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Commit e6b9c777 authored by Andy Hung's avatar Andy Hung
Browse files

AudioMetadata: Add documentation 

Update comments only for IStreamOutEventCallback::onCodecFormatChanged

Test: compiles, this is a comment change only.
Bug: 150175043
Change-Id: I1895c737997fbf3cb509b4078b545658d11df198
parent 2023afbe

audio/6.0/IStreamOutEventCallback.hal

+108 −3
Original line number Diff line number Diff line
@@ -25,11 +25,116 @@ interface IStreamOutEventCallback { 
    /**

     * Codec format changed.

     *

     * onCodecFormatChanged returns an AudioMetadata object in read-only ByteString format.

     * It represents the most recent codec format decoded by a HW audio decoder.

     *

     * Codec format is an optional message from HW audio decoders. It serves to

     * notify the application about the codec format and audio objects contained

     * within the compressed audio stream for control, informational,

     * and display purposes.

     *

     * audioMetadata ByteString is convertible to an AudioMetadata object through

     * both a C++ and a C API present in Metadata.h [1], or through a Java API present

     * in AudioMetadata.java [2].

     *

     * The ByteString format is a stable format used for parcelling (marshalling) across

     * JNI, AIDL, and HIDL interfaces.  The test for R compatibility for native marshalling

     * is TEST(metadata_tests, compatibility_R) [3].  The test for R compatibility for JNI

     * marshalling is android.media.cts.AudioMetadataTest#testCompatibilityR [4].

     *

     * R (audio HAL 6.0) defined keys are as follows [2]:

     * "bitrate", int32

     * "channel-mask", int32

     * "mime", string

     * "sample-rate", int32

     * "bit-width", int32

     * "has-atmos", int32

     * "audio-encoding", int32

     *

     * Parceling Format:

     * All values are native endian order. [1]

     *

     * using type_size_t = uint32_t;

     * using index_size_t = uint32_t;

     * using datum_size_t = uint32_t;

     *

     * Permitted type indexes are

     * TYPE_NONE = 0, // Reserved

     * TYPE_INT32 = 1,

     * TYPE_INT64 = 2,

     * TYPE_FLOAT = 3,

     * TYPE_DOUBLE = 4,

     * TYPE_STRING = 5,

     * TYPE_DATA = 6,  // A data table of <String, Datum>

     *

     * Datum = {

     *           (type_size_t)  Type (the type index from type_as_value<T>.)

     *           (datum_size_t) Size (size of the Payload)

     *           (byte string)  Payload<Type>

     *         }

     *

     * The data is specified in native endian order.

     * Since the size of the Payload is always present, unknown types may be skipped.

     *

     * Payload<Fixed-size Primitive_Value>

     * [ sizeof(Primitive_Value) in raw bytes ]

     *

     * Example of Payload<Int32> of 123:

     * Payload<Int32>

     * [ value of 123                   ] =  0x7b 0x00 0x00 0x00       123

     *

     * Payload<String>

     * [ (index_size_t) length, not including zero terminator.]

     * [ (length) raw bytes ]

     *

     * Example of Payload<String> of std::string("hi"):

     * [ (index_size_t) length          ] = 0x02 0x00 0x00 0x00        2 strlen("hi")

     * [ raw bytes "hi"                 ] = 0x68 0x69                  "hi"

     *

     * Payload<Data>

     * [ (index_size_t) entries ]

     * [ raw bytes   (entry 1) Key   (Payload<String>)

     *                         Value (Datum)

     *                ...  (until #entries) ]

     *

     * Example of Payload<Data> of {{"hello", "world"},

     *                              {"value", (int32_t)1000}};

     * [ (index_size_t) #entries        ] = 0x02 0x00 0x00 0x00        2 entries

     *    Key (Payload<String>)

     *    [ index_size_t length         ] = 0x05 0x00 0x00 0x00        5 strlen("hello")

     *    [ raw bytes "hello"           ] = 0x68 0x65 0x6c 0x6c 0x6f   "hello"

     *    Value (Datum)

     *    [ (type_size_t) type          ] = 0x05 0x00 0x00 0x00        5 (TYPE_STRING)

     *    [ (datum_size_t) size         ] = 0x09 0x00 0x00 0x00        sizeof(index_size_t) +

     *                                                                 strlen("world")

     *       Payload<String>

     *       [ (index_size_t) length    ] = 0x05 0x00 0x00 0x00        5 strlen("world")

     *       [ raw bytes "world"        ] = 0x77 0x6f 0x72 0x6c 0x64   "world"

     *    Key (Payload<String>)

     *    [ index_size_t length         ] = 0x05 0x00 0x00 0x00        5 strlen("value")

     *    [ raw bytes "value"           ] = 0x76 0x61 0x6c 0x75 0x65   "value"

     *    Value (Datum)

     *    [ (type_size_t) type          ] = 0x01 0x00 0x00 0x00        1 (TYPE_INT32)

     *    [ (datum_size_t) size         ] = 0x04 0x00 0x00 0x00        4 sizeof(int32_t)

     *        Payload<Int32>

     *        [ raw bytes 1000          ] = 0xe8 0x03 0x00 0x00        1000

     *

     * The contents of audioMetadata is a Payload<Data>.

     * An implementation dependent detail is that the Keys are always

     * stored sorted, so the byte string representation generated is unique.

     *

     * Vendor keys are allowed for informational and debugging purposes.

     * Vendor keys should consist of the vendor company name followed

     * by a dot; for example, "vendorCompany.someVolume" [2].

     *

     * [1] system/media/audio_utils/include/audio_utils/Metadata.h

     * [2] frameworks/base/media/java/android/media/AudioMetadata.java

     * [3] system/media/audio_utils/tests/metadata_tests.cpp

     * [4] cts/tests/tests/media/src/android/media/cts/AudioMetadataTest.java

     *

     * @param audioMetadata is a buffer containing decoded format changes

     *     reported by codec. The buffer contains data that can be transformed

     *     to audio metadata, which is a C++ object based map. See

     *     `system/media/audio_utils/include/audio_utils/Metadata.h` for

     *     more details.

     *     to audio metadata, which is a C++ object based map.

     */

    oneway onCodecFormatChanged(vec<uint8_t> audioMetadata);

};

current.txt

+1 −0
Original line number Diff line number Diff line
@@ -619,6 +619,7 @@ fd1f1b29f26b42e886220f04a08086c00e5ade9d7b53f095438e578ab9d42a93 android.hardwar 
164826a380f4c1700183003f62d7532e367b67381c30ea44f946c0cf00008f85 android.hardware.audio@6.0::IStreamOut

997fdaad7a9d17ee7e01feb7031a753e2365e72ad30b11d950e9183fabdf3844 android.hardware.audio@6.0::IStreamOutCallback

e7ca0db9a1098210f327a9b152fa6afe6bf019c41e5264c64829d04d50c0a526 android.hardware.audio@6.0::IStreamOutEventCallback

aa2211abd803e03d05ea11c18749db068f785fe026f8d99bce64bd764f63d194 android.hardware.audio@6.0::IStreamOutEventCallback  # b/150175043

822369cf4dc16a6f6b9622bcf86cbdc0b692dc82193fc15e967767175cbfdd8f android.hardware.audio@6.0::types

bee662c62d997d8065e2bcb5c1e7a9578931f22ce28fd02c219fdb4d0630abf7 android.hardware.audio.common@6.0::types

525bec6b44f1103869c269a128d51b8dccd73af5340ba863c8886c68357c7faf android.hardware.audio.effect@6.0::IAcousticEchoCancelerEffect