[libcamera-devel] [PATCH v4 10/16] libcamera: stream: Add StreamFormats
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Jun 19 11:49:29 CEST 2019
Hi Niklas,
Thank you for the patch.
On Wed, Jun 19, 2019 at 04:51:23AM +0200, Niklas Söderlund wrote:
> Add a StreamFormats class which describes all the formats supported by a
> stream. The object does not collect any information itself but can
> simplify user interactions with formats as it's able to translate a
> stream format range into a discrete list and a discrete list to a range.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
> * Changes since v3
> - Fix spelling and grammar.
> - Add \todo markers for potential caching of calculated values.
> - Change std::vector<> to std::array<> for list of sizes in sizes().
> ---
> include/libcamera/stream.h | 16 +++
> src/libcamera/stream.cpp | 230 +++++++++++++++++++++++++++++++++++++
> 2 files changed, 246 insertions(+)
>
> diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
> index e38c0e7e827d5888..48daf5ac23f55d85 100644
> --- a/include/libcamera/stream.h
> +++ b/include/libcamera/stream.h
> @@ -7,6 +7,7 @@
> #ifndef __LIBCAMERA_STREAM_H__
> #define __LIBCAMERA_STREAM_H__
>
> +#include <map>
> #include <string>
> #include <vector>
>
> @@ -18,6 +19,21 @@ namespace libcamera {
> class Camera;
> class Stream;
>
> +class StreamFormats
> +{
> +public:
> + StreamFormats();
> + StreamFormats(const std::map<unsigned int, std::vector<SizeRange>> &formats);
> +
> + std::vector<unsigned int> pixelformats() const;
> + std::vector<Size> sizes(unsigned int pixelformat) const;
> +
> + SizeRange range(unsigned int pixelformat) const;
> +
> +private:
> + std::map<unsigned int, std::vector<SizeRange>> formats_;
> +};
> +
> struct StreamConfiguration {
> StreamConfiguration()
> : stream_(nullptr)
> diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
> index 0c59a31a3a0501d3..bfb072d691ae0e25 100644
> --- a/src/libcamera/stream.cpp
> +++ b/src/libcamera/stream.cpp
> @@ -7,9 +7,13 @@
>
> #include <libcamera/stream.h>
>
> +#include <algorithm>
> +#include <climits>
> #include <iomanip>
> #include <sstream>
>
> +#include "log.h"
> +
> /**
> * \file stream.h
> * \brief Video stream for a Camera
> @@ -32,6 +36,232 @@
>
> namespace libcamera {
>
> +LOG_DEFINE_CATEGORY(Stream)
> +
> +/**
> + * \class StreamFormats
> + * \brief Hold information about supported stream formats
> + *
> + * The StreamFormats class holds information about the pixel formats and frame
> + * sizes a stream supports. The class groups size information by the pixel
> + * format which can produce it.
> + *
> + * There are two ways to examine the size information, as a range or as a list
> + * of discrete sizes. When sizes are viewed as a range it describes the minimum
> + * and maximum width and height values. The range description can include
> + * horizontal and vertical steps.
> + *
> + * When sizes are viewed as a list of discrete sizes they describe the exact
> + * dimensions which can be selected and used.
> + *
> + * Pipeline handlers can create StreamFormats describing each pixel format using
> + * either a range or a list of discrete sizes. The StreamFormats class attempts
> + * to translate between the two different ways to view them. The translations
> + * are performed as:
> + *
> + * - If the StreamFormat is constructed using a list of discrete image sizes
> + * and a range is requested, it gets created by taking the minimum and
> + * maximum width/height in the list. The step information is not recreated
> + * and is set to 0 to indicate the range is generated.
> + *
> + * - If the image sizes used to construct a StreamFormat are expressed as a
> + * range and a list of discrete sizes is requested, one which fits inside
> + * that range are selected from a list of common sizes. The step information
> + * is taken into consideration when generating the sizes.
> + *
> + * Applications examining sizes as a range with step values of 0 shall be
> + * aware that the range are generated from a list of discrete sizes and there
> + * could be a large number of possible Size combinations that may not be
> + * supported by the Stream.
> + *
> + * All sizes retrieved from StreamFormats shall be treated as advisory and no
> + * size shall be considered to be supported until it has been verified using
> + * CameraConfiguration::validate().
I would move the todo you added below here, and write it as
* \todo Review the usage patterns of this class, and cache the
* computed pixelformats(), sizes() and range() if this would improve
* performances.
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> + */
> +
> +StreamFormats::StreamFormats()
> +{
> +}
> +
> +/**
> + * \brief Construct a StreamFormats object with a map of image formats
> + * \param[in] formats A map of pixel formats to a sizes description
> + */
> +StreamFormats::StreamFormats(const std::map<unsigned int, std::vector<SizeRange>> &formats)
> + : formats_(formats)
> +{
> +}
> +
> +/**
> + * \brief Retrieve the list of supported pixel formats
> + * \return The list of supported pixel formats
> + */
> +std::vector<unsigned int> StreamFormats::pixelformats() const
> +{
> + std::vector<unsigned int> formats;
> +
> + /* \todo: Should this be cached instead of computed each time? */
> + for (auto const &it : formats_)
> + formats.push_back(it.first);
> +
> + return formats;
> +}
> +
> +/**
> + * \brief Retrieve the list of frame sizes supported for \a pixelformat
> + * \param[in] pixelformat Pixel format to retrieve sizes for
> + *
> + * If the sizes described for \a pixelformat are discrete they are returned
> + * directly.
> + *
> + * If the sizes are described as a range, a list of discrete sizes are computed
> + * from a list of common resolutions that fit inside the described range. When
> + * computing the discrete list step values are considered but there are no
> + * guarantees that all sizes computed are supported.
> + *
> + * \todo: Should the sizes be cached instead of computed each time?
> + *
> + * \return A list of frame sizes or an empty list on error
> + */
> +std::vector<Size> StreamFormats::sizes(unsigned int pixelformat) const
> +{
> + /*
> + * Sizes to try and extract from ranges.
> + * \todo Verify list of resolutions are good, current list compiled
> + * from v4l2 documentation and source code as well as lists of
> + * common frame sizes.
> + */
> + static const std::array<Size, 53> rangeDiscreteSizes = {
> + Size(160, 120),
> + Size(240, 160),
> + Size(320, 240),
> + Size(400, 240),
> + Size(480, 320),
> + Size(640, 360),
> + Size(640, 480),
> + Size(720, 480),
> + Size(720, 576),
> + Size(768, 480),
> + Size(800, 600),
> + Size(854, 480),
> + Size(960, 540),
> + Size(960, 640),
> + Size(1024, 576),
> + Size(1024, 600),
> + Size(1024, 768),
> + Size(1152, 864),
> + Size(1280, 1024),
> + Size(1280, 1080),
> + Size(1280, 720),
> + Size(1280, 800),
> + Size(1360, 768),
> + Size(1366, 768),
> + Size(1400, 1050),
> + Size(1440, 900),
> + Size(1536, 864),
> + Size(1600, 1200),
> + Size(1600, 900),
> + Size(1680, 1050),
> + Size(1920, 1080),
> + Size(1920, 1200),
> + Size(2048, 1080),
> + Size(2048, 1152),
> + Size(2048, 1536),
> + Size(2160, 1080),
> + Size(2560, 1080),
> + Size(2560, 1440),
> + Size(2560, 1600),
> + Size(2560, 2048),
> + Size(2960, 1440),
> + Size(3200, 1800),
> + Size(3200, 2048),
> + Size(3200, 2400),
> + Size(3440, 1440),
> + Size(3840, 1080),
> + Size(3840, 1600),
> + Size(3840, 2160),
> + Size(3840, 2400),
> + Size(4096, 2160),
> + Size(5120, 2160),
> + Size(5120, 2880),
> + Size(7680, 4320),
> + };
> + std::vector<Size> sizes;
> +
> + /* Make sure pixel format exists. */
> + auto const &it = formats_.find(pixelformat);
> + if (it == formats_.end())
> + return {};
> +
> + /* Try creating a list of discrete sizes. */
> + const std::vector<SizeRange> &ranges = it->second;
> + bool discrete = true;
> + for (const SizeRange &range : ranges) {
> + if (range.min != range.max) {
> + discrete = false;
> + break;
> + }
> + sizes.emplace_back(range.min);
> + }
> +
> + /* If discrete not possible generate from range. */
> + if (!discrete) {
> + if (ranges.size() != 1) {
> + LOG(Stream, Error) << "Range format is ambiguous";
> + return {};
> + }
> +
> + const SizeRange &limit = ranges.front();
> + sizes.clear();
> +
> + for (const Size &size : rangeDiscreteSizes)
> + if (limit.contains(size))
> + sizes.push_back(size);
> + }
> +
> + std::sort(sizes.begin(), sizes.end());
> +
> + return sizes;
> +}
> +
> +/**
> + * \brief Retrieve the range of minimum and maximum sizes
> + * \param[in] pixelformat Pixel format to retrieve range for
> + *
> + * If the size described for \a pixelformat is a range, that range is returned
> + * directly. If the sizes described are a list of discrete sizes, a range is
> + * created from the minimum and maximum sizes in the list. The step values of
> + * the range are set to 0 to indicate that the range is generated and that not
> + * all image sizes contained in the range might be supported.
> + *
> + * \return A range of valid image sizes or an empty range on error
> + */
> +SizeRange StreamFormats::range(unsigned int pixelformat) const
> +{
> + auto const it = formats_.find(pixelformat);
> + if (it == formats_.end())
> + return {};
> +
> + const std::vector<SizeRange> &ranges = it->second;
> + if (ranges.size() == 1)
> + return ranges[0];
> +
> + LOG(Stream, Debug) << "Building range from discrete sizes";
> + SizeRange range(UINT_MAX, UINT_MAX, 0, 0);
> + for (const SizeRange &limit : ranges) {
> + if (limit.min < range.min)
> + range.min = limit.min;
> +
> + if (limit.max > range.max)
> + range.max = limit.max;
> + }
> +
> + range.hStep = 0;
> + range.vStep = 0;
> +
> + return range;
> +}
> +
> /**
> * \struct StreamConfiguration
> * \brief Configuration parameters for a stream
--
Regards,
Laurent Pinchart
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