Add defines and support for audio offload
- Add non-blocking write support, set_callback() function
- Add pause, resume, flush, drain functions to audio output stream
- Add audio parameter defines for compressed audio metadata
- Extend audio_config_t to include an audio_offload_info_t field
- Add is_offload_supported() function to test whether there is
hardware decode support for a given compressed audio format
- Change audio_stream_frame_size() to handle offloaded streams.
For an offloaded stream the size is always counted in bytes
(frame size == 1) and the number of channels is irrelevant.
Change-Id: I5b82c3fdcfa1456502d0042888f166bf02d8d54b
Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Eric Laurent <elaurent@google.com>
diff --git a/include/hardware/audio.h b/include/hardware/audio.h
index 3a0962e..b0c0c0e 100644
--- a/include/hardware/audio.h
+++ b/include/hardware/audio.h
@@ -67,6 +67,7 @@
#define AUDIO_HARDWARE_MODULE_ID_A2DP "a2dp"
#define AUDIO_HARDWARE_MODULE_ID_USB "usb"
#define AUDIO_HARDWARE_MODULE_ID_REMOTE_SUBMIX "r_submix"
+#define AUDIO_HARDWARE_MODULE_ID_CODEC_OFFLOAD "codec_offload"
/**************************************/
@@ -117,16 +118,35 @@
* "sup_sampling_rates=44100|48000" */
#define AUDIO_PARAMETER_STREAM_SUP_SAMPLING_RATES "sup_sampling_rates"
+/**
+ * audio codec parameters
+ */
+
+#define AUDIO_OFFLOAD_CODEC_PARAMS "music_offload_codec_param"
+#define AUDIO_OFFLOAD_CODEC_BIT_PER_SAMPLE "music_offload_bit_per_sample"
+#define AUDIO_OFFLOAD_CODEC_BIT_RATE "music_offload_bit_rate"
+#define AUDIO_OFFLOAD_CODEC_AVG_BIT_RATE "music_offload_avg_bit_rate"
+#define AUDIO_OFFLOAD_CODEC_ID "music_offload_codec_id"
+#define AUDIO_OFFLOAD_CODEC_BLOCK_ALIGN "music_offload_block_align"
+#define AUDIO_OFFLOAD_CODEC_SAMPLE_RATE "music_offload_sample_rate"
+#define AUDIO_OFFLOAD_CODEC_ENCODE_OPTION "music_offload_encode_option"
+#define AUDIO_OFFLOAD_CODEC_NUM_CHANNEL "music_offload_num_channels"
+#define AUDIO_OFFLOAD_CODEC_DOWN_SAMPLING "music_offload_down_sampling"
+#define AUDIO_OFFLOAD_CODEC_DELAY_SAMPLES "delay_samples"
+#define AUDIO_OFFLOAD_CODEC_PADDING_SAMPLES "padding_samples"
/**************************************/
-/* common audio stream configuration parameters */
+/* common audio stream configuration parameters
+ * You should memset() the entire structure to zero before use to
+ * ensure forward compatibility
+ */
struct audio_config {
uint32_t sample_rate;
audio_channel_mask_t channel_mask;
audio_format_t format;
+ audio_offload_info_t offload_info;
};
-
typedef struct audio_config audio_config_t;
/* common audio stream parameters and operations */
@@ -213,6 +233,22 @@
};
typedef struct audio_stream audio_stream_t;
+/* type of asynchronous write callback events. Mutually exclusive */
+typedef enum {
+ STREAM_CBK_EVENT_WRITE_READY, /* non blocking write completed */
+ STREAM_CBK_EVENT_DRAIN_READY /* drain completed */
+} stream_callback_event_t;
+
+typedef int (*stream_callback_t)(stream_callback_event_t event, void *param, void *cookie);
+
+/* type of drain requested to audio_stream_out->drain(). Mutually exclusive */
+typedef enum {
+ AUDIO_DRAIN_ALL, /* drain() returns when all data has been played */
+ AUDIO_DRAIN_EARLY_NOTIFY /* drain() returns a short time before all data
+ from the current track has been played to
+ give time for gapless track switch */
+} audio_drain_type_t;
+
/**
* audio_stream_out is the abstraction interface for the audio output hardware.
*
@@ -242,6 +278,13 @@
* negative status_t. If at least one frame was written successfully prior to the error,
* it is suggested that the driver return that successful (short) byte count
* and then return an error in the subsequent call.
+ *
+ * If set_callback() has previously been called to enable non-blocking mode
+ * the write() is not allowed to block. It must write only the number of
+ * bytes that currently fit in the driver/hardware buffer and then return
+ * this byte count. If this is less than the requested write size the
+ * callback function must be called when more space is available in the
+ * driver/hardware buffer.
*/
ssize_t (*write)(struct audio_stream_out *stream, const void* buffer,
size_t bytes);
@@ -259,6 +302,60 @@
int (*get_next_write_timestamp)(const struct audio_stream_out *stream,
int64_t *timestamp);
+ /**
+ * set the callback function for notifying completion of non-blocking
+ * write and drain.
+ * Calling this function implies that all future write() and drain()
+ * must be non-blocking and use the callback to signal completion.
+ */
+ int (*set_callback)(struct audio_stream_out *stream,
+ stream_callback_t callback, void *cookie);
+
+ /**
+ * Notifies to the audio driver to stop playback however the queued buffers are
+ * retained by the hardware. Useful for implementing pause/resume. Empty implementation
+ * if not supported however should be implemented for hardware with non-trivial
+ * latency. In the pause state audio hardware could still be using power. User may
+ * consider calling suspend after a timeout.
+ *
+ * Implementation of this function is mandatory for offloaded playback.
+ */
+ int (*pause)(struct audio_stream_out* stream);
+
+ /**
+ * Notifies to the audio driver to resume playback following a pause.
+ * Returns error if called without matching pause.
+ *
+ * Implementation of this function is mandatory for offloaded playback.
+ */
+ int (*resume)(struct audio_stream_out* stream);
+
+ /**
+ * Requests notification when data buffered by the driver/hardware has
+ * been played. If set_callback() has previously been called to enable
+ * non-blocking mode, the drain() must not block, instead it should return
+ * quickly and completion of the drain is notified through the callback.
+ * If set_callback() has not been called, the drain() must block until
+ * completion.
+ * If type==AUDIO_DRAIN_ALL, the drain completes when all previously written
+ * data has been played.
+ * If type==AUDIO_DRAIN_EARLY_NOTIFY, the drain completes shortly before all
+ * data for the current track has played to allow time for the framework
+ * to perform a gapless track switch.
+ *
+ * Drain must return immediately on stop() and flush() call
+ *
+ * Implementation of this function is mandatory for offloaded playback.
+ */
+ int (*drain)(struct audio_stream_out* stream, audio_drain_type_t type );
+
+ /**
+ * Notifies to the audio driver to flush the queued data. Stream must already
+ * be paused before calling flush().
+ *
+ * Implementation of this function is mandatory for offloaded playback.
+ */
+ int (*flush)(struct audio_stream_out* stream);
};
typedef struct audio_stream_out audio_stream_out_t;
@@ -296,18 +393,14 @@
static inline size_t audio_stream_frame_size(const struct audio_stream *s)
{
size_t chan_samp_sz;
+ audio_format_t format = s->get_format(s);
- switch (s->get_format(s)) {
- case AUDIO_FORMAT_PCM_16_BIT:
- chan_samp_sz = sizeof(int16_t);
- break;
- case AUDIO_FORMAT_PCM_8_BIT:
- default:
- chan_samp_sz = sizeof(int8_t);
- break;
+ if (audio_is_linear_pcm(format)) {
+ chan_samp_sz = audio_bytes_per_sample(format);
+ return popcount(s->get_channels(s)) * chan_samp_sz;
}
- return popcount(s->get_channels(s)) * chan_samp_sz;
+ return sizeof(int8_t);
}