diff options
| -rw-r--r-- | include/system/audio_policy.h | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/include/system/audio_policy.h b/include/system/audio_policy.h index d45758a52..70fc5340a 100644 --- a/include/system/audio_policy.h +++ b/include/system/audio_policy.h @@ -30,12 +30,23 @@ __BEGIN_DECLS * frameworks/base/include/media/AudioSystem.h */ -/* request to open a direct output with get_output() (by opposition to - * sharing an output with other AudioTracks) +/* the audio output flags serve two purposes: + * - when an AudioTrack is created they indicate a "wish" to be connected to an output stream with + * attributes corresponding to the specified flags + * - when present in an output profile descriptor listed for a particular audio hardware module, + * they indicate that an output stream can be opened that supports the attributes indicated by + * the flags. + * the audio policy manager will try to match the flags in the request (when getOuput() is called) + * to an available output stream. */ typedef enum { - AUDIO_POLICY_OUTPUT_FLAG_NONE = 0x0, - AUDIO_POLICY_OUTPUT_FLAG_DIRECT = 0x1 + AUDIO_POLICY_OUTPUT_FLAG_NONE = 0x0, // no attributes + AUDIO_POLICY_OUTPUT_FLAG_DIRECT = 0x1, // this output directly connects a track to one output + // stream (no software mixer) + AUDIO_POLICY_OUTPUT_FLAG_PRIMARY = 0x2 // this output is the primary output of the device. + // it is unique and must be present. it is opened by + // default and receives routing, audio mode and + // volume controls related to voice calls. } audio_policy_output_flags_t; /* device categories used for audio_policy->set_force_use() */ |