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_SPDIF_STREAM_OUT_H
19 #define ANDROID_SPDIF_STREAM_OUT_H
20 
21 #include <stdint.h>
22 #include <sys/types.h>
23 
24 #include <system/audio.h>
25 
26 #include "AudioStreamOut.h"
27 
28 #include <audio_utils/spdif/SPDIFEncoder.h>
29 
30 namespace android {
31 
32 /**
33  * Stream that is a PCM data burst in the HAL but looks like an encoded stream
34  * to the AudioFlinger. Wraps encoded data in an SPDIF wrapper per IEC61973-3.
35  */
36 class SpdifStreamOut : public AudioStreamOut {
37 public:
38 
39     SpdifStreamOut(AudioHwDevice *dev, audio_output_flags_t flags,
40             audio_format_t format);
41 
~SpdifStreamOut()42     virtual ~SpdifStreamOut() { }
43 
44     virtual status_t open(
45             audio_io_handle_t handle,
46             audio_devices_t devices,
47             struct audio_config *config,
48             const char *address);
49 
50     /**
51     * Write audio buffer to driver. Returns number of bytes written, or a
52     * negative status_t. If at least one frame was written successfully prior to the error,
53     * it is suggested that the driver return that successful (short) byte count
54     * and then return an error in the subsequent call.
55     *
56     * If set_callback() has previously been called to enable non-blocking mode
57     * the write() is not allowed to block. It must write only the number of
58     * bytes that currently fit in the driver/hardware buffer and then return
59     * this byte count. If this is less than the requested write size the
60     * callback function must be called when more space is available in the
61     * driver/hardware buffer.
62     */
63     virtual ssize_t write(const void* buffer, size_t bytes);
64 
65     /**
66      * @return frame size from the perspective of the application and the AudioFlinger.
67      */
getFrameSize()68     virtual size_t getFrameSize() const { return sizeof(int8_t); }
69 
70     /**
71      * @return format from the perspective of the application and the AudioFlinger.
72      */
getFormat()73     virtual audio_format_t getFormat() const { return mApplicationFormat; }
74 
75     /**
76      * The HAL may be running at a higher sample rate if, for example, playing wrapped EAC3.
77      * @return sample rate from the perspective of the application and the AudioFlinger.
78      */
getSampleRate()79     virtual uint32_t getSampleRate() const { return mApplicationSampleRate; }
80 
81     /**
82      * The HAL is in stereo mode when playing multi-channel compressed audio over HDMI.
83      * @return channel mask from the perspective of the application and the AudioFlinger.
84      */
getChannelMask()85     virtual audio_channel_mask_t getChannelMask() const { return mApplicationChannelMask; }
86 
87     virtual status_t flush();
88     virtual status_t standby();
89 
90 private:
91 
92     class MySPDIFEncoder : public SPDIFEncoder
93     {
94     public:
MySPDIFEncoder(SpdifStreamOut * spdifStreamOut,audio_format_t format)95         MySPDIFEncoder(SpdifStreamOut *spdifStreamOut, audio_format_t format)
96           :  SPDIFEncoder(format)
97           , mSpdifStreamOut(spdifStreamOut)
98         {
99         }
100 
writeOutput(const void * buffer,size_t bytes)101         virtual ssize_t writeOutput(const void* buffer, size_t bytes)
102         {
103             return mSpdifStreamOut->writeDataBurst(buffer, bytes);
104         }
105     protected:
106         SpdifStreamOut * const mSpdifStreamOut;
107     };
108 
109     MySPDIFEncoder       mSpdifEncoder;
110     audio_format_t       mApplicationFormat;
111     uint32_t             mApplicationSampleRate;
112     audio_channel_mask_t mApplicationChannelMask;
113 
114     ssize_t  writeDataBurst(const void* data, size_t bytes);
115     ssize_t  writeInternal(const void* buffer, size_t bytes);
116 
117 };
118 
119 } // namespace android
120 
121 #endif // ANDROID_SPDIF_STREAM_OUT_H
122