Index: media/formats/mp2t/descriptors.cc |
diff --git a/media/formats/mp2t/descriptors.cc b/media/formats/mp2t/descriptors.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..7808ef4494281368a9cf1819a5fc1c871ec8f3c2 |
--- /dev/null |
+++ b/media/formats/mp2t/descriptors.cc |
@@ -0,0 +1,153 @@ |
+// Copyright 2015 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/formats/mp2t/descriptors.h" |
+ |
+#include <vector> |
+ |
+#include "base/logging.h" |
+#include "media/base/bit_reader.h" |
+#include "media/formats/mp2t/mp2t_common.h" |
+ |
+namespace media { |
+namespace mp2t { |
+ |
+namespace { |
+ |
+// Tag values for various kinds of descriptors for which there is specific |
+// parsing support herein. |
+enum DescriptorTag { |
+ DESCRIPTOR_TAG_REGISTRATION = 5, |
+ DESCRIPTOR_TAG_CA = 9, |
+ DESCRIPTOR_TAG_PRIVATE_DATA_INDICATOR = 15, |
+}; |
+ |
+const int kCASystemIdCenc = 0x6365; // 'ce' |
+ |
+class StringBitReader : public BitReader { |
+ public: |
+ StringBitReader(const std::string& input); |
+ ~StringBitReader() override; |
+}; |
+ |
+StringBitReader::StringBitReader(const std::string& input) |
+ : BitReader(reinterpret_cast<const uint8_t*>(input.data()), input.size()) {} |
+ |
+StringBitReader::~StringBitReader() {} |
+ |
+} // namespace |
+ |
+Descriptors::Descriptors() {} |
+ |
+Descriptors::~Descriptors() {} |
+ |
+bool Descriptors::Read(BitReader* reader, int size) { |
+ DCHECK(reader); |
+ DCHECK(size >= 0); |
+ descriptors_.clear(); |
+ if (size == 0) |
+ return true; |
+ int initial_bits_read = reader->bits_read(); |
+ int bits_read = 0; |
+ int bits_available = reader->bits_available(); |
+ int size_in_bits = 8 * size; |
+ if (size_in_bits > bits_available) |
+ return false; |
+ bits_available = size_in_bits; |
+ do { |
+ int tag; |
+ size_t length; |
+ RCHECK(reader->ReadBits(8, &tag)); |
+ RCHECK(reader->ReadBits(8, &length)); |
+ char data[256]; |
+ for (size_t i = 0; i < length; i++) { |
+ RCHECK(reader->ReadBits(8, &data[i])); |
+ } |
+ descriptors_.insert(Descriptor(tag, std::string(data, length))); |
+ bits_read = reader->bits_read() - initial_bits_read; |
+ } while (bits_read < bits_available); |
+ return bits_read == bits_available; |
+} |
+ |
+bool Descriptors::HasRegistrationDescriptor( |
+ int64_t* format_identifier, |
+ std::string* additional_info) const { |
+ DCHECK(format_identifier); |
+ DCHECK(additional_info); |
+ auto search = descriptors_.find(DESCRIPTOR_TAG_REGISTRATION); |
+ if (search == descriptors_.end()) |
+ return false; |
+ const std::string& data = search->second; |
+ StringBitReader reader(data); |
+ RCHECK(reader.ReadBits(32, format_identifier)); |
+ size_t extra_bits = reader.bits_available(); |
+ RCHECK(extra_bits % 8 == 0); |
+ RCHECK(reader.ReadString(extra_bits, additional_info)); |
+ return true; |
+} |
+ |
+bool Descriptors::HasCADescriptor(int* system_id, |
+ int* pid, |
+ std::string* private_data) const { |
+ DCHECK(system_id); |
+ DCHECK(pid); |
+ DCHECK(private_data); |
+ auto search = descriptors_.find(DESCRIPTOR_TAG_CA); |
+ if (search == descriptors_.end()) |
+ return false; |
+ const std::string& data = search->second; |
+ StringBitReader reader(data); |
+ RCHECK(reader.ReadBits(16, system_id)); |
+ RCHECK(reader.SkipBits(3)); |
+ RCHECK(reader.ReadBits(13, pid)); |
+ size_t extra_bits = reader.bits_available(); |
+ RCHECK(extra_bits % 8 == 0); |
+ RCHECK(reader.ReadString(extra_bits, private_data)); |
+ return true; |
+} |
+ |
+bool Descriptors::HasCADescriptorCenc(int* ca_pid, int* pssh_pid) const { |
+ DCHECK(ca_pid); |
+ DCHECK(pssh_pid); |
+ int system_id; |
+ std::string private_data; |
+ if (!HasCADescriptor(&system_id, ca_pid, &private_data)) |
+ return false; |
+ if (system_id != kCASystemIdCenc) |
+ return false; |
+ StringBitReader reader(private_data); |
+ uint32_t scheme_type; |
+ uint32_t scheme_version; |
+ int num_systems; |
+ int encryption_algorithm; |
+ char pssh_system_id[16]; |
+ // TODO(dougsteed). Currently we don't check many of the following values. |
+ // When we flesh out this implementation to cover all of ISO/IEC 23001-9 we |
+ // will need to use and check these values. |
+ RCHECK(reader.ReadBits(32, &scheme_type)); |
+ RCHECK(reader.ReadBits(32, &scheme_version)); |
+ RCHECK(reader.ReadBits(8, &num_systems)); |
+ RCHECK(num_systems == 1); |
+ RCHECK(reader.ReadBits(24, &encryption_algorithm)); |
+ for (size_t i = 0; i < 16; i++) { |
+ RCHECK(reader.ReadBits(8, &pssh_system_id[i])); |
+ } |
+ RCHECK(reader.ReadBits(13, pssh_pid)); |
+ return true; |
+} |
+ |
+bool Descriptors::HasPrivateDataIndicator(int64_t value) const { |
+ int64_t private_data_indicator; |
+ auto search = descriptors_.find(DESCRIPTOR_TAG_PRIVATE_DATA_INDICATOR); |
+ if (search == descriptors_.end()) |
+ return false; |
+ const std::string& data = search->second; |
+ StringBitReader reader(data); |
+ RCHECK(reader.ReadBits(32, &private_data_indicator)); |
+ RCHECK(reader.bits_available() == 0); |
+ return private_data_indicator == value; |
+} |
+ |
+} // namespace mp2t |
+} // namespace media |