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How to capture, stream, and play audio using audio_capture and audio_play.
Description: This tutorial covers the audio_capture and audio_play packages. The audio_capture package records audio from a microphone and publishes audio messages on the /audio topic. The audio_play package listens to /audio and outputs the audio messages to speakers.Keywords: audio, sound, stream
Tutorial Level: BEGINNER
Next Tutorial: For remote robot teleoperators, learn how to remotely listen through robot ears
Installation
Install ROS: Installation Instructions
- Instructions for Ubuntu
Install from debs; replace <distro> with the ROS distribution you're using (eg. fuerte)
sudo apt-get install ros-<distro>-audio-common
- Instructions for other Linux distributions
- Install git
sudo aptitude install git
- Download code
cd ~/catkin_ws/src git clone https://github.com/ros-drivers/audio_common.git
- Install dependencies
rosdep install audio_common
- Build audio_common along with your other ROS packages
cd ~/catkin_ws catkin_make source ~/catkin_ws/devel/setup.bash
Testing Your Setup
Test that gstreamer is working successfully with ALSA by capturing audio from your microphone and playing it back through your speakers.
Before executing the following command, make sure your microphone is enabled and selected as your default audio input device. You may want to turn down your volume as well.
gst-launch-0.10 alsasrc ! audioconvert ! audioresample ! alsasink
If the above command doesn't work, try using the command "gst-launch-1.0" instead of the command "gst-launch-0.10".
The above command should play audio from the microphone through the speakers. If no audio is heard, make sure your system settings take audio input from your intended source as default. It may be helpful to debug whether audio from your source is being received using an external audio recording program such as audacity.
Once it is working, control-c the script to stop it.
Capturing sounds
Start capturing audio data using the following command
roslaunch audio_capture capture.launch
This will produce an /audio topic. Check for its existence using:
rostopic list
Check to see if it is streaming any data:
rostopic hz /audio
Do not kill this node, and continue to the next section.
Listening to captured sounds
Once the audio_capture node is running, we can use the audio_play node to listen to the output.
Open a new terminal, and source your ROS workspace variables.
source ~/catkin_ws/devel/setup.bash
Now launch the audio_play node.
roslaunch audio_play play.launch
This will start a new node that listens to the /audio topic, and plays the incoming messages.
