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-rw-r--r-- | third_party/libwebrtc/sdk/objc/components/video_codec/nalu_rewriter.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/third_party/libwebrtc/sdk/objc/components/video_codec/nalu_rewriter.h b/third_party/libwebrtc/sdk/objc/components/video_codec/nalu_rewriter.h new file mode 100644 index 0000000000..c6474971e2 --- /dev/null +++ b/third_party/libwebrtc/sdk/objc/components/video_codec/nalu_rewriter.h @@ -0,0 +1,113 @@ +/* + * 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_ |