Changes in this update:
**Enhancements**
* Added the `ExternalMediaPlayer` Capability Agent. This allows playback from music providers that control their own playback queue. Example: Spotify.
* Added support for AU and NZ to the `SampleApp`.
* Firmware version can now be sent to Alexa via the `SoftwareInfo` event. The firmware version is specified in the config file under the `sampleApp` object as an integer value named [`firmwareVersion`](https://github.com/alexa/avs-device-sdk/blob/master/Integration/AlexaClientSDKConfig.json#L52).
* The new `f` command was added to the `SampleApp` which allows the firmware version to be updated at run-time.
* Optional configuration changes have been introduced. Now a [default log level](https://github.com/alexa/avs-device-sdk/blob/master/Integration/AlexaClientSDKConfig.json#L93) can be set for `ACSDK_LOG_MODULE` components, globally or individually. This value is specified under a new root level configuration object called `logger`, and the value itself is named `logLevel`. This allows you to limit the degree of logging to that default value, such as `ERROR`or `INFO`.
**Bug Fixes**
* Fixed bug where `AudioPlayer` progress reports were not being sent, or were being sent incorrectly.
* [Issue 408](https://github.com/alexa/avs-device-sdk/issues/408) - Irrelevant code related to `UrlSource` was removed from the `GStreamer-based MediaPlayer` implementation.
* The `TZ` variable no longer needs to be set to `UTC` when building the `SampleApp`.
* Fixed a bug where `CurlEasyHandleWrapper` logged unwanted data on failure conditions.
* Fixed a bug to improve `SIGPIPE` handling.
* Fixed a bug where the filename and classname were mismatched. Changed `UrlToAttachmentConverter.h` to `UrlContentToAttachmentConverter.h`,and `UrlToAttachmentConverter.cpp` to `UrlContentToAttachmentConverter.cpp`
**Known Issues**
* The `ACL` may encounter issues if audio attachments are received but not consumed.
* Display Cards for Kindle don't render.
* If using the GStreamer-based `MediaPlayer` implementation, after muting and un-muting an audio item, the next item in the queue will begin playing rather than continuing playback of the originally muted audio item.
* `SpeechSynthesizerState` currently uses `GAINING_FOCUS` and `LOSING_FOCUS` as a workaround for handling intermediate state. These states may be removed in a future release.
* Music playback doesn't immediately stop when a user barges-in on iHeartRadio.
**Enhancements**
* ContextManager now passes the namespace/name of the desired state to StateProv
iderInterface::provideState(). This is helpful when a single StateProvider obje
ct provides multiple states, and needs to know which one ContextManager is askin
g for.
* The mime parser was hardened against duplicate boundaries.
* Added functionality to add and remove AudioPlayer observers to the DefaultClie
nt.
* Unit tests for Alerts were added.
* Added en-IN, en-CA and ja-JP to the SampleApp locale selection menu.
* Added default alert and timer audio data to the SDK SampleApp. There is no lo
nger a requirement to download these audio files and configure them in the json
configuration file.
* Added support in SDS Reader and AttachmentReader for seeking into the future.
This allows a reader to move to an index which has not yet arrived in the SDS a
nd poll/block until it arrives.
* Added support for blocking Writers in the SharedDataStream class.
* Changed the default status code sent by MessageRequestObserverInterface::onSen
dCompleted() to SERVER_OTHER_ERROR, and mapped HTTP code 500 to SERVER_INTERNAL_
ERROR_V2.
* Added support for parsing stream duration out of playlists.
* Added a configuration option ("sampleApp":"displayCardsSupported") that allows
the displaying of display cards to be enabled or disabled.
* Named Timers and Reminders have been updated to fall back to the on-device bac
kground audio sound when cloud urls cannot be accessed or rendered.
**Bug Fixes**
* Removed floating point dependencies from core SDK libraries.
* Fixed bug in SpeechSynthesizer where it's erroneously calling stop more than once.
* Fixed an issue in ContentFetcher where it could hang during destruction until an active GET request completed.
* Fixed a couple of parsing bugs in LibCurlHttpContentFetcher related to case-sensitivity and mime-type handling.
* Fixed a bug where MediaPlayerObserverInterface::onPlaybackResumed() wasn't being called after resuming from a pause with a pending play/resume.
* Fixed a bug in LibCurlContentFetcher where it could error out if data is written to the SDS faster than it is consumed.
* The GStreamer-based MediaPlayer reference implementation now uses the ACL HTTP configured client.
* An API change has been made to MediaPlayerInterface::setSource(). This method now takes in an optional offset as well to allow for immediately streaming to the offset if possible.
* Next and Previous buttons now work with Audible.
* Pandora resume stuttering is addressed.
* Pausing and resuming Amazon music no longer seeks back to the beginning of the song.
* libcurl CURLOPT_NOSIGNAL option is set to 1 (https://curl.haxx.se/libcurl/c/CURLOPT_NOSIGNAL.html) to avoid crashes observed in SampleApp.
* Fixed the timing of the PlaybackReportIntervalEvent and PlaybackReportDelayEvent as specified in the directives.
* Fixed potential deadlocks in MediaPlayer during shutdown related to queued callbacks.
* Fixed a crash in MediaPlayer that could occur if the network is disconnected during playback.
* Fixed a bug where music could keep playing while Alexa is speaking.
* Fixed a bug which was causing problems with pause/resume and next/previous with Amazon Music.
* Fixed a bug where music could briefly start playing between speaks.
* Fixed a bug where HLS playlists would stop streaming after the initial playlist had been played to completion.
* Fixed a bug where Audible playback could not advance to the next chapter.
* Fixed some occurrences of SDK entering the IDLE state during the transition between Listening and Speaking states.
* Fixed a bug where PlaybackFinished events were not reporting the correct offset.
* An API change has been made to MediaPlayerInterface::getOffset(). This method is now required to return the final offset when called after playback has stopped.
* Fixed a problem where AIP was erroneously resetting its state upon getting a cancelDirective() callback.
**Known Issues**
* Capability agent for Notifications is not included in this release.
* `ACL`'s asynchronous receipt of audio attachments may manage resources poorly in scenarios where attachments are received but not consumed.
* GUI cards don't show for Kindle.
* The new SpeechSynthesizerState state values GAINING_FOCUS and LOSING_FOCUS were added as part of a work-around. The will likely be removed in subsequent releases.
* With the gstreamer-based MediaPlayer, after muting and unmuting, the next item starts playing rather than continuing with the current item.