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-rw-r--r-- | third_party/libwebrtc/api/video_codecs/video_decoder_factory_template.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/third_party/libwebrtc/api/video_codecs/video_decoder_factory_template.h b/third_party/libwebrtc/api/video_codecs/video_decoder_factory_template.h new file mode 100644 index 0000000000..703ae11664 --- /dev/null +++ b/third_party/libwebrtc/api/video_codecs/video_decoder_factory_template.h @@ -0,0 +1,95 @@ +/* + * Copyright (c) 2022 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef API_VIDEO_CODECS_VIDEO_DECODER_FACTORY_TEMPLATE_H_ +#define API_VIDEO_CODECS_VIDEO_DECODER_FACTORY_TEMPLATE_H_ + +#include <memory> +#include <vector> + +#include "absl/algorithm/container.h" +#include "api/array_view.h" +#include "api/video_codecs/video_decoder.h" +#include "api/video_codecs/video_decoder_factory.h" + +namespace webrtc { +// The VideoDecoderFactoryTemplate supports decoder implementations given as +// template arguments. +// +// To include a decoder in the factory it requires two static members +// functions to be defined: +// +// // Returns the supported SdpVideoFormats this decoder can decode. +// static std::vector<SdpVideoFormat> SupportedFormats(); +// +// // Creates a decoder instance for the given format. +// static std::unique_ptr<VideoDecoder> +// CreateDecoder(const SdpVideoFormat& format); +// +// Note that the order of the template arguments matter as the factory will +// return the first decoder implementation supporting the given SdpVideoFormat. +template <typename... Ts> +class VideoDecoderFactoryTemplate : public VideoDecoderFactory { + public: + std::vector<SdpVideoFormat> GetSupportedFormats() const override { + return GetSupportedFormatsInternal<Ts...>(); + } + + std::unique_ptr<VideoDecoder> CreateVideoDecoder( + const SdpVideoFormat& format) override { + return CreateVideoDecoderInternal<Ts...>(format); + } + + private: + bool IsFormatInList( + const SdpVideoFormat& format, + rtc::ArrayView<const SdpVideoFormat> supported_formats) const { + return absl::c_any_of( + supported_formats, [&](const SdpVideoFormat& supported_format) { + return supported_format.name == format.name && + supported_format.parameters == format.parameters; + }); + } + + template <typename V, typename... Vs> + std::vector<SdpVideoFormat> GetSupportedFormatsInternal() const { + auto supported_formats = V::SupportedFormats(); + + if constexpr (sizeof...(Vs) > 0) { + // Supported formats may overlap between implementations, so duplicates + // should be filtered out. + for (const auto& other_format : GetSupportedFormatsInternal<Vs...>()) { + if (!IsFormatInList(other_format, supported_formats)) { + supported_formats.push_back(other_format); + } + } + } + + return supported_formats; + } + + template <typename V, typename... Vs> + std::unique_ptr<VideoDecoder> CreateVideoDecoderInternal( + const SdpVideoFormat& format) { + if (IsFormatInList(format, V::SupportedFormats())) { + return V::CreateDecoder(format); + } + + if constexpr (sizeof...(Vs) > 0) { + return CreateVideoDecoderInternal<Vs...>(format); + } + + return nullptr; + } +}; + +} // namespace webrtc + +#endif // API_VIDEO_CODECS_VIDEO_DECODER_FACTORY_TEMPLATE_H_ |