| // Copyright (c) 2013 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/webm/tracks_builder.h" |
| |
| #include "media/webm/webm_constants.h" |
| |
| namespace media { |
| |
| // Returns size of an integer, formatted using Matroska serialization. |
| static int GetUIntMkvSize(uint64 value) { |
| if (value < 0x07FULL) |
| return 1; |
| if (value < 0x03FFFULL) |
| return 2; |
| if (value < 0x01FFFFFULL) |
| return 3; |
| if (value < 0x0FFFFFFFULL) |
| return 4; |
| if (value < 0x07FFFFFFFFULL) |
| return 5; |
| if (value < 0x03FFFFFFFFFFULL) |
| return 6; |
| if (value < 0x01FFFFFFFFFFFFULL) |
| return 7; |
| return 8; |
| } |
| |
| // Returns the minimium size required to serialize an integer value. |
| static int GetUIntSize(uint64 value) { |
| if (value < 0x0100ULL) |
| return 1; |
| if (value < 0x010000ULL) |
| return 2; |
| if (value < 0x01000000ULL) |
| return 3; |
| if (value < 0x0100000000ULL) |
| return 4; |
| if (value < 0x010000000000ULL) |
| return 5; |
| if (value < 0x01000000000000ULL) |
| return 6; |
| if (value < 0x0100000000000000ULL) |
| return 7; |
| return 8; |
| } |
| |
| static int MasterElementSize(int element_id, int payload_size) { |
| return GetUIntSize(element_id) + GetUIntMkvSize(payload_size) + payload_size; |
| } |
| |
| static int IntElementSize(int element_id, int value) { |
| return GetUIntSize(element_id) + 1 + GetUIntSize(value); |
| } |
| |
| static int StringElementSize(int element_id, const std::string& value) { |
| return GetUIntSize(element_id) + |
| GetUIntMkvSize(value.length()) + |
| value.length(); |
| } |
| |
| static void SerializeInt(uint8** buf_ptr, int* buf_size_ptr, |
| int64 value, int size) { |
| uint8*& buf = *buf_ptr; |
| int& buf_size = *buf_size_ptr; |
| |
| for (int idx = 1; idx <= size; ++idx) { |
| *buf++ = static_cast<uint8>(value >> ((size - idx) * 8)); |
| --buf_size; |
| } |
| } |
| |
| static void WriteElementId(uint8** buf, int* buf_size, int element_id) { |
| SerializeInt(buf, buf_size, element_id, GetUIntSize(element_id)); |
| } |
| |
| static void WriteUInt(uint8** buf, int* buf_size, uint64 value) { |
| const int size = GetUIntMkvSize(value); |
| value |= (1ULL << (size * 7)); // Matroska formatting |
| SerializeInt(buf, buf_size, value, size); |
| } |
| |
| static void WriteMasterElement(uint8** buf, int* buf_size, |
| int element_id, int payload_size) { |
| WriteElementId(buf, buf_size, element_id); |
| WriteUInt(buf, buf_size, payload_size); |
| } |
| |
| static void WriteIntElement(uint8** buf, int* buf_size, |
| int element_id, int value) { |
| WriteElementId(buf, buf_size, element_id); |
| |
| const int size = GetUIntSize(value); |
| WriteUInt(buf, buf_size, size); |
| |
| SerializeInt(buf, buf_size, value, size); |
| } |
| |
| static void WriteStringElement(uint8** buf_ptr, int* buf_size_ptr, |
| int element_id, const std::string& value) { |
| uint8*& buf = *buf_ptr; |
| int& buf_size = *buf_size_ptr; |
| |
| WriteElementId(&buf, &buf_size, element_id); |
| |
| const uint64 size = value.length(); |
| WriteUInt(&buf, &buf_size, size); |
| |
| memcpy(buf, value.data(), size); |
| buf += size; |
| buf_size -= size; |
| } |
| |
| TracksBuilder::TracksBuilder() {} |
| TracksBuilder::~TracksBuilder() {} |
| |
| void TracksBuilder::AddTrack( |
| int track_num, |
| int track_type, |
| int track_uid, |
| const std::string& codec_id, |
| const std::string& name, |
| const std::string& language) { |
| tracks_.push_back(Track(track_num, track_type, track_uid, codec_id, name, |
| language)); |
| } |
| |
| std::vector<uint8> TracksBuilder::Finish() { |
| // Allocate the storage |
| std::vector<uint8> buffer; |
| buffer.resize(GetTracksSize()); |
| |
| // Populate the storage with a tracks header |
| WriteTracks(&buffer[0], buffer.size()); |
| |
| return buffer; |
| } |
| |
| int TracksBuilder::GetTracksSize() const { |
| return MasterElementSize(kWebMIdTracks, GetTracksPayloadSize()); |
| } |
| |
| int TracksBuilder::GetTracksPayloadSize() const { |
| int payload_size = 0; |
| |
| for (TrackList::const_iterator itr = tracks_.begin(); |
| itr != tracks_.end(); ++itr) { |
| payload_size += itr->GetSize(); |
| } |
| |
| return payload_size; |
| } |
| |
| void TracksBuilder::WriteTracks(uint8* buf, int buf_size) const { |
| WriteMasterElement(&buf, &buf_size, kWebMIdTracks, GetTracksPayloadSize()); |
| |
| for (TrackList::const_iterator itr = tracks_.begin(); |
| itr != tracks_.end(); ++itr) { |
| itr->Write(&buf, &buf_size); |
| } |
| } |
| |
| TracksBuilder::Track::Track(int track_num, int track_type, int track_uid, |
| const std::string& codec_id, |
| const std::string& name, |
| const std::string& language) |
| : track_num_(track_num), |
| track_type_(track_type), |
| track_uid_(track_uid), |
| codec_id_(codec_id), |
| name_(name), |
| language_(language) { |
| } |
| |
| int TracksBuilder::Track::GetSize() const { |
| return MasterElementSize(kWebMIdTrackEntry, GetPayloadSize()); |
| } |
| |
| int TracksBuilder::Track::GetPayloadSize() const { |
| int size = 0; |
| |
| size += IntElementSize(kWebMIdTrackNumber, track_num_); |
| size += IntElementSize(kWebMIdTrackType, track_type_); |
| size += IntElementSize(kWebMIdTrackUID, track_uid_); |
| |
| if (!codec_id_.empty()) |
| size += StringElementSize(kWebMIdCodecID, codec_id_); |
| |
| if (!name_.empty()) |
| size += StringElementSize(kWebMIdName, name_); |
| |
| if (!language_.empty()) |
| size += StringElementSize(kWebMIdLanguage, language_); |
| |
| return size; |
| } |
| |
| void TracksBuilder::Track::Write(uint8** buf, int* buf_size) const { |
| WriteMasterElement(buf, buf_size, kWebMIdTrackEntry, GetPayloadSize()); |
| |
| WriteIntElement(buf, buf_size, kWebMIdTrackNumber, track_num_); |
| WriteIntElement(buf, buf_size, kWebMIdTrackType, track_type_); |
| WriteIntElement(buf, buf_size, kWebMIdTrackUID, track_uid_); |
| |
| if (!codec_id_.empty()) |
| WriteStringElement(buf, buf_size, kWebMIdCodecID, codec_id_); |
| |
| if (!name_.empty()) |
| WriteStringElement(buf, buf_size, kWebMIdName, name_); |
| |
| if (!language_.empty()) |
| WriteStringElement(buf, buf_size, kWebMIdLanguage, language_); |
| } |
| |
| } // namespace media |