> ## Documentation Index > Fetch the complete documentation index at: https://dragonwingdocs-staging.qualcomm.com/llms.txt > Use this file to discover all available pages before exploring further. # AAC Encoder API **Header:** `spf/api/modules/aac_encoder_api.h` ## Structures ### `aac_bitrate_level_map_t` **Members** ### `param_id_aac_bitrate_level_map_payload_t` **Members** ### `cutoff_freq_level_info_t` **Members** } ### `param_id_aac_enc_cutoff_freq_config_t` **Members** Mode0 – use to retain existing logic in encoder w\.r.t cutoff frequency handling. Mode1 – Use to enable a global cutoff frequency. For example, for usecases with requirement to limit cutoff frequency to a particular level irrespective of configuration(sampling rate, bit rate etc.,) Mode2 – Use to enable a cutoff frequency table based on bitrate range. For example, user can choose to configure different cutoff frequencies for different bitrate ranges, with upto 6 levels. Mode3 – Use to disable cutoff frequency logic in the encoder. This will pick max cutoff frequency as default, i.e., half the sampling rate. All other values are reserved. } This value will be picked as global cutoff frequency when 'freq\_cutoff\_mode' field is set to 'mode1'. NOTE : Any value above maximum cutoff frequency will be discarded and cutoff frequency will be set to max cutoff frequency.} This value and immediately following variable size array based on num\_cutoff\_levels will be chosen for cutoff frequency configuration when 'freq\_cutoff\_mode' field is set to ‘mode2’.} ## Type Definitions ### `aac_bitrate_level_map_t` ```cpp theme={null} typedef struct aac_bitrate_level_map_t aac_bitrate_level_map_t ``` ### `param_id_aac_bitrate_level_map_payload_t` ```cpp theme={null} typedef struct param_id_aac_bitrate_level_map_payload_t param_id_aac_bitrate_level_map_payload_t ``` ### `cutoff_freq_level_info_t` ```cpp theme={null} typedef struct cutoff_freq_level_info_t cutoff_freq_level_info_t ``` ### `param_id_aac_enc_cutoff_freq_config_t` ```cpp theme={null} typedef struct param_id_aac_enc_cutoff_freq_config_t param_id_aac_enc_cutoff_freq_config_t ``` ## Macros ### `AAC_ENC_DATA_INPUT_PORT` ```c theme={null} #define AAC_ENC_DATA_INPUT_PORT 0x2 ``` ### `AAC_ENC_DATA_OUTPUT_PORT` ```c theme={null} #define AAC_ENC_DATA_OUTPUT_PORT 0x1 ``` ### `AAC_ENC_DATA_MAX_INPUT_PORTS` ```c theme={null} #define AAC_ENC_DATA_MAX_INPUT_PORTS 0x1 ``` ### `AAC_ENC_DATA_MAX_OUTPUT_PORTS` ```c theme={null} #define AAC_ENC_DATA_MAX_OUTPUT_PORTS 0x1 ``` ### `AAC_ENC_MODULE_STACK_SIZE` ```c theme={null} #define AAC_ENC_MODULE_STACK_SIZE 4096 ``` ### `MAX_NUM_CUTOFF_LEVELS` ```c theme={null} #define MAX_NUM_CUTOFF_LEVELS 6 ``` ### `COP_ENCODER_FEEDBACK_IN` ```c theme={null} #define COP_ENCODER_FEEDBACK_IN AR_NON_GUID(0xC0000001) ``` ### `PARAM_ID_AAC_BIT_RATE_LEVEL_MAP` ID of the encoder Bit Rate level map parameter.This parameter can be set at run time. ```c theme={null} #define PARAM_ID_AAC_BIT_RATE_LEVEL_MAP 0x08001312 ``` ### `PARAM_ID_AAC_CUTOFF_FREQ_CONFIG` -> Quality levels are always in ascending order of bit rate ```c theme={null} #define PARAM_ID_AAC_CUTOFF_FREQ_CONFIG 0x08001A5C ``` ### `MODULE_ID_AAC_ENC` ```c theme={null} #define MODULE_ID_AAC_ENC 0x0700101E ``` ### `MODULE_ID_AAC_LC_ENC` End of the Module --> ```c theme={null} #define MODULE_ID_AAC_LC_ENC 0x070010DF ```