Apple Inc.

Douglas S Wyatt

William George Stewart

James E McCartney

Anthony Joseph Guetta

Jeffrey Chandler Moore

Camille Moussette

Roger N Pantos

Gregory R Chapman

Deepak R Iyer

Eric Joseph Johnson

Andrew E Rostaing

Eric A Allamanche

Zhenheng Li

A system determines to use at least two independent renderers to render at least two output streams that are to be synchronized. The independent renderers are provided with a shared synchronization object when instructed to render the respective output stream. A time when all of the independent renderers can render a respective first buffer of the respective output stream is determined from the shared synchronization object. Rendering of the output streams utilizing the independent renderers is begun at the determined time. In this way, rendering of the output streams may be synchronized.

Synchronization of independent output streams

An operating system of a device receives, from an application executing on that device, data that identifies a category of hardware resources that the application needs to use in order to function. That category is mapped to a specified set of hardware resources of the device. The operating system also receives, from the application, data that identifies a mode. The mode corresponds to an intended use of a set of hardware resources and is mapped to a group of hardware resource settings that are consistent with the intended use. The operating system allocates, to the application, a particular set of hardware resources that are mapped to the category. The operating system configures one or more hardware resources in the particular set of hardware resources in conformity with a particular group of settings that are mapped to the mode.

Audio configuration based on selectable audio modes

Techniques are provided for determining, at an audio processing device, whether to produce high quality or low quality audio output based on one or more factors. The one or more factors may include the type of output device (e.g., headphones, built-in speakers, or USB audio devices) that is connected to the audio processing device and whether certain operations (e.g., mixing and/or scaling) are to be performed on the decoded audio content. Thus, the highest quality audio output is produced based on current conditions of the audio system, which includes the output device. If the current conditions of the audio system indicate that producing high quality audio output does not yield sufficient perceived benefits, then the audio processing device may produce lower quality audio output.

Automatic audio configuration based on an audio output device

Systems and methods for switching between encoded media streams are disclosed. A system may be configured to receive at least two media streams of differing qualities that are associated with an identical media asset. The system can seamlessly switch between a first media stream and a second media stream using an algorithm that can determine which frames of a second stream must be discarded to sync the second stream with the first media stream. The two media streams can then be cross faded to switch from the first media stream to the second media stream.

Systems and methods for seamlessly switching between media streams

An application and audio driver communicate audio data via a ring buffer using a system interface. An application reads or writes data from the buffer in a unit of data. Positions within the buffer correspond to a particular time. To write data to the buffer at a particular position in the buffer that corresponds to a particular time, an application is awaken a period of time ('client-side offset') before the driver reaches the position. The period of time is computed based on a variety factors. One factor is the amount of time the system interface assumes an application uses to write the unit of data to the buffer. For operations that entail the application inserting data into the buffer, the application may specify a weight value to apply to the factor to reduce it and the latency period.

IO latency reduction

Storing audio data encoded in any of a plurality of different audio encoding formats is enabled by parametrically defining the underlying format in which the audio data is encoded, in audio format and packet table chunks. A flag can be used to manage storage of the size of the audio data portion of the file, such that premature termination of an audio recording session does not result in an unreadable corrupted file. This capability can be enabled by initially setting the flag to a value that does not correspond to a valid audio data size and that indicates that the last chunk in the file contains the audio data. State information for the audio data, to effectively denote a version of the file, and a dependency indicator for dependent metadata, may be maintained, where the dependency indicator indicates the state of the audio data on which the metadata is dependent.

Growing community of inventors

Sunnyvale, CA, United States of America

Douglas S Wyatt