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      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 
     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      */
     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      */
     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      */
     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      */
     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:
     95         MySPDIFEncoder(SpdifStreamOut *spdifStreamOut, audio_format_t format)
     96           :  SPDIFEncoder(format)
     97           , mSpdifStreamOut(spdifStreamOut)
     98         {
     99         }
    100 
    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