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/*
* Copyright (c) 2015 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 SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_
#define SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_
#include "modules/video_coding/codecs/h264/include/h264.h"
#include <CoreMedia/CoreMedia.h>
#include <vector>
#include "common_video/h264/h264_common.h"
#include "rtc_base/buffer.h"
using webrtc::H264::NaluIndex;
namespace webrtc {
// Converts a sample buffer emitted from the VideoToolbox encoder into a buffer
// suitable for RTP. The sample buffer is in avcc format whereas the rtp buffer
// needs to be in Annex B format. Data is written directly to `annexb_buffer`.
bool H264CMSampleBufferToAnnexBBuffer(CMSampleBufferRef avcc_sample_buffer,
bool is_keyframe,
rtc::Buffer* annexb_buffer);
// Converts a buffer received from RTP into a sample buffer suitable for the
// VideoToolbox decoder. The RTP buffer is in annex b format whereas the sample
// buffer is in avcc format.
// If `is_keyframe` is true then `video_format` is ignored since the format will
// be read from the buffer. Otherwise `video_format` must be provided.
// Caller is responsible for releasing the created sample buffer.
bool H264AnnexBBufferToCMSampleBuffer(const uint8_t* annexb_buffer,
size_t annexb_buffer_size,
CMVideoFormatDescriptionRef video_format,
CMSampleBufferRef* out_sample_buffer,
CMMemoryPoolRef memory_pool);
// Returns a video format description created from the sps/pps information in
// the Annex B buffer. If there is no such information, nullptr is returned.
// The caller is responsible for releasing the description.
CMVideoFormatDescriptionRef CreateVideoFormatDescription(
const uint8_t* annexb_buffer,
size_t annexb_buffer_size);
// Helper class for reading NALUs from an RTP Annex B buffer.
class AnnexBBufferReader final {
public:
AnnexBBufferReader(const uint8_t* annexb_buffer, size_t length);
~AnnexBBufferReader();
AnnexBBufferReader(const AnnexBBufferReader& other) = delete;
void operator=(const AnnexBBufferReader& other) = delete;
// Returns a pointer to the beginning of the next NALU slice without the
// header bytes and its length. Returns false if no more slices remain.
bool ReadNalu(const uint8_t** out_nalu, size_t* out_length);
// Returns the number of unread NALU bytes, including the size of the header.
// If the buffer has no remaining NALUs this will return zero.
size_t BytesRemaining() const;
// Reset the reader to start reading from the first NALU
void SeekToStart();
// Seek to the next position that holds a NALU of the desired type,
// or the end if no such NALU is found.
// Return true if a NALU of the desired type is found, false if we
// reached the end instead
bool SeekToNextNaluOfType(H264::NaluType type);
private:
// Returns the the next offset that contains NALU data.
size_t FindNextNaluHeader(const uint8_t* start,
size_t length,
size_t offset) const;
const uint8_t* const start_;
std::vector<NaluIndex> offsets_;
std::vector<NaluIndex>::iterator offset_;
const size_t length_;
};
// Helper class for writing NALUs using avcc format into a buffer.
class AvccBufferWriter final {
public:
AvccBufferWriter(uint8_t* const avcc_buffer, size_t length);
~AvccBufferWriter() {}
AvccBufferWriter(const AvccBufferWriter& other) = delete;
void operator=(const AvccBufferWriter& other) = delete;
// Writes the data slice into the buffer. Returns false if there isn't
// enough space left.
bool WriteNalu(const uint8_t* data, size_t data_size);
// Returns the unused bytes in the buffer.
size_t BytesRemaining() const;
private:
uint8_t* const start_;
size_t offset_;
const size_t length_;
};
} // namespace webrtc
#endif // SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_
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