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chromium / webm / webmdshow / webmmf-1.0.1.0-20131004 / . / webmoggsource / oggparser.cpp
blob: 747c84afdc7f82a1ff5ff3d9f0d38070c5f32df5 [file] [log] [blame]
#include "oggparser.hpp"
#include <cstring>
#include <cassert>
//#include <malloc.h>
typedef std::list<oggparser::OggPage> pages_t;
long oggparser::ReadInt(
IOggReader* pReader,
long long pos,
long len,
long long& val)
{
val = 0;
for (long i = 0; i < len; ++i)
{
unsigned char b;
const long result = pReader->Read(pos++, 1, &b);
if (result < 0) //error
return len;
const long long bb = static_cast<long long>(b) << (i * 8);
val |= bb;
}
return 0; //success
}
namespace oggparser
{
IOggReader::~IOggReader()
{
}
long OggPage::Read(IOggReader* pReader, long long& pos)
{
if (pos < 0)
return -1;
long result = pReader->Read(pos, 4, capture_pattern);
if (result < 0) //error
return result;
if (memcmp(capture_pattern, "OggS", 4) != 0)
return E_FILE_FORMAT_INVALID;
pos += 4; //consume capture_pattern
long long version_;
result = ReadInt(pReader, pos, 1, version_);
if (result < 0) //error
return result;
++pos; //consume version
version = static_cast<unsigned char>(version_);
long long header_;
result = ReadInt(pReader, pos, 1, header_);
if (result < 0) //error
return result;
++pos; //consume header flag
header = static_cast<unsigned char>(header_);
result = ReadInt(pReader, pos, 8, granule_pos);
if (result < 0) //error
return result;
pos += 8; //consume granule pos
long long serial_num_;
result = ReadInt(pReader, pos, 4, serial_num_);
if (result < 0) //error
return result;
pos += 4; //consume serial number
serial_num = static_cast<unsigned long>(serial_num_);
long long sequence_num_;
result = ReadInt(pReader, pos, 4, sequence_num_);
if (result < 0) //error
return result;
pos += 4; //consume page sequence number
sequence_num = static_cast<unsigned long>(sequence_num_);
long long crc_;
result = ReadInt(pReader, pos, 4, crc_);
if (result < 0) //error
return result;
pos += 4; //consume crc
//http://www.ross.net/crc/download/crc_v3.txt
crc = static_cast<unsigned long>(crc_);
long long segments_count;
result = ReadInt(pReader, pos, 1, segments_count);
if (result < 0) //error
return result;
if (segments_count <= 0) //TODO: confirm this
return E_FILE_FORMAT_INVALID;
++pos; //consume segment count
descriptors.clear();
while (segments_count > 0)
{
descriptors.push_back(Descriptor());
{
Descriptor& data = descriptors.back();
data.pos = -1; //fill in later
data.len = 0;
}
for (;;)
{
long long lacing_value;
result = ReadInt(pReader, pos, 1, lacing_value);
if (result < 0) //error
return result;
++pos; //consume lacing value
{
Descriptor& payload = descriptors.back();
payload.len += static_cast<long>(lacing_value);
if (--segments_count <= 0)
{
if (lacing_value == 255) //pkt continued on next page
payload.len = -payload.len;
else //pkt completed on curr page
header |= OggPage::fDone;
break;
}
}
if (lacing_value != 255)
break;
}
}
typedef descriptors_t::iterator iter_t;
iter_t iter = descriptors.begin();
const iter_t iter_end = descriptors.end();
while (iter != iter_end)
{
Descriptor& payload = *iter++;
payload.pos = pos;
pos += labs(payload.len);
}
return 0;
}
#if 0
long OggStream::Create(IOggReader* pReader, OggStream*& pStream)
{
if (pReader == NULL)
return -1;
//the stream of bytes we have is the "physical" bitstream.
//there are the bytes stored in the container file.
//the physical bitstream encapsulates one or more "logical"
//bitstreams, provided by the encoder. i assume this is
//the same as a matroska track or an avi stream.
//a logical bitream contains "packets", which is the same
//thing as a frame.
//a physical bitstream comprises "pages". does a single page
//contain only single logical bitstream or can it include
//multiple logical bistreams??? [one logical bitstream only]
//a page has a unique serial number that identifies the
//logical bitstream. this is analogous to a matroska track number
//or an avi stream identifier
//a logical bitstream has a special(?) start page (bos) and
//another special(?) stop page (eos)
//the bos identifies the codec type, for audio it contains
//sampling rate, etc
//bos uses a magic number to uniquely identify the codec type
//the format of a bos is specific to each codec type
//ogg allows "secondary header packets" to follow bos but
//precede data packets; these are put on an integral number
//of pages, which do not also have data packets
//"Ogg Vorbis" is a "media mapping" that describes how the
//logical bitstream for vorbis audio is encapsulated into
//an ogg physical bitstream.
//bos
// name of vorbis codec
// revision of vorbis codec
// audio rate
// audio quality
//two more header pages
//
//bos: 1st 7 bytes are:
// 0x01
// "vorbis"
//data for a logical bitstream comes in order and has
//position markers called "Granule positions". This is an
//alternative to using "time" directly: position markers are
//unitless and increase sequentially. To get a time you
//must convert the granule position.
//Ogg pages have a max size of 64kB (65307); this means that a large
//packet ("frame") will need to be distributed over one or more
//pages.
//a packet is itself divided into 255-byte chunks called "segments",
//plus one more segment with fewer than 255 bytes
//the segments (which have no header boundaries themselves) are
//grouped into a page preceded by a header. The page header
//contains a "segment table" gives info about the sizes ("lacing")
//of the segments.
//a flag in page hdr tells whether this page contains a packet
//continued from a previous page.
//from rfc5334.txt:
//"In particular, .ogg is used for Ogg files that
//contain only a Vorbis bitstream,"
//Vorbis_I_spec.html
//
//A.2 Encapsulation
//Ogg encapsulation of a Vorbis packet stream is straightforward.
//The first Vorbis packet (the identification header),
//which uniquely identifies a stream as Vorbis audio,
//is placed alone in the first page of the logical Ogg stream.
//This results in a first Ogg page of exactly 58 bytes at the
//very beginning of the logical stream.
//This first page is marked Â’beginning of streamÂ’ in the page flags.
//The second and third vorbis packets (comment and setup headers)
//may span one or more pages beginning on the second page of the
//logical stream. However many pages they span, the third header
//packet finishes the page on which it ends. The next (first audio)
//packet must begin on a fresh page.
//The granule position of these first pages containing only
//headers is zero.
//The first audio packet of the logical stream begins a fresh Ogg page.
//Packets are placed into ogg pages in order until the end of stream.
//The last page is marked Â’end of streamÂ’ in the page flags.
//Vorbis packets may span page boundaries.
//The granule position of pages containing Vorbis audio is in units of
//PCM audio samples (per channel; a stereo streamÂ’s granule position does
//not increment at twice the speed of a mono stream).
//The granule position of a page represents the end PCM sample position
//of the last packet completed on that page. The Â’last PCM sampleÂ’ is
//the last complete sample returned by decode, not an internal sample
//awaiting lapping with a subsequent block. A page that is entirely
//spanned by a single packet (that completes on a subsequent page)
//has no granule position, and the granule position is set to Â’-1Â’.
//
//Note that the last decoded (fully lapped) PCM sample from a packet
//is not necessarily the middle sample from that block. If, eg,
//the current Vorbis packet encodes a ”long block” and the next
//Vorbis packet encodes a ”short block”, the last decodable sample
//from the current packet be at position
// (3*long_block_length/4) - (short_block_length/4).
//The granule (PCM) position of the first page need not indicate that
//the stream started at position zero. Although the granule position
//belongs to the last completed packet on the page and a valid
//granule position must be positive, by inference it may indicate
//that the PCM position of the beginning of audio is positive or negative.
//
//A positive starting value simply indicates that this stream begins
//at some positive time offset, potentially within a larger program.
//This is a common case when connecting to the middle of broadcast stream.
//
//A negative value indicates that output samples preceeding time zero
//should be discarded during decoding; this technique is used to allow
//sample-granularity editing of the stream start time of already-encoded
//Vorbis streams. The number of samples to be discarded must not exceed
//the overlap-add span of the first two audio packets.
//
//In both of these cases in which the initial audio PCM starting
//offset is nonzero, the second finished audio packet must flush
//the page on which it appears and the third packet begin a fresh page.
//This allows the decoder to always be able to perform PCM position
//adjustments before needing to return any PCM data from synthesis,
//resulting in correct positioning information without any aditional
//seeking logic.
//
//Note: Failure to do so should, at worst, cause a decoder implementation
//to return incorrect positioning information for seeking operations at
//the very beginning of the stream.
//A granule position on the final page in a stream that indicates
//less audio data than the final packet would normally return is
//used to end the stream on other than even frame boundaries.
//The difference between the actual available data returned and
//the declared amount indicates how many trailing samples to
//discard from the decoding process.
//rfc3533.txt:
//
//6. The Ogg page format
// A physical Ogg bitstream consists of a sequence of concatenated
// pages. Pages are of variable size, usually 4-8 kB, maximum 65307
// bytes. A page header contains all the information needed to
// demultiplex the logical bitstreams out of the physical bitstream and
// to perform basic error recovery and landmarks for seeking. Each page
// is a self-contained entity such that the page decode mechanism can
// recognize, verify, and handle single pages at a time without
// requiring the overall bitstream.
// The Ogg page header has the following format:
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1| Byte
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| capture_pattern: Magic number for page start "OggS" | 0-3
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| version | header_type | granule_position | 4-7
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| | 8-11
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| | bitstream_serial_number | 12-15
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| | page_sequence_number | 16-19
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| | CRC_checksum | 20-23
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| |page_segments | segment_table | 24-27
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//| ... | 28-
//+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// The LSb (least significant bit) comes first in the Bytes. Fields
// with more than one byte length are encoded LSB (least significant
// byte) first.
pStream = new OggStream(pReader);
//Vorbis_I_spec.html
//Section A.2
//Ogg page
//http://en.wikipedia.org/wiki/Ogg_page
const long result = pStream->Init();
if (result >= 0)
return 0; //must capture ident, comment, and setup pkts
delete pStream;
pStream = NULL;
return result;
}
#endif
OggStream::OggStream(IOggReader* p) :
m_pReader(p),
m_page_num(0),
m_page_base(0),
m_pos(0),
m_base(0),
m_serial_num(0)
{
}
OggStream::~OggStream()
{
}
long OggStream::Init(
Packet& ident,
Packet& comment,
Packet& setup)
{
assert(m_packets.empty());
assert(m_page_num == 0);
OggPage page;
for (;;)
{
long result = page.Read(m_pReader, m_pos);
if (result < 0)
return result;
if (!(page.header & OggPage::fBOS))
return E_FILE_FORMAT_INVALID;
if (OggPage::Match(page.descriptors, m_pReader, "\x01vorbis") >= 1)
break;
}
if (page.descriptors.size() != 1)
return E_FILE_FORMAT_INVALID;
if (OggPage::GetLength(page.descriptors) != 30)
return E_FILE_FORMAT_INVALID;
if (page.header & OggPage::fContinued)
return E_FILE_FORMAT_INVALID;
//if (!(page.header & OggPage::fBOS))
// return E_FILE_FORMAT_INVALID;
if (page.header & OggPage::fEOS)
return E_FILE_FORMAT_INVALID;
if (!(page.header & OggPage::fDone))
return E_FILE_FORMAT_INVALID;
if (page.granule_pos != 0)
return E_FILE_FORMAT_INVALID;
if (page.sequence_num != m_page_num++)
return E_FILE_FORMAT_INVALID;
m_serial_num = page.serial_num;
ident.descriptors = page.descriptors;
ident.granule_pos = 0;
long result = GetPacket(comment, 10);
if (result < 0)
return result;
if (comment.IsHeader(m_pReader, "\x03vorbis") <= 0)
return E_FILE_FORMAT_INVALID;
result = GetPacket(setup, 10);
if (result < 0)
return result;
if (setup.IsHeader(m_pReader, "\x05vorbis") <= 0)
return E_FILE_FORMAT_INVALID;
if (!m_packets.empty())
return E_FILE_FORMAT_INVALID;
m_base = m_pos;
m_page_base = m_page_num;
return 0;
}
long OggStream::Reset()
{
m_pos = m_base;
m_page_num = m_page_base;
m_packets.clear();
return 0; //success
}
#if 0
long OggStream::GetPackets(OggPage& page, long long page_pos)
{
#if 0
const long long page_pos = m_pos;
long result = page.Read(m_pReader, m_pos);
if (result < 0) //error
return result;
#endif
assert(!page.descriptors.empty());
if (page.header & OggPage::fContinued)
{
if (m_packets.empty())
return E_FILE_FORMAT_INVALID;
Packet& pkt = m_packets.back();
OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
OggPage::Descriptor& d = dd.back();
if (d.len >= 0)
return E_FILE_FORMAT_INVALID;
d.len = labs(d.len);
}
dd.push_back(page.descriptors.front());
page.descriptors.pop_front();
}
else if (!m_packets.empty())
{
const Packet& pkt = m_packets.back();
const OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
const OggPage::Descriptor& d = dd.back();
if (d.len < 0)
return E_FILE_FORMAT_INVALID;
}
}
OggPage::descriptors_t& dd = page.descriptors;
while (!dd.empty())
{
OggPage::Descriptor& d = dd.front();
m_packets.push_back(Packet());
Packet& pkt = m_packets.back();
pkt.descriptors.push_back(d);
pkt.granule_pos = -1;
dd.pop_front();
}
assert(!m_packets.empty());
if (page.granule_pos < 0) //no packet was completed by this page
{
const Packet& pkt = m_packets.back();
const OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
const OggPage::Descriptor& d = dd.back();
if (d.len >= 0) //not incomplete
return E_FILE_FORMAT_INVALID;
}
return 0; //no granule pos, so nothing else to do just yet
}
typedef packets_t::reverse_iterator iter_t;
iter_t iter = m_packets.rbegin();
const iter_t iter_end = m_packets.rend();
while (iter != iter_end)
{
Packet& pkt = *iter++;
OggPage::descriptors_t& dd = pkt.descriptors;
if (dd.empty()) //weird
continue;
OggPage::Descriptor& d = dd.back();
if (d.len < 0) //last packet wasn't completed on this cluster
continue; //try earlier packet
if (d.pos <= page_pos) //we have navigated off of curr page
return E_FILE_FORMAT_INVALID;
assert(pkt.granule_pos < 0);
pkt.granule_pos = page.granule_pos;
return 0;
}
return E_FILE_FORMAT_INVALID;
//Granule pos info:
//http://lists.xiph.org/pipermail/vorbis/2005-September/025955.html
//
//> If this is true:
//>
//> "Granule Position Information in Ogg Header is a hint
//> for the decoder and gives some timing and position
//> information."
//>
//> So say if granule position is 10000, it means that
//> 10000 PCM samples are encoded in this page
//> approximately.
//
//Incorrect. It means that if you decode up to the end of this page from
//the beginning of the stream, you'll have a total of precisely 10000
//samples (assuming all the data was there, and you didn't lose any).
//Thus it gives precise and absolute positioning information, as
//required for seeking, for instance.
//>
//> If this is true we can neglect this information, it
//> will not effect the decoding right(but might effect
//> for streaming)?
//
//Incorrect. Vorbis sort of 'overloads' this field; it must be provided
//to the decoder for correct handling of beginning and end of stream.
//
//You also need it for seeking, obviously.
}
#endif
long OggStream::ParsePage()
{
if (m_pos < 0)
return E_END_OF_FILE;
OggPage page;
const long long page_pos = m_pos;
const long result = page.Read(m_pReader, m_pos);
if (result < 0) //error
return result;
if (page.serial_num != m_serial_num)
return 0;
if (page.sequence_num != m_page_num++)
return E_FILE_FORMAT_INVALID;
assert(!page.descriptors.empty());
if (page.header & OggPage::fContinued)
{
if (m_packets.empty())
return E_FILE_FORMAT_INVALID;
Packet& pkt = m_packets.back();
OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
OggPage::Descriptor& d = dd.back();
if (d.len >= 0)
return E_FILE_FORMAT_INVALID;
d.len = labs(d.len);
}
dd.push_back(page.descriptors.front());
page.descriptors.pop_front();
}
else if (!m_packets.empty())
{
const Packet& pkt = m_packets.back();
const OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
const OggPage::Descriptor& d = dd.back();
if (d.len < 0)
return E_FILE_FORMAT_INVALID;
}
}
OggPage::descriptors_t& dd = page.descriptors;
while (!dd.empty())
{
OggPage::Descriptor& d = dd.front();
m_packets.push_back(Packet());
Packet& pkt = m_packets.back();
pkt.descriptors.push_back(d);
pkt.granule_pos = -1;
dd.pop_front();
}
assert(!m_packets.empty());
if (page.granule_pos < 0) //no packet was completed by this page
{
const Packet& pkt = m_packets.back();
const OggPage::descriptors_t& dd = pkt.descriptors;
if (!dd.empty()) //predicate should always be true
{
const OggPage::Descriptor& d = dd.back();
if (d.len >= 0) //not incomplete
return E_FILE_FORMAT_INVALID;
}
return 0; //no granule pos, so nothing else to do just yet
}
typedef packets_t::reverse_iterator iter_t;
iter_t iter = m_packets.rbegin();
const iter_t iter_end = m_packets.rend();
while (iter != iter_end)
{
Packet& pkt = *iter++;
OggPage::descriptors_t& dd = pkt.descriptors;
if (dd.empty()) //weird
continue;
OggPage::Descriptor& d = dd.back();
if (d.len < 0) //last packet wasn't completed on this cluster
continue; //try earlier packet
if (d.pos <= page_pos) //we have navigated off of curr page
return E_FILE_FORMAT_INVALID;
assert(pkt.granule_pos < 0);
pkt.granule_pos = page.granule_pos;
if (page.header & OggPage::fEOS)
m_pos = -1; //means end-of-stream
return 0;
}
return E_FILE_FORMAT_INVALID;
}
long OggStream::GetPacket(Packet& pkt)
{
return GetPacket(pkt, 0);
}
long OggStream::GetPacket(Packet& pkt, int max_count)
{
int count = 0;
while (ParsePacket(pkt) < 1)
{
const long result = ParsePage();
if (result < 0) //error
return result;
++count;
if ((max_count > 0) && (count >= max_count))
return E_FILE_FORMAT_INVALID;
}
return 1; //success
}
long OggStream::ParsePacket(Packet& pkt_)
{
if (m_packets.empty())
return 0; //no packet available for consumption
const Packet& pkt = m_packets.front();
const OggPage::descriptors_t& dd = pkt.descriptors;
assert(!dd.empty());
const OggPage::Descriptor& d = dd.back();
if (d.len < 0) //hasn't been completed yet
return 0; //packet not available for consumption yet
pkt_ = pkt;
m_packets.pop_front();
return 1; //successfully consumed pkt
}
long OggPage::GetLength(const descriptors_t& dd)
{
long result = 0;
typedef descriptors_t::const_iterator iter_t;
iter_t i = dd.begin();
const iter_t j = dd.end();
while (i != j)
{
const Descriptor& d = *i++;
if (d.len < 0)
return -1;
result += d.len;
}
return result;
}
long OggStream::Packet::GetLength() const
{
return OggPage::GetLength(descriptors);
}
long OggPage::Copy(
const descriptors_t& dd,
IOggReader* pReader,
unsigned char* buf)
{
if (buf == NULL)
return -1;
unsigned char* const buf_base = buf;
typedef descriptors_t::const_iterator iter_t;
iter_t i = dd.begin();
const iter_t j = dd.end();
while (i != j)
{
const Descriptor& d = *i++;
const long result = pReader->Read(d.pos, d.len, buf);
if (result < 0) //error
return result;
buf += d.len;
}
const ptrdiff_t len_ = buf - buf_base;
const long len = static_cast<long>(len_);
return len;
}
long OggStream::Packet::Copy(
IOggReader* pReader,
unsigned char* buf) const
{
return OggPage::Copy(descriptors, pReader, buf);
}
long OggStream::Packet::IsHeader(IOggReader* pReader, const char* str) const
{
return OggPage::Match(descriptors, pReader, str);
}
long OggPage::Match(
const descriptors_t& dd,
IOggReader* pReader,
const char* str)
{
if (pReader == NULL)
return -1;
if (str == NULL)
return -1;
typedef OggPage::descriptors_t::const_iterator iter_t;
iter_t i = dd.begin();
const iter_t j = dd.end();
while (i != j)
{
const OggPage::Descriptor& d = *i++;
long long pos = d.pos;
const long long pos_end = d.pos + d.len;
while ((*str != '\0') && (pos != pos_end))
{
unsigned char c;
const long result = pReader->Read(pos++, 1, &c);
if (result < 0) //error
return result;
if (*str++ != c)
return 0; //does not match
}
if (*str == '\0')
return 1; //match
}
return -1; //ran out of payload to compare
}
long VorbisIdent::Read(IOggReader* pReader, const OggStream::Packet& ident)
{
if (pReader == NULL)
return -1;
const OggPage::descriptors_t& dd = ident.descriptors;
if (dd.size() != 1)
return -1;
const OggPage::Descriptor& d = dd.front();
//58 = size of first page
//26 + 1 + 1 = 28
//30 = size of ident pkt
if (d.len != 30) //weird
return -1;
long long pos = d.pos;
unsigned char h[7];
long result = pReader->Read(pos, 7, h);
if (result < 0)
return result;
pos += 7;
if (memcmp(h, "\x01vorbis", 7) != 0)
return -1;
long long val;
result = ReadInt(pReader, pos, 4, val);
if (result < 0)
return result;
pos += 4; //consume version
version = static_cast<unsigned long>(val);
result = ReadInt(pReader, pos, 1, val);
if (result < 0)
return result;
++pos; //consume channels
channels = static_cast<unsigned char>(val);
result = ReadInt(pReader, pos, 4, val);
if (result < 0)
return result;
pos += 4; //consume sample_rate
sample_rate = static_cast<unsigned long>(val);
result = ReadInt(pReader, pos, 4, val);
if (result < 0)
return result;
pos += 4; //consume bitrate_max
bitrate_maximum = static_cast<long>(val);
result = ReadInt(pReader, pos, 4, val);
if (result < 0)
return result;
pos += 4; //consume bitrate_avg
bitrate_nominal = static_cast<long>(val);
result = ReadInt(pReader, pos, 4, val);
if (result < 0)
return result;
pos += 4; //consume bitrate_min
bitrate_minimum = static_cast<long>(val);
unsigned char b;
result = pReader->Read(pos, 1, &b);
if (result < 0)
return result;
++pos;
int e = b & 0x0F;
blocksize_0 = 1 << e;
e = (b & 0xF0) >> 4;
blocksize_1 = 1 << e;
result = pReader->Read(pos, 1, &b);
if (result < 0)
return result;
++pos;
assert((pos - d.pos) == 30);
framing = (b & 0x01);
return 0;
}
} //end namespace oggparser