1 /* 2 ** 3 ** Copyright 2015, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #ifndef ANDROID_AUDIO_STREAM_OUT_H 19 #define ANDROID_AUDIO_STREAM_OUT_H 20 21 #include <stdint.h> 22 #include <sys/types.h> 23 24 #include <system/audio.h> 25 26 namespace android { 27 28 class AudioHwDevice; 29 class DeviceHalInterface; 30 class StreamOutHalInterface; 31 32 /** 33 * Managed access to a HAL output stream. 34 */ 35 class AudioStreamOut { 36 public: 37 // AudioStreamOut is immutable, so its fields are const. 38 // For emphasis, we could also make all pointers to them be "const *", 39 // but that would clutter the code unnecessarily. 40 AudioHwDevice * const audioHwDev; 41 sp<StreamOutHalInterface> stream; 42 const audio_output_flags_t flags; 43 44 sp<DeviceHalInterface> hwDev() const; 45 46 AudioStreamOut(AudioHwDevice *dev, audio_output_flags_t flags); 47 48 virtual status_t open( 49 audio_io_handle_t handle, 50 audio_devices_t devices, 51 struct audio_config *config, 52 const char *address); 53 54 virtual ~AudioStreamOut(); 55 56 // Get the bottom 32-bits of the 64-bit render position. 57 status_t getRenderPosition(uint32_t *frames); 58 59 virtual status_t getRenderPosition(uint64_t *frames); 60 61 virtual status_t getPresentationPosition(uint64_t *frames, struct timespec *timestamp); 62 63 /** 64 * Write audio buffer to driver. Returns number of bytes written, or a 65 * negative status_t. If at least one frame was written successfully prior to the error, 66 * it is suggested that the driver return that successful (short) byte count 67 * and then return an error in the subsequent call. 68 * 69 * If set_callback() has previously been called to enable non-blocking mode 70 * the write() is not allowed to block. It must write only the number of 71 * bytes that currently fit in the driver/hardware buffer and then return 72 * this byte count. If this is less than the requested write size the 73 * callback function must be called when more space is available in the 74 * driver/hardware buffer. 75 */ 76 virtual ssize_t write(const void *buffer, size_t bytes); 77 78 /** 79 * @return frame size from the perspective of the application and the AudioFlinger. 80 */ 81 virtual size_t getFrameSize() const { return mHalFrameSize; } 82 83 /** 84 * @return format from the perspective of the application and the AudioFlinger. 85 */ 86 virtual audio_format_t getFormat() const; 87 88 /** 89 * The HAL may be running at a higher sample rate if, for example, playing wrapped EAC3. 90 * @return sample rate from the perspective of the application and the AudioFlinger. 91 */ 92 virtual uint32_t getSampleRate() const; 93 94 /** 95 * The HAL is in stereo mode when playing multi-channel compressed audio over HDMI. 96 * @return channel mask from the perspective of the application and the AudioFlinger. 97 */ 98 virtual audio_channel_mask_t getChannelMask() const; 99 100 101 virtual status_t flush(); 102 virtual status_t standby(); 103 104 protected: 105 uint64_t mFramesWritten; // reset by flush 106 uint64_t mFramesWrittenAtStandby; 107 uint64_t mRenderPosition; // reset by flush or standby 108 int mRateMultiplier; 109 bool mHalFormatHasProportionalFrames; 110 size_t mHalFrameSize; 111 }; 112 113 } // namespace android 114 115 #endif // ANDROID_AUDIO_STREAM_OUT_H 116
