content/media/fmp4/demuxer/es_descriptor.cc@a63d609f5ebe (annotated)
content/media/fmp4/demuxer/es_descriptor.cc
Thu, 15 Jan 2015 15:55:04 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:55:04 +0100
- branch
- TOR_BUG_9701
- changeset 9
- a63d609f5ebe
- permissions
- -rw-r--r--
Back out 97036ab72558 which inappropriately compared turds to third parties.
| michael@0 | 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| michael@0 | 2 | // Use of this source code is governed by a BSD-style license that can be |
| michael@0 | 3 | // found in the LICENSE file. |
| michael@0 | 4 | |
| michael@0 | 5 | #include "mp4_demuxer/es_descriptor.h" |
| michael@0 | 6 | #include "mp4_demuxer/bit_reader.h" |
| michael@0 | 7 | |
| michael@0 | 8 | namespace mp4_demuxer { |
| michael@0 | 9 | |
| michael@0 | 10 | // The elementary stream size is specific by up to 4 bytes. |
| michael@0 | 11 | // The MSB of a byte indicates if there are more bytes for the size. |
| michael@0 | 12 | static bool ReadESSize(BitReader* reader, uint32_t* size) { |
| michael@0 | 13 | uint8_t msb; |
| michael@0 | 14 | uint8_t byte; |
| michael@0 | 15 | |
| michael@0 | 16 | *size = 0; |
| michael@0 | 17 | |
| michael@0 | 18 | for (size_t i = 0; i < 4; ++i) { |
| michael@0 | 19 | RCHECK(reader->ReadBits(1, &msb)); |
| michael@0 | 20 | RCHECK(reader->ReadBits(7, &byte)); |
| michael@0 | 21 | *size = (*size << 7) + byte; |
| michael@0 | 22 | |
| michael@0 | 23 | if (msb == 0) |
| michael@0 | 24 | break; |
| michael@0 | 25 | } |
| michael@0 | 26 | |
| michael@0 | 27 | return true; |
| michael@0 | 28 | } |
| michael@0 | 29 | |
| michael@0 | 30 | ESDescriptor::ESDescriptor() |
| michael@0 | 31 | : object_type_(kForbidden) { |
| michael@0 | 32 | } |
| michael@0 | 33 | |
| michael@0 | 34 | ESDescriptor::~ESDescriptor() {} |
| michael@0 | 35 | |
| michael@0 | 36 | bool ESDescriptor::Parse(const std::vector<uint8_t>& data) { |
| michael@0 | 37 | BitReader reader(&data[0], data.size()); |
| michael@0 | 38 | uint8_t tag; |
| michael@0 | 39 | uint32_t size; |
| michael@0 | 40 | uint8_t stream_dependency_flag; |
| michael@0 | 41 | uint8_t url_flag; |
| michael@0 | 42 | uint8_t ocr_stream_flag; |
| michael@0 | 43 | uint16_t dummy; |
| michael@0 | 44 | |
| michael@0 | 45 | RCHECK(reader.ReadBits(8, &tag)); |
| michael@0 | 46 | RCHECK(tag == kESDescrTag); |
| michael@0 | 47 | RCHECK(ReadESSize(&reader, &size)); |
| michael@0 | 48 | |
| michael@0 | 49 | RCHECK(reader.ReadBits(16, &dummy)); // ES_ID |
| michael@0 | 50 | RCHECK(reader.ReadBits(1, &stream_dependency_flag)); |
| michael@0 | 51 | RCHECK(reader.ReadBits(1, &url_flag)); |
| michael@0 | 52 | RCHECK(!url_flag); // We don't support url flag |
| michael@0 | 53 | RCHECK(reader.ReadBits(1, &ocr_stream_flag)); |
| michael@0 | 54 | RCHECK(reader.ReadBits(5, &dummy)); // streamPriority |
| michael@0 | 55 | |
| michael@0 | 56 | if (stream_dependency_flag) |
| michael@0 | 57 | RCHECK(reader.ReadBits(16, &dummy)); // dependsOn_ES_ID |
| michael@0 | 58 | if (ocr_stream_flag) |
| michael@0 | 59 | RCHECK(reader.ReadBits(16, &dummy)); // OCR_ES_Id |
| michael@0 | 60 | |
| michael@0 | 61 | RCHECK(ParseDecoderConfigDescriptor(&reader)); |
| michael@0 | 62 | |
| michael@0 | 63 | return true; |
| michael@0 | 64 | } |
| michael@0 | 65 | |
| michael@0 | 66 | uint8_t ESDescriptor::object_type() const { |
| michael@0 | 67 | return object_type_; |
| michael@0 | 68 | } |
| michael@0 | 69 | |
| michael@0 | 70 | const std::vector<uint8_t>& ESDescriptor::decoder_specific_info() const { |
| michael@0 | 71 | return decoder_specific_info_; |
| michael@0 | 72 | } |
| michael@0 | 73 | |
| michael@0 | 74 | bool ESDescriptor::ParseDecoderConfigDescriptor(BitReader* reader) { |
| michael@0 | 75 | uint8_t tag; |
| michael@0 | 76 | uint32_t size; |
| michael@0 | 77 | uint64_t dummy; |
| michael@0 | 78 | |
| michael@0 | 79 | RCHECK(reader->ReadBits(8, &tag)); |
| michael@0 | 80 | RCHECK(tag == kDecoderConfigDescrTag); |
| michael@0 | 81 | RCHECK(ReadESSize(reader, &size)); |
| michael@0 | 82 | |
| michael@0 | 83 | RCHECK(reader->ReadBits(8, &object_type_)); |
| michael@0 | 84 | RCHECK(reader->ReadBits(64, &dummy)); |
| michael@0 | 85 | RCHECK(reader->ReadBits(32, &dummy)); |
| michael@0 | 86 | RCHECK(ParseDecoderSpecificInfo(reader)); |
| michael@0 | 87 | |
| michael@0 | 88 | return true; |
| michael@0 | 89 | } |
| michael@0 | 90 | |
| michael@0 | 91 | bool ESDescriptor::ParseDecoderSpecificInfo(BitReader* reader) { |
| michael@0 | 92 | uint8_t tag; |
| michael@0 | 93 | uint32_t size; |
| michael@0 | 94 | |
| michael@0 | 95 | RCHECK(reader->ReadBits(8, &tag)); |
| michael@0 | 96 | RCHECK(tag == kDecoderSpecificInfoTag); |
| michael@0 | 97 | RCHECK(ReadESSize(reader, &size)); |
| michael@0 | 98 | |
| michael@0 | 99 | decoder_specific_info_.resize(size); |
| michael@0 | 100 | for (uint32_t i = 0; i < size; ++i) |
| michael@0 | 101 | RCHECK(reader->ReadBits(8, &decoder_specific_info_[i])); |
| michael@0 | 102 | |
| michael@0 | 103 | return true; |
| michael@0 | 104 | } |
| michael@0 | 105 | |
| michael@0 | 106 | } // namespace mp4_demuxer |
