protected function extract_audio( $richtext, $plaintext, $extra_args = array() ) {
		$data   = array( 'has' => array( 'audio' => 0 ), 'audio' => array() );
		$audios = $this->extract_shortcodes( $richtext, $plaintext, $extra_args );
		$links  = $this->extract_links( $richtext, $plaintext, $extra_args );

		$audio_types = wp_get_audio_extensions();


		// [audio]
		$audios = wp_list_filter( $audios['shortcodes'], array( 'type' => 'audio' ) );
		foreach ( $audios as $audio ) {

			// Media URL can appear as the first parameter inside the shortcode brackets.
			if ( isset( $audio['attributes']['src'] ) ) {
				$src_param = 'src';
			} elseif ( isset( $audio['attributes'][0] ) ) {
				$src_param = 0;
			} else {
				continue;
			}

			$path = untrailingslashit( parse_url( $audio['attributes'][ $src_param ], PHP_URL_PATH ) );

			foreach ( $audio_types as $extension ) {
				$extension = '.' . $extension;

				// Check this URL's file extension matches that of an accepted audio format.
				if ( ! $path || substr( $path, -4 ) !== $extension ) {
					continue;
				}

				$data['audio'][] = array(
					'original' => '[audio src="' . esc_url_raw( $audio['attributes'][ $src_param ] ) . '"]',
					'source'   => 'shortcodes',
					'url'      => esc_url_raw( $audio['attributes'][ $src_param ] ),
				);
			}
		}

		// <a href="*.mp3"> tags.
		foreach ( $audio_types as $extension ) {
			$extension = '.' . $extension;

			foreach ( $links['links'] as $link ) {
				$path = untrailingslashit( parse_url( $link['url'], PHP_URL_PATH ) );

				// Check this URL's file extension matches that of an accepted audio format.
				if ( ! $path || substr( $path, -4 ) !== $extension ) {
					continue;
				}

				$data['audio'][] = array(
					'original' => '[audio src="' . esc_url_raw( $link['url'] ) . '"]',  // Build an audio shortcode.
					'source'   => 'html',
					'url'      => esc_url_raw( $link['url'] ),
				);
			}
		}

		$data['has']['audio'] = count( $data['audio'] );

		/**
		 * Filters audio extracted from text.
		 *
		 * @since 2.3.0
		 *
		 * @param array  $data       Extracted audio. See {@link BP_Media_Extractor::extract_audio()} for format.
		 * @param string $richtext   Content to parse.
		 * @param string $plaintext  Copy of $richtext without any markup.
		 * @param array  $extra_args Bespoke data for a particular extractor.
		 */
		return apply_filters( 'bp_media_extractor_audio', $data, $richtext, $plaintext, $extra_args );
	}