1 /* 2 ** Copyright 2011, 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 #ifndef ANDROID_ECHO_REFERENCE_H 18 #define ANDROID_ECHO_REFERENCE_H 19 20 #include <stdint.h> 21 #include <sys/time.h> 22 23 __BEGIN_DECLS 24 25 /* Buffer descriptor used by read() and write() methods, including the time stamp and delay. */ 26 struct echo_reference_buffer { 27 void *raw; // pointer to audio frame 28 size_t frame_count; // number of frames in buffer 29 int32_t delay_ns; // delay for this buffer (see comment below) 30 struct timespec time_stamp; // time stamp for this buffer (see comment below) 31 // default ALSA gettimeofday() format 32 }; 33 /** 34 * + as input: 35 * - delay_ns is the delay introduced by playback buffers 36 * - time_stamp is the time stamp corresponding to the delay calculation 37 * + as output: 38 * unused 39 * when used for EchoReference::read(): 40 * + as input: 41 * - delay_ns is the delay introduced by capture buffers 42 * - time_stamp is the time stamp corresponding to the delay calculation 43 * + as output: 44 * - delay_ns is the delay between the returned frames and the capture time derived from 45 * delay and time stamp indicated as input. This delay is to be communicated to the AEC. 46 * - frame_count is updated with the actual number of frames returned 47 */ 48 49 struct echo_reference_itfe { 50 int (*read)(struct echo_reference_itfe *echo_reference, struct echo_reference_buffer *buffer); 51 int (*write)(struct echo_reference_itfe *echo_reference, struct echo_reference_buffer *buffer); 52 }; 53 54 int create_echo_reference(audio_format_t rdFormat, 55 uint32_t rdChannelCount, 56 uint32_t rdSamplingRate, 57 audio_format_t wrFormat, 58 uint32_t wrChannelCount, 59 uint32_t wrSamplingRate, 60 struct echo_reference_itfe **); 61 62 void release_echo_reference(struct echo_reference_itfe *echo_reference); 63 64 __END_DECLS 65 66 #endif // ANDROID_ECHO_REFERENCE_H 67
