72 lines
2.6 KiB
C
72 lines
2.6 KiB
C
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/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*
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*/
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#ifndef COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
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#define COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
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#include <stddef.h>
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#include <stdint.h>
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#include "absl/types/optional.h"
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#include "api/video/color_space.h"
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#include "common_video/h264/sps_parser.h"
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#include "rtc_base/buffer.h"
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namespace webrtc {
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// A class that can parse an SPS+VUI and if necessary creates a copy with
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// updated parameters.
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// The rewriter disables frame buffering. This should force decoders to deliver
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// decoded frame immediately and, thus, reduce latency.
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// The rewriter updates video signal type parameters if external parameters are
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// provided.
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class SpsVuiRewriter : private SpsParser {
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public:
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enum class ParseResult { kFailure, kVuiOk, kVuiRewritten };
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enum class Direction { kIncoming, kOutgoing };
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// Parses an SPS block and if necessary copies it and rewrites the VUI.
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// Returns kFailure on failure, kParseOk if parsing succeeded and no update
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// was necessary and kParsedAndModified if an updated copy of buffer was
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// written to destination. destination may be populated with some data even if
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// no rewrite was necessary, but the end offset should remain unchanged.
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// Unless parsing fails, the sps parameter will be populated with the parsed
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// SPS state. This function assumes that any previous headers
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// (NALU start, type, Stap-A, etc) have already been parsed and that RBSP
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// decoding has been performed.
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static ParseResult ParseAndRewriteSps(
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const uint8_t* buffer,
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size_t length,
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absl::optional<SpsParser::SpsState>* sps,
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const ColorSpace* color_space,
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rtc::Buffer* destination,
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Direction Direction);
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// Parses NAL units from |buffer| and rewrites VUI in SPS blocks if necessary.
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static rtc::Buffer ParseOutgoingBitstreamAndRewriteSps(
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rtc::ArrayView<const uint8_t> buffer,
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const ColorSpace* color_space);
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private:
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static ParseResult ParseAndRewriteSps(
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const uint8_t* buffer,
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size_t length,
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absl::optional<SpsParser::SpsState>* sps,
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const ColorSpace* color_space,
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rtc::Buffer* destination);
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static void UpdateStats(ParseResult result, Direction direction);
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};
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} // namespace webrtc
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#endif // COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
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