55 lines
2.3 KiB
C
55 lines
2.3 KiB
C
|
/*
|
||
|
|
* Copyright (c) 2016 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 WEBRTC_COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
|
||
|
|
#define WEBRTC_COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
|
||
|
|
|
||
|
|
#include "webrtc/base/buffer.h"
|
||
|
|
#include "webrtc/base/optional.h"
|
||
|
|
#include "webrtc/common_video/h264/sps_parser.h"
|
||
|
|
|
||
|
|
namespace rtc {
|
||
|
|
class BitBuffer;
|
||
|
|
}
|
||
|
|
|
||
|
|
namespace webrtc {
|
||
|
|
|
||
|
|
// A class that can parse an SPS block of a NAL unit and if necessary
|
||
|
|
// creates a copy with updated settings to allow for faster decoding for streams
|
||
|
|
// that use picture order count type 0. Streams in that format incur additional
|
||
|
|
// delay because it allows decode order to differ from render order.
|
||
|
|
// The mechanism used is to rewrite (edit or add) the SPS's VUI to contain
|
||
|
|
// restrictions on the maximum number of reordered pictures. This reduces
|
||
|
|
// latency significantly, though it still adds about a frame of latency to
|
||
|
|
// decoding.
|
||
|
|
class SpsVuiRewriter : private SpsParser {
|
||
|
|
public:
|
||
|
|
enum class ParseResult { kFailure, kPocOk, kVuiOk, kVuiRewritten };
|
||
|
|
|
||
|
|
// Parses an SPS block and if necessary copies it and rewrites the VUI.
|
||
|
|
// Returns kFailure on failure, kParseOk if parsing succeeded and no update
|
||
|
|
// was necessary and kParsedAndModified if an updated copy of buffer was
|
||
|
|
// written to destination. destination may be populated with some data even if
|
||
|
|
// no rewrite was necessary, but the end offset should remain unchanged.
|
||
|
|
// Unless parsing fails, the sps parameter will be populated with the parsed
|
||
|
|
// SPS state. This function assumes that any previous headers
|
||
|
|
// (NALU start, type, Stap-A, etc) have already been parsed and that RBSP
|
||
|
|
// decoding has been performed.
|
||
|
|
static ParseResult ParseAndRewriteSps(const uint8_t* buffer,
|
||
|
|
size_t length,
|
||
|
|
rtc::Optional<SpsParser::SpsState>* sps,
|
||
|
|
rtc::Buffer* destination);
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace webrtc
|
||
|
|
|
||
|
|
#endif // WEBRTC_COMMON_VIDEO_H264_SPS_VUI_REWRITER_H_
|