ROS nodes and utilities for audio streams.

Author(s): Marc-Antoine Maheux

The following subsections explain how to use the library on Ubuntu.

sudo apt-get install cmake build-essential gfortran texinfo libasound2-dev

git submodule update --init --recursive

This node captures the sound from an ALSA device and publishes it to a topic.

• device (string): The ALSA device to capture (ex: hw:CARD=1,DEV=0).
• format (string): The audio format (see audio_utils/AudioFrame).
• channel_count (int): The device channel count.
• sampling_frequency (int): The device sampling frequency.
• frame_sample_count (int): The number of samples in each frame.
• merge (bool): Indicate to merge the channels or not.
• merge_gain: The gain to apply after the merge.

• audio_out (audio_utils/AudioFrame) The captured sound.

This node captures the sound from a topic and plays it to an ALSA device.

• device (string): The ALSA device to capture (ex: hw:CARD=1,DEV=0).
• format (string): The audio format (see audio_utils/AudioFrame).
• channel_count (int): The device channel count.
• sampling_frequency (int): The device sampling frequency.
• frame_sample_count (int): The number of samples in each frame.

• audio_in (audio_utils/AudioFrame) The sound to play.

This node estimates the song tempo and detects if the beat is in the current frame.

• audio_in (audio_utils/AudioFrame) The sound to analyze. The channel count must be 1, the sampling frequency must be 44100 Hz and the frame sample count must be 256.

• bpm (std_msgs/Float32): The tempo in bpm (beats per minute) for each frame.
• beat (std_msgs/Bool): Indicate if the beat is in the current frame.

This node converts the format of an audio topic.

• input_format (string): The input audio format (see audio_utils/AudioFrame).
• output_format (string): The output audio format (see audio_utils/AudioFrame).

• audio_in (audio_utils/AudioFrame) The sound topic to convert.

• audio_out (audio_utils/AudioFrame) The converted sound.

This node resamples an audio topic.

• input_format (string): The input audio format (see audio_utils/AudioFrame).
• output_format (string): The output audio format (see audio_utils/AudioFrame).
• channel_count (int): The device channel count.
• input_sampling_frequency (int): The input sampling frequency.
• output_sampling_frequency (int): The output sampling frequency.
• input_frame_sample_count (int): The number of samples in each frame of the input.

• audio_in (audio_utils/AudioFrame) The sound topic to resample.

• audio_out (audio_utils/AudioFrame) The resampled sound.

This node split a multichannel audio topic into several mono audio topics.

• input_format (string): The input audio format (see audio_utils/AudioFrame).
• output_format (string): The output audio format (see audio_utils/AudioFrame).
• channel_count (int): The device channel count.

• audio_in (audio_utils/AudioFrame) The sound topic to split.

• audio_out_0 (audio_utils/AudioFrame) The first channel sound.
• audio_out_1 (audio_utils/AudioFrame) The second channel sound.
• ...

This node writes the raw sound data to a file.

• output_path (string): The output file path.

• audio_in (audio_utils/AudioFrame) The sound topic to write.