1 /*
2  * Copyright 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 //
18 // A2DP Codecs API
19 //
20 
21 #ifndef A2DP_CODEC_API_H
22 #define A2DP_CODEC_API_H
23 
24 #include <stddef.h>
25 #include <string.h>
26 #include <functional>
27 #include <list>
28 #include <map>
29 #include <mutex>
30 #include <string>
31 
32 #include <hardware/bt_av.h>
33 
34 #include "a2dp_api.h"
35 #include "audio_a2dp_hw/include/audio_a2dp_hw.h"
36 #include "avdt_api.h"
37 
38 class tBT_A2DP_OFFLOAD;
39 
40 /**
41  * Structure used to initialize the A2DP encoder with A2DP peer information
42  */
43 typedef struct {
44   bool is_peer_edr;          // True if the A2DP peer supports EDR
45   bool peer_supports_3mbps;  // True if the A2DP peer supports 3 Mbps EDR
46   uint16_t peer_mtu;         // MTU of the A2DP peer
47 } tA2DP_ENCODER_INIT_PEER_PARAMS;
48 
49 class A2dpCodecConfig {
50   friend class A2dpCodecs;
51 
52  public:
53   // Creates a codec entry. The selected codec is defined by |codec_index|,
54   // Returns the codec entry on success, otherwise nullptr.
55   static A2dpCodecConfig* createCodec(
56       btav_a2dp_codec_index_t codec_index,
57       btav_a2dp_codec_priority_t codec_priority =
58           BTAV_A2DP_CODEC_PRIORITY_DEFAULT);
59 
60   virtual ~A2dpCodecConfig() = 0;
61 
62   // Gets the pre-defined codec index.
codecIndex()63   btav_a2dp_codec_index_t codecIndex() const { return codec_index_; }
64 
65   // Gets the codec name.
name()66   const std::string& name() const { return name_; }
67 
68   // Gets the current priority of the codec.
codecPriority()69   btav_a2dp_codec_priority_t codecPriority() const { return codec_priority_; }
70 
71   // gets current OTA codec specific config to |p_a2dp_offload->codec_info|.
72   // Returns true if the current codec config is valid and copied,
73   // otherwise false.
74   bool getCodecSpecificConfig(tBT_A2DP_OFFLOAD* p_a2dp_offload);
75 
76   // Gets the bitRate for the A2DP codec.
77   // Returns the bitrate of current codec configuration, or 0 if not configured
78   int getTrackBitRate() const;
79 
80   // Copies out the current OTA codec config to |p_codec_info|.
81   // Returns true if the current codec config is valid and copied,
82   // otherwise false.
83   bool copyOutOtaCodecConfig(uint8_t* p_codec_info);
84 
85   // Gets the current codec configuration.
86   // Returns a copy of the current codec configuration.
87   btav_a2dp_codec_config_t getCodecConfig();
88 
89   // Gets the current codec capability.
90   // The capability is computed by intersecting the local codec's capability
91   // and the peer's codec capability. However, if there is an explicit user
92   // configuration for some of the parameters, the result codec configuration
93   // and capability is restricted to the user's configuration choice.
94   // Returns a copy of the current codec capability.
95   btav_a2dp_codec_config_t getCodecCapability();
96 
97   // Gets the codec local capability.
98   // Returns a copy of the codec local capability.
99   btav_a2dp_codec_config_t getCodecLocalCapability();
100 
101   // Gets the codec selectable capability.
102   // The capability is computed by intersecting the local codec's capability
103   // and the peer's codec capability. Any explicit user configuration is
104   // not included in the result.
105   // Returns a copy of the codec selectable capability.
106   btav_a2dp_codec_config_t getCodecSelectableCapability();
107 
108   // Gets the current codec user configuration.
109   // Returns a copy of the current codec user configuration.
110   btav_a2dp_codec_config_t getCodecUserConfig();
111 
112   // Gets the current codec audio configuration.
113   // Returns a copy of the current codec audio configuration.
114   btav_a2dp_codec_config_t getCodecAudioConfig();
115 
116   // Gets the number of bits per sample of the current codec configuration,
117   // or 0 if not configured.
118   uint8_t getAudioBitsPerSample();
119 
120   // Checks whether the codec uses the RTP Header Marker bit (see RFC 6416).
121   // NOTE: Even if the encoded data uses RTP headers, some codecs do not use
122   // the Marker bit - that bit is expected to be set to 0.
123   // Returns true if the encoded data packets have RTP headers, and
124   // the Marker bit in the header is set according to RFC 6416.
125   virtual bool useRtpHeaderMarkerBit() const = 0;
126 
127   // Gets the effective MTU for the A2DP codec.
128   // Returns the effective MTU of current codec configuration, or 0 if not
129   // configured.
130   virtual int getEffectiveMtu() const = 0;
131 
132   // Checks whether |codec_config| is empty and contains no configuration.
133   // Returns true if |codec_config| is empty, otherwise false.
134   static bool isCodecConfigEmpty(const btav_a2dp_codec_config_t& codec_config);
135 
136  protected:
137   // Sets the current priority of the codec to |codec_priority|.
138   // If |codec_priority| is BTAV_A2DP_CODEC_PRIORITY_DEFAULT, the priority is
139   // reset to its default value.
140   void setCodecPriority(btav_a2dp_codec_priority_t codec_priority);
141 
142   // Sets the current priority of the codec to its default value.
143   void setDefaultCodecPriority();
144 
145   // Sets the A2DP Source-to-Sink codec configuration to be used
146   // with a peer Sink device.
147   // |p_peer_codec_info| is the peer's A2DP Sink codec information
148   // to use. If |is_capability| is true, then |p_peer_codec_info| contains the
149   // peer's A2DP Sink codec capability, otherwise it contains the peer's
150   // preferred A2DP codec configuration to use.
151   // The result codec configuration is stored in |p_result_codec_config|.
152   // See |A2dpCodecs.setCodecConfig| for detailed description of
153   // the actual mechanism used to compute the configuration.
154   // Returns true on success, othewise false.
155   virtual bool setCodecConfig(const uint8_t* p_peer_codec_info,
156                               bool is_capability,
157                               uint8_t* p_result_codec_config) = 0;
158 
159   // Sets the user prefered codec configuration.
160   // |codec_user_config| contains the preferred codec user configuration.
161   // |codec_audio_config| contains the selected audio feeding configuration.
162   // |p_peer_params| contains the A2DP peer information.
163   // |p_peer_codec_info| is the peer's A2DP Sink codec information
164   // to use. If |is_capability| is true, then |p_peer_codec_info| contains the
165   // peer's A2DP Sink codec capability, otherwise it contains the peer's
166   // preferred A2DP codec configuration to use.
167   // If there is a change in the codec configuration that requires restarting
168   // if the audio input stream, flag |p_restart_input| is set to true.
169   // If there is a change in the encoder configuration that requires restarting
170   // of the A2DP connection, the new codec configuration is stored in
171   // |p_result_codec_config|, and flag |p_restart_output| is set to true.
172   // If there is any change in the codec configuration, flag |p_config_updated|
173   // is set to true.
174   // Returns true on success, otherwise false.
175   virtual bool setCodecUserConfig(
176       const btav_a2dp_codec_config_t& codec_user_config,
177       const btav_a2dp_codec_config_t& codec_audio_config,
178       const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
179       const uint8_t* p_peer_codec_info, bool is_capability,
180       uint8_t* p_result_codec_config, bool* p_restart_input,
181       bool* p_restart_output, bool* p_config_updated);
182 
183   // Updates the encoder with the user prefered codec configuration.
184   // |p_peer_params| contains the A2DP peer information.
185   // If there is a change in the encoder configuration that requires restarting
186   // the audio input stream, flag |p_restart_input| is set to true.
187   // If there is a change in the encoder configuration that requires restarting
188   // of the A2DP connection, flag |p_restart_output| is set to true.
189   // If there is any change in the codec configuration, flag |p_config_updated|
190   // is set to true.
191   // Returns true on success, otherwise false.
192   virtual bool updateEncoderUserConfig(
193       const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
194       bool* p_restart_input, bool* p_restart_output,
195       bool* p_config_updated) = 0;
196 
197   // Sets the codec capabilities for a peer.
198   // |p_peer_codec_capabiltities| is the peer codec capabilities to set.
199   // Returns true on success, otherwise false.
200   virtual bool setPeerCodecCapabilities(
201       const uint8_t* p_peer_codec_capabilities) = 0;
202 
203   // Constructor where |codec_index| is the unique index that identifies the
204   // codec. The user-friendly name is |name|.
205   // The default codec priority is |codec_priority|. If the value is
206   // |BTAV_A2DP_CODEC_PRIORITY_DEFAULT|, the codec priority is computed
207   // internally.
208   A2dpCodecConfig(btav_a2dp_codec_index_t codec_index, const std::string& name,
209                   btav_a2dp_codec_priority_t codec_priority);
210 
211   // Initializes the codec entry.
212   // Returns true on success, otherwise false.
213   virtual bool init() = 0;
214 
215   // Checks whether the internal state is valid
216   virtual bool isValid() const;
217 
218   // Returns the encoder's periodic interval (in milliseconds).
219   virtual uint64_t encoderIntervalMs() const = 0;
220 
221   // Checks whether the A2DP Codec Configuration is valid.
222   // Returns true if A2DP Codec Configuration stored in |codec_config|
223   // is valid, otherwise false.
224   static bool codecConfigIsValid(const btav_a2dp_codec_config_t& codec_config);
225 
226   // Gets the string representation of A2DP Codec Configuration.
227   // Returns the string representation of A2DP Codec Configuration stored
228   // in |codec_config|. The format is:
229   // "Rate=44100|48000 Bits=16|24 Mode=MONO|STEREO"
230   static std::string codecConfig2Str(
231       const btav_a2dp_codec_config_t& codec_config);
232 
233   // Gets the string representation of A2DP Codec Sample Rate.
234   // Returns the string representation of A2DP Codec Sample Rate stored
235   // in |codec_sample_rate|. If there are multiple values stored in
236   // |codec_sample_rate|, the return string format is "rate1|rate2|rate3".
237   static std::string codecSampleRate2Str(
238       btav_a2dp_codec_sample_rate_t codec_sample_rate);
239 
240   // Gets the string representation of A2DP Codec Bits Per Sample.
241   // Returns the string representation of A2DP Codec Bits Per Sample stored
242   // in |codec_bits_per_sample|. If there are multiple values stored in
243   // |codec_bits_per_sample|, the return string format is "bits1|bits2|bits3".
244   static std::string codecBitsPerSample2Str(
245       btav_a2dp_codec_bits_per_sample_t codec_bits_per_sample);
246 
247   // Gets the string representation of A2DP Codec Channel Mode.
248   // Returns the string representation of A2DP Channel Mode stored
249   // in |codec_channel_mode|. If there are multiple values stored in
250   // |codec_channel_mode|, the return string format is "mode1|mode2|mode3".
251   static std::string codecChannelMode2Str(
252       btav_a2dp_codec_channel_mode_t codec_channel_mode);
253 
254   // Dumps codec-related information.
255   // The information is written in user-friendly form to file descriptor |fd|.
256   virtual void debug_codec_dump(int fd);
257 
258   std::recursive_mutex codec_mutex_;
259   const btav_a2dp_codec_index_t codec_index_;  // The unique codec index
260   const std::string name_;                     // The codec name
261   btav_a2dp_codec_priority_t codec_priority_;  // Codec priority: must be unique
262   btav_a2dp_codec_priority_t default_codec_priority_;
263 
264   btav_a2dp_codec_config_t codec_config_;
265   btav_a2dp_codec_config_t codec_capability_;
266   btav_a2dp_codec_config_t codec_local_capability_;
267   btav_a2dp_codec_config_t codec_selectable_capability_;
268 
269   // The optional user configuration. The values (if set) are used
270   // as a preference when there is a choice. If a particular value
271   // is not supported by the local or remote device, it is ignored.
272   btav_a2dp_codec_config_t codec_user_config_;
273 
274   // The selected audio feeding configuration.
275   btav_a2dp_codec_config_t codec_audio_config_;
276 
277   uint8_t ota_codec_config_[AVDT_CODEC_SIZE];
278   uint8_t ota_codec_peer_capability_[AVDT_CODEC_SIZE];
279   uint8_t ota_codec_peer_config_[AVDT_CODEC_SIZE];
280 };
281 
282 class A2dpCodecs {
283  public:
284   // Constructor for class |A2dpCodecs|.
285   // |codec_priorities| contains the codec priorities to use.
286   A2dpCodecs(const std::vector<btav_a2dp_codec_config_t>& codec_priorities);
287   ~A2dpCodecs();
288 
289   // Initializes all supported codecs.
290   // Returns true if at least one Source codec and one Sink codec were
291   // initialized, otherwise false.
292   bool init();
293 
294   // Finds the Source codec that corresponds to the A2DP over-the-air
295   // |p_codec_info| information.
296   // Returns the Source codec if found, otherwise nullptr.
297   A2dpCodecConfig* findSourceCodecConfig(const uint8_t* p_codec_info);
298 
299   // Finds the Sink codec that corresponds to the A2DP over-the-air
300   // |p_codec_info| information.
301   // Returns the Sink codec if found, otherwise nullptr.
302   A2dpCodecConfig* findSinkCodecConfig(const uint8_t* p_codec_info);
303 
304   // Checks whether the codec for |codec_index| is supported.
305   // Returns true if the codec is supported, otherwise false.
306   bool isSupportedCodec(btav_a2dp_codec_index_t codec_index);
307 
308   // Gets the codec config that is currently selected.
309   // Returns the codec config that is currently selected, or nullptr if
310   // no codec is selected.
getCurrentCodecConfig()311   A2dpCodecConfig* getCurrentCodecConfig() const {
312     return current_codec_config_;
313   }
314 
315   // Gets the list of Source codecs ordered by priority: higher priority first.
orderedSourceCodecs()316   const std::list<A2dpCodecConfig*> orderedSourceCodecs() const {
317     return ordered_source_codecs_;
318   }
319 
320   // Gets the list of Sink codecs ordered by priority: higher priority first.
orderedSinkCodecs()321   const std::list<A2dpCodecConfig*> orderedSinkCodecs() const {
322     return ordered_sink_codecs_;
323   }
324 
325   // Sets the A2DP Source-to-Sink codec configuration to be used
326   // with a peer Sink device.
327   // |p_peer_codec_info| is the peer's A2DP Sink codec information
328   // to use. If |is_capability| is true, then |p_peer_codec_info| contains the
329   // peer's A2DP Sink codec capability, otherwise it contains the peer's
330   // preferred A2DP codec configuration to use.
331   // If the codec can be used and |select_current_codec| is true, then
332   // this codec is selected as the current one.
333   //
334   // The codec configuration is built by considering the optional user
335   // configuration, the local codec capabilities, the peer's codec
336   // capabilities, and the codec's locally-defined default values.
337   // For each codec parameter:
338   //
339   // 1. If it is user-configurable parameter (sample rate, bits per sample,
340   //    channel mode, and some codec-specific parameters),
341   //    if the user has an explicit preference, and that preference
342   //    is supported by both the local and remote device, this is the
343   //    parameter value that is used.
344   // 2. Otherwise, if the explicit internal default value is supported
345   //    by both the local and remote device, this is the parameter value
346   //    that is used.
347   // 3. Otherwise, the best match is chosen among all values supported by
348   //    the local and remote device.
349   //
350   // In addition, the codec's internal state is updated to reflect
351   // the capabilities that are advertised to the upstream audio source
352   // (Media Framework) to make run-time audio parameter choices:
353   // 4. If the user-configurable parameter was selected, this is the
354   //    only parameter value that is advertised to the Media Framework.
355   // 5. Otherwise, all values supported by both the local and remote
356   //    devices are advertised to the Media Framework.
357   //
358   // The result codec configuration is stored in |p_result_codec_config|.
359   // Returns true on success, othewise false.
360   bool setCodecConfig(const uint8_t* p_peer_codec_info, bool is_capability,
361                       uint8_t* p_result_codec_config,
362                       bool select_current_codec);
363 
364   // Sets the A2DP Sink codec configuration to be used with a peer Source
365   // device.
366   // [See setCodecConfig() for description]
367   bool setSinkCodecConfig(const uint8_t* p_peer_codec_info, bool is_capability,
368                           uint8_t* p_result_codec_config,
369                           bool select_current_codec);
370 
371   // Sets the user prefered codec configuration.
372   // |codec_user_config| contains the preferred codec configuration.
373   // |p_peer_params| contains the A2DP peer information.
374   // |p_peer_sink_capabilities| is the peer's A2DP Sink codec capabilities
375   // to use.
376   // If there is a change in the encoder configuration that requires restarting
377   // the audio input stream, flag |p_restart_input| is set to true.
378   // If there is a change in the encoder configuration that requires restarting
379   // of the A2DP connection, flag |p_restart_output| is set to true, and the
380   // new codec is stored in |p_result_codec_config|.
381   // If there is any change in the codec configuration, flag |p_config_updated|
382   // is set to true.
383   // Returns true on success, otherwise false.
384   bool setCodecUserConfig(const btav_a2dp_codec_config_t& codec_user_config,
385                           const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
386                           const uint8_t* p_peer_sink_capabilities,
387                           uint8_t* p_result_codec_config, bool* p_restart_input,
388                           bool* p_restart_output, bool* p_config_updated);
389 
390   // Sets the Audio HAL selected audio feeding parameters.
391   // Those parameters are applied only to the currently selected codec.
392   // |codec_audio_config| contains the selected audio feeding configuration.
393   // |p_peer_params| contains the A2DP peer information.
394   // |p_peer_sink_capabilities| is the peer's A2DP Sink codec capabilities
395   // to use.
396   // If there is a change in the encoder configuration that requires restarting
397   // of the A2DP connection, flag |p_restart_output| is set to true, and the
398   // new codec is stored in |p_result_codec_config|.
399   // If there is any change in the codec configuration, flag |p_config_updated|
400   // is set to true.
401   // Returns true on success, otherwise false.
402   bool setCodecAudioConfig(const btav_a2dp_codec_config_t& codec_audio_config,
403                            const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
404                            const uint8_t* p_peer_sink_capabilities,
405                            uint8_t* p_result_codec_config,
406                            bool* p_restart_output, bool* p_config_updated);
407 
408   // Sets the Over-The-Air preferred codec configuration.
409   // The OTA prefered codec configuration is ignored if the current
410   // codec configuration contains explicit user configuration, or if the
411   // codec configuration for the same codec contains explicit user
412   // configuration.
413   // |p_ota_codec_config| contains the received OTA A2DP codec configuration
414   // from the remote peer. Note: this is not the peer codec capability,
415   // but the codec configuration that the peer would like to use.
416   // |p_peer_params| contains the A2DP peer information.
417   // If there is a change in the encoder configuration that requires restarting
418   // the audio input stream, flag |p_restart_input| is set to true.
419   // If there is a change in the encoder configuration that requires restarting
420   // of the A2DP connection, flag |p_restart_output| is set to true, and the
421   // new codec is stored in |p_result_codec_config|.
422   // If there is any change in the codec configuration, flag |p_config_updated|
423   // is set to true.
424   // Returns true on success, otherwise false.
425   bool setCodecOtaConfig(const uint8_t* p_ota_codec_config,
426                          const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
427                          uint8_t* p_result_codec_config, bool* p_restart_input,
428                          bool* p_restart_output, bool* p_config_updated);
429 
430   // Sets the codec capabilities for a Sink peer.
431   // |p_peer_codec_capabiltities| is the peer codec capabilities to set.
432   // Returns true on success, otherwise false.
433   bool setPeerSinkCodecCapabilities(const uint8_t* p_peer_codec_capabilities);
434 
435   // Sets the codec capabilities for a Source peer.
436   // |p_peer_codec_capabiltities| is the peer codec capabilities to set.
437   // Returns true on success, otherwise false.
438   bool setPeerSourceCodecCapabilities(const uint8_t* p_peer_codec_capabilities);
439 
440   // Gets the current codec configuration and the capabilities of
441   // all configured codecs.
442   // The current codec configuration is stored in |p_codec_config|.
443   // Local device's codecs capabilities are stored in
444   // |p_codecs_local_capabilities|.
445   // The codecs capabilities that can be used between the local device
446   // and the remote device are stored in |p_codecs_selectable_capabilities|.
447   // Returns true on success, otherwise false.
448   bool getCodecConfigAndCapabilities(
449       btav_a2dp_codec_config_t* p_codec_config,
450       std::vector<btav_a2dp_codec_config_t>* p_codecs_local_capabilities,
451       std::vector<btav_a2dp_codec_config_t>* p_codecs_selectable_capabilities);
452 
453   // Dumps codec-related information.
454   // The information is written in user-friendly form to file descriptor |fd|.
455   void debug_codec_dump(int fd);
456 
457  private:
458   struct CompareBtBdaddr
459       : public std::binary_function<RawAddress, RawAddress, bool> {
operatorCompareBtBdaddr460     bool operator()(const RawAddress& lhs, const RawAddress& rhs) const {
461       return (memcmp(&lhs, &rhs, sizeof(lhs)) < 0);
462     }
463   };
464   typedef std::map<btav_a2dp_codec_index_t, A2dpCodecConfig*> IndexedCodecs;
465 
466   std::recursive_mutex codec_mutex_;
467   A2dpCodecConfig* current_codec_config_;  // Currently selected codec
468   std::map<btav_a2dp_codec_index_t, btav_a2dp_codec_priority_t>
469       codec_priorities_;
470 
471   IndexedCodecs indexed_codecs_;           // The codecs indexed by codec index
472   IndexedCodecs disabled_codecs_;          // The disabled codecs
473 
474   // A2DP Source codecs ordered by priority
475   std::list<A2dpCodecConfig*> ordered_source_codecs_;
476 
477   // A2DP Sink codecs ordered by priority
478   std::list<A2dpCodecConfig*> ordered_sink_codecs_;
479 
480   std::map<RawAddress, IndexedCodecs*, CompareBtBdaddr> peer_codecs_;
481 };
482 
483 /**
484  * Structure used to configure the A2DP feeding.
485  */
486 typedef struct {
487   tA2DP_SAMPLE_RATE sample_rate;          // 44100, 48000, etc
488   tA2DP_BITS_PER_SAMPLE bits_per_sample;  // 8, 16, 24, 32
489   tA2DP_CHANNEL_COUNT channel_count;      // 1 for mono or 2 for stereo
490 } tA2DP_FEEDING_PARAMS;
491 
492 // Prototype for a callback to read audio data for encoding.
493 // |p_buf| is the buffer to store the data. |len| is the number of octets to
494 // read.
495 // Returns the number of octets read.
496 typedef uint32_t (*a2dp_source_read_callback_t)(uint8_t* p_buf, uint32_t len);
497 
498 // Prototype for a callback to enqueue A2DP Source packets for transmission.
499 // |p_buf| is the buffer with the audio data to enqueue. The callback is
500 // responsible for freeing |p_buf|.
501 // |frames_n| is the number of audio frames in |p_buf| - it is used for
502 // statistics purpose.
503 // |num_bytes| is the number of audio bytes in |p_buf| - it is used for
504 // delay reporting.
505 // Returns true if the packet was enqueued, otherwise false.
506 typedef bool (*a2dp_source_enqueue_callback_t)(BT_HDR* p_buf, size_t frames_n,
507                                                uint32_t num_bytes);
508 
509 //
510 // A2DP encoder callbacks interface.
511 //
512 typedef struct {
513   // Initialize the A2DP encoder.
514   // |p_peer_params| contains the A2DP peer information
515   // The current A2DP codec config is in |a2dp_codec_config|.
516   // |read_callback| is the callback for reading the input audio data.
517   // |enqueue_callback| is the callback for enqueueing the encoded audio data.
518   void (*encoder_init)(const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
519                        A2dpCodecConfig* a2dp_codec_config,
520                        a2dp_source_read_callback_t read_callback,
521                        a2dp_source_enqueue_callback_t enqueue_callback);
522 
523   // Cleanup the A2DP encoder.
524   void (*encoder_cleanup)(void);
525 
526   // Reset the feeding for the A2DP encoder.
527   void (*feeding_reset)(void);
528 
529   // Flush the feeding for the A2DP encoder.
530   void (*feeding_flush)(void);
531 
532   // Get the A2DP encoder interval (in milliseconds).
533   uint64_t (*get_encoder_interval_ms)(void);
534 
535   // Prepare and send A2DP encoded frames.
536   // |timestamp_us| is the current timestamp (in microseconds).
537   void (*send_frames)(uint64_t timestamp_us);
538 
539   // Set transmit queue length for the A2DP encoder.
540   void (*set_transmit_queue_length)(size_t transmit_queue_length);
541 } tA2DP_ENCODER_INTERFACE;
542 
543 // Prototype for a callback to receive decoded audio data from a
544 // tA2DP_DECODER_INTERFACE|.
545 // |buf| is a pointer to the data.
546 // |len| is the number of octets pointed to by |buf|.
547 typedef void (*decoded_data_callback_t)(uint8_t* buf, uint32_t len);
548 
549 //
550 // A2DP decoder callbacks interface.
551 //
552 typedef struct {
553   // Initialize the decoder. Can be called multiple times, will reinitalize.
554   bool (*decoder_init)(decoded_data_callback_t decode_callback);
555 
556   // Cleanup the A2DP decoder.
557   void (*decoder_cleanup)();
558 
559   // Decodes |p_buf| and calls |decode_callback| passed into init for the
560   // decoded data.
561   bool (*decode_packet)(BT_HDR* p_buf);
562 
563   // Start the A2DP decoder.
564   void (*decoder_start)();
565 
566   // Suspend the A2DP decoder.
567   void (*decoder_suspend)();
568 
569   // A2DP decoder configuration.
570   void (*decoder_configure)(const uint8_t* p_codec_info);
571 } tA2DP_DECODER_INTERFACE;
572 
573 // Gets the A2DP codec type.
574 // |p_codec_info| contains information about the codec capabilities.
575 tA2DP_CODEC_TYPE A2DP_GetCodecType(const uint8_t* p_codec_info);
576 
577 // Checks whether the codec capabilities contain a valid A2DP Source codec.
578 // NOTE: only codecs that are implemented are considered valid.
579 // Returns true if |p_codec_info| contains information about a valid codec,
580 // otherwise false.
581 bool A2DP_IsSourceCodecValid(const uint8_t* p_codec_info);
582 
583 // Checks whether the codec capabilities contain a valid A2DP Sink codec.
584 // NOTE: only codecs that are implemented are considered valid.
585 // Returns true if |p_codec_info| contains information about a valid codec,
586 // otherwise false.
587 bool A2DP_IsSinkCodecValid(const uint8_t* p_codec_info);
588 
589 // Checks whether the codec capabilities contain a valid peer A2DP Source
590 // codec.
591 // NOTE: only codecs that are implemented are considered valid.
592 // Returns true if |p_codec_info| contains information about a valid codec,
593 // otherwise false.
594 bool A2DP_IsPeerSourceCodecValid(const uint8_t* p_codec_info);
595 
596 // Checks whether the codec capabilities contain a valid peer A2DP Sink codec.
597 // NOTE: only codecs that are implemented are considered valid.
598 // Returns true if |p_codec_info| contains information about a valid codec,
599 // otherwise false.
600 bool A2DP_IsPeerSinkCodecValid(const uint8_t* p_codec_info);
601 
602 // Checks whether an A2DP Sink codec is supported.
603 // |p_codec_info| contains information about the codec capabilities.
604 // Returns true if the A2DP Sink codec is supported, otherwise false.
605 bool A2DP_IsSinkCodecSupported(const uint8_t* p_codec_info);
606 
607 // Checks whether an A2DP Source codec for a peer Source device is supported.
608 // |p_codec_info| contains information about the codec capabilities of the
609 // peer device.
610 // Returns true if the A2DP Source codec for a peer Source device is supported,
611 // otherwise false.
612 bool A2DP_IsPeerSourceCodecSupported(const uint8_t* p_codec_info);
613 
614 // Initialize state with the default A2DP codec.
615 // The initialized state with the codec capabilities is stored in
616 // |p_codec_info|.
617 void A2DP_InitDefaultCodec(uint8_t* p_codec_info);
618 
619 // Checks whether the A2DP data packets should contain RTP header.
620 // |content_protection_enabled| is true if Content Protection is
621 // enabled. |p_codec_info| contains information about the codec capabilities.
622 // Returns true if the A2DP data packets should contain RTP header, otherwise
623 // false.
624 bool A2DP_UsesRtpHeader(bool content_protection_enabled,
625                         const uint8_t* p_codec_info);
626 
627 // Gets the |AVDT_MEDIA_TYPE_*| media type from the codec capability
628 // in |p_codec_info|.
629 uint8_t A2DP_GetMediaType(const uint8_t* p_codec_info);
630 
631 // Gets the A2DP codec name for a given |p_codec_info|.
632 const char* A2DP_CodecName(const uint8_t* p_codec_info);
633 
634 // Checks whether two A2DP codecs |p_codec_info_a| and |p_codec_info_b| have
635 // the same type.
636 // Returns true if the two codecs have the same type, otherwise false.
637 // If the codec type is not recognized, the return value is false.
638 bool A2DP_CodecTypeEquals(const uint8_t* p_codec_info_a,
639                           const uint8_t* p_codec_info_b);
640 
641 // Checks whether two A2DP codecs p_codec_info_a| and |p_codec_info_b| are
642 // exactly the same.
643 // Returns true if the two codecs are exactly the same, otherwise false.
644 // If the codec type is not recognized, the return value is false.
645 bool A2DP_CodecEquals(const uint8_t* p_codec_info_a,
646                       const uint8_t* p_codec_info_b);
647 
648 // Gets the track sample rate value for the A2DP codec.
649 // |p_codec_info| is a pointer to the codec_info to decode.
650 // Returns the track sample rate on success, or -1 if |p_codec_info|
651 // contains invalid codec information.
652 int A2DP_GetTrackSampleRate(const uint8_t* p_codec_info);
653 
654 // Gets the track bits per sample value for the A2DP codec.
655 // |p_codec_info| is a pointer to the codec_info to decode.
656 // Returns the track bits per sample on success, or -1 if |p_codec_info|
657 // contains invalid codec information.
658 int A2DP_GetTrackBitsPerSample(const uint8_t* p_codec_info);
659 
660 // Gets the channel count for the A2DP codec.
661 // |p_codec_info| is a pointer to the codec_info to decode.
662 // Returns the channel count on success, or -1 if |p_codec_info|
663 // contains invalid codec information.
664 int A2DP_GetTrackChannelCount(const uint8_t* p_codec_info);
665 
666 // Gets the channel type for the A2DP Sink codec:
667 // 1 for mono, or 3 for dual/stereo/joint.
668 // |p_codec_info| is a pointer to the codec_info to decode.
669 // Returns the channel type on success, or -1 if |p_codec_info|
670 // contains invalid codec information.
671 int A2DP_GetSinkTrackChannelType(const uint8_t* p_codec_info);
672 
673 // Gets the A2DP audio data timestamp from an audio packet.
674 // |p_codec_info| contains the codec information.
675 // |p_data| contains the audio data.
676 // The timestamp is stored in |p_timestamp|.
677 // Returns true on success, otherwise false.
678 bool A2DP_GetPacketTimestamp(const uint8_t* p_codec_info, const uint8_t* p_data,
679                              uint32_t* p_timestamp);
680 
681 // Builds A2DP codec header for audio data.
682 // |p_codec_info| contains the codec information.
683 // |p_buf| contains the audio data.
684 // |frames_per_packet| is the number of frames in this packet.
685 // Returns true on success, otherwise false.
686 bool A2DP_BuildCodecHeader(const uint8_t* p_codec_info, BT_HDR* p_buf,
687                            uint16_t frames_per_packet);
688 
689 // Gets the A2DP encoder interface that can be used to encode and prepare
690 // A2DP packets for transmission - see |tA2DP_ENCODER_INTERFACE|.
691 // |p_codec_info| contains the codec information.
692 // Returns the A2DP encoder interface if the |p_codec_info| is valid and
693 // supported, otherwise NULL.
694 const tA2DP_ENCODER_INTERFACE* A2DP_GetEncoderInterface(
695     const uint8_t* p_codec_info);
696 
697 // Gets the A2DP decoder interface that can be used to decode received A2DP
698 // packets - see |tA2DP_DECODER_INTERFACE|.
699 // |p_codec_info| contains the codec information.
700 // Returns the A2DP decoder interface if the |p_codec_info| is valid and
701 // supported, otherwise NULL.
702 const tA2DP_DECODER_INTERFACE* A2DP_GetDecoderInterface(
703     const uint8_t* p_codec_info);
704 
705 // Adjusts the A2DP codec, based on local support and Bluetooth specification.
706 // |p_codec_info| contains the codec information to adjust.
707 // Returns true if |p_codec_info| is valid and supported, otherwise false.
708 bool A2DP_AdjustCodec(uint8_t* p_codec_info);
709 
710 // Gets the A2DP Source codec index for a given |p_codec_info|.
711 // Returns the corresponding |btav_a2dp_codec_index_t| on success,
712 // otherwise |BTAV_A2DP_CODEC_INDEX_MAX|.
713 btav_a2dp_codec_index_t A2DP_SourceCodecIndex(const uint8_t* p_codec_info);
714 
715 // Gets the A2DP Sink codec index for a given |p_codec_info|.
716 // Returns the corresponding |btav_a2dp_codec_index_t| on success,
717 // otherwise |BTAV_A2DP_CODEC_INDEX_MAX|.
718 btav_a2dp_codec_index_t A2DP_SinkCodecIndex(const uint8_t* p_codec_info);
719 
720 // Gets the A2DP codec name for a given |codec_index|.
721 const char* A2DP_CodecIndexStr(btav_a2dp_codec_index_t codec_index);
722 
723 // Initializes A2DP codec-specific information into |AvdtpSepConfig|
724 // configuration entry pointed by |p_cfg|. The selected codec is defined
725 // by |codec_index|.
726 // Returns true on success, otherwise false.
727 bool A2DP_InitCodecConfig(btav_a2dp_codec_index_t codec_index,
728                           AvdtpSepConfig* p_cfg);
729 
730 // Decodes A2DP codec info into a human readable string.
731 // |p_codec_info| is a pointer to the codec_info to decode.
732 // Returns a string describing the codec information.
733 std::string A2DP_CodecInfoString(const uint8_t* p_codec_info);
734 
735 // Add enum-based flag operators to the btav_a2dp_codec_config_t fields
736 #ifndef DEFINE_ENUM_FLAG_OPERATORS
737 // Use NOLINT to suppress missing parentheses warnings around bitmask.
738 #define DEFINE_ENUM_FLAG_OPERATORS(bitmask)                                 \
739   extern "C++" {                                                            \
740   inline constexpr bitmask operator&(bitmask X, bitmask Y) {  /* NOLINT */  \
741     return static_cast<bitmask>(static_cast<int>(X) & static_cast<int>(Y)); \
742   }                                                                         \
743   inline constexpr bitmask operator|(bitmask X, bitmask Y) {  /* NOLINT */  \
744     return static_cast<bitmask>(static_cast<int>(X) | static_cast<int>(Y)); \
745   }                                                                         \
746   inline constexpr bitmask operator^(bitmask X, bitmask Y) {  /* NOLINT */  \
747     return static_cast<bitmask>(static_cast<int>(X) ^ static_cast<int>(Y)); \
748   }                                                                         \
749   inline constexpr bitmask operator~(bitmask X) {             /* NOLINT */  \
750     return static_cast<bitmask>(~static_cast<int>(X));                      \
751   }                                                                         \
752   inline bitmask& operator&=(bitmask& X, bitmask Y) {         /* NOLINT */  \
753     X = X & Y;                                                              \
754     return X;                                                               \
755   }                                                                         \
756   inline bitmask& operator|=(bitmask& X, bitmask Y) {         /* NOLINT */  \
757     X = X | Y;                                                              \
758     return X;                                                               \
759   }                                                                         \
760   inline bitmask& operator^=(bitmask& X, bitmask Y) {         /* NOLINT */  \
761     X = X ^ Y;                                                              \
762     return X;                                                               \
763   }                                                                         \
764   }
765 #endif  // DEFINE_ENUM_FLAG_OPERATORS
766 DEFINE_ENUM_FLAG_OPERATORS(btav_a2dp_codec_sample_rate_t);
767 DEFINE_ENUM_FLAG_OPERATORS(btav_a2dp_codec_bits_per_sample_t);
768 DEFINE_ENUM_FLAG_OPERATORS(btav_a2dp_codec_channel_mode_t);
769 
770 #endif  // A2DP_CODEC_API_H
771