/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * stream.cpp - Video stream for a Camera
 */

#include <libcamera/stream.h>

/**
 * \file stream.h
 * \brief Video stream for a Camera
 *
 * A camera device can provide frames in different resolutions and formats
 * concurrently from a single image source. The Stream class represents
 * one of the multiple concurrent streams.
 *
 * All streams exposed by a camera device share the same image source and are
 * thus not fully independent. Parameters related to the image source, such as
 * the exposure time or flash control, are common to all streams. Other
 * parameters, such as format or resolution, may be specified per-stream,
 * depending on the capabilities of the camera device.
 *
 * Camera devices expose at least one stream, and may expose additional streams
 * based on the device capabilities. This can be used, for instance, to
 * implement concurrent viewfinder and video capture, or concurrent viewfinder,
 * video capture and still image capture.
 */

namespace libcamera {

/**
 * \struct StreamConfiguration
 * \brief Configuration parameters for a stream
 *
 * The StreamConfiguration structure models all information which can be
 * configured for a single video stream.
 */

/**
 * \var StreamConfiguration::width
 * \brief Stream width in pixels
 */

/**
 * \var StreamConfiguration::height
 * \brief Stream height in pixels
 */

/**
 * \var StreamConfiguration::pixelFormat
 * \brief Stream pixel format
 *
 * This is a little endian four character code representation of the pixel
 * format described in V4L2 using the V4L2_PIX_FMT_* definitions.
 */

/**
 * \var StreamConfiguration::bufferCount
 * \brief Requested number of buffers to allocate for the stream
 */

/**
 * \class Stream
 * \brief Video stream for a camera
 *
 * The Stream class models all static information which are associated with a
 * single video stream. Streams are exposed by the Camera object they belong to.
 *
 * Cameras may supply more than one stream from the same video source. In such
 * cases an application can inspect all available streams and select the ones
 * that best fit its use case.
 *
 * \todo Add capabilities to the stream API. Without this the Stream class only
 * serves to reveal how many streams of unknown capabilities a camera supports.
 * This in itself is productive as it allows applications to configure and
 * capture from one or more streams even if they won't be able to select the
 * optimal stream for the task.
 */

/**
 * \brief Construct a stream with default parameters
 */
Stream::Stream()
{
}

/**
 * \fn Stream::bufferPool()
 * \brief Retrieve the buffer pool for the stream
 *
 * The buffer pool handles the buffers used to capture frames at the output of
 * the stream. It is initially created empty and shall be populated with
 * buffers before being used.
 *
 * \return A reference to the buffer pool
 */

/**
 * \fn Stream::configuration()
 * \brief Retrieve the active configuration of the stream
 * \return The active configuration of the stream
 */

} /* namespace libcamera */