/*
* /// <summary>
* /// Contains the children of the box.
* /// </summary>
* private BoxList children;
*/
#endregion
#region Constructors
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoVisualSampleEntry" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoVisualSampleEntry(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
file.Seek(base.DataPosition + 16);
width = file.ReadBlock(2).ToUShort();
height = file.ReadBlock(2).ToUShort();
/*
* TODO: What are the children anyway?
* children = LoadChildren (file);
*/
}
/// <summary>
/// Searches for an audio header in a <see cref="TagLibSharp.File"
/// /> starting at a specified position and searching through
/// a specified number of bytes.
/// </summary>
/// <param name="header">
/// A <see cref="AudioHeader" /> object in which the found
/// header will be stored.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to search.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value specifying the seek position
/// in <paramref name="file" /> at which to start searching.
/// </param>
/// <param name="length">
/// A <see cref="int" /> value specifying the maximum number
/// of bytes to search before aborting.
/// </param>
/// <returns>
/// A <see cref="bool" /> value indicating whether or not a
/// header was found.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public static bool Find(out AudioHeader header,
TagLibSharp.File file, long position,
int length)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
long end = position + length;
header = AudioHeader.Unknown;
file.Seek(position);
ByteVector buffer = file.ReadBlock(3);
if (buffer.Count < 3)
{
return(false);
}
do
{
file.Seek(position + 3);
buffer = buffer.Mid(buffer.Count - 3);
buffer.Add(file.ReadBlock(
(int)File.BufferSize));
for (int i = 0; i < buffer.Count - 3 &&
(length < 0 || position + i < end); i++)
{
if (buffer [i] == 0xFF &&
buffer [i + 1] > 0xE0)
{
try {
header = new AudioHeader(
buffer.Mid(i, 4),
file, position + i);
return(true);
} catch (CorruptFileException) {
}
}
}
position += File.BufferSize;
} while (buffer.Count > 3 && (length < 0 || position < end));
return(false);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoVisualSampleEntry" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoAudioSampleEntry(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
file.Seek(base.DataPosition + 8);
channel_count = file.ReadBlock(2).ToUShort();
sample_size = file.ReadBlock(2).ToUShort();
file.Seek(base.DataPosition + 16);
sample_rate = file.ReadBlock(4).ToUInt();
children = LoadChildren(file);
}
/// <summary>
/// Looks for a tag starting at a specified position and moves
/// the cursor to its start position.
/// </summary>
/// <param name="position">
/// A <see cref="long" /> value reference specifying at what
/// position the potential tag starts. If a tag is found,
/// this value will be updated to the position at which the
/// found tag ends.
/// </param>
/// <returns>
/// A <see cref="TagTypes" /> value specifying the
/// type of tag found at the specified position, or <see
/// cref="TagTypes.None" /> if no tag was found.
/// </returns>
private TagTypes ReadTagInfo(ref long position)
{
file.Seek(position);
ByteVector data = file.ReadBlock(read_size);
try {
if (data.StartsWith(Footer.FileIdentifier))
{
Footer footer =
new Footer(data);
position += footer.CompleteTagSize;
return(TagTypes.Ape);
}
if (data.StartsWith(Header.FileIdentifier))
{
Header header =
new Header(data);
position += header.CompleteTagSize;
return(TagTypes.Id3v2);
}
} catch (CorruptFileException) {
}
return(TagTypes.None);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="BoxHeader" /> by reading it from a specified seek
/// position in a specified file.
/// </summary>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the new
/// instance from.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value specifiying the seek position
/// in <paramref name="file" /> at which to start reading.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
/// <exception cref="CorruptFileException">
/// There isn't enough data in the file to read the complete
/// header.
/// </exception>
public BoxHeader(TagLibSharp.File file, long position)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
this.box = null;
this.from_disk = true;
this.position = position;
file.Seek(position);
ByteVector data = file.ReadBlock(32);
int offset = 0;
if (data.Count < 8 + offset)
{
throw new CorruptFileException(
"Not enough data in box header.");
}
header_size = 8;
box_size = data.Mid(offset, 4).ToUInt();
box_type = data.Mid(offset + 4, 4);
// If the size is 1, that just tells us we have a
// massive ULONG size waiting for us in the next 8
// bytes.
if (box_size == 1)
{
if (data.Count < 8 + offset)
{
throw new CorruptFileException(
"Not enough data in box header.");
}
header_size += 8;
box_size = data.Mid(offset, 8).ToULong();
offset += 8;
}
// UUID has a special header with 16 extra bytes.
if (box_type == Mpeg4.BoxType.Uuid)
{
if (data.Count < 16 + offset)
{
throw new CorruptFileException(
"Not enough data in box header.");
}
header_size += 16;
extended_type = data.Mid(offset, 16);
}
else
{
extended_type = null;
}
}
/// <summary>
/// Looks for a tag ending at a specified position and moves
/// the cursor to its start position.
/// </summary>
/// <param name="position">
/// A <see cref="long" /> value reference specifying at what
/// position the potential tag ends. If a tag is found,
/// this value will be updated to the position at which the
/// found tag starts.
/// </param>
/// <returns>
/// A <see cref="TagTypes" /> value specifying the
/// type of tag found at the specified position, or <see
/// cref="TagTypes.None" /> if no tag was found.
/// </returns>
private TagTypes ReadTagInfo(ref long position)
{
if (position - read_size < 0)
{
return(TagTypes.None);
}
file.Seek(position - read_size);
ByteVector data = file.ReadBlock(read_size);
try {
int offset = (int)(data.Count - Footer.Size);
if (data.ContainsAt(Footer.FileIdentifier,
offset))
{
Footer footer =
new Footer(
data.Mid(offset));
// If the complete tag size is zero or
// the tag is a header, this indicates
// some sort of corruption.
if (footer.CompleteTagSize == 0 ||
(footer.Flags &
FooterFlags.IsHeader) != 0)
{
return(TagTypes.None);
}
position -= footer.CompleteTagSize;
return(TagTypes.Ape);
}
offset = (int)(data.Count - Id3v2.Footer.Size);
if (data.ContainsAt(Id3v2.Footer.FileIdentifier,
offset))
{
Id3v2.Footer footer =
new Id3v2.Footer(
data.Mid(offset));
position -= footer.CompleteTagSize;
return(TagTypes.Id3v2);
}
if (data.StartsWith(
Id3v1.Tag.FileIdentifier))
{
position -= Id3v1.Tag.Size;
return(TagTypes.Id3v1);
}
} catch (CorruptFileException) {
}
return(TagTypes.None);
}
/// <summary>
/// Loads the data of the current instance from a specified
/// file using the internal data position and size.
/// </summary>
/// <param name="file">
/// The <see cref="TagLibSharp.File" /> from which the current
/// instance was read and from which to read the data.
/// </param>
/// <returns>
/// A <see cref="ByteVector" /> object containing the data
/// read from the file.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
protected ByteVector LoadData(TagLibSharp.File file)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
file.Seek(DataPosition);
return(file.ReadBlock(DataSize));
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoSampleEntry" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoSampleEntry(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, handler)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
file.Seek(base.DataPosition + 6);
data_reference_index = file.ReadBlock(2).ToUShort();
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoSampleDescriptionBox" /> with a provided header
/// and handler by reading the contents from a specified
/// file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoSampleDescriptionBox(BoxHeader header,
TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
entry_count = file.ReadBlock(4).ToUInt();
children = LoadChildren(file);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoChunkOffsetBox" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
public IsoChunkOffsetBox(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
ByteVector box_data = file.ReadBlock(DataSize);
offsets = new uint [(int)
box_data.Mid(0, 4).ToUInt()];
for (int i = 0; i < offsets.Length; i++)
{
offsets [i] = box_data.Mid(4 + i * 4,
4).ToUInt();
}
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="FullBox" /> with a provided header and handler by
/// reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
protected FullBox(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, handler)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
file.Seek(base.DataPosition);
ByteVector header_data = file.ReadBlock(4);
version = header_data [0];
flags = header_data.Mid(1, 3).ToUInt();
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="List" /> by reading the contents of a raw RIFF list
/// from a specified position in a <see cref="TagLibSharp.File"/>.
/// </summary>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object containing the file
/// from which the contents of the new instance is to be
/// read.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value specify at what position to
/// read the list.
/// </param>
/// <param name="length">
/// A <see cref="int" /> value specifying the number of bytes
/// to read.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="position" /> is less than zero or greater
/// than the size of the file.
/// </exception>
public List(TagLibSharp.File file, long position, int length)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
if (length < 0)
{
throw new ArgumentOutOfRangeException(
"length");
}
if (position < 0 || position > file.Length - length)
{
throw new ArgumentOutOfRangeException(
"position");
}
file.Seek(position);
Parse(file.ReadBlock(length));
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoHandlerBox" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoHandlerBox(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
if (file == null)
{
throw new System.ArgumentNullException("file");
}
file.Seek(DataPosition + 4);
ByteVector box_data = file.ReadBlock(DataSize - 4);
handler_type = box_data.Mid(0, 4);
int end = box_data.Find((byte)0, 16);
if (end < 16)
{
end = box_data.Count;
}
name = box_data.ToString(StringType.UTF8, 16, end - 16);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="VideoHeader" /> by reading it from a specified
/// location in a specified file.
/// </summary>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read from.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value indicating the position in
/// <paramref name="file" /> at which the header begins.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
/// <exception cref="CorruptFileException">
/// Insufficient data could be read for the header.
/// </exception>
public VideoHeader(TagLibSharp.File file, long position)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
file.Seek(position);
ByteVector data = file.ReadBlock(7);
if (data.Count < 7)
{
throw new CorruptFileException(
"Insufficient data in header.");
}
width = data.Mid(0, 2).ToUShort() >> 4;
height = data.Mid(1, 2).ToUShort() & 0x0FFF;
frame_rate_index = data [3] & 0x0F;
bitrate = (int)((data.Mid(4, 3).ToUInt() >> 6) &
0x3FFFF);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="AudioHeader" /> by reading its contents from a
/// <see cref="ByteVector" /> object and its Xing Header from
/// the appropriate location in the specified file.
/// </summary>
/// <param name="data">
/// A <see cref="ByteVector" /> object containing the header
/// to read.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the Xing
/// header from.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value indicating the position in
/// <paramref name="file" /> at which the header begins.
/// </param>
/// <exception cref="CorruptFileException">
/// <paramref name="data" /> is less than 4 bytes long,
/// does not begin with a MPEG audio synch, has a negative
/// bitrate, or has a sample rate of zero.
/// </exception>
private AudioHeader(ByteVector data, TagLibSharp.File file,
long position)
{
this.duration = TimeSpan.Zero;
stream_length = 0;
if (data.Count < 4)
{
throw new CorruptFileException(
"Insufficient header length.");
}
if (data [0] != 0xFF)
{
throw new CorruptFileException(
"First byte did not match MPEG synch.");
}
// Checking bits from high to low:
//
// First 3 bits MUST be set. Bits 4 and 5 can
// be 00, 10, or 11 but not 01. One or more of
// bits 6 and 7 must be set. Bit 8 can be
// anything.
if ((data [1] & 0xE6) <= 0xE0 || (data [1] & 0x18) == 0x08)
{
throw new CorruptFileException(
"Second byte did not match MPEG synch.");
}
flags = data.ToUInt();
if (((flags >> 12) & 0x0F) == 0x0F)
{
throw new CorruptFileException(
"Header uses invalid bitrate index.");
}
if (((flags >> 10) & 0x03) == 0x03)
{
throw new CorruptFileException(
"Invalid sample rate.");
}
xing_header = XingHeader.Unknown;
vbri_header = VBRIHeader.Unknown;
// Check for a Xing header that will help us in
// gathering information about a VBR stream.
file.Seek(position + XingHeader.XingHeaderOffset(
Version, ChannelMode));
ByteVector xing_data = file.ReadBlock(16);
if (xing_data.Count == 16 && xing_data.StartsWith(
XingHeader.FileIdentifier))
{
xing_header = new XingHeader(xing_data);
}
if (xing_header.Present)
{
return;
}
// A Xing header could not be found, next chec for a
// Fraunhofer VBRI header.
file.Seek(position + VBRIHeader.VBRIHeaderOffset());
// Only get the first 24 bytes of the Header.
// We're not interested in the TOC entries.
ByteVector vbri_data = file.ReadBlock(24);
if (vbri_data.Count == 24 &&
vbri_data.StartsWith(VBRIHeader.FileIdentifier))
{
vbri_header = new VBRIHeader(vbri_data);
}
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="AppleAdditionalInfoBox" /> with a provided header
/// and handler by reading the contents from a specified
/// file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public AppleAdditionalInfoBox(BoxHeader header, TagLibSharp.File file, IsoHandlerBox handler) : base(header, file, handler)
{
Data = file.ReadBlock(DataSize);
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="IsoMovieHeaderBox" /> with a provided header and
/// handler by reading the contents from a specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public IsoMovieHeaderBox(BoxHeader header, TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
int bytes_remaining = DataSize;
ByteVector data;
if (Version == 1)
{
// Read version one (large integers).
data = file.ReadBlock(Math.Min(28,
bytes_remaining));
if (data.Count >= 8)
{
creation_time = data.Mid(0,
8).ToULong();
}
if (data.Count >= 16)
{
modification_time = data.Mid(8,
8).ToULong();
}
if (data.Count >= 20)
{
timescale = data.Mid(16, 4).ToUInt();
}
if (data.Count >= 28)
{
duration = data.Mid(20, 8).ToULong();
}
bytes_remaining -= 28;
}
else
{
// Read version zero (normal integers).
data = file.ReadBlock(Math.Min(16,
bytes_remaining));
if (data.Count >= 4)
{
creation_time = data.Mid(0,
4).ToUInt();
}
if (data.Count >= 8)
{
modification_time = data.Mid(4,
4).ToUInt();
}
if (data.Count >= 12)
{
timescale = data.Mid(8, 4).ToUInt();
}
if (data.Count >= 16)
{
duration = data.Mid(12, 4).ToUInt();
}
bytes_remaining -= 16;
}
data = file.ReadBlock(Math.Min(6, bytes_remaining));
if (data.Count >= 4)
{
rate = data.Mid(0, 4).ToUInt();
}
if (data.Count >= 6)
{
volume = data.Mid(4, 2).ToUShort();
}
file.Seek(file.Tell + 70);
bytes_remaining -= 76;
data = file.ReadBlock(Math.Min(4,
bytes_remaining));
if (data.Count >= 4)
{
next_track_id = data.Mid(0, 4).ToUInt();
}
}
/// <summary>
/// Constructs and initializes a new instance of <see
/// cref="AppleElementaryStreamDescriptor" /> with a provided
/// header and handler by reading the contents from a
/// specified file.
/// </summary>
/// <param name="header">
/// A <see cref="BoxHeader" /> object containing the header
/// to use for the new instance.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to read the contents
/// of the box from.
/// </param>
/// <param name="handler">
/// A <see cref="IsoHandlerBox" /> object containing the
/// handler that applies to the new instance.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
/// <exception cref="CorruptFileException">
/// Valid data could not be read.
/// </exception>
public AppleElementaryStreamDescriptor(BoxHeader header,
TagLibSharp.File file,
IsoHandlerBox handler)
: base(header, file, handler)
{
int offset = 0;
ByteVector box_data = file.ReadBlock(DataSize);
decoder_config = new ByteVector();
// Elementary Stream Descriptor Tag
if (box_data [offset++] == 3)
{
// We have a descriptor tag. Check that it's at
// least 20 long.
if (ReadLength(box_data, ref offset) < 20)
{
throw new CorruptFileException(
"Insufficient data present.");
}
es_id = box_data.Mid(offset, 2).ToUShort();
offset += 2;
stream_priority = box_data [offset++];
}
else
{
// The tag wasn't found, so the next two byte
// are the ID, and after that, business as
// usual.
es_id = box_data.Mid(offset, 2).ToUShort();
offset += 2;
}
// Verify that the next data is the Decoder
// Configuration Descriptor Tag and escape if it won't
// work out.
if (box_data [offset++] != 4)
{
throw new CorruptFileException(
"Could not identify decoder configuration descriptor.");
}
// Check that it's at least 15 long.
if (ReadLength(box_data, ref offset) < 15)
{
throw new CorruptFileException(
"Could not read data. Too small.");
}
// Read a lot of good info.
object_type_id = box_data [offset++];
stream_type = box_data [offset++];
buffer_size_db = box_data.Mid(offset, 3).ToUInt();
offset += 3;
max_bitrate = box_data.Mid(offset, 4).ToUInt();
offset += 4;
average_bitrate = box_data.Mid(offset, 4).ToUInt();
offset += 4;
// Verify that the next data is the Decoder Specific
// Descriptor Tag and escape if it won't work out.
if (box_data [offset++] != 5)
{
throw new CorruptFileException(
"Could not identify decoder specific descriptor.");
}
// The rest of the info is decoder specific.
uint length = ReadLength(box_data, ref offset);
decoder_config = box_data.Mid(offset, (int)length);
}
/// <summary>
/// Searches for an audio header in a <see cref="TagLibSharp.File"
/// /> starting at a specified position and searching through
/// a specified number of bytes.
/// </summary>
/// <param name="header">
/// A <see cref="AudioHeader" /> object in which the found
/// header will be stored.
/// </param>
/// <param name="file">
/// A <see cref="TagLibSharp.File" /> object to search.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value specifying the seek position
/// in <paramref name="file" /> at which to start searching.
/// </param>
/// <param name="length">
/// A <see cref="int" /> value specifying the maximum number
/// of bytes to search before aborting.
/// </param>
/// <returns>
/// A <see cref="bool" /> value indicating whether or not a
/// header was found.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
public static bool Find(out AudioHeader header,
TagLibSharp.File file, long position, int length)
{
if (file == null)
{
throw new ArgumentNullException("file");
}
long end = position + length;
header = AudioHeader.Unknown;
file.Seek(position);
ByteVector buffer = file.ReadBlock(3);
if (buffer.Count < 3)
{
return(false);
}
do
{
file.Seek(position + 3);
buffer = buffer.Mid(buffer.Count - 3);
buffer.Add(file.ReadBlock(
(int)File.BufferSize));
for (int i = 0; i < buffer.Count - 3 &&
(length < 0 || position + i < end); i++)
{
if (buffer[i] == 0xFF &&
buffer[i + 1] >= 0xF0) // 0xFFF
{
try
{
BitStream bits = new BitStream(buffer.Mid(i, 7).Data);
// 12 bits sync header
bits.ReadInt32(12);
// 1 bit mpeg 2/4
bits.ReadInt32(1);
// 2 bits layer
bits.ReadInt32(2);
// 1 bit protection absent
bits.ReadInt32(1);
// 2 bits profile object type
bits.ReadInt32(2);
// 4 bits sampling frequency index
int samplerateindex = bits.ReadInt32(4);
if (samplerateindex >= sample_rates.Length)
{
return(false);
}
long samplerate = sample_rates[samplerateindex];
// 1 bit private bit
bits.ReadInt32(1);
// 3 bits channel configuration
int channelconfigindex = bits.ReadInt32(3);
if (channelconfigindex >= channels.Length)
{
return(false);
}
// 4 copyright bits
bits.ReadInt32(4);
// 13 bits frame length
long framelength = bits.ReadInt32(13); // double check framelength
if (framelength < 7)
{
return(false);
}
// 11 bits buffer fullness
bits.ReadInt32(11);
// 2 bits number of raw data blocks in frame
int numberofframes = bits.ReadInt32(2) + 1;
long numberofsamples = numberofframes * 1024;
long bitrate = framelength * 8 * samplerate / numberofsamples;
header = new AudioHeader(channels[channelconfigindex],
(int)bitrate,
(int)samplerate,
(int)numberofsamples,
numberofframes);
return(true);
}
catch (CorruptFileException)
{
}
}
}
position += File.BufferSize;
} while (buffer.Count > 3 && (length < 0 || position < end));
return(false);
}
