This document records all changes made to the Starboard interface, up to the current version, but not including the experimental version. This file will be updated each time a new Starboard version is released. Each section in this file describes the changes made to the Starboard interface since the version previous to it.
NOTE: Starboard versions 9 and below are no longer supported.
A description of all changes currently in the experimental Starboard version can be found in the comments of the “Experimental Feature Defines” section of configuration.h.
The system can be disabled by implementing the function
SbUiNavGetInterface() to return
false. Platform-based UI navigation allows the platform to receive feedback on where UI elements are located and also lets the platform control what is selected and what the scroll parameters are.
NOTE: This API is not used in the production web app yet, so please use the stub implementation for
SbUiNavGetInterface() for now.
The system must implement
starboard/gles.h or use the provided stub implementation.
This change also effectively deprecates the gyp variable “enable_map_to_mesh” in favor of CobaltGraphicsExtensionApi function
IsMapToMeshEnabled() and the command line switch --disable_map_to_mesh. Now, Cobalt will assume the platform supports map_to_mesh, so platforms that do not will have to have return |false| from
IsMapToMeshEnabled() or use the provided command line switch.
The system must implement the captions functions in
starboard/accessibility.h or use the provided stub implementations. System caption can be disabled by implementing the function
SbAccessibilityGetCaptionSettings(SbAccessibilityCaptionSettings* caption_settings) to return false as the stub implementation does. This change also deprecates the SB_HAS_CAPTIONS flag.
Cobalt must be able to determine at runtime if the system supports IPv6. IPv6 can be disabled by defining SB_HAS_IPV6 to 0.
The system must implement the microphone functions in
starboard/microphone.h or use the provided stub functions. The microphone can be disabled by having
SbMicrophoneCreate() return |kSbMicrophoneInvalid|. This change also deprecates the SB_HAS_MICROPHONE flag.
The system must implement the memory mapping functions in
starboard/shared/dlmalloc.h or use the provided stub implementations. This change also deprecates the SB_HAS_MMAP flag.
The system must implement the on screen keyboard functions in
starboard/window.h or use the provided stub implementations. The on screen keyboard can be disabled by implementing the function
SbWindowOnScreenKeyboardIsSupported() to return false as the stub implementation does.
The system must implement the functions in
starboard/speech_recognizer.h or use the provided stub implementations. The speech recognizer can be disabled by implementing the function
SbSpeechRecognizerIsSupported() to return
false as the stub implementation does.
The system must implement the speech synthesis function in
starboard/speech_synthesis.h or use the provided stub implementations. Speech synthesis can be disabled by implementing the function
SbSpeechSynthesisIsSupported() to return false as the stub implementation does.
The system must implement the time thread now functions in
starboard/time.h or use the provided stub implementations. Time thread now can be disabled by implementing the function
SbTimeIsTimeThreadNowSupported() to return false as the stub implementation does.
Introduce the Starboard function SbFileAtomicReplace() to provide the ability to atomically replace the content of a file.
Path to directory for permanent storage. Both read and write access are required.
SABI files are used to describe the configuration for targets such that two targets, built with the same SABI file and varying toolchains, have compatible Starboard APIs and ABIs.
With this define, we have:
For further information on what is provided by SABI files, or how these values are consumed, take a look at //starboard/sabi.
SbMutexAcquireTry now has undefined behavior when it is invoked on a mutex that has already been locked by the calling thread. In addition, since SbMutexAcquireTry was used in SbMutexDestroy, SbMutexDestroy now has undefined behavior when invoked on a locked mutex.
The migration allows Cobalt to make platform level decisions at runtime instead of compile time which lets us create a more comprehensive Cobalt binary.
This means Cobalt must remove all references to these macros that would not translate well to constants, i.e. in compile time references or initializing arrays. Therefore, we needed to change the functionality of the function
SbDirectoryGetNext in “starboard/directory.h”. Because we do not want to use variable length arrays, we pass in a c-string and length to the function to achieve the same result as before when passing in a
A platform will define the extern constants declared in “starboard/configuration_constants.h”. The definitions are done in “starboard/<PLATFORM_PATH>/configuration_constants.cc”.
The exact mapping between macros and extern variables can be found in “starboard/shared/starboard/configuration_constants_compatibility_defines.h” though the naming scheme is very nearly the same: the old SB_FOO macro will always become the constant kSbFoo.
Introduce the new type SbPlayerCreationParam that holds the common parameters used to create an SbPlayer() and to query for the output mode support.
Replace SbPlayerOutputModeSupported() by SbPlayerGetPreferredOutputMode() so the SbPlayer implementation can explicitly indicate its preference on output mode, when all output modes are supported. For example, Cobalt used to always query for |kSbPlayerOutputModePunchOut| first, without providing details about the video going to be played, and not query for output modes if punch out is supported. The new interface allows the implementation to fine tune its output mode. For example, it may decide to use |kSbPlayerOutputModeDecodeToTexture| for low resolution videos.
The implementation is in: “starboard/shared/starboard/audio_sink/audio_sink_internal.*”.
The following types were updated: SbThread, SbMutex, SbOnce and SbConditionVariable.
The definition follows ISO/IEC 23001 part 7.
This change moves all of the GYP configuration variables to be members of the struct declared in “cobalt/extension/configuration.h”. All members are function pointers that can be set for each platform, otherwise defaults will be used. These can be referenced through functions declared in “cobalt/configuration/configuration.h”, which will use the extension API if available, but will otherwise fall back onto default values.
The PCLMULQDQ was added to the Starboard CPU features interface for x86 architectures.
This change also deprecates
kSbSystemPropertySystemIntegratorName value will represent the corporate entity responsible for submitting the device to YouTube certification and for the device maintenance/updates.
Blitter API is no longer supported on any platform. Use the OpenGL ES interface instead.
Crypto API is no longer supported on any platform. BoringSSL CPU optimizations are used instead.
The variable ‘cobalt_minimum_frame_time_in_milliseconds’ is deprecated in favor of the usage of ‘CobaltExtensionGraphicsApi::GetMinimumFrameIntervalInMilliseconds’ API. The declaration of ‘GetMinimumFrameIntervalInMilliseconds’ can be found in cobalt/renderer/backend/graphics_context.h
The Platform Services API should be used instead. See cobalt/doc/platform_services.md.
If the platform supports text-to-speech settings, it must use the new kSbEventTypeAccessiblityTextToSpeechSettingsChanged event to inform the app when those settings change. For older starboard versions, use kSbEventTypeAccessiblitySettingsChanged instead.
Now the Starboard implementation may choose to support |key_system| with extra attributes, in order to selectively support encryption schemes on particular containers or codecs. The Starboard implementation needn't support |key_system| with extra attributes if it meets the requirements for the default implementation of
Navigator.requestMediaKeySystemAccess(), which assumes that:
Please see the comment of
media.h for more details.
Add arguments for profile, level, bit depth, color primaries, transfer characteristics, and matrix coefficients. See comments of
SbMediaIsVideoSupported for more details. Also, the function
SbMediaIsTransferCharacteristicsSupported() is no longer necessary and is removed.
This gives the application the option to specify to the
SbPlayer object what the maximum video specifications will be, as a hint to the platform on how to allocate resources for the
SbPlayer. For example, if the player will never exceed a 240p playback resolution, then a software decoder may be initialized. Please see comment in
SbPlayerCreate() for more details.
Additionally, add audio and codec info for every sample.
Add a function
starboard/media.h which communicates to the platform how much audio will be sent to the platform at a time.
Cobalt extensions implement app & platform specific functionality.
SB_HAS_STD_UNORDERED_HASH to 1, a platform can be configured to use C++11 standard hash table implementations, specifically, using:
SB_HAS_STD_UNORDERED_HASH is used, it is no longer necessary to specify
When a platform knows its physical screen diagonal length, it can now provide that data to the application via
The system properties
kSbSystemPropertyBase64EncodedCertificationSecret have been added to enable client apps to perform device authentication. The values will be queried by calls to
starboard/system.h. An alternative to providing the
kSbSystemPropertyBase64EncodedCertificationSecret property is to implement the SbSystemSignWithCertificationSecretKey() function, enabling the key to remain private and secure.
This is helpful for enabling the implementation of sampling-based profilers. A full implementation is only required if the new function
true. A valid implementation will need to implement the new
A new API in
starboard/window.h is introduced which declares the functions
SbWindowOnScreenKeyboardSuggestionsSupported(). This is only relevant if
The new code, added to
starboard/file.h, should match “EIO” on Posix platforms.
SbDecodeTargetInfoContentRegion struct is modified to accept
floats instead of
ints. The primary motivation for this change is to make it so that on platforms where it is difficult to obtain the width and height of a texture, we can still correctly identify a precise fractional “normalized” content region with the texture width and height set to 1.
This change also deprecates
kSbSystemPropertyOriginalDesignManufacturerName value will represent the corporate entity responsible for the manufacturing/assembly of the device on behalf of the business entity owning the brand.
Cross-platform helper Starboard definitions refactored out of
/starboard/ and into
/starboard/common/. In order to more explicitly identify the core Starboard API, multiple files, or parts of them, were moved into the static library
The application is no longer responsible for synchronizing (e.g. via mutex) calls to Starboard logging, this is now expected to be done by the Starboard implementation. Logging functions, such as
SbLogRaw, must now have implementations that are thread-safe because they will be called from multiple threads without external synchronization.
Additionally, the minimum logging level is no longer set by the application, and is instead set by grabbing the value as a command-line argument within Starboard.
To remove the direct inclusion of EGL and GLES system libraries throughout the application, we need to move this dependency behind a Starboardized API. This API can be found in
The new interface enables the platform to communicate to the application which CPU features are available, which can enable the application to perform certain CPU-specific optimizations (e.g. SIMD).
These macros must always be set to 1 for Starboard version 6 or later. They will be removed in a future version. Any implementation that supports Starboard version 6 or later should be modified to no longer depend on these macros, with the assumption that their values are always 1.
In particular, the following methods are introduced:
Require compiling ‘player_filter_tests’ test target sources on all platforms, including
video_decoder_test.cc. For this Starboard API version and beyond,
SB_HAS(PLAYER_FILTER_TESTS) is true.
SbMediaTime, which is 90khz based, was used to represent timestamps and duration related to SbPlayer. As most of the platforms represent video related times in milliseconds or microseconds, this causes a lot of otherwise unnecessary conversion. Now all timestamps and duration related to SbPlayer are represented by SbTime directly.
Added two new functions
SbPlayerWriteSample2(). The former allows implementation to specify the maximum numbers of samples that can be written using the latter at once. As it takes multiple thread context switches to call
SbPlayerWriteSample2() once, it can optimize performance on low end platforms by reducing the frequence of calling
SbPlayerCreate() now accepts an additional parameter,
player_error_func, that can be called when an error occurs to propagate the error to the application.
SbAccessibilitySetCaptionsEnabled() along with a number of supporting structure definitions have been added to
accessibility.h. Platforms will need to define SB_HAS_CAPTIONS to 1 in order to enable the interface.
SbPlayer can be created with only a video track, without any accompanying audio track. The SbPlayer implementation must now be able to play back a sole video track.
SbPlayer can be created with only an audio track, without any accompanying video track. The SbPlayer implementation must now be able to play back a sole audio track.
Formerly, there were no tests ensuring that calling
SbPlayerCreate() multiple times (without calling
SbPlayerDestroy() in between) would not crash, and likewise no tests ensuring that calling
SbAudioSinkCreate() multiple times (without calling
SbAudioSinkDestroy() in between) would not crash.
SbPlayerCreate() may return
kSbPlayerInvalid if additional players are not supported.
SbAudioSinkCreate() may return
kSbAudionSinkInvalid if additional audio sinks are not supported.
SbDrmCreateSystem() must result in invalid return values (e.g.
Specifically, the following changes have been made:
SbDrmSessionUpdatedFuncwith extra status and optional error message.
SbDrmSessionUpdateRequestFuncto support individualization, license renewal, and license release.
Test code looking for its static input files should instead use the
test subdirectory in
This property was only ever used in platforms using
in_app_dial. The only usage of this system property was replaced with a self-contained mechanism.
SB_HAS_QUIRK_SUPPORT_INT16_AUDIO_SAMPLES has to be defined to continue support int16 audio samples after this version.
This allows the SbPlayer implementation to notify the app that its playback capability has changed during a video playback. For example, the system may support vp9 decoding with an external GPU. When the external GPU is detached, this error code can signal the app to retry the playback, possibly with h264.
Platforms doesn't need to resume after suspend can return false in
SbSystemSupportsResume() to free up the resource used by resume after suspend. Please see the comment in
system.h for more details.
kSbDecodeTargetFormat3Plane10BitYUVI420 to the
SbDecodeTargetFormat enum in order to support 10-bit YUV textures.
SbAudioSinkConsumeFramesFunc() can now optionally accept an absolute timestamp parameter that indicates when the frames are consumed. Platforms that have the
frames_consumed updated asynchronously can have more accurate audio time reporting with this extra parameter. Please see the comment in
audio_sink.h for more details.
SbMemoryProtect() allows memory access permissions to be changed after they have been mapped with
This allows platforms to provide more precise information on exactly when an input event was generated. Note that if
SbSystemHasCapability(kSbSystemCapabilitySetsInputTimestamp) returns false, the
timestamp field of
SbInputData should be ignored by applications.
kSbMemoryMapProtectReserved, which is identical to
SbMemoryMapFlags(0), is introduced. When
SbMemoryMap() is called with
kSbMemoryMapProtectReserved, only virtual address space should be reserved for the mapped memory, and not actual physical memory.
An extra version agnostic ffmpeg dynamic dispatch layer is added in order to support multiple different versions of ffmpeg as may appear on user systems.
While common Cobalt code still targets EGL/GLES2, we now use Angle on linux-x64x11 builds to translate those calls to GLX/GL calls. Thus, from the perspective of the system, linux-x64x11 builds now appear to use GLX/GL. This change was made because GLX/GL was generally found to have better desktop support than EGL/GLES2. The logic for this is added in the Starboard enable_glx_via_angle.gypi file.
Up until now, both Cobalt-specific build configuration options as well as application-independent Starboard build configuration options were mixed together within base.gypi. They have now been split apart, and the application independent options have been moved into Starboard under base_configuration.gypi. The Cobalt-specific options have been left in Cobalt, though renamed to
Please see contrib/README.md for description of expectations for contents in this directory.