Implement ISO BMFF support in Media Source.

media/mp4/avc.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/avc.h"
+
+#include <algorithm>
+
+#include "media/mp4/box_reader.h"
+
+namespace media {
+namespace mp4 {
+
+const static uint8 kAnnexBStartCode[] = {0, 0, 0, 1};

[acolwell GONE FROM CHROMIUM, 2012/06/08 16:10:38]

lint nit: static comes first here and below

[strobe_, 2012/06/11 18:44:21]

Done.

+const static int kAnnexBStartCodeSize = 4;
+
+static bool ConvertAVCCToAnnexBInPlaceForLengthSize4(int buf_size,
+                                                     uint8* buf) {
+  const int kLengthSize = 4;
+  int pos = 0;
+  while (pos + kLengthSize < buf_size) {
+    int nal_size = buf[pos];
+    nal_size = (nal_size << 8) + buf[pos+1];
+    nal_size = (nal_size << 8) + buf[pos+2];
+    nal_size = (nal_size << 8) + buf[pos+3];
+    memcpy(&buf[pos], kAnnexBStartCode, kAnnexBStartCodeSize);
+    pos += kLengthSize + nal_size;
+  }
+  return pos == buf_size;
+}
+
+bool ConvertAVCCToAnnexB(int length_size, std::vector<uint8>* buffer) {
+  RCHECK(length_size == 1 || length_size == 2 || length_size == 4);
+
+  if (length_size == 4) {
+    return ConvertAVCCToAnnexBInPlaceForLengthSize4(buffer->size(),
+                                                    &((*buffer)[0]));
+  } else {

[acolwell GONE FROM CHROMIUM, 2012/06/08 16:10:38]

drop else

[strobe_, 2012/06/11 18:44:21]

Done.

+    std::vector<uint8_t> temp;
+    temp.swap(*buffer);
+    buffer->reserve(temp.size() + 32);
+
+    size_t pos = 0;
+    while (pos + length_size < temp.size()) {
+      int nal_size = temp[pos];
+      if (length_size == 2) nal_size = (nal_size << 8) + temp[pos+1];
+      pos += length_size;
+
+      RCHECK(pos + nal_size <= temp.size());
+      buffer->insert(buffer->end(), kAnnexBStartCode,
+                     kAnnexBStartCode + kAnnexBStartCodeSize);
+      buffer->insert(buffer->end(), temp.begin() + pos,
+                     temp.begin() + pos + nal_size);
+      pos += nal_size;
+    }
+    return pos == temp.size();
+  }
+}
+
+ChannelLayout ConvertAACChannelCountToChannelLayout(int count) {
+  switch (count) {
+    case 1:
+      return CHANNEL_LAYOUT_MONO;
+    case 2:
+      return CHANNEL_LAYOUT_STEREO;
+    case 3:
+      return CHANNEL_LAYOUT_SURROUND;
+    case 4:
+      return CHANNEL_LAYOUT_4_0;
+    case 5:
+      return CHANNEL_LAYOUT_5_0;
+    case 6:
+      return CHANNEL_LAYOUT_5_1;
+    case 8:
+      return CHANNEL_LAYOUT_7_1;
+    default:
+      return CHANNEL_LAYOUT_UNSUPPORTED;
+  }
+}
+

[acolwell GONE FROM CHROMIUM, 2012/06/08 16:10:38]

lint nit: remove blank line.

[strobe_, 2012/06/11 18:44:21]

Done.

+}
+}