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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "FlacFrameParser.h"
#include "nsTArray.h"
#include "OggCodecState.h"
#include "OpusParser.h"
#include "VideoUtils.h"
#include "BufferReader.h"
#include "mozilla/ResultExtensions.h"
namespace mozilla {
#define OGG_FLAC_METADATA_TYPE_STREAMINFO 0x7F
#define FLAC_STREAMINFO_SIZE 34
#define BITMASK(x) ((1ULL << x) - 1)
enum {
FLAC_METADATA_TYPE_STREAMINFO = 0,
FLAC_METADATA_TYPE_PADDING,
FLAC_METADATA_TYPE_APPLICATION,
FLAC_METADATA_TYPE_SEEKTABLE,
FLAC_METADATA_TYPE_VORBIS_COMMENT,
FLAC_METADATA_TYPE_CUESHEET,
FLAC_METADATA_TYPE_PICTURE,
FLAC_METADATA_TYPE_INVALID = 127
};
FlacFrameParser::FlacFrameParser()
: mMinBlockSize(0),
mMaxBlockSize(0),
mMinFrameSize(0),
mMaxFrameSize(0),
mNumFrames(0),
mFullMetadata(false),
mPacketCount(0){};
FlacFrameParser::~FlacFrameParser() = default;
uint32_t FlacFrameParser::HeaderBlockLength(const uint8_t* aPacket) const {
uint32_t extra = 4;
if (aPacket[0] == 'f') {
// This must be the first block read, which contains the fLaC signature.
aPacket += 4;
extra += 4;
}
return (BigEndian::readUint32(aPacket) & BITMASK(24)) + extra;
}
Result<Ok, nsresult> FlacFrameParser::DecodeHeaderBlock(const uint8_t* aPacket,
size_t aLength) {
if (aLength < 4 || aPacket[0] == 0xff) {
// Not a header block.
return Err(NS_ERROR_FAILURE);
}
BufferReader br(aPacket, aLength);
mPacketCount++;
if (aPacket[0] == 'f') {
if (mPacketCount != 1 || memcmp(br.Read(4), "fLaC", 4) ||
br.Remaining() != FLAC_STREAMINFO_SIZE + 4) {
return Err(NS_ERROR_FAILURE);
}
}
uint8_t blockHeader;
MOZ_TRY_VAR(blockHeader, br.ReadU8());
// blockType is a misnomer as it could indicate here either a packet type
// should it points to the start of a Flac in Ogg metadata, or an actual
// block type as per the flac specification.
uint32_t blockType = blockHeader & 0x7f;
bool lastBlock = blockHeader & 0x80;
if (blockType == OGG_FLAC_METADATA_TYPE_STREAMINFO) {
if (mPacketCount != 1 || memcmp(br.Read(4), "FLAC", 4) ||
br.Remaining() != FLAC_STREAMINFO_SIZE + 12) {
return Err(NS_ERROR_FAILURE);
}
uint32_t major;
MOZ_TRY_VAR(major, br.ReadU8());
if (major != 1) {
// unsupported version;
return Err(NS_ERROR_FAILURE);
}
MOZ_TRY(br.ReadU8()); // minor version
uint32_t header;
MOZ_TRY_VAR(header, br.ReadU16());
mNumHeaders = Some(header);
br.Read(4); // fLaC
MOZ_TRY_VAR(blockType, br.ReadU8());
blockType &= BITMASK(7);
// First METADATA_BLOCK_STREAMINFO
if (blockType != FLAC_METADATA_TYPE_STREAMINFO) {
// First block must be a stream info.
return Err(NS_ERROR_FAILURE);
}
}
uint32_t blockDataSize;
MOZ_TRY_VAR(blockDataSize, br.ReadU24());
const uint8_t* blockDataStart = br.Peek(blockDataSize);
if (!blockDataStart) {
// Incomplete block.
return Err(NS_ERROR_FAILURE);
}
switch (blockType) {
case FLAC_METADATA_TYPE_STREAMINFO: {
if (mPacketCount != 1 || blockDataSize != FLAC_STREAMINFO_SIZE) {
// STREAMINFO must be the first metadata block found, and its size
// is constant.
return Err(NS_ERROR_FAILURE);
}
MOZ_TRY_VAR(mMinBlockSize, br.ReadU16());
MOZ_TRY_VAR(mMaxBlockSize, br.ReadU16());
MOZ_TRY_VAR(mMinFrameSize, br.ReadU24());
MOZ_TRY_VAR(mMaxFrameSize, br.ReadU24());
uint64_t blob;
MOZ_TRY_VAR(blob, br.ReadU64());
uint32_t sampleRate = (blob >> 44) & BITMASK(20);
if (!sampleRate) {
return Err(NS_ERROR_FAILURE);
}
uint32_t numChannels = ((blob >> 41) & BITMASK(3)) + 1;
if (numChannels > FLAC_MAX_CHANNELS) {
return Err(NS_ERROR_FAILURE);
}
uint32_t bps = ((blob >> 36) & BITMASK(5)) + 1;
if (bps > 24) {
return Err(NS_ERROR_FAILURE);
}
mNumFrames = blob & BITMASK(36);
mInfo.mMimeType = "audio/flac";
mInfo.mRate = sampleRate;
mInfo.mChannels = numChannels;
mInfo.mBitDepth = bps;
FlacCodecSpecificData flacCodecSpecificData;
flacCodecSpecificData.mStreamInfoBinaryBlob->AppendElements(
blockDataStart, blockDataSize);
mInfo.mCodecSpecificConfig =
AudioCodecSpecificVariant{std::move(flacCodecSpecificData)};
auto duration = media::TimeUnit(mNumFrames, sampleRate);
mInfo.mDuration = duration.IsValid() ? duration : media::TimeUnit::Zero();
mParser = MakeUnique<OpusParser>();
break;
}
case FLAC_METADATA_TYPE_VORBIS_COMMENT: {
if (!mParser) {
// We must have seen a valid streaminfo first.
return Err(NS_ERROR_FAILURE);
}
nsTArray<uint8_t> comments(blockDataSize + 8);
comments.AppendElements("OpusTags", 8);
comments.AppendElements(blockDataStart, blockDataSize);
if (!mParser->DecodeTags(comments.Elements(), comments.Length())) {
return Err(NS_ERROR_FAILURE);
}
break;
}
default:
break;
}
if (mNumHeaders && mPacketCount > mNumHeaders.ref() + 1) {
// Received too many header block. assuming invalid.
return Err(NS_ERROR_FAILURE);
}
if (lastBlock || (mNumHeaders && mNumHeaders.ref() + 1 == mPacketCount)) {
mFullMetadata = true;
}
return Ok();
}
int64_t FlacFrameParser::BlockDuration(const uint8_t* aPacket,
size_t aLength) const {
if (!mInfo.IsValid()) {
return -1;
}
if (mMinBlockSize == mMaxBlockSize) {
// block size is fixed, use this instead of looking at the frame header.
return mMinBlockSize;
}
// TODO
return 0;
}
Result<bool, nsresult> FlacFrameParser::IsHeaderBlock(const uint8_t* aPacket,
size_t aLength) const {
// Ogg Flac header
// The one-byte packet type 0x7F
// The four-byte ASCII signature "FLAC", i.e. 0x46, 0x4C, 0x41, 0x43
// Flac header:
// "fLaC", the FLAC stream marker in ASCII, meaning byte 0 of the stream is
// 0x66, followed by 0x4C 0x61 0x43
// If we detect either a ogg or plain flac header, then it must be valid.
if (aLength < 4 || aPacket[0] == 0xff) {
// A header is at least 4 bytes.
return false;
}
if (aPacket[0] == 0x7f) {
// Ogg packet
BufferReader br(aPacket + 1, aLength - 1);
const uint8_t* signature = br.Read(4);
return signature && !memcmp(signature, "FLAC", 4);
}
BufferReader br(aPacket, aLength - 1);
const uint8_t* signature = br.Read(4);
if (signature && !memcmp(signature, "fLaC", 4)) {
// Flac start header, must have STREAMINFO as first metadata block;
uint32_t blockType;
MOZ_TRY_VAR(blockType, br.ReadU8());
blockType &= 0x7f;
return blockType == FLAC_METADATA_TYPE_STREAMINFO;
}
char type = aPacket[0] & 0x7f;
return type >= 1 && type <= 6;
}
UniquePtr<MetadataTags> FlacFrameParser::GetTags() const {
if (!mParser) {
return nullptr;
}
auto tags = MakeUnique<MetadataTags>();
for (uint32_t i = 0; i < mParser->mTags.Length(); i++) {
OggCodecState::AddVorbisComment(tags, mParser->mTags[i].Data(),
mParser->mTags[i].Length());
}
return tags;
}
} // namespace mozilla
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