1// Copyright (C) 2024 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#ifndef QFFMPEGTEXTURECONVERTER_P_H
5#define QFFMPEGTEXTURECONVERTER_P_H
6
7#include <QtFFmpegMediaPluginImpl/private/qffmpegdefs_p.h>
8#include <QtMultimedia/private/qhwvideobuffer_p.h>
9
10#include <memory>
11
12//
13// W A R N I N G
14// -------------
15//
16// This file is not part of the Qt API. It exists purely as an
17// implementation detail. This header file may change from version to
18// version without notice, or even be removed.
19//
20// We mean it.
21//
22
23QT_BEGIN_NAMESPACE
24
25class QRhi;
26
27namespace QFFmpeg {
28
29/**
30 * @brief The base class for platform-specific implementations of TextureConverter
31 * One of two virtual methods, createTextures and createTextureHandles, must be overridden.
32 * If the implementation operates with QRhiTexture under the hood, overriding of
33 * createTextures is prefferable, otherwise expose texture handles of native textures
34 * by createTextureHandles.
35 */
36class TextureConverterBackend : public std::enable_shared_from_this<TextureConverterBackend>
37{
38public:
39 TextureConverterBackend(QRhi *rhi) : rhi(rhi) { }
40
41 virtual ~TextureConverterBackend();
42
43 virtual QVideoFrameTexturesUPtr createTextures(AVFrame * /*hwFrame*/,
44 QVideoFrameTexturesUPtr & /*oldTextures*/)
45 {
46 return nullptr;
47 }
48
49 virtual QVideoFrameTexturesHandlesUPtr
50 createTextureHandles(AVFrame * /*hwFrame*/, QVideoFrameTexturesHandlesUPtr /*oldHandles*/)
51 {
52 return nullptr;
53 }
54
55 /**
56 * @brief Points to the matching QRhi.
57 * If the constructor, createTextures, or createTextureHandles get failed without
58 * chances for recovery, it may set the pointer to nullptr, which will invalidate
59 * the parent TextureConverter, and textures creation won't be invoked anymore.
60 */
61 QRhi *rhi = nullptr;
62};
63using TextureConverterBackendPtr = std::shared_ptr<TextureConverterBackend>;
64
65/**
66 * @brief The TextureConverter class implements conversion of AVFrame hw textures to
67 * textures for rendering by the specified QRhi. Any instance of TextureConverter
68 * matches the pair of FFmpeg hw frames context + QRhi.
69 */
70class TextureConverter
71{
72public:
73 /**
74 * @brief Construct uninitialized texture converter for the specified QRhi
75 */
76 TextureConverter(QRhi &rhi);
77
78 /**
79 * @brief Initializes the instance of the texture converter for the frame context
80 * associated with the specified frame. The method tries to initialize
81 * the conversion backend during the first call with the specified frame format.
82 * If frame format is not changed, the method does nothing even if the first
83 * attempt failed.
84 * @return Whether the instance has been initialized.
85 */
86 bool init(AVFrame &hwFrame);
87
88 /**
89 * @brief Creates video frame textures basing on the current hw frame and the previous textures
90 * from the texture pool. We should strive to reuse oldTextures if we can do so.
91 * If the method returns null, try createTextureHandles.
92 */
93 QVideoFrameTexturesUPtr createTextures(AVFrame &hwFrame, QVideoFrameTexturesUPtr &oldTextures);
94
95 /**
96 * @brief Creates video frame texture handles basing on the current hw frame and the previous
97 * texture handles from the pool. We should strive to reuse oldHandles if we can do so.
98 */
99 QVideoFrameTexturesHandlesUPtr createTextureHandles(AVFrame &hwFrame,
100 QVideoFrameTexturesHandlesUPtr oldHandles);
101
102 /**
103 * @brief Indicates whether the texture converter is not initialized or the initialization
104 * failed. If hw texture conversion is disabled, it always true.
105 */
106 bool isNull() const { return !m_backend || !m_backend->rhi; }
107
108 /**
109 * @brief Applies platform-specific hw texture conversion presets for a decoder.
110 * The function is supposed to be invoked for the get_format callback.
111 */
112 static void applyDecoderPreset(AVPixelFormat format, AVCodecContext &codecContext);
113
114 /**
115 * @brief Indicates whether hw texture conversion is enabled for the application.
116 */
117 static bool hwTextureConversionEnabled();
118
119 /**
120 * @brief Indicates whether the matching textute converter backend can be created.
121 * If isBackendAvailable returns false, instances cannot be initialized with
122 * the specified frame. If it returns true, init will attempt to create backend,
123 * but it may fail if something goes wrong in the backend.
124 */
125 static bool isBackendAvailable(AVFrame &hwFrame);
126
127private:
128 void updateBackend(AVPixelFormat format);
129
130private:
131 QRhi &m_rhi;
132 AVPixelFormat m_format = AV_PIX_FMT_NONE;
133 TextureConverterBackendPtr m_backend;
134};
135
136} // namespace QFFmpeg
137
138QT_END_NAMESPACE
139
140#endif // QFFMPEGTEXTURECONVERTER_P_H
141

source code of qtmultimedia/src/plugins/multimedia/ffmpeg/qffmpegtextureconverter_p.h