Reland of Split iOS sdk in to separate targets

webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.h

+/*
+ *  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 WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_
+#define WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_
+
+#include "webrtc/modules/video_coding/codecs/h264/include/h264.h"
+
+#include <CoreMedia/CoreMedia.h>
+#include <vector>
+
+#include "webrtc/base/buffer.h"
+#include "webrtc/common_video/h264/h264_common.h"
+#include "webrtc/modules/include/module_common_types.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|
+// and a new RTPFragmentationHeader is returned in |out_header|.
+bool H264CMSampleBufferToAnnexBBuffer(
+    CMSampleBufferRef avcc_sample_buffer,
+    bool is_keyframe,
+    rtc::Buffer* annexb_buffer,
+    webrtc::RTPFragmentationHeader** out_header);
+
+// 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);
+
+// Returns true if the type of the first NALU in the supplied Annex B buffer is
+// the SPS type.
+bool H264AnnexBBufferHasVideoFormatDescription(const uint8_t* annexb_buffer,
+                                               size_t annexb_buffer_size);
+
+// 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;
+
+ 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  // WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOX_NALU_REWRITER_H_