xref: /btstack/src/classic/hfp_codec.h (revision 360d44f609bbebbf954ea85f461752a6b07644cd)
1 /*
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37 
38 /**
39  * @title HFP Audio Encoder
40  * @brief Create SCO packet with H2 Synchronization Header and encoded audio samples
41  */
42 
43 #ifndef HFP_CODEC_H
44 #define HFP_CODEC_H
45 
46 #include "btstack_config.h"
47 #include "hfp.h"    // hfp_h2_framing
48 
49 #include <stdint.h>
50 
51 #ifdef ENABLE_HFP_WIDE_BAND_SPEECH
52 #include "btstack_sbc.h"
53 #endif
54 
55 #ifdef ENABLE_HFP_SUPER_WIDE_BAND_SPEECH
56 #include "btstack_lc3_google.h"
57 #endif
58 
59 #if defined __cplusplus
60 extern "C" {
61 #endif
62 
63 #define SCO_FRAME_SIZE 60
64 
65 struct hfp_codec {
66     // to allow for 24 byte USB payloads, we encode up to two SCO packets
67     uint8_t sco_packet[2*SCO_FRAME_SIZE];
68     uint16_t read_pos;
69     uint16_t write_pos;
70     uint16_t samples_per_frame;
71     hfp_h2_framing_t h2_framing;
72     void (*encode)(struct hfp_codec * hfp_codec, int16_t * pcm_samples);
73 #ifdef ENABLE_HFP_WIDE_BAND_SPEECH
74     btstack_sbc_encoder_state_t msbc_state;
75 #endif
76 #ifdef ENABLE_HFP_SUPER_WIDE_BAND_SPEECH
77     const btstack_lc3_encoder_t * lc3_encoder;
78     btstack_lc3_encoder_google_t lc3_encoder_context;
79 #endif
80 };
81 
82 /* API_START */
83 
84 typedef struct hfp_codec hfp_codec_t;
85 
86 /**
87  * @brief Initialize HFP Audio Codec
88  * @note  btstack_assert if codec_id is not supported
89  * @param hfp_codec
90  * @param codec_id see HFP_CODEC_xxx in hfp.h
91  * @return status
92  */
93 void hfp_codec_init(hfp_codec_t * hfp_codec, uint8_t codec_id);
94 
95 /**
96  * @brief Get number of audio samples per HFP SCO frame
97  * @param hfp_codec
98  * @return num audio samples per 7.5ms SCO packet
99  */
100 uint16_t hfp_codec_num_audio_samples_per_frame(const hfp_codec_t * hfp_codec);
101 
102 /**
103  * @brief Checks if next frame can be encoded
104  * @param hfp_codec
105  */
106 bool hfp_codec_can_encode_audio_frame_now(const hfp_codec_t * hfp_codec);
107 
108 /**
109  * Get number of bytes ready for sending
110  * @param hfp_codec
111  * @return num bytes ready for current packet
112  */
113 uint16_t hfp_codec_num_bytes_available(const hfp_codec_t * hfp_codec);
114 
115 /**
116  * Encode audio samples for HFP SCO packet
117  * @param hfp_codec
118  * @param pcm_samples - complete audio frame of hfp_msbc_num_audio_samples_per_frame int16 samples
119  */
120 void hfp_codec_encode_audio_frame(hfp_codec_t * hfp_codec, int16_t * pcm_samples);
121 
122 /**
123  * Read from stream into SCO packet buffer
124  * @param hfp_codec
125  * @param buffer to store stream
126  * @param size num bytes to read from stream
127  */
128 void hfp_codec_read_from_stream(hfp_codec_t * hfp_codec, uint8_t * buffer, uint16_t size);
129 
130 /**
131  * @param hfp_codec
132  */
133 void hfp_codec_deinit(hfp_codec_t * hfp_codec);
134 
135 /* API_END */
136 
137 #if defined __cplusplus
138 }
139 #endif
140 
141 #endif
142