Implement ISO BMFF support in Media Source (try 2).

media/mp4/cenc.cc

+// Copyright (c) 2012 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/mp4/cenc.h"
+
+#include "media/mp4/box_reader.h"
+#include "media/mp4/rcheck.h"
+
+namespace media {
+namespace mp4 {
+
+FrameCENCInfo::FrameCENCInfo() {}
+FrameCENCInfo::~FrameCENCInfo() {}
+
+bool FrameCENCInfo::Parse(int iv_size, BufferReader* reader) {
+  const int kEntrySize = 6;
+
+  // Mandated by CENC spec
+  RCHECK(iv_size == 8 || iv_size == 16);
+  iv.resize(iv_size);
+
+  uint16 subsample_count;
+  RCHECK(reader->ReadVec(&iv, iv_size) &&
+         reader->Read2(&subsample_count) &&
+         reader->HasBytes(subsample_count * kEntrySize));
+  subsamples.resize(subsample_count);
+
+  for (int i = 0; i < subsample_count; i++) {
+    RCHECK(reader->Read2(&subsamples[i].clear_size) &&
+           reader->Read4(&subsamples[i].encrypted_size));
+  }
+  return true;
+}
+
+size_t FrameCENCInfo::GetTotalSize() const {
+  size_t size = 0;
+  for (size_t i = 0; i < subsamples.size(); i++) {
+    size += subsamples[i].clear_size + subsamples[i].encrypted_size;
+  }
+  return size;
+}
+
+}  // namespace mp4
+}  // namespace media