How can I record audio while it is playing?

Question

Is it possible to record playing audio on an Ubuntu 16.04 laptop? I mean part of audio the from a video file or playing music.

As requested in comments:

Output of arecord -l

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: 92HD87B1/3 Analog [92HD87B1/3 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

I tried

ffmpeg -f alsa -i hw:0 -t 360 na_re_full.wav

The output was just a blank file (of chosen length) with some random noise. Nothing was recorded from the streaming music :(

$ arecord -L
default
    Playback/recording through the PulseAudio sound server
null
    Discard all samples (playback) or generate zero samples (capture)
pulse
    PulseAudio Sound Server
sysdefault:CARD=PCH
    HDA Intel PCH, 92HD87B1/3 Analog
    Default Audio Device
front:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    Front speakers
surround21:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
dmix:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    Direct sample mixing device
dsnoop:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    Direct sample snooping device
hw:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    Direct hardware device without any conversions
plughw:CARD=PCH,DEV=0
    HDA Intel PCH, 92HD87B1/3 Analog
    Hardware device with all software conversions

score 3 · Answer 1 · answered Dec 10 '17 at 09:39

Use Audacity
Remove any headphones/mic plugged in
Use recording source as default ( if not working, try trial and error )
Click the " Record " button ( a maroon dot )
You can see the GUI listing variations if audio is recording
Start and stop at desired points
Save as Audacity project
Delete unwanted part of the audio
Use File > Save other > Export as mp3 to your desired location

How can I record audio while it is playing?

1 Answers1