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gecko-dev/dom/media/flac/FlacDemuxer.cpp

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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 "FlacDemuxer.h"
#include "mozilla/Maybe.h"
#include "BitReader.h"
#include "prenv.h"
#include "FlacFrameParser.h"
#include "VideoUtils.h"
#include "TimeUnits.h"
extern mozilla::LazyLogModule gMediaDemuxerLog;
#define LOG(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, msg, ##__VA_ARGS__)
#define LOGV(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, msg, ##__VA_ARGS__)
using namespace mozilla::media;
namespace mozilla {
namespace flac {
// flac::FrameHeader - Holds the flac frame header and its parsing
// state.
class FrameHeader {
public:
const AudioInfo& Info() const { return mInfo; }
uint32_t Size() const { return mSize; }
bool IsValid() const { return mValid; }
// Parse the current packet and check that it made a valid flac frame header.
// From https://xiph.org/flac/format.html#frame_header
// A valid header is one that can be decoded without error and that has a
// valid CRC.
bool Parse(const uint8_t* aPacket, size_t aBytes) {
BitReader br(aPacket, aBytes * 8);
// Frame sync code.
if ((br.ReadBits(15) & 0x7fff) != 0x7ffc) {
return false;
}
// Variable block size stream code.
mVariableBlockSize = br.ReadBit();
// Block size and sample rate codes.
int bs_code = br.ReadBits(4);
int sr_code = br.ReadBits(4);
// Channels and decorrelation.
int ch_mode = br.ReadBits(4);
if (ch_mode < FLAC_MAX_CHANNELS) {
mInfo.mChannels = ch_mode + 1;
} else if (ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
// This is a special flac channels, we can't handle those yet. Treat it
// as stereo.
mInfo.mChannels = 2;
} else {
// invalid channel mode
return false;
}
// Bits per sample.
int bps_code = br.ReadBits(3);
if (bps_code == 3 || bps_code == 7) {
// Invalid sample size code.
return false;
}
mInfo.mBitDepth = FlacSampleSizeTable[bps_code];
// Reserved bit, must be 0.
if (br.ReadBit()) {
// Broken stream, invalid padding.
return false;
}
// Sample or frame count.
int64_t frameOrSampleNum = br.ReadUTF8();
if (frameOrSampleNum < 0) {
return false;
}
mFrameOrSampleNum = frameOrSampleNum;
// Blocksize
if (bs_code == 0) {
// reserved blocksize code
return false;
} else if (bs_code == 6) {
mBlocksize = br.ReadBits(8) + 1;
} else if (bs_code == 7) {
mBlocksize = br.ReadBits(16) + 1;
} else {
mBlocksize = FlacBlocksizeTable[bs_code];
}
// Sample rate.
if (sr_code < 12) {
mInfo.mRate = FlacSampleRateTable[sr_code];
} else if (sr_code == 12) {
mInfo.mRate = br.ReadBits(8) * 1000;
} else if (sr_code == 13) {
mInfo.mRate = br.ReadBits(16);
} else if (sr_code == 14) {
mInfo.mRate = br.ReadBits(16) * 10;
} else {
// Illegal sample rate code.
return false;
}
// Header CRC-8 check.
uint8_t crc = 0;
for (uint32_t i = 0; i < br.BitCount() / 8; i++) {
crc = CRC8Table[crc ^ aPacket[i]];
}
mValid =
#ifdef FUZZING
true;
#else
crc == br.ReadBits(8);
#endif
mSize = br.BitCount() / 8;
if (mValid) {
// Set the mimetype to make it a valid AudioInfo.
mInfo.mMimeType = "audio/flac";
}
return mValid;
}
private:
friend class Frame;
enum {
FLAC_CHMODE_INDEPENDENT = 0,
FLAC_CHMODE_LEFT_SIDE,
FLAC_CHMODE_RIGHT_SIDE,
FLAC_CHMODE_MID_SIDE,
};
AudioInfo mInfo;
// mFrameOrSampleNum is either:
// 1- coded sample number if blocksize is variable or
// 2- coded frame number if blocksize is fixed.
// A frame is made of Blocksize sample.
uint64_t mFrameOrSampleNum = 0;
bool mVariableBlockSize = false;
uint32_t mBlocksize = 0;
;
uint32_t mSize = 0;
bool mValid = false;
static const int FlacSampleRateTable[16];
static const int32_t FlacBlocksizeTable[16];
static const uint8_t FlacSampleSizeTable[8];
static const uint8_t CRC8Table[256];
};
const int FrameHeader::FlacSampleRateTable[16] = {
0, 88200, 176400, 192000, 8000, 16000, 22050, 24000,
32000, 44100, 48000, 96000, 0, 0, 0, 0};
const int32_t FrameHeader::FlacBlocksizeTable[16] = {
0, 192, 576 << 0, 576 << 1, 576 << 2, 576 << 3,
0, 0, 256 << 0, 256 << 1, 256 << 2, 256 << 3,
256 << 4, 256 << 5, 256 << 6, 256 << 7};
const uint8_t FrameHeader::FlacSampleSizeTable[8] = {0, 8, 12, 0,
16, 20, 24, 0};
const uint8_t FrameHeader::CRC8Table[256] = {
0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15, 0x38, 0x3F, 0x36, 0x31,
0x24, 0x23, 0x2A, 0x2D, 0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D, 0xE0, 0xE7, 0xEE, 0xE9,
0xFC, 0xFB, 0xF2, 0xF5, 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85, 0xA8, 0xAF, 0xA6, 0xA1,
0xB4, 0xB3, 0xBA, 0xBD, 0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA, 0xB7, 0xB0, 0xB9, 0xBE,
0xAB, 0xAC, 0xA5, 0xA2, 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32, 0x1F, 0x18, 0x11, 0x16,
0x03, 0x04, 0x0D, 0x0A, 0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A, 0x89, 0x8E, 0x87, 0x80,
0x95, 0x92, 0x9B, 0x9C, 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC, 0xC1, 0xC6, 0xCF, 0xC8,
0xDD, 0xDA, 0xD3, 0xD4, 0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44, 0x19, 0x1E, 0x17, 0x10,
0x05, 0x02, 0x0B, 0x0C, 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B, 0x76, 0x71, 0x78, 0x7F,
0x6A, 0x6D, 0x64, 0x63, 0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13, 0xAE, 0xA9, 0xA0, 0xA7,
0xB2, 0xB5, 0xBC, 0xBB, 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB, 0xE6, 0xE1, 0xE8, 0xEF,
0xFA, 0xFD, 0xF4, 0xF3};
// flac::Frame - Frame meta container used to parse and hold a frame
// header and side info.
class Frame {
public:
// The FLAC signature is made of 14 bits set to 1; however the 15th bit is
// mandatorily set to 0, so we need to find either of 0xfffc or 0xfffd 2-bytes
// signature. We first use a bitmask to see if 0xfc or 0xfd is present. And if
// so we check for the whole signature.
int64_t FindNext(const uint8_t* aData, const uint32_t aLength) {
// The non-variable size of a FLAC header is 32 bits followed by variable
// size data and a 8 bits CRC.
// There's no need to read the last 4 bytes, it can never make a complete
// header.
if (aLength < 4) {
return -1;
}
uint32_t modOffset = aLength % 4;
uint32_t i, j;
for (i = 0; i < modOffset; i++) {
if ((BigEndian::readUint16(aData + i) & 0xfffe) == 0xfff8) {
if (mHeader.Parse(aData + i, aLength - i)) {
return i;
}
}
}
for (; i < aLength - 4; i += 4) {
uint32_t x = BigEndian::readUint32(aData + i);
if (((x & ~(x + 0x01010101)) & 0x80808080)) {
for (j = 0; j < 4; j++) {
if ((BigEndian::readUint16(aData + i + j) & 0xfffe) == 0xfff8) {
if (mHeader.Parse(aData + i + j, aLength - i - j)) {
return i + j;
}
}
}
}
}
return -1;
}
// Find the next frame start in the current resource.
// On exit return true, offset is set and resource points to the frame found.
bool FindNext(MediaResourceIndex& aResource) {
static const int BUFFER_SIZE = 4096;
uint32_t previousBlocksize = Header().mBlocksize;
Reset();
nsTArray<char> buffer;
int64_t originalOffset = aResource.Tell();
int64_t offset = originalOffset;
uint32_t innerOffset = 0;
do {
uint32_t read = 0;
buffer.SetLength(BUFFER_SIZE + innerOffset);
nsresult rv =
aResource.Read(buffer.Elements() + innerOffset, BUFFER_SIZE, &read);
if (NS_FAILED(rv)) {
return false;
}
const size_t bufSize = read + innerOffset;
int64_t foundOffset =
FindNext(reinterpret_cast<uint8_t*>(buffer.Elements()), bufSize);
if (foundOffset >= 0) {
SetOffset(aResource, foundOffset + offset);
SetIndex(previousBlocksize);
return true;
}
if (read < BUFFER_SIZE) {
// Nothing more to try on as we had reached EOS during the previous
// read.
mEOS = true;
return false;
}
// Scan the next block;
// We rewind a bit to re-try what could have been an incomplete packet.
// The maximum size of a FLAC header being FLAC_MAX_FRAME_HEADER_SIZE so
// we need to retry just after that amount.
offset += bufSize - (FLAC_MAX_FRAME_HEADER_SIZE + 1);
buffer.RemoveElementsAt(0, bufSize - (FLAC_MAX_FRAME_HEADER_SIZE + 1));
innerOffset = buffer.Length();
} while (offset - originalOffset < FLAC_MAX_FRAME_SIZE);
return false;
}
int64_t Offset() const { return mOffset; }
const AudioInfo& Info() const { return Header().Info(); }
void SetEndOffset(int64_t aOffset) { mSize = aOffset - mOffset; }
// Return the index (in samples) from the beginning of the track.
uint64_t Index() const { return mIndex; }
void SetEndTime(uint64_t aIndex) {
if (aIndex > Index()) {
mDuration = aIndex - Index();
}
}
uint32_t Size() const { return mSize; }
TimeUnit Time() const {
if (!IsValid()) {
return TimeUnit::Invalid();
}
MOZ_ASSERT(Header().Info().mRate, "Invalid Frame. Need Header");
return FramesToTimeUnit(Index(), Header().Info().mRate);
}
TimeUnit Duration() const {
if (!IsValid()) {
return TimeUnit();
}
MOZ_ASSERT(Header().Info().mRate, "Invalid Frame. Need Header");
return FramesToTimeUnit(mDuration, Header().Info().mRate);
}
// Returns the parsed frame header.
const FrameHeader& Header() const { return mHeader; }
bool IsValid() const { return mHeader.IsValid(); }
bool EOS() const { return mEOS; }
void SetRate(uint32_t aRate) { mHeader.mInfo.mRate = aRate; };
void SetBitDepth(uint32_t aBitDepth) { mHeader.mInfo.mBitDepth = aBitDepth; }
void SetInvalid() { mHeader.mValid = false; }
// Resets the frame header and data.
void Reset() { *this = Frame(); }
private:
void SetOffset(MediaResourceIndex& aResource, int64_t aOffset) {
mOffset = aOffset;
aResource.Seek(SEEK_SET, mOffset);
}
void SetIndex(uint32_t aPreviousBlocksize) {
// Make sure the header has been parsed.
MOZ_ASSERT(Header().mBlocksize);
// If the blocksize is fixed, the frame's starting sample number will be
// the frame number times the blocksize. However, the last block may be
// shorter than the stream blocksize. Its starting sample number will be
// calculated as the frame number times the previous frame's blocksize,
// or zero if it is the first frame(mFrameOrSampleNum is 0 in that case).
mIndex = Header().mVariableBlockSize
? Header().mFrameOrSampleNum
: Header().mFrameOrSampleNum *
std::max(Header().mBlocksize, aPreviousBlocksize);
}
// The index in samples from start.
uint64_t mIndex = 0;
// The offset to the start of the header.
int64_t mOffset = 0;
uint32_t mSize = 0;
uint32_t mDuration = 0;
bool mEOS = false;
// The currently parsed frame header.
FrameHeader mHeader;
};
class FrameParser {
public:
// Returns the currently parsed frame. Reset via EndFrameSession.
const Frame& CurrentFrame() const { return mFrame; }
// Returns the first parsed frame.
const Frame& FirstFrame() const { return mFirstFrame; }
// Clear the last parsed frame to allow for next frame parsing
void EndFrameSession() {
mNextFrame.Reset();
mFrame.Reset();
}
// Attempt to find the next frame.
bool FindNextFrame(MediaResourceIndex& aResource) {
mFrame = mNextFrame;
if (GetNextFrame(aResource)) {
if (!mFrame.IsValid()) {
mFrame = mNextFrame;
// We need two frames to be able to start playing (or have reached EOS).
GetNextFrame(aResource);
}
}
if (mFrame.IsValid()) {
if (mNextFrame.EOS()) {
mFrame.SetEndOffset(aResource.Tell());
} else if (mNextFrame.IsValid()) {
mFrame.SetEndOffset(mNextFrame.Offset());
mFrame.SetEndTime(mNextFrame.Index());
}
}
if (!mFirstFrame.IsValid()) {
mFirstFrame = mFrame;
}
return mFrame.IsValid();
}
// Convenience methods to external FlacFrameParser ones.
bool IsHeaderBlock(const uint8_t* aPacket, size_t aLength) const {
auto res = mParser.IsHeaderBlock(aPacket, aLength);
return res.isOk() ? res.unwrap() : false;
}
uint32_t HeaderBlockLength(const uint8_t* aPacket) const {
return mParser.HeaderBlockLength(aPacket);
}
bool DecodeHeaderBlock(const uint8_t* aPacket, size_t aLength) {
return mParser.DecodeHeaderBlock(aPacket, aLength).isOk();
}
bool HasFullMetadata() const { return mParser.HasFullMetadata(); }
AudioInfo Info() const { return mParser.mInfo; }
// Return a hash table with tag metadata.
UniquePtr<MetadataTags> GetTags() const { return mParser.GetTags(); }
private:
bool GetNextFrame(MediaResourceIndex& aResource) {
while (mNextFrame.FindNext(aResource)) {
// Move our offset slightly, so that we don't find the same frame at the
// next FindNext call.
aResource.Seek(SEEK_CUR, mNextFrame.Header().Size());
if (mFrame.IsValid() &&
mNextFrame.Offset() - mFrame.Offset() < FLAC_MAX_FRAME_SIZE &&
!CheckCRC16AtOffset(mFrame.Offset(), mNextFrame.Offset(),
aResource)) {
// The frame doesn't match its CRC or would be too far, skip it..
continue;
}
CheckFrameData();
break;
}
return mNextFrame.IsValid();
}
bool CheckFrameData() {
if (mNextFrame.Header().Info().mRate == 0 ||
mNextFrame.Header().Info().mBitDepth == 0) {
if (!Info().IsValid()) {
// We can only use the STREAMINFO data if we have one.
mNextFrame.SetInvalid();
} else {
if (mNextFrame.Header().Info().mRate == 0) {
mNextFrame.SetRate(Info().mRate);
}
if (mNextFrame.Header().Info().mBitDepth == 0) {
mNextFrame.SetBitDepth(Info().mBitDepth);
}
}
}
return mNextFrame.IsValid();
}
bool CheckCRC16AtOffset(int64_t aStart, int64_t aEnd,
MediaResourceIndex& aResource) const {
int64_t size = aEnd - aStart;
if (size <= 0) {
return false;
}
UniquePtr<char[]> buffer(new char[size]);
uint32_t read = 0;
if (NS_FAILED(aResource.ReadAt(aStart, buffer.get(), size, &read)) ||
read != size) {
NS_WARNING("Couldn't read frame content");
return false;
}
uint16_t crc = 0;
uint8_t* buf = reinterpret_cast<uint8_t*>(buffer.get());
const uint8_t* end = buf + size;
while (buf < end) {
crc = CRC16Table[((uint8_t)crc) ^ *buf++] ^ (crc >> 8);
}
#ifdef FUZZING
return true;
#else
return !crc;
#endif
}
const uint16_t CRC16Table[256] = {
0x0000, 0x0580, 0x0F80, 0x0A00, 0x1B80, 0x1E00, 0x1400, 0x1180, 0x3380,
0x3600, 0x3C00, 0x3980, 0x2800, 0x2D80, 0x2780, 0x2200, 0x6380, 0x6600,
0x6C00, 0x6980, 0x7800, 0x7D80, 0x7780, 0x7200, 0x5000, 0x5580, 0x5F80,
0x5A00, 0x4B80, 0x4E00, 0x4400, 0x4180, 0xC380, 0xC600, 0xCC00, 0xC980,
0xD800, 0xDD80, 0xD780, 0xD200, 0xF000, 0xF580, 0xFF80, 0xFA00, 0xEB80,
0xEE00, 0xE400, 0xE180, 0xA000, 0xA580, 0xAF80, 0xAA00, 0xBB80, 0xBE00,
0xB400, 0xB180, 0x9380, 0x9600, 0x9C00, 0x9980, 0x8800, 0x8D80, 0x8780,
0x8200, 0x8381, 0x8601, 0x8C01, 0x8981, 0x9801, 0x9D81, 0x9781, 0x9201,
0xB001, 0xB581, 0xBF81, 0xBA01, 0xAB81, 0xAE01, 0xA401, 0xA181, 0xE001,
0xE581, 0xEF81, 0xEA01, 0xFB81, 0xFE01, 0xF401, 0xF181, 0xD381, 0xD601,
0xDC01, 0xD981, 0xC801, 0xCD81, 0xC781, 0xC201, 0x4001, 0x4581, 0x4F81,
0x4A01, 0x5B81, 0x5E01, 0x5401, 0x5181, 0x7381, 0x7601, 0x7C01, 0x7981,
0x6801, 0x6D81, 0x6781, 0x6201, 0x2381, 0x2601, 0x2C01, 0x2981, 0x3801,
0x3D81, 0x3781, 0x3201, 0x1001, 0x1581, 0x1F81, 0x1A01, 0x0B81, 0x0E01,
0x0401, 0x0181, 0x0383, 0x0603, 0x0C03, 0x0983, 0x1803, 0x1D83, 0x1783,
0x1203, 0x3003, 0x3583, 0x3F83, 0x3A03, 0x2B83, 0x2E03, 0x2403, 0x2183,
0x6003, 0x6583, 0x6F83, 0x6A03, 0x7B83, 0x7E03, 0x7403, 0x7183, 0x5383,
0x5603, 0x5C03, 0x5983, 0x4803, 0x4D83, 0x4783, 0x4203, 0xC003, 0xC583,
0xCF83, 0xCA03, 0xDB83, 0xDE03, 0xD403, 0xD183, 0xF383, 0xF603, 0xFC03,
0xF983, 0xE803, 0xED83, 0xE783, 0xE203, 0xA383, 0xA603, 0xAC03, 0xA983,
0xB803, 0xBD83, 0xB783, 0xB203, 0x9003, 0x9583, 0x9F83, 0x9A03, 0x8B83,
0x8E03, 0x8403, 0x8183, 0x8002, 0x8582, 0x8F82, 0x8A02, 0x9B82, 0x9E02,
0x9402, 0x9182, 0xB382, 0xB602, 0xBC02, 0xB982, 0xA802, 0xAD82, 0xA782,
0xA202, 0xE382, 0xE602, 0xEC02, 0xE982, 0xF802, 0xFD82, 0xF782, 0xF202,
0xD002, 0xD582, 0xDF82, 0xDA02, 0xCB82, 0xCE02, 0xC402, 0xC182, 0x4382,
0x4602, 0x4C02, 0x4982, 0x5802, 0x5D82, 0x5782, 0x5202, 0x7002, 0x7582,
0x7F82, 0x7A02, 0x6B82, 0x6E02, 0x6402, 0x6182, 0x2002, 0x2582, 0x2F82,
0x2A02, 0x3B82, 0x3E02, 0x3402, 0x3182, 0x1382, 0x1602, 0x1C02, 0x1982,
0x0802, 0x0D82, 0x0782, 0x0202,
};
FlacFrameParser mParser;
// We keep the first parsed frame around for static info access
// and the currently parsed frame.
Frame mFirstFrame;
Frame mNextFrame;
Frame mFrame;
};
} // namespace flac
// FlacDemuxer
FlacDemuxer::FlacDemuxer(MediaResource* aSource) : mSource(aSource) {
DDLINKCHILD("source", aSource);
}
bool FlacDemuxer::InitInternal() {
if (!mTrackDemuxer) {
mTrackDemuxer = new FlacTrackDemuxer(mSource);
DDLINKCHILD("track demuxer", mTrackDemuxer.get());
}
return mTrackDemuxer->Init();
}
RefPtr<FlacDemuxer::InitPromise> FlacDemuxer::Init() {
if (!InitInternal()) {
LOG("Init() failure: waiting for data");
return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
__func__);
}
LOG("Init() successful");
return InitPromise::CreateAndResolve(NS_OK, __func__);
}
uint32_t FlacDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
return (aType == TrackInfo::kAudioTrack) ? 1 : 0;
}
already_AddRefed<MediaTrackDemuxer> FlacDemuxer::GetTrackDemuxer(
TrackInfo::TrackType aType, uint32_t aTrackNumber) {
if (!mTrackDemuxer) {
return nullptr;
}
return RefPtr<FlacTrackDemuxer>(mTrackDemuxer).forget();
}
bool FlacDemuxer::IsSeekable() const {
return mTrackDemuxer && mTrackDemuxer->IsSeekable();
}
// FlacTrackDemuxer
FlacTrackDemuxer::FlacTrackDemuxer(MediaResource* aSource)
: mSource(aSource), mParser(new flac::FrameParser()), mTotalFrameLen(0) {
DDLINKCHILD("source", aSource);
Reset();
}
FlacTrackDemuxer::~FlacTrackDemuxer() {}
bool FlacTrackDemuxer::Init() {
static const int BUFFER_SIZE = 4096;
// First check if we have a valid Flac start.
char buffer[BUFFER_SIZE];
const uint8_t* ubuffer = // only needed due to type constraints of ReadAt.
reinterpret_cast<uint8_t*>(buffer);
int64_t offset = 0;
do {
uint32_t read = 0;
nsresult ret = mSource.ReadAt(offset, buffer, BUFFER_SIZE, &read);
if (NS_FAILED(ret) || read < BUFFER_SIZE) {
// Assume that if we can't read that many bytes while parsing the header,
// that something is wrong.
return false;
}
if (!mParser->IsHeaderBlock(ubuffer, BUFFER_SIZE)) {
// Not a header and we haven't reached the end of the metadata blocks.
// Will fall back to using the frames header instead.
break;
}
uint32_t sizeHeader = mParser->HeaderBlockLength(ubuffer);
RefPtr<MediaByteBuffer> block = mSource.MediaReadAt(offset, sizeHeader);
if (!block || block->Length() != sizeHeader) {
break;
}
if (!mParser->DecodeHeaderBlock(block->Elements(), sizeHeader)) {
break;
}
offset += sizeHeader;
} while (!mParser->HasFullMetadata());
// First flac frame is found after the metadata.
// Can seek there immediately to avoid reparsing it all.
mSource.Seek(SEEK_SET, offset);
// Find the first frame to fully initialise our parser.
if (mParser->FindNextFrame(mSource)) {
// Ensure that the next frame returned will be the first.
mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
mParser->EndFrameSession();
} else if (!mParser->Info().IsValid() || !mParser->FirstFrame().IsValid()) {
// We must find at least a frame to determine the metadata.
// We can't play this stream.
return false;
}
if (!mParser->Info().IsValid() || !mParser->Info().mDuration.IsPositive()) {
// Check if we can look at the last frame for the end time to determine the
// duration when we don't have any.
TimeAtEnd();
}
return true;
}
UniquePtr<TrackInfo> FlacTrackDemuxer::GetInfo() const {
if (mParser->Info().IsValid()) {
// We have a proper metadata header.
UniquePtr<TrackInfo> info = mParser->Info().Clone();
UniquePtr<MetadataTags> tags(mParser->GetTags());
if (tags) {
for (auto iter = tags->Iter(); !iter.Done(); iter.Next()) {
info->mTags.AppendElement(MetadataTag(iter.Key(), iter.Data()));
}
}
return info;
} else if (mParser->FirstFrame().Info().IsValid()) {
// Use the first frame header.
UniquePtr<TrackInfo> info = mParser->FirstFrame().Info().Clone();
info->mDuration = Duration();
return info;
}
return nullptr;
}
bool FlacTrackDemuxer::IsSeekable() const {
// For now we only allow seeking if a STREAMINFO block was found and with
// a known number of samples (duration is set).
return mParser->Info().IsValid() && mParser->Info().mDuration.IsPositive();
}
RefPtr<FlacTrackDemuxer::SeekPromise> FlacTrackDemuxer::Seek(
const TimeUnit& aTime) {
// Efficiently seek to the position.
FastSeek(aTime);
// Correct seek position by scanning the next frames.
const TimeUnit seekTime = ScanUntil(aTime);
return SeekPromise::CreateAndResolve(seekTime, __func__);
}
TimeUnit FlacTrackDemuxer::FastSeek(const TimeUnit& aTime) {
LOG("FastSeek(%f) avgFrameLen=%f mParsedFramesDuration=%f offset=%" PRId64,
aTime.ToSeconds(), AverageFrameLength(),
mParsedFramesDuration.ToSeconds(), GetResourceOffset());
// Invalidate current frames in the parser.
mParser->EndFrameSession();
if (!mParser->FirstFrame().IsValid()) {
// Something wrong, and there's nothing to seek to anyway, so we can
// do whatever here.
mSource.Seek(SEEK_SET, 0);
return TimeUnit();
}
if (aTime <= mParser->FirstFrame().Time()) {
// We're attempting to seek prior the first frame, return the first frame.
mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
return mParser->FirstFrame().Time();
}
// We look for the seek position using a bisection search, starting where the
// estimated position might be using the average frame length.
// Typically, with flac such approximation is typically useless.
// Estimate where the position might be.
int64_t pivot =
aTime.ToSeconds() * AverageFrameLength() + mParser->FirstFrame().Offset();
// Time in seconds where we can stop seeking and will continue using
// ScanUntil.
static const int GAP_THRESHOLD = 5;
int64_t first = mParser->FirstFrame().Offset();
int64_t last = mSource.GetLength();
Maybe<int64_t> lastFoundOffset;
uint32_t iterations = 0;
TimeUnit timeSeekedTo;
do {
iterations++;
mSource.Seek(SEEK_SET, pivot);
flac::Frame frame;
if (!frame.FindNext(mSource)) {
NS_WARNING("We should have found a point");
break;
}
timeSeekedTo = frame.Time();
LOGV("FastSeek: interation:%u found:%f @ %" PRId64, iterations,
timeSeekedTo.ToSeconds(), frame.Offset());
if (lastFoundOffset && lastFoundOffset.ref() == frame.Offset()) {
// Same frame found twice. We're done.
break;
}
lastFoundOffset = Some(frame.Offset());
if (frame.Time() == aTime) {
break;
}
if (aTime > frame.Time() &&
aTime - frame.Time() <= TimeUnit::FromSeconds(GAP_THRESHOLD)) {
// We're close enough to the target, experimentation shows that bisection
// search doesn't help much after that.
break;
}
if (frame.Time() > aTime) {
last = pivot;
pivot -= (pivot - first) / 2;
} else {
first = pivot;
pivot += (last - pivot) / 2;
}
} while (true);
if (lastFoundOffset) {
mSource.Seek(SEEK_SET, lastFoundOffset.ref());
}
return timeSeekedTo;
}
TimeUnit FlacTrackDemuxer::ScanUntil(const TimeUnit& aTime) {
LOG("ScanUntil(%f avgFrameLen=%f mParsedFramesDuration=%f offset=%" PRId64,
aTime.ToSeconds(), AverageFrameLength(),
mParsedFramesDuration.ToSeconds(), mParser->CurrentFrame().Offset());
if (!mParser->FirstFrame().IsValid() ||
aTime <= mParser->FirstFrame().Time()) {
return FastSeek(aTime);
}
int64_t previousOffset = 0;
TimeUnit previousTime;
while (FindNextFrame().IsValid() && mParser->CurrentFrame().Time() < aTime) {
previousOffset = mParser->CurrentFrame().Offset();
previousTime = mParser->CurrentFrame().Time();
}
if (!mParser->CurrentFrame().IsValid()) {
// We reached EOS.
return Duration();
}
// Seek back to the last frame found prior the target.
mParser->EndFrameSession();
mSource.Seek(SEEK_SET, previousOffset);
return previousTime;
}
RefPtr<FlacTrackDemuxer::SamplesPromise> FlacTrackDemuxer::GetSamples(
int32_t aNumSamples) {
LOGV("GetSamples(%d) Begin offset=%" PRId64
" mParsedFramesDuration=%f"
" mTotalFrameLen=%" PRIu64,
aNumSamples, GetResourceOffset(), mParsedFramesDuration.ToSeconds(),
mTotalFrameLen);
if (!aNumSamples) {
return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
__func__);
}
RefPtr<SamplesHolder> frames = new SamplesHolder();
while (aNumSamples--) {
RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame()));
if (!frame) break;
if (!frame->HasValidTime()) {
return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
__func__);
}
frames->AppendSample(frame);
}
LOGV("GetSamples() End mSamples.Length=%zu aNumSamples=%d offset=%" PRId64
" mParsedFramesDuration=%f mTotalFrameLen=%" PRIu64,
frames->GetSamples().Length(), aNumSamples, GetResourceOffset(),
mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
if (frames->GetSamples().IsEmpty()) {
return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM,
__func__);
}
return SamplesPromise::CreateAndResolve(frames, __func__);
}
void FlacTrackDemuxer::Reset() {
LOG("Reset()");
MOZ_ASSERT(mParser);
if (mParser->FirstFrame().IsValid()) {
mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
} else {
mSource.Seek(SEEK_SET, 0);
}
mParser->EndFrameSession();
}
RefPtr<FlacTrackDemuxer::SkipAccessPointPromise>
FlacTrackDemuxer::SkipToNextRandomAccessPoint(const TimeUnit& aTimeThreshold) {
// Will not be called for audio-only resources.
return SkipAccessPointPromise::CreateAndReject(
SkipFailureHolder(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, 0), __func__);
}
int64_t FlacTrackDemuxer::GetResourceOffset() const { return mSource.Tell(); }
TimeIntervals FlacTrackDemuxer::GetBuffered() {
TimeUnit duration = Duration();
if (duration <= TimeUnit()) {
return TimeIntervals();
}
// We could simply parse the cached data instead and read the timestamps.
// However, for now this will do.
AutoPinned<MediaResource> stream(mSource.GetResource());
return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
}
const flac::Frame& FlacTrackDemuxer::FindNextFrame() {
LOGV("FindNext() Begin offset=%" PRId64
" mParsedFramesDuration=%f"
" mTotalFrameLen=%" PRIu64,
GetResourceOffset(), mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
if (mParser->FindNextFrame(mSource)) {
// Update our current progress stats.
mParsedFramesDuration =
std::max(mParsedFramesDuration, mParser->CurrentFrame().Time() -
mParser->FirstFrame().Time() +
mParser->CurrentFrame().Duration());
mTotalFrameLen =
std::max<uint64_t>(mTotalFrameLen, mParser->CurrentFrame().Offset() -
mParser->FirstFrame().Offset() +
mParser->CurrentFrame().Size());
LOGV("FindNext() End time=%f offset=%" PRId64
" mParsedFramesDuration=%f"
" mTotalFrameLen=%" PRIu64,
mParser->CurrentFrame().Time().ToSeconds(), GetResourceOffset(),
mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
}
return mParser->CurrentFrame();
}
already_AddRefed<MediaRawData> FlacTrackDemuxer::GetNextFrame(
const flac::Frame& aFrame) {
if (!aFrame.IsValid()) {
LOG("GetNextFrame() EOS");
return nullptr;
}
LOG("GetNextFrame() Begin(time=%f offset=%" PRId64 " size=%u)",
aFrame.Time().ToSeconds(), aFrame.Offset(), aFrame.Size());
const int64_t offset = aFrame.Offset();
const uint32_t size = aFrame.Size();
RefPtr<MediaRawData> frame = new MediaRawData();
frame->mOffset = offset;
UniquePtr<MediaRawDataWriter> frameWriter(frame->CreateWriter());
if (!frameWriter->SetSize(size)) {
LOG("GetNext() Exit failed to allocated media buffer");
return nullptr;
}
const uint32_t read = Read(frameWriter->Data(), offset, size);
if (read != size) {
LOG("GetNextFrame() Exit read=%u frame->Size=%zu", read, frame->Size());
return nullptr;
}
frame->mTime = aFrame.Time();
frame->mDuration = aFrame.Duration();
frame->mTimecode = frame->mTime;
frame->mOffset = aFrame.Offset();
frame->mKeyframe = true;
MOZ_ASSERT(!frame->mTime.IsNegative());
MOZ_ASSERT(!frame->mDuration.IsNegative());
return frame.forget();
}
int32_t FlacTrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
int32_t aSize) {
uint32_t read = 0;
const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
static_cast<uint32_t>(aSize), &read);
NS_ENSURE_SUCCESS(rv, 0);
return static_cast<int32_t>(read);
}
double FlacTrackDemuxer::AverageFrameLength() const {
if (mParsedFramesDuration.ToMicroseconds()) {
return mTotalFrameLen / mParsedFramesDuration.ToSeconds();
}
return 0.0;
}
TimeUnit FlacTrackDemuxer::Duration() const {
return std::max(mParsedFramesDuration, mParser->Info().mDuration);
}
TimeUnit FlacTrackDemuxer::TimeAtEnd() {
// Scan the last 128kB if available to determine the last frame.
static const int OFFSET_FROM_END = 128 * 1024;
// Seek to the end of the file and attempt to find the last frame.
MediaResourceIndex source(mSource.GetResource());
TimeUnit previousDuration;
TimeUnit previousTime;
const int64_t streamLen = mSource.GetLength();
if (streamLen < 0) {
return TimeUnit::FromInfinity();
}
flac::FrameParser parser;
source.Seek(SEEK_SET, std::max<int64_t>(0LL, streamLen - OFFSET_FROM_END));
while (parser.FindNextFrame(source)) {
// FFmpeg flac muxer can generate a last frame with earlier than the others.
previousTime = std::max(previousTime, parser.CurrentFrame().Time());
if (parser.CurrentFrame().Duration() > TimeUnit()) {
// The last frame doesn't have a duration, so only update our duration
// if we do have one.
previousDuration = parser.CurrentFrame().Duration();
}
if (source.Tell() >= streamLen) {
// Limit the read, in case the length change half-way.
break;
}
}
// Update our current progress stats.
mParsedFramesDuration =
previousTime + previousDuration - mParser->FirstFrame().Time();
mTotalFrameLen = streamLen - mParser->FirstFrame().Offset();
return mParsedFramesDuration;
}
/* static */
bool FlacDemuxer::FlacSniffer(const uint8_t* aData, const uint32_t aLength) {
if (aLength < FLAC_MIN_FRAME_SIZE) {
return false;
}
flac::Frame frame;
return frame.FindNext(aData, aLength) >= 0;
}
} // namespace mozilla
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