qffmpeg_p.h

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QFFMPEG_P_H
#define QFFMPEG_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include <QtFFmpegMediaPluginImpl/private/qffmpegdefs_p.h>
#include <QtFFmpegMediaPluginImpl/private/qffmpegcodec_p.h>
#include <QtFFmpegMediaPluginImpl/private/qffmpegavaudioformat_p.h>
#include <QtMultimedia/qvideoframeformat.h>
#include <QtMultimedia/private/qmultimedia_ranges_p.h>
 
#include <qstring.h>
#include <optional>
 
[[maybe_unused]] static inline bool operator==(const AVRational &lhs, const AVRational &rhs)
{
    return lhs.num == rhs.num && lhs.den == rhs.den;
}
 
[[maybe_unused]] static inline bool operator!=(const AVRational &lhs, const AVRational &rhs)
{
    return !(lhs == rhs);
}
 
QT_BEGIN_NAMESPACE
 
namespace QFFmpeg
{
 
namespace ranges = QtMultimediaPrivate::ranges;
 
inline std::optional<qint64> mul(qint64 a, AVRational b)
{
    if (b.den == 0)
        return {};
 
    auto multiplyAndRound = [](qint64 a, AVRational b) { //
        return (a * b.num + b.den / 2) / b.den;
    };
 
    if (a < 0)
        return -multiplyAndRound(-a, b);
    else
        return multiplyAndRound(a, b);
}
 
inline std::optional<qreal> mul(qreal a, AVRational b)
{
    return b.den != 0 ? a * qreal(b.num) / qreal(b.den) : std::optional<qreal>{};
}
 
inline std::optional<qint64> timeStampMs(qint64 ts, AVRational base)
{
    return mul(1'000 * ts, base);
}
 
inline std::optional<qint64> timeStampUs(qint64 ts, AVRational base)
{
    return mul(1'000'000 * ts, base);
}
 
inline std::optional<float> toFloat(AVRational r)
{
    return r.den != 0 ? float(r.num) / float(r.den) : std::optional<float>{};
}
 
inline QString err2str(int errnum)
{
    char buffer[AV_ERROR_MAX_STRING_SIZE + 1] = {};
    av_make_error_string(buffer, AV_ERROR_MAX_STRING_SIZE, errnum);
    return QString::fromLocal8Bit(buffer);
}
 
inline void setAVFrameTime(AVFrame &frame, int64_t pts, const AVRational &timeBase)
{
    frame.pts = pts;
#if QT_FFMPEG_HAS_FRAME_TIME_BASE
    frame.time_base = timeBase;
#else
    Q_UNUSED(timeBase);
#endif
}
 
inline void getAVFrameTime(const AVFrame &frame, int64_t &pts, AVRational &timeBase)
{
    pts = frame.pts;
#if QT_FFMPEG_HAS_FRAME_TIME_BASE
    timeBase = frame.time_base;
#else
    timeBase = { 0, 1 };
#endif
}
 
inline int64_t getAVFrameDuration(const AVFrame &frame)
{
#if QT_FFMPEG_HAS_FRAME_DURATION
    return frame.duration;
#else
    return frame.pkt_duration;
#endif
}
 
struct AVDictionaryHolder
{
    AVDictionary *opts = nullptr;
 
    operator AVDictionary **() { return &opts; }
 
    AVDictionaryHolder() = default;
 
    Q_DISABLE_COPY(AVDictionaryHolder)
 
    AVDictionaryHolder(AVDictionaryHolder &&other) noexcept
        : opts(std::exchange(other.opts, nullptr))
    {
    }
 
    ~AVDictionaryHolder()
    {
        if (opts)
            av_dict_free(&opts);
    }
};
 
template <auto F>
struct AVDeleter
{
    template <typename T>
    void operator()(T *object) const
    {
        using FunctionType = decltype(F);
 
        static_assert(std::is_invocable_v<FunctionType, T *>
                              || std::is_invocable_v<FunctionType, T **>,
                      "F must be invocable with either T* or T**");
 
        if constexpr (std::is_invocable_v<FunctionType, T **>) {
            if (object)
                F(&object);
        } else
            F(object);
    }
};
 
using AVFrameUPtr = std::unique_ptr<AVFrame, AVDeleter<av_frame_free>>;
 
inline AVFrameUPtr makeAVFrame()
{
    return AVFrameUPtr(av_frame_alloc());
}
 
using AVPacketUPtr = std::unique_ptr<AVPacket, AVDeleter<av_packet_free>>;
using AVCodecContextUPtr = std::unique_ptr<AVCodecContext, AVDeleter<avcodec_free_context>>;
using AVBufferUPtr = std::unique_ptr<AVBufferRef, AVDeleter<av_buffer_unref>>;
using AVHWFramesConstraintsUPtr =
        std::unique_ptr<AVHWFramesConstraints, AVDeleter<av_hwframe_constraints_free>>;
using SwrContextUPtr = std::unique_ptr<SwrContext, AVDeleter<swr_free>>;
using SwsContextUPtr = std::unique_ptr<SwsContext, AVDeleter<sws_freeContext>>;
 
bool isAVFormatSupported(const Codec &codec, PixelOrSampleFormat format);
 
// Search for the first element in the range that satisfies the predicate
// The predicate is evaluated for each value in the range until it returns
// true, and the corresponding value is returned. If no match is found,
// std::nullopt is returned.
template <typename Value, typename Predicate>
std::optional<Value> findIf(QSpan<const Value> range, const Predicate &predicate)
{
    const auto value = ranges::find_if(range, predicate);
    if (value == range.end())
        return {};
    return *value;
}
 
// Search the codec's pixel formats for a format that matches the predicate.
// If no pixel format is found, repeat the search through the pixel formats
// of all the codec's hardware configs. If no matching pixel format is found,
// std::nullopt is returned. The predicate is evaluated once for each pixel
// format until the predicate returns true.
template <typename Predicate>
std::optional<AVPixelFormat> findAVPixelFormat(const Codec &codec, const Predicate &predicate)
{
    if (codec.type() != AVMEDIA_TYPE_VIDEO)
        return {};
 
    const auto pixelFormats = codec.pixelFormats();
 
    if (const auto format = findIf(pixelFormats, predicate))
        return format;
 
    // No matching pixel format was found. Check the pixel format
    // of the codec's hardware config.
    for (const AVCodecHWConfig *const config : codec.hwConfigs()) {
        const AVPixelFormat format = config->pix_fmt;
 
        if (format == AV_PIX_FMT_NONE)
            continue;
 
        if (predicate(format))
            return format;
    }
    return {};
}
 
// Evaluate the function for each of the codec's pixel formats and each of
// the pixel formats supported by the codec's hardware configs.
template <typename Function>
void forEachAVPixelFormat(const Codec &codec, const Function &function)
{
    findAVPixelFormat(codec, [&function](AVPixelFormat format) {
        function(format);
        return false; // Evaluate the function for all pixel formats
    });
}
 
template <typename ValueT, typename ScoreT = AVScore>
struct ValueAndScore
{
    std::optional<ValueT> value;
    ScoreT score = std::numeric_limits<ScoreT>::min();
};
 
template <typename Value, typename CalculateScore,
          typename ScoreType = std::invoke_result_t<CalculateScore, Value>>
ValueAndScore<Value, ScoreType> findBestAVValueWithScore(QSpan<const Value> values,
                                                         const CalculateScore &calculateScore)
{
    static_assert(std::is_invocable_v<CalculateScore, Value>);
 
    ValueAndScore<Value, ScoreType> result;
    for (const Value &val : values) {
        const ScoreType score = calculateScore(val);
        if (score > result.score)
            result = { val, score }; // Note: Optional is only set if score > Limits::min()
 
        if (result.score == std::numeric_limits<ScoreType>::max())
            break;
    }
 
    return result;
}
 
template <typename Value, typename CalculateScore>
std::optional<Value> findBestAVValue(QSpan<const Value> values,
                                     const CalculateScore &calculateScore)
{
    return findBestAVValueWithScore(values, calculateScore).value;
}
 
bool isHwPixelFormat(AVPixelFormat format);
 
inline bool isSwPixelFormat(AVPixelFormat format)
{
    return !isHwPixelFormat(format);
}
 
void applyExperimentalCodecOptions(const Codec &codec, AVDictionary **opts);
 
AVPixelFormat pixelFormatForHwDevice(AVHWDeviceType deviceType);
 
AVPacketSideData *addStreamSideData(AVStream *stream, AVPacketSideData sideData);
 
const AVPacketSideData *streamSideData(const AVStream *stream, AVPacketSideDataType type);
 
SwrContextUPtr createResampleContext(const AVAudioFormat &inputFormat,
                                     const AVAudioFormat &outputFormat);
 
QVideoFrameFormat::ColorTransfer fromAvColorTransfer(AVColorTransferCharacteristic colorTrc);
 
AVColorTransferCharacteristic toAvColorTransfer(QVideoFrameFormat::ColorTransfer colorTrc);
 
QVideoFrameFormat::ColorSpace fromAvColorSpace(AVColorSpace colorSpace);
 
AVColorSpace toAvColorSpace(QVideoFrameFormat::ColorSpace colorSpace);
 
QVideoFrameFormat::ColorRange fromAvColorRange(AVColorRange colorRange);
 
AVColorRange toAvColorRange(QVideoFrameFormat::ColorRange colorRange);
 
AVHWDeviceContext *avFrameDeviceContext(const AVFrame *frame);
 
SwsContextUPtr createSwsContext(const QSize &srcSize, AVPixelFormat srcPixFmt, const QSize &dstSize,
                                AVPixelFormat dstPixFmt, SwsFlags conversionType = SWS_BICUBIC);
 
#ifdef Q_OS_DARWIN
bool isCVFormatSupported(uint32_t format);
 
std::string cvFormatToString(uint32_t format);
 
#endif
 
enum class AVError : int {
    Success = 0,
};
 
} // namespace QFFmpeg
 
QDebug operator<<(QDebug, const AVRational &);
QDebug operator<<(QDebug, const AVDictionary &);
QDebug operator<<(QDebug, const QFFmpeg::AVDictionaryHolder &);
QDebug operator<<(QDebug, QFFmpeg::AVError);
QDebug operator<<(QDebug, AVPixelFormat);
QDebug operator<<(QDebug, AVHWDeviceType);
QDebug operator<<(QDebug, AVCodecID);
QDebug operator<<(QDebug, const AVOutputFormat *);
QDebug operator<<(QDebug, const AVInputFormat *);
 
#if QT_FFMPEG_HAS_AV_CHANNEL_LAYOUT
QDebug operator<<(QDebug, const AVChannelLayout &);
#endif
 
QT_END_NAMESPACE
 
#endif