1|' | sed 's/%3A/:/g;s/%2F/\//g') | mpg123 -; }
    matthewbauer · 2010-03-13 04:23:56 4
  • change the *.avi to whatever you want to match, you can remove it altogether if you want to check all files.


    10
    find -type f -name "*.avi" -print0 | xargs -0 mplayer -vo dummy -ao dummy -identify 2>/dev/null | perl -nle '/ID_LENGTH=([0-9\.]+)/ && ($t +=$1) && printf "%02d:%02d:%02d\n",$t/3600,$t/60%60,$t%60' | tail -n 1
    syssyphus · 2009-09-24 15:50:39 4
  • find . -type f -iname '*.flac' # searches from the current folder recursively for .flac audio files | # the output (a .flac audio files with relative path from ./ ) is piped to while read FILE; do FILENAME="${FILE%.*}"; flac -cd "$FILE" | lame -b 192 - "${FILENAME}.mp3"; done # for each line on the list: # FILE gets the file with .flac extension and relative path # FILENAME gets FILE without the .flac extension # run flac for that FILE with output piped to lame conversion to mp3 using 192Kb bitrate Show Sample Output


    8
    find . -type f -iname '*.flac' | while read FILE; do FILENAME="${FILE%.*}"; flac -cd "$FILE" | lame -b 192 - "${FILENAME}.mp3"; done
    paulochf · 2010-08-15 19:02:19 0

  • 6
    ffmpeg -loop 1 -i image.png -i sound.mp3 -shortest video.mp4
    ekinertac · 2013-04-23 20:20:33 2
  • Pick a mp3 at random and play it. Assumes the availability of locate with an updated db and mpg123 Not the most useful command I guess, but all of the really useful ones are taken...


    5
    mpg123 "`locate -r '\.mp3$'|awk '{a[NR]=$0}END{print a['"$RANDOM"' % NR]}'`"
    unixmonkey1730 · 2009-02-23 13:53:12 6
  • Do you have an entire album in a unique file and want to split it in individual tracks? If you also have the cue file you can do it! Packages for Debian-based systems users: * cuetools shntool * FLAC (.flac): flac * WavPack (.wv): wavpack * Monkey's Audio (.ape): libmac2 monkeys-audio (deb http://www.debian-multimedia.org sid main) NOTE: "sid" packages are unstable, but I didn't have problems with them. If you prefer, use the "stable" version repository. To transfer the tags, you can use this (works with .flac, .ogg and .mp3): cuetag sample.cue split-track*.flac Show Sample Output


    5
    cuebreakpoints <cue file> | shnsplit -o <lossless audio type> <audio file>
    o6291408 · 2009-04-29 10:42:57 0
  • This will record the capture channel of your soundcard, directly encoded in Ogg Vorbis, in stereo at quality 5 (I'm using this to record live jam sessions from my line input). You can choose which device to capture (eg. line input, microphone or PCM output) with alsamixer -V capture You can do the same thing and live encode in MP3 or FLAC if you wish, just check FLAC and LAME man pages.


    5
    rec -c 2 -r 44100 -s -t wav - | oggenc -q 5 --raw --raw-chan=2 --raw-rate=44100 --raw-bits=16 - > MyLiveRecording.ogg
    bohwaz · 2009-05-18 15:26:34 0
  • rips the audio and video stream of a movie. The two streams are stored separately.


    5
    ffmpeg -i source_movie.flv -vcodec mpeg2video target_video.m2v -acodec copy target_audio.mp3
    dcabanis · 2009-05-23 23:52:51 1
  • Record from a webcam, audio using ALSA encoded as MP3, video as MPEG-4.


    5
    ffmpeg -f alsa -r 16000 -i hw:2,0 -f video4linux2 -s 800x600 -i /dev/video0 -r 30 -f avi -vcodec mpeg4 -vtag xvid -sameq -acodec libmp3lame -ab 96k output.avi
    ivalladt · 2009-09-15 17:03:25 0
  • The original was a little bit too complicated for me. This one does not use any variables.


    5
    pronounce(){ wget -qO- $(wget -qO- "http://www.m-w.com/dictionary/$@" | grep 'return au' | sed -r "s|.*return au\('([^']*)', '([^'])[^']*'\).*|http://cougar.eb.com/soundc11/\2/\1|") | aplay -q; }
    matthewbauer · 2010-03-12 17:44:16 3
  • Takes all .flac directories, feeds them into a simple transcode pipeline to spit out .wavs with the same name (but correct extension).


    5
    for i in *.flac; do gst-launch filesrc location="$i" ! flacdec ! wavenc ! filesink location="${i%.flac}.wav"; done
    JamesHarrison · 2010-07-17 22:48:22 0

  • 5
    for f in *;do flac -cd $f |lame -b 192 - $f.mp3;done
    nickleus · 2010-10-19 07:55:11 0
  • Useful contexts : You are doing yoga or some other physical training in which you are holding a position. Or you practice the pomodoro productivity technique. Or your girlfriend said "We're leaving in 40 minutes". Design details: sleep executes before espeak to give you a 5 seconds head start. espeak is run in the background so it doesn't mess up the timing.


    5
    for ((x=0;;x+=5)); do sleep 5; espeak $x & done
    adeverteuil · 2012-02-22 00:26:57 0
  • This will lower the quality of mp3 files, but is necessary to play them on some mobile devices.


    4
    for f in *.mp3 ; do lame --mp3input -b 128 "$f" ./resamp/"$f" ; done
    jjclarkson · 2009-03-23 14:39:14 1
  • This assumes that there is a 10.2 sec delay between the video and the audio (delayed). To extract the original video into a audio and video composites look at the command on extracting audio and video from a movie


    4
    ffmpeg -i source_audio.mp3 -itsoffset 00:00:10.2 -i source_video.m2v target_video.flv
    dcabanis · 2009-05-23 23:47:41 0
  • Record audio to an MP3 file via ALSA. Adjust -i argument according to arecord -l output.


    4
    ffmpeg -f alsa -ac 2 -i hw:1,0 -acodec libmp3lame -ab 96k output.mp3
    ivalladt · 2009-09-16 12:45:44 0
  • Creates a 5 minute flv file, with the given sequence of images and audio with 0.5 fps. The images were created using the following command: for x in `seq 0 300`; do cp ../head.PNG head-`printf '%03d' $x`.png; done You can also inject metadata to seek easier using yamdi as follows: yamdi -i muxed.flv -o video.flv Show Sample Output


    4
    ffmpeg -t 300 -r '0.5' -i head-%03d.png -i ../TvQuran.com__144.mp3 -acodec copy muxed.flv
    pykler · 2010-10-07 16:29:08 0
  • Using mplayer to extract audio file from a CD


    3
    mplayer -fs cdda://9 -ao pcm:file=track9.wav
    dcabanis · 2009-05-23 23:23:45 1
  • There are some pretty good live performances on late night TV. With Mythtv I record David Letterman, Jimmy Fallon, and Conan nightly all in HD from over the air broadcasts. If I find a live performance I like I copy it to my Rockboxed iPod using this command. The Rockbox firmware knows how to downmix 5.1 audio. The command above extracts the audio from the video starting at 58 minutes and 15 seconds. It ends at the end of the file since this was the last performance of the recording. The command creates an ac3 file. I copy the ac3 file to my Rockbox iPod and rock on.


    3
    ffmpeg -ss 0:58:15 -i DavidLettermanBlackCrowes.mpg -acodec copy DavidLettermanBlackCrowes.ac3
    PLA · 2009-09-14 00:08:36 0
  • Takes two input video files and an external audio track and encodes them together to an MPEG-4 DivX output video file with the correct size ready for uploading.


    3
    mencoder -audiofile input.mp3 -oac copy -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc xvid -vf scale=320:240,harddup input1.avi input2.avi -o output.avi
    ivalladt · 2010-01-28 21:14:03 0
  • Looks up a word on merriam-webster.com, does a screen scrape for the FIRST audio pronunciation and plays it. USAGE: Put this one-liner into a shell script (e.g., ~/bin/pronounce) and run it from the command line giving it the word to say: pronounce lek If the word isn't found in merriam-webster, no audio is played and the script returns an error value. However, M-W is a fairly complete dictionary (better than howjsay.com which won't let you hear how to pronounce naughty words). ASSUMPTIONS: GNU's sed (which supports -r for extended regular expressions) and Linux's aplay. Aplay can be replaced by any program that can play .WAV files from stdin. KNOWN BUGS: only the FIRST pronunciation is played, which is problematic if you wanted a particular form (plural, adjectival, etc) of the word. For example, if you run this: pronounce onomatopoetic you'll hear a voice saying "onomatopoeia". Playing the correct form of the word is possible, but doing so might make the screen scraper even more fragile than it already is. (The slightest change to the format of m-w.com could break it). Show Sample Output


    3
    cmd=$(wget -qO- "http://www.m-w.com/dictionary/$(echo "$@"|tr '[A-Z]' '[a-z]')" | sed -rn "s#return au\('([^']+?)', '([^'])[^']*'\);.*#\nwget -qO- http://cougar.eb.com/soundc11/\2/\1 | aplay -q#; s/[^\n]*\n//p"); [ "$cmd" ] && eval "$cmd" || exit 1
    hackerb9 · 2010-03-12 13:56:41 0
  • The FLAC audio must be encoded at 16000Hz sampling rate (SoX is your friend). Outputs a short JSON string, the actual speech is in the hypotheses->utterance, the accuracy is stored in hypotheses->confidence (ranging from 0 to 1). Google also accepts audio in some special speex format (audio/x-speex-with-header-byte), which is much smaller in comparison with losless FLAC, but I haven't been able to encode such a sample. Show Sample Output


    3
    wget -q -U "Mozilla/5.0" --post-file speech.flac --header="Content-Type: audio/x-flac; rate=16000" -O - "http://www.google.com/speech-api/v1/recognize?lang=en-us&client=chromium"
    sairon · 2011-03-08 13:39:01 0
  • -vn removes tha video content, the copy option tells ffmpeg to use the same codec for generating the output


    2
    ffmpeg -i source.flv -vn acodec copy destination.mp3
    dcabanis · 2009-05-23 23:34:32 1
  • Takes an mpeg video and coverts it to a youtube compatible flv file. The -r 25 sets the frame rate for PAL, for NTSC use 29.97


    2
    ffmpeg -i mymovie.mpg -ar 22050 -acodec libmp3lame -ab 32K -r 25 -s 320x240 -vcodec flv mytarget.flv
    dcabanis · 2009-05-23 23:39:46 1
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What is the use of this switch ?
Find the usage of a switch with out searching through the entire man page. Usage: manswitch [cmd] [switch] Eg: $manswitch grep silent ____________________________ In simple words $man | grep "\-" Eg: $man grep | grep "\-o" This is not a standard method but works.

An alias to re-run last command with sudo. Similar to "sudo !!"
I didn't come up with this myself, but I always add this to my .bash_aliases file. It's essentially the same idea as running "sudo !!" except it's much easier to type. (You can't just alias "sudo !!", it doesn't really work for reasons I don't understand.) "fc" is a shell built-in for editing and re-running previous commands. The -l flag tells it to display the line rather than edit it, and the -n command tells it to omit the line number. -1 tells it to print the previous line. For more detail: $help fc

Report the established connections for a particular port

Apply permissions only to files
To apply only to dirs: $ chmod 755 $(find . -type d) Use -R parameters for recursive walk.

rename files according to file with colums of corresponding names
Maybe simpler, but again, don't know how it will work with space in filename.

check open ports without netstat or lsof

For finding out if something is listening on a port and if so what the daemon is.

generate 30 x 30 matrix
or $ od /dev/urandom -w60 -An|sed 's/ ..../ /g'|head -n 30 (this one lacks digits 8 and 9)

translate what is in the clipboard in english and write it to the terminal
Uses google api to translate, you can modify the language in which translate modifying the parameter "langpair=|en", the format is language input|language output.

Execute a command at a given time
This is an alternative to cron which allows a one-off task to be scheduled for a certain time.


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