+ * Sampling rate
+ */
+#define SAMPLING_RATE 48000
+
+/**
+ * How many ms of audio to buffer before encoding them.
+ * Possible values:
+ * 60, 40, 20, 10, 5, 2.5
+ */
+#define FRAME_SIZE_MS 40
+
+/**
+ * How many samples to buffer before encoding them.
+ */
+#define FRAME_SIZE (SAMPLING_RATE / 1000 * FRAME_SIZE_MS)
+
+/**
+ * Pages are commited when their size goes over this value.
+ * Note that in practice we flush pages VERY often (every frame),
+ * which means that pages NEVER really get to be this big.
+ * With one-packet-per-page, pages are roughly 100-300 bytes each.
+ *
+ * This value is chosen to make MAX_PAYLOAD_BYTES=1024 fit
+ * into a single page.
+ */
+#define PAGE_WATERLINE 800
+
+/**
+ * Maximum length of opus payload
+ */
+#define MAX_PAYLOAD_BYTES 1024
+
+/**
+ * Number of channels
+ */
+#define CHANNELS 1
+
+/**
+ * Configures the encoder's expected packet loss percentage.
+ *
+ * Higher values will trigger progressively more loss resistant behavior
+ * in the encoder at the expense of quality at a given bitrate
+ * in the lossless case, but greater quality under loss.
+ */
+#define CONV_OPUS_PACKET_LOSS_PERCENTAGE 1
+
+/**
+ * Configures the encoder's computational complexity.
+ *
+ * The supported range is 0-10 inclusive with 10 representing
+ * the highest complexity.
+ */
+#define CONV_OPUS_ENCODING_COMPLEXITY 10
+
+/**
+ * Configures the encoder's use of inband forward error correction (FEC).
+ *
+ * Note: This is only applicable to the LPC layer.
+ */
+#define CONV_OPUS_INBAND_FEC 1
+
+/**
+ * Configures the type of signal being encoded.
+ *
+ * This is a hint which helps the encoder's mode selection.
+ *
+ * Possible values:
+ * OPUS_AUTO - (default) Encoder detects the type automatically.
+ * OPUS_SIGNAL_VOICE - Bias thresholds towards choosing LPC or Hybrid modes.
+ * OPUS_SIGNAL_MUSIC - Bias thresholds towards choosing MDCT modes.
+ */
+#define CONV_OPUS_SIGNAL OPUS_AUTO
+
+/**
+ * Coding mode.
+ *
+ * Possible values:
+ * OPUS_APPLICATION_VOIP - gives best quality at a given bitrate for voice
+ * signals. It enhances the input signal by high-pass filtering and
+ * emphasizing formants and harmonics. Optionally it includes in-band forward
+ * error correction to protect against packet loss. Use this mode for typical
+ * VoIP applications. Because of the enhancement, even at high bitrates
+ * the output may sound different from the input.
+ * OPUS_APPLICATION_AUDIO - gives best quality at a given bitrate for most
+ * non-voice signals like music. Use this mode for music and mixed
+ * (music/voice) content, broadcast, and applications requiring less than
+ * 15 ms of coding delay.
+ * OPUS_APPLICATION_RESTRICTED_LOWDELAY - configures low-delay mode that
+ * disables the speech-optimized mode in exchange for slightly reduced delay.
+ * This mode can only be set on an newly initialized or freshly reset encoder
+ * because it changes the codec delay.
+ */
+#define CONV_OPUS_APP_TYPE OPUS_APPLICATION_VOIP
+
+/**
+ * Specification for recording. May change in the future to spec negotiation.
+ */