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Diffstat (limited to 'third_party/libwebrtc/api/video_codecs/video_encoder_factory_template.h')
-rw-r--r-- | third_party/libwebrtc/api/video_codecs/video_encoder_factory_template.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/third_party/libwebrtc/api/video_codecs/video_encoder_factory_template.h b/third_party/libwebrtc/api/video_codecs/video_encoder_factory_template.h new file mode 100644 index 0000000000..10212ac816 --- /dev/null +++ b/third_party/libwebrtc/api/video_codecs/video_encoder_factory_template.h @@ -0,0 +1,145 @@ +/* + * 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_ENCODER_FACTORY_TEMPLATE_H_ +#define API_VIDEO_CODECS_VIDEO_ENCODER_FACTORY_TEMPLATE_H_ + +#include <memory> +#include <string> +#include <vector> + +#include "absl/algorithm/container.h" +#include "api/array_view.h" +#include "api/video_codecs/sdp_video_format.h" +#include "api/video_codecs/video_encoder.h" +#include "api/video_codecs/video_encoder_factory.h" +#include "modules/video_coding/svc/scalability_mode_util.h" + +namespace webrtc { +// The VideoEncoderFactoryTemplate supports encoders implementations given as +// template arguments. +// +// To include an encoder in the factory it requires three static members +// functions to be defined: +// +// // Returns the supported SdpVideoFormats this encoder can produce. +// static std::vector<SdpVideoFormat> SupportedFormats(); +// +// // Creates an encoder instance for the given format. +// static std::unique_ptr<VideoEncoder> +// CreateEncoder(const SdpVideoFormat& format); +// +// // Returns true if the encoder supports the given scalability mode. +// static bool +// IsScalabilityModeSupported(ScalabilityMode scalability_mode); +// +// Note that the order of the template arguments matter as the factory will +// query/return the first encoder implementation supporting the given +// SdpVideoFormat. +template <typename... Ts> +class VideoEncoderFactoryTemplate : public VideoEncoderFactory { + public: + std::vector<SdpVideoFormat> GetSupportedFormats() const override { + return GetSupportedFormatsInternal<Ts...>(); + } + + std::unique_ptr<VideoEncoder> CreateVideoEncoder( + const SdpVideoFormat& format) override { + // We fuzzy match the specified format for both valid and not so valid + // reasons. The valid reason is that there are many standardized codec + // specific fmtp parameters that have not been implemented, and in those + // cases we should not fail to instantiate an encoder just because we don't + // recognize the parameter. The not so valid reason is that we have started + // adding parameters completely unrelated to the SDP to the SdpVideoFormat. + // TODO(bugs.webrtc.org/13868): Remove FuzzyMatchSdpVideoFormat + absl::optional<SdpVideoFormat> matched = + FuzzyMatchSdpVideoFormat(GetSupportedFormats(), format); + return CreateVideoEncoderInternal<Ts...>(matched.value_or(format)); + } + + CodecSupport QueryCodecSupport( + const SdpVideoFormat& format, + absl::optional<std::string> scalability_mode) const override { + return QueryCodecSupportInternal<Ts...>(format, scalability_mode); + } + + 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> + bool IsScalabilityModeSupported( + const absl::optional<std::string>& scalability_mode_string) const { + if (!scalability_mode_string.has_value()) { + return true; + } + absl::optional<ScalabilityMode> scalability_mode = + ScalabilityModeFromString(*scalability_mode_string); + return scalability_mode.has_value() && + V::IsScalabilityModeSupported(*scalability_mode); + } + + 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<VideoEncoder> CreateVideoEncoderInternal( + const SdpVideoFormat& format) { + if (IsFormatInList(format, V::SupportedFormats())) { + return V::CreateEncoder(format); + } + + if constexpr (sizeof...(Vs) > 0) { + return CreateVideoEncoderInternal<Vs...>(format); + } + + return nullptr; + } + + template <typename V, typename... Vs> + CodecSupport QueryCodecSupportInternal( + const SdpVideoFormat& format, + const absl::optional<std::string>& scalability_mode) const { + if (IsFormatInList(format, V::SupportedFormats())) { + return {.is_supported = IsScalabilityModeSupported<V>(scalability_mode)}; + } + + if constexpr (sizeof...(Vs) > 0) { + return QueryCodecSupportInternal<Vs...>(format, scalability_mode); + } + + return {.is_supported = false}; + } +}; + +} // namespace webrtc + +#endif // API_VIDEO_CODECS_VIDEO_ENCODER_FACTORY_TEMPLATE_H_ |