iOS HW H264 support.

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_nalu.cc

+/*
+ *  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.
+ *
+ */
+
+#include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_nalu.h"
+
+#if defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <vector>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+
+namespace webrtc {
+
+const char kAnnexBHeaderBytes[4] = {0, 0, 0, 1};
+const size_t kAvccHeaderByteSize = sizeof(uint32_t);
+
+bool H264CMSampleBufferToAnnexBBuffer(
+    CMSampleBufferRef avcc_sample_buffer,
+    bool is_keyframe,
+    rtc::Buffer* annexb_buffer,
+    webrtc::RTPFragmentationHeader** out_header) {
+  DCHECK(avcc_sample_buffer);
+  DCHECK(out_header);
+  *out_header = nullptr;
+
+  // Get format description from the sample buffer.
+  CMVideoFormatDescriptionRef description =
+      CMSampleBufferGetFormatDescription(avcc_sample_buffer);
+  if (description == nullptr) {
+    LOG(LS_ERROR) << "Failed to get sample buffer's description.";
+    return false;
+  }
+
+  // Get parameter set information.
+  int nalu_header_size = 0;
+  size_t param_set_count = 0;
+  OSStatus status = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(
+      description, 0, nullptr, nullptr, &param_set_count, &nalu_header_size);
+  if (status != noErr) {
+    LOG(LS_ERROR) << "Failed to get parameter set.";
+    return false;
+  }
+  // TODO(tkchin): handle other potential sizes.
+  DCHECK_EQ(nalu_header_size, 4);
+  DCHECK_EQ(param_set_count, 2u);
+
+  // Truncate any previous data in the buffer without changing its capacity.
+  annexb_buffer->SetSize(0);
+
+  size_t nalu_offset = 0;
+  std::vector<size_t> frag_offsets;
+  std::vector<size_t> frag_lengths;
+
+  // Place all parameter sets at the front of buffer.
+  if (is_keyframe) {
+    size_t param_set_size = 0;
+    const uint8_t* param_set = nullptr;
+    for (size_t i = 0; i < param_set_count; ++i) {
+      status = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(
+          description, i, &param_set, &param_set_size, nullptr, nullptr);
+      if (status != noErr) {
+        LOG(LS_ERROR) << "Failed to get parameter set.";
+        return false;
+      }
+      // Update buffer.
+      annexb_buffer->AppendData(kAnnexBHeaderBytes, sizeof(kAnnexBHeaderBytes));
+      annexb_buffer->AppendData(reinterpret_cast<const char*>(param_set),
+                                param_set_size);
+      // Update fragmentation.
+      frag_offsets.push_back(nalu_offset + sizeof(kAnnexBHeaderBytes));
+      frag_lengths.push_back(param_set_size);
+      nalu_offset += sizeof(kAnnexBHeaderBytes) + param_set_size;
+    }
+  }
+
+  // Get block buffer from the sample buffer.
+  CMBlockBufferRef block_buffer =
+      CMSampleBufferGetDataBuffer(avcc_sample_buffer);
+  if (block_buffer == nullptr) {
+    LOG(LS_ERROR) << "Failed to get sample buffer's block buffer.";
+    return false;
+  }
+  CMBlockBufferRef contiguous_buffer = nullptr;
+  // Make sure block buffer is contiguous.
+  if (!CMBlockBufferIsRangeContiguous(block_buffer, 0, 0)) {
+    status = CMBlockBufferCreateContiguous(
+        nullptr, block_buffer, nullptr, nullptr, 0, 0, 0, &contiguous_buffer);
+    if (status != noErr) {
+      LOG(LS_ERROR) << "Failed to flatten non-contiguous block buffer: "
+                    << status;
+      return false;
+    }
+  } else {
+    contiguous_buffer = block_buffer;
+    // Retain to make cleanup easier.
+    CFRetain(contiguous_buffer);
+    block_buffer = nullptr;
+  }
+
+  // Now copy the actual data.
+  char* data_ptr = nullptr;
+  size_t block_buffer_size = CMBlockBufferGetDataLength(contiguous_buffer);
+  status = CMBlockBufferGetDataPointer(contiguous_buffer, 0, nullptr, nullptr,
+                                       &data_ptr);
+  if (status != noErr) {
+    LOG(LS_ERROR) << "Failed to get block buffer data.";
+    CFRelease(contiguous_buffer);
+    return false;
+  }
+  size_t bytes_remaining = block_buffer_size;
+  while (bytes_remaining > 0) {
+    // The size type here must match |nalu_header_size|, we expect 4 bytes.
+    // Read the length of the next packet of data. Must convert from big endian
+    // to host endian.
+    DCHECK_GE(bytes_remaining, (size_t)nalu_header_size);
+    uint32_t* uint32_data_ptr = reinterpret_cast<uint32*>(data_ptr);
+    uint32_t packet_size = CFSwapInt32BigToHost(*uint32_data_ptr);
+    // Update buffer.
+    annexb_buffer->AppendData(kAnnexBHeaderBytes, sizeof(kAnnexBHeaderBytes));
+    annexb_buffer->AppendData(data_ptr + nalu_header_size, packet_size);
+    // Update fragmentation.
+    frag_offsets.push_back(nalu_offset + sizeof(kAnnexBHeaderBytes));
+    frag_lengths.push_back(packet_size);
+    nalu_offset += sizeof(kAnnexBHeaderBytes) + packet_size;
+
+    size_t bytes_written = packet_size + nalu_header_size;
+    bytes_remaining -= bytes_written;
+    data_ptr += bytes_written;
+  }
+  DCHECK_EQ(bytes_remaining, (size_t)0);
+
+  rtc::scoped_ptr<webrtc::RTPFragmentationHeader> header;
+  header.reset(new webrtc::RTPFragmentationHeader());
+  header->VerifyAndAllocateFragmentationHeader(frag_offsets.size());
+  DCHECK_EQ(frag_lengths.size(), frag_offsets.size());
+  for (size_t i = 0; i < frag_offsets.size(); ++i) {
+    header->fragmentationOffset[i] = frag_offsets[i];
+    header->fragmentationLength[i] = frag_lengths[i];
+    header->fragmentationPlType[i] = 0;
+    header->fragmentationTimeDiff[i] = 0;
+  }
+  *out_header = header.release();
+  CFRelease(contiguous_buffer);
+  return true;
+}
+
+bool H264AnnexBBufferToCMSampleBuffer(
+    const uint8_t* annexb_buffer,
+    size_t annexb_buffer_size,
+    CMVideoFormatDescriptionRef video_format,
+    CMSampleBufferRef* out_sample_buffer) {
+  DCHECK(annexb_buffer);
+  DCHECK(out_sample_buffer);
+  *out_sample_buffer = nullptr;
+
+  // The buffer we receive via RTP has 00 00 00 01 start code artifically
+  // embedded by the RTP depacketizer. Extract NALU information.
+  // TODO(tkchin): handle potential case where sps and pps are delivered
+  // separately.
+  uint8_t first_nalu_type = annexb_buffer[4] & 0x1f;
+  bool is_first_nalu_type_sps = first_nalu_type == 0x7;
+
+  AnnexBBufferReader reader(annexb_buffer, annexb_buffer_size);
+  CMVideoFormatDescriptionRef description = nullptr;
+  OSStatus status = noErr;
+  if (is_first_nalu_type_sps) {
+    // Parse the SPS and PPS into a CMVideoFormatDescription.
+    const uint8_t* param_set_ptrs[2] = {};
+    size_t param_set_sizes[2] = {};
+    if (!reader.ReadNalu(&param_set_ptrs[0], &param_set_sizes[0])) {
+      LOG(LS_ERROR) << "Failed to read SPS";
+      return false;
+    }
+    if (!reader.ReadNalu(&param_set_ptrs[1], &param_set_sizes[1])) {
+      LOG(LS_ERROR) << "Failed to read PPS";
+      return false;
+    }
+    status = CMVideoFormatDescriptionCreateFromH264ParameterSets(
+        kCFAllocatorDefault, 2, param_set_ptrs, param_set_sizes, 4,
+        &description);
+    if (status != noErr) {
+      LOG(LS_ERROR) << "Failed to create video format description.";
+      return false;
+    }
+  } else {
+    DCHECK(video_format);
+    description = video_format;
+    // We don't need to retain, but it makes logic easier since we are creating
+    // in the other block.
+    CFRetain(description);
+  }
+
+  // Allocate memory as a block buffer.
+  // TODO(tkchin): figure out how to use a pool.
+  CMBlockBufferRef block_buffer = nullptr;
+  status = CMBlockBufferCreateWithMemoryBlock(
+      nullptr, nullptr, reader.BytesRemaining(), nullptr, nullptr, 0,
+      reader.BytesRemaining(), kCMBlockBufferAssureMemoryNowFlag,
+      &block_buffer);
+  if (status != kCMBlockBufferNoErr) {
+    LOG(LS_ERROR) << "Failed to create block buffer.";
+    CFRelease(description);
+    return false;
+  }
+
+  // Make sure block buffer is contiguous.
+  CMBlockBufferRef contiguous_buffer = nullptr;
+  if (!CMBlockBufferIsRangeContiguous(block_buffer, 0, 0)) {
+    status = CMBlockBufferCreateContiguous(
+        nullptr, block_buffer, nullptr, nullptr, 0, 0, 0, &contiguous_buffer);
+    if (status != noErr) {
+      LOG(LS_ERROR) << "Failed to flatten non-contiguous block buffer: "
+                    << status;
+      CFRelease(description);
+      CFRelease(block_buffer);
+      return false;
+    }
+  } else {
+    contiguous_buffer = block_buffer;
+    block_buffer = nullptr;
+  }
+
+  // Get a raw pointer into allocated memory.
+  size_t block_buffer_size = 0;
+  char* data_ptr = nullptr;
+  status = CMBlockBufferGetDataPointer(contiguous_buffer, 0, nullptr,
+                                       &block_buffer_size, &data_ptr);
+  if (status != kCMBlockBufferNoErr) {
+    LOG(LS_ERROR) << "Failed to get block buffer data pointer.";
+    CFRelease(description);
+    CFRelease(contiguous_buffer);
+    return false;
+  }
+  DCHECK(block_buffer_size == reader.BytesRemaining());
+
+  // Write Avcc NALUs into block buffer memory.
+  AvccBufferWriter writer(reinterpret_cast<uint8_t*>(data_ptr),
+                          block_buffer_size);
+  while (reader.BytesRemaining() > 0) {
+    const uint8_t* nalu_data_ptr = nullptr;
+    size_t nalu_data_size = 0;
+    if (reader.ReadNalu(&nalu_data_ptr, &nalu_data_size)) {
+      writer.WriteNalu(nalu_data_ptr, nalu_data_size);
+    }
+  }
+
+  // Create sample buffer.
+  status = CMSampleBufferCreate(nullptr, contiguous_buffer, true, nullptr,
+                                nullptr, description, 1, 0, nullptr, 0, nullptr,
+                                out_sample_buffer);
+  if (status != noErr) {
+    LOG(LS_ERROR) << "Failed to create sample buffer.";
+    CFRelease(description);
+    CFRelease(contiguous_buffer);
+    return false;
+  }
+  CFRelease(description);
+  CFRelease(contiguous_buffer);
+  return true;
+}
+
+AnnexBBufferReader::AnnexBBufferReader(const uint8_t* annexb_buffer,
+                                       size_t length)
+    : start_(annexb_buffer), offset_(0), next_offset_(0), length_(length) {
+  DCHECK(annexb_buffer);
+  offset_ = FindNextNaluHeader(start_, length_, 0);
+  next_offset_ =
+      FindNextNaluHeader(start_, length_, offset_ + sizeof(kAnnexBHeaderBytes));
+}
+
+bool AnnexBBufferReader::ReadNalu(const uint8_t** out_nalu,
+                                  size_t* out_length) {
+  DCHECK(out_nalu);
+  DCHECK(out_length);
+  *out_nalu = nullptr;
+  *out_length = 0;
+
+  size_t data_offset = offset_ + sizeof(kAnnexBHeaderBytes);
+  if (data_offset > length_) {
+    return false;
+  }
+  *out_nalu = start_ + data_offset;
+  *out_length = next_offset_ - data_offset;
+  offset_ = next_offset_;
+  next_offset_ =
+      FindNextNaluHeader(start_, length_, offset_ + sizeof(kAnnexBHeaderBytes));
+  return true;
+}
+
+size_t AnnexBBufferReader::BytesRemaining() const {
+  return length_ - offset_;
+}
+
+size_t AnnexBBufferReader::FindNextNaluHeader(const uint8_t* start,
+                                              size_t length,
+                                              size_t offset) const {
+  DCHECK(start);
+  if (offset + sizeof(kAnnexBHeaderBytes) > length) {
+    return length;
+  }
+  // NALUs are separated by an 00 00 00 01 header. Scan the byte stream
+  // starting from the offset for the next such sequence.
+  const uint8_t* current = start + offset;
+  // The loop reads sizeof(kAnnexBHeaderBytes) at a time, so stop when there
+  // aren't enough bytes remaining.
+  const uint8_t* const end = start + length - sizeof(kAnnexBHeaderBytes);
+  while (current < end) {
+    if (current[3] > 1) {
+      current += 4;
+    } else if (current[3] == 1 && current[2] == 0 && current[1] == 0 &&
+               current[0] == 0) {
+      return current - start;
+    } else {
+      ++current;
+    }
+  }
+  return length;
+}
+
+AvccBufferWriter::AvccBufferWriter(uint8_t* const avcc_buffer, size_t length)
+    : start_(avcc_buffer), offset_(0), length_(length) {
+  DCHECK(avcc_buffer);
+}
+
+bool AvccBufferWriter::WriteNalu(const uint8_t* data, size_t data_size) {
+  // Check if we can write this length of data.
+  if (data_size + kAvccHeaderByteSize > BytesRemaining()) {
+    return false;
+  }
+  // Write length header, which needs to be big endian.
+  uint32_t big_endian_length = CFSwapInt32HostToBig(data_size);
+  memcpy(start_ + offset_, &big_endian_length, sizeof(big_endian_length));
+  offset_ += sizeof(big_endian_length);
+  // Write data.
+  memcpy(start_ + offset_, data, data_size);
+  offset_ += data_size;
+  return true;
+}
+
+size_t AvccBufferWriter::BytesRemaining() const {
+  return length_ - offset_;
+}
+
+}  // namespace webrtc
+
+#endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)