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* Copyright (c) 2017 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.
#include <memory>
#include <string>
#include <vector>
#include "absl/types/optional.h"
#include "api/video_codecs/sdp_video_format.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
class VideoDecoder;
// A factory that creates VideoDecoders.
// NOTE: This class is still under development and may change without notice.
class RTC_EXPORT VideoDecoderFactory {
struct CodecSupport {
bool is_supported = false;
bool is_power_efficient = false;
// Returns a list of supported video formats in order of preference, to use
// for signaling etc.
virtual std::vector<SdpVideoFormat> GetSupportedFormats() const = 0;
// Query whether the specifed format is supported or not and if it will be
// power efficient, which is currently interpreted as if there is support for
// hardware acceleration.
// The parameter `reference_scaling` is used to query support for prediction
// across spatial layers. An example where support for reference scaling is
// needed is if the video stream is produced with a scalability mode that has
// a dependency between the spatial layers. See
//* for a specification of
// different scalabilty modes. NOTE: QueryCodecSupport is currently an
// experimental feature that is subject to change without notice.
virtual CodecSupport QueryCodecSupport(const SdpVideoFormat& format,
bool reference_scaling) const {
// Default implementation, query for supported formats and check if the
// specified format is supported. Returns false if `reference_scaling` is
// true.
CodecSupport codec_support;
codec_support.is_supported =
!reference_scaling && format.IsCodecInList(GetSupportedFormats());
return codec_support;
// Creates a VideoDecoder for the specified format.
virtual std::unique_ptr<VideoDecoder> CreateVideoDecoder(
const SdpVideoFormat& format) = 0;
virtual ~VideoDecoderFactory() {}
} // namespace webrtc