H264 HW encode using VideoToolbox

media/base/mac/videotoolbox_helpers.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/mac/videotoolbox_helpers.h"
+
+#include <vector>
+
+#include "base/big_endian.h"
+
+namespace media {
+
+// Copy a H.264 frame stored in a CM sample buffer to an Annex B buffer. Copies
+// parameter sets for keyframes before the frame data as well.
+void CopySampleBufferToAnnexBBuffer(CoreMediaGlue::CMSampleBufferRef sbuf,
+                                    std::string* annexb_buffer,
+                                    bool keyframe) {
+  // Perform two pass, one to figure out the total output size, and another to
+  // copy the data after having performed a single output allocation. Note that
+  // we'll allocate a bit more because we'll count 4 bytes instead of 3 for
+  // video NALs.
+
+  OSStatus status;
+
+  // Get the sample buffer's block buffer and format description.
+  auto bb = CoreMediaGlue::CMSampleBufferGetDataBuffer(sbuf);
+  DCHECK(bb);
+  auto fdesc = CoreMediaGlue::CMSampleBufferGetFormatDescription(sbuf);
+  DCHECK(fdesc);
+
+  size_t bb_size = CoreMediaGlue::CMBlockBufferGetDataLength(bb);
+  size_t total_bytes = bb_size;
+
+  size_t pset_count;
+  int nal_size_field_bytes;
+  status = CoreMediaGlue::CMVideoFormatDescriptionGetH264ParameterSetAtIndex(
+      fdesc, 0, nullptr, nullptr, &pset_count, &nal_size_field_bytes);
+  if (status ==
+      CoreMediaGlue::kCMFormatDescriptionBridgeError_InvalidParameter) {
+    DLOG(WARNING) << " assuming 2 parameter sets and 4 bytes NAL length header";
+    pset_count = 2;
+    nal_size_field_bytes = 4;
+  } else if (status != noErr) {
+    DLOG(ERROR)
+        << " CMVideoFormatDescriptionGetH264ParameterSetAtIndex failed: "
+        << status;
+    return;
+  }
+
+  if (keyframe) {
+    const uint8_t* pset;
+    size_t pset_size;
+    for (size_t pset_i = 0; pset_i < pset_count; ++pset_i) {
+      status =
+          CoreMediaGlue::CMVideoFormatDescriptionGetH264ParameterSetAtIndex(
+              fdesc, pset_i, &pset, &pset_size, nullptr, nullptr);
+      if (status != noErr) {
+        DLOG(ERROR)
+            << " CMVideoFormatDescriptionGetH264ParameterSetAtIndex failed: "
+            << status;
+        return;
+      }
+      total_bytes += pset_size + nal_size_field_bytes;
+    }
+  }
+
+  annexb_buffer->reserve(total_bytes);
+
+  // Copy all parameter sets before keyframes.
+  if (keyframe) {
+    const uint8_t* pset;
+    size_t pset_size;
+    for (size_t pset_i = 0; pset_i < pset_count; ++pset_i) {
+      status =
+          CoreMediaGlue::CMVideoFormatDescriptionGetH264ParameterSetAtIndex(
+              fdesc, pset_i, &pset, &pset_size, nullptr, nullptr);
+      if (status != noErr) {
+        DLOG(ERROR)
+            << " CMVideoFormatDescriptionGetH264ParameterSetAtIndex failed: "
+            << status;
+        return;
+      }
+      static const char startcode_4[4] = {0, 0, 0, 1};
+      annexb_buffer->append(startcode_4, sizeof(startcode_4));
+      annexb_buffer->append(reinterpret_cast<const char*>(pset), pset_size);
+    }
+  }
+
+  // Block buffers can be composed of non-contiguous chunks. For the sake of
+  // keeping this code simple, flatten non-contiguous block buffers.
+  base::ScopedCFTypeRef<CoreMediaGlue::CMBlockBufferRef> contiguous_bb(
+      bb, base::scoped_policy::RETAIN);
+  if (!CoreMediaGlue::CMBlockBufferIsRangeContiguous(bb, 0, 0)) {
+    contiguous_bb.reset();
+    status = CoreMediaGlue::CMBlockBufferCreateContiguous(
+        kCFAllocatorDefault, bb, kCFAllocatorDefault, nullptr, 0, 0, 0,
+        contiguous_bb.InitializeInto());
+    if (status != noErr) {
+      DLOG(ERROR) << " CMBlockBufferCreateContiguous failed: " << status;
+      return;
+    }
+  }
+
+  // Copy all the NAL units. In the process convert them from AVCC format
+  // (length header) to AnnexB format (start code).
+  char* bb_data;
+  status = CoreMediaGlue::CMBlockBufferGetDataPointer(contiguous_bb, 0, nullptr,
+                                                      nullptr, &bb_data);
+  if (status != noErr) {
+    DLOG(ERROR) << " CMBlockBufferGetDataPointer failed: " << status;
+    return;
+  }
+
+  if (nal_size_field_bytes == 1) {
+    CopyNalsToAnnexB<uint8_t>(bb_data, bb_size, annexb_buffer);
+  } else if (nal_size_field_bytes == 2) {
+    CopyNalsToAnnexB<uint16_t>(bb_data, bb_size, annexb_buffer);
+  } else if (nal_size_field_bytes == 4) {
+    CopyNalsToAnnexB<uint32_t>(bb_data, bb_size, annexb_buffer);
+  } else {
+    NOTREACHED();
+  }
+}
+
+template <typename NalSizeType>
+void CopyNalsToAnnexB(char* avcc_buffer,
+                      const size_t avcc_size,
+                      std::string* annexb_buffer) {
+  static_assert(sizeof(NalSizeType) == 1 || sizeof(NalSizeType) == 2 ||
+                    sizeof(NalSizeType) == 4,
+                "NAL size type has unsupported size");
+  static const char startcode_3[3] = {0, 0, 1};
+  DCHECK(avcc_buffer);
+  DCHECK(annexb_buffer);
+  size_t bytes_left = avcc_size;
+  while (bytes_left > 0) {
+    DCHECK_GT(bytes_left, sizeof(NalSizeType));
+    NalSizeType nal_size;
+    base::ReadBigEndian(avcc_buffer, &nal_size);
+    bytes_left -= sizeof(NalSizeType);
+    avcc_buffer += sizeof(NalSizeType);
+
+    DCHECK_GE(bytes_left, nal_size);
+    annexb_buffer->append(startcode_3, sizeof(startcode_3));
+    annexb_buffer->append(avcc_buffer, nal_size);
+    bytes_left -= nal_size;
+    avcc_buffer += nal_size;
+  }
+}
+
+base::ScopedCFTypeRef<CFDictionaryRef>
+DictionaryWithKeysAndValues(CFTypeRef* keys, CFTypeRef* values, size_t size) {
+  return base::ScopedCFTypeRef<CFDictionaryRef>(CFDictionaryCreate(
+      kCFAllocatorDefault, keys, values, size, &kCFTypeDictionaryKeyCallBacks,
+      &kCFTypeDictionaryValueCallBacks));
+}
+
+base::ScopedCFTypeRef<CFDictionaryRef> DictionaryWithKeyValue(CFTypeRef key,
+                                                              CFTypeRef value) {
+  CFTypeRef keys[1] = {key};
+  CFTypeRef values[1] = {value};
+  return DictionaryWithKeysAndValues(keys, values, 1);
+}
+
+base::ScopedCFTypeRef<CFArrayRef> ArrayWithIntegers(const int* v, size_t size) {
+  std::vector<CFNumberRef> numbers;
+  numbers.reserve(size);
+  for (const int* end = v + size; v < end; ++v)
+    numbers.push_back(CFNumberCreate(nullptr, kCFNumberSInt32Type, v));
+  base::ScopedCFTypeRef<CFArrayRef> array(CFArrayCreate(
+      kCFAllocatorDefault, reinterpret_cast<const void**>(&numbers[0]),
+      numbers.size(), &kCFTypeArrayCallBacks));
+  for (auto& number : numbers) {
+    CFRelease(number);
+  }
+  return array;
+}
+
+bool SetSessionProperty(base::ScopedCFTypeRef<VTCompressionSessionRef> session,
+                        const VideoToolboxGlue* const glue,
+                        CFStringRef key,
+                        int32_t value) {
+  base::ScopedCFTypeRef<CFNumberRef> cfvalue(
+      CFNumberCreate(nullptr, kCFNumberSInt32Type, &value));
+  return glue->VTSessionSetProperty(session, key, cfvalue) == noErr;
+}
+
+bool SetSessionProperty(base::ScopedCFTypeRef<VTCompressionSessionRef> session,
+                        const VideoToolboxGlue* const glue,
+                        CFStringRef key,
+                        bool value) {
+  CFBooleanRef cfvalue = (value) ? kCFBooleanTrue : kCFBooleanFalse;
+  return glue->VTSessionSetProperty(session, key, cfvalue) == noErr;
+}
+
+bool SetSessionProperty(base::ScopedCFTypeRef<VTCompressionSessionRef> session,
+                        const VideoToolboxGlue* const glue,
+                        CFStringRef key,
+                        CFStringRef value) {
+  return glue->VTSessionSetProperty(session, key, value) == noErr;
+}
+
+}  // namespace media