audio_defines.h

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/*
 * Copyright (c) 2023 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */
 
#ifndef _AUDIO_DEFINES_H_
#define _AUDIO_DEFINES_H_
 
#include <zephyr/toolchain.h>
#include <zephyr/types.h>
#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
 
enum audio_channel {
        AUDIO_CH_L,
        AUDIO_CH_R,
        AUDIO_CH_NUM,
};
 
enum coding {
        /* Raw PCM audio data */
        PCM = 1,
 
        /* LC3-coded audio data */
        LC3
};
 
struct audio_metadata {
        /* Indicates the data type/encoding. */
        enum coding data_coding;
 
        /* Playback length in microseconds. */
        uint32_t data_len_us;
 
        /* The audio sample rate.
         * This may typically be 16000, 24000, 44100 or 48000 Hz.
         */
        uint32_t sample_rate_hz;
 
        /* Number of valid bits for a sample (bit depth). Typically 16 or 24. */
        uint8_t bits_per_sample;
 
        /* Number of bytes per active location in the bitstream */
        uint32_t bytes_per_location;
 
        /* Number of bits used to carry a sample of size bits_per_sample.
         * For example, say we have a 24 bit sample stored in a 32 bit
         * word (int32_t), then:
         *     bits_per_sample = 24
         *     carrier_size    = 32
         */
        uint8_t carried_bits_per_sample;
 
        /* The bit-rate for the data stream.
         * For example, say we have a 16 bit sample stored in a 32 bit
         * word (int_32), 100 samples in each of 2 locations and a sample rate of 48000 Hz then:
         *     bitrate_bps = 32 * 48000 * 2
         *                 = 3.072 Mbps
         *
         * For encoded data the bit-rate will be determined by the encoding process.
         */
        uint32_t bitrate_bps;
 
        /* A flag to specify if the data is interleaved or de-interleaved
         * (true = interleaved, false = de-interleaved).
         *
         * @note This flag is only valid for data types that support interleaving (e.g. PCM
         * channel interleaving, where interleaved is LRLRLRLRL..... and de-interleaved is
         * LLLLLRRRRRLL...
         */
        bool interleaved;
 
        /* A 32 bit mask indicating which channel(s)/locations are active within
         * the data. A bit set indicates the location is active and
         * a count of these will give the number of locations within the
         * audio stream.
         * Note: This will follow the ANSI/CTA-861-G’s Table 34 codes
         * for speaker placement (as used by Bluetooth Low Energy Audio).
         *
         * @note For Bluetooth Low Energy Audio a value of 0 indicates mono.
         */
        uint32_t locations;
 
        /* Reference time stamp (e.g. ISO timestamp reference from BLE controller). */
        uint32_t ref_ts_us;
 
        /* The timestamp for when the data was received. */
        uint32_t data_rx_ts_us;
 
        /* A bit field to indicate if any channel has errors (1 = bad, 0 = good).
         *
         * Note: Timestamps are still valid when this is set.
         */
        uint32_t bad_data;
};
 
static inline uint8_t audio_metadata_num_loc_get(struct audio_metadata const *const meta)
{
        if (meta == NULL) {
                return 0;
        }
 
        if (meta->locations == 0) {
                return 1;
        }
 
        return POPCOUNT(meta->locations);
}
 
#endif /* _AUDIO_DEFINES_H_ */