public JpegDecoder(Stream input)
{
jpegReader = new JPEGBinaryReader(input);
if (jpegReader.GetNextMarker() != JPEGMarker.SOI)
throw new Exception("Failed to find SOI marker.");
}
public void DecodeScanBaseline(byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
// Set the decode function for all the components
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.Decode = comp.DecodeBaseline;
}
DecodeScan(numberOfComponents, componentSelector, resetInterval, jpegReader, ref marker);
}
public void DecodeScanProgressive(byte successiveApproximation, byte startSpectralSelection, byte endSpectralSelection,
byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
byte successiveHigh = (byte)(successiveApproximation >> 4);
byte successiveLow = (byte)(successiveApproximation & 0x0f);
if ((startSpectralSelection > endSpectralSelection) || (endSpectralSelection > 63))
throw new Exception("Bad spectral selection.");
bool dcOnly = startSpectralSelection == 0;
bool refinementScan = (successiveHigh != 0);
if (dcOnly) // DC scan
{
if (endSpectralSelection != 0)
throw new Exception("Bad spectral selection for DC only scan.");
}
else // AC scan
{
if (numberOfComponents > 1)
throw new Exception("Too many components for AC scan!");
}
// Set the decode function for all the components
// TODO: set this for the scan and let the component figure it out
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.successiveLow = successiveLow;
if (dcOnly)
{
if (refinementScan) // DC refine
comp.Decode = comp.DecodeDCRefine;
else // DC first
comp.Decode = comp.DecodeDCFirst;
}
else
{
comp.spectralStart = startSpectralSelection;
comp.spectralEnd = endSpectralSelection;
if (refinementScan) // AC refine
comp.Decode = comp.DecodeACRefine;
else // AC first
comp.Decode = comp.DecodeACFirst;
}
}
DecodeScan(numberOfComponents, componentSelector, resetInterval, jpegReader, ref marker);
}
/// <summary>Figure F.16 - Reads the huffman code bit-by-bit.</summary>
public int Decode(JPEGBinaryReader JPEGStream)
{
int i = 0;
short code = (short)JPEGStream.ReadBits(1);
while (code > maxcode[i])
{
i++;
code <<= 1;
code |= (short)JPEGStream.ReadBits(1);
}
int val = huffval[code + (valptr[i])];
if (val < 0)
{
val = 256 + val;
}
return(val);
}
public void DecodeACFirst(JPEGBinaryReader stream, float[] zz)
{
if (stream.eob_run > 0)
{
stream.eob_run--;
return;
}
for (int k = spectralStart; k <= spectralEnd; k++)
{
int s = ACTable.Decode(stream);
int r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
r = (int)stream.ReadBits(s);
s = (int)HuffmanTable.Extend(r, s);
zz[k] = s << successiveLow;
}
else
{
if (r != 15)
{
stream.eob_run = 1 << r;
if (r != 0)
{
stream.eob_run += stream.ReadBits(r);
}
stream.eob_run--;
break;
}
k += 15;
}
}
}
public void DecodeACRefine(JPEGBinaryReader stream, float[] dest)
{
int p1 = 1 << successiveLow;
int m1 = (-1) << successiveLow;
int k = spectralStart;
if (stream.eob_run == 0)
for (; k <= spectralEnd; k++)
{
#region Decode and check S
int s = ACTable.Decode(stream);
int r = s >> 4;
s &= 15;
if (s != 0)
{
if (s != 1)
throw new Exception("Decode Error");
if (stream.ReadBits(1) == 1)
s = p1;
else
s = m1;
}
else
{
if (r != 15)
{
stream.eob_run = 1 << r;
if (r > 0)
stream.eob_run += stream.ReadBits(r);
break;
}
} // if (s != 0)
#endregion
// Apply the update
do
{
if (dest[k] != 0)
{
if (stream.ReadBits(1) == 1)
{
if (((int)dest[k] & p1) == 0)
{
if (dest[k] >= 0)
dest[k] += p1;
else
dest[k] += m1;
}
}
}
else
{
if (--r < 0)
break;
}
k++;
} while (k <= spectralEnd);
if( (s != 0) && k < 64)
{
dest[k] = s;
}
} // for k = start ... end
if (stream.eob_run > 0)
{
for (; k <= spectralEnd; k++)
{
if (dest[k] != 0)
{
if (stream.ReadBits(1) == 1)
{
if (((int)dest[k] & p1) == 0)
{
if (dest[k] >= 0)
dest[k] += p1;
else
dest[k] += m1;
}
}
}
}
stream.eob_run--;
}
}
private void DecodeScan(byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
//TODO: not necessary
jpegReader.eob_run = 0;
int mcuIndex = 0;
int mcuTotalIndex = 0;
// This loops through until a MarkerTagFound exception is
// found, if the marker tag is a RST (Restart Marker) it
// simply skips it and moves on this system does not handle
// corrupt data streams very well, it could be improved by
// handling misplaced restart markers.
int h = 0, v = 0;
int x = 0;
long lastPosition = jpegReader.BaseStream.Position;
//TODO: replace this with a loop which knows how much data to expect
while (true)
{
#region Inform caller of decode progress
if (ProgressUpdateMethod != null)
{
if (jpegReader.BaseStream.Position >= lastPosition + JpegDecoder.ProgressUpdateByteInterval)
{
lastPosition = jpegReader.BaseStream.Position;
ProgressUpdateMethod(lastPosition);
}
}
#endregion
try
{
// Loop though capturing MCU, instruct each
// component to read in its necessary count, for
// scaling factors the components automatically
// read in how much they need
// Sec A.2.2 from CCITT Rec. T.81 (1992 E)
bool interleaved = !(numberOfComponents == 1);
if (!interleaved)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[0]);
comp.SetBlock(mcuIndex);
comp.DecodeMCU(jpegReader, h, v);
int mcus_per_line = mcus_per_row(comp);
int blocks_per_line = (int) Math.Ceiling((double)this.Width / (8 * comp.factorH));
// TODO: Explain the non-interleaved scan ------
h++; x++;
if (h == comp.factorH)
{
h = 0; mcuIndex++;
}
if( (x % mcus_per_line) == 0)
{
x = 0;
v++;
if (v == comp.factorV)
{
if (h != 0) { mcuIndex++; h = 0; }
v = 0;
}
else
{
mcuIndex -= blocks_per_line;
// we were mid-block
if (h != 0) { mcuIndex++; h = 0; }
}
}
// -----------------------------------------------
}
else // Components are interleaved
{
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.SetBlock(mcuTotalIndex);
for (int j = 0; j < comp.factorV; j++)
for (int i = 0; i < comp.factorH; i++)
{
comp.DecodeMCU(jpegReader, i, j);
}
}
mcuIndex++;
mcuTotalIndex++;
}
}
// We've found a marker, see if the marker is a restart
// marker or just the next marker in the stream. If
// it's the next marker in the stream break out of the
// while loop, if it's just a restart marker skip it
catch (JPEGMarkerFoundException ex)
{
marker = ex.Marker;
// Handle JPEG Restart Markers, this is where the
// count of MCU's per interval is compared with
// the count actually obtained, if it's short then
// pad on some MCU's ONLY for components that are
// greater than one. Also restart the DC prediction
// to zero.
if (marker == JPEGMarker.RST0
|| marker == JPEGMarker.RST1
|| marker == JPEGMarker.RST2
|| marker == JPEGMarker.RST3
|| marker == JPEGMarker.RST4
|| marker == JPEGMarker.RST5
|| marker == JPEGMarker.RST6
|| marker == JPEGMarker.RST7)
{
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
if (compIndex > 1)
comp.padMCU(mcuTotalIndex, resetInterval - mcuIndex);
comp.resetInterval();
}
mcuTotalIndex += (resetInterval - mcuIndex);
mcuIndex = 0;
}
else
{
break; // We're at the end of our scan, exit out.
}
}
}
}
/// <summary>
/// Generated from text on F-23, F.13 - Huffman decoded of AC coefficients
/// on ISO DIS 10918-1. Requirements and Guidelines.
/// </summary>
internal void decode_ac_coefficients(JPEGBinaryReader JPEGStream, float[] zz)
{
for (int k = 1; k < 64; k++)
{
int s = ACTable.Decode(JPEGStream);
int r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
r = (int)JPEGStream.ReadBits(s);
s = (int)HuffmanTable.Extend(r, s);
zz[k] = s;
}
else
{
if (r != 15)
{
//throw new JPEGMarkerFoundException();
return;
}
k += 15;
}
}
}
/// <summary>
/// Generated from text on F-22, F.2.2.1 - Huffman decoding of DC
/// coefficients on ISO DIS 10918-1. Requirements and Guidelines.
/// </summary>
/// <param name="JPEGStream">Stream that contains huffman bits</param>
/// <returns>DC coefficient</returns>
public float decode_dc_coefficient(JPEGBinaryReader JPEGStream)
{
int t = DCTable.Decode(JPEGStream);
float diff = JPEGStream.ReadBits(t);
diff = HuffmanTable.Extend((int)diff, t);
diff = (previousDC + diff);
previousDC = diff;
return diff;
}
public void DecodeMCU(JPEGBinaryReader jpegReader, int i, int j)
{
Decode(jpegReader, scanMCUs[i,j]);
}
public void DecodeDCRefine(JPEGBinaryReader stream, float[] dest)
{
if (stream.ReadBits(1) == 1)
{
dest[0] = (int)dest[0] | (1 << successiveLow);
}
}
public void DecodeDCFirst(JPEGBinaryReader stream, float[] dest)
{
float[] datablock = new float[64];
int s = DCTable.Decode(stream);
int r = stream.ReadBits(s);
s = HuffmanTable.Extend(r, s);
s = (int)previousDC + s;
previousDC = s;
dest[0] = s << successiveLow;
}
public void DecodeACFirst(JPEGBinaryReader stream, float[] zz)
{
if (stream.eob_run > 0)
{
stream.eob_run--;
return;
}
for (int k = spectralStart; k <= spectralEnd; k++)
{
int s = ACTable.Decode(stream);
int r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
r = (int)stream.ReadBits(s);
s = (int)HuffmanTable.Extend(r, s);
zz[k] = s << successiveLow;
}
else
{
if (r != 15)
{
stream.eob_run = 1 << r;
if (r != 0)
stream.eob_run += stream.ReadBits(r);
stream.eob_run--;
break;
}
k += 15;
}
}
}
public void DecodeMCU(JPEGBinaryReader jpegReader, int i, int j)
{
Decode(jpegReader, scanMCUs[i, j]);
}
public void DecodeACRefine(JPEGBinaryReader stream, float[] dest)
{
int p1 = 1 << successiveLow;
int m1 = (-1) << successiveLow;
int k = spectralStart;
if (stream.eob_run == 0)
{
for (; k <= spectralEnd; k++)
{
#region Decode and check S
int s = ACTable.Decode(stream);
int r = s >> 4;
s &= 15;
if (s != 0)
{
if (s != 1)
{
throw new Exception("Decode Error");
}
if (stream.ReadBits(1) == 1)
{
s = p1;
}
else
{
s = m1;
}
}
else
{
if (r != 15)
{
stream.eob_run = 1 << r;
if (r > 0)
{
stream.eob_run += stream.ReadBits(r);
}
break;
}
} // if (s != 0)
#endregion
// Apply the update
do
{
if (dest[k] != 0)
{
if (stream.ReadBits(1) == 1)
{
if (((int)dest[k] & p1) == 0)
{
if (dest[k] >= 0)
{
dest[k] += p1;
}
else
{
dest[k] += m1;
}
}
}
}
else
{
if (--r < 0)
{
break;
}
}
k++;
} while (k <= spectralEnd);
if ((s != 0) && k < 64)
{
dest[k] = s;
}
} // for k = start ... end
}
if (stream.eob_run > 0)
{
for (; k <= spectralEnd; k++)
{
if (dest[k] != 0)
{
if (stream.ReadBits(1) == 1)
{
if (((int)dest[k] & p1) == 0)
{
if (dest[k] >= 0)
{
dest[k] += p1;
}
else
{
dest[k] += m1;
}
}
}
}
}
stream.eob_run--;
}
}
private void DecodeScan(byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
//TODO: not necessary
jpegReader.eob_run = 0;
int mcuIndex = 0;
int mcuTotalIndex = 0;
// This loops through until a MarkerTagFound exception is
// found, if the marker tag is a RST (Restart Marker) it
// simply skips it and moves on this system does not handle
// corrupt data streams very well, it could be improved by
// handling misplaced restart markers.
int h = 0, v = 0;
int x = 0;
long lastPosition = jpegReader.BaseStream.Position;
//TODO: replace this with a loop which knows how much data to expect
while (true)
{
#region Inform caller of decode progress
if (ProgressUpdateMethod != null)
{
if (jpegReader.BaseStream.Position >= lastPosition + JpegDecoder.ProgressUpdateByteInterval)
{
lastPosition = jpegReader.BaseStream.Position;
ProgressUpdateMethod(lastPosition);
}
}
#endregion
try
{
// Loop though capturing MCU, instruct each
// component to read in its necessary count, for
// scaling factors the components automatically
// read in how much they need
// Sec A.2.2 from CCITT Rec. T.81 (1992 E)
bool interleaved = !(numberOfComponents == 1);
if (!interleaved)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[0]);
comp.SetBlock(mcuIndex);
comp.DecodeMCU(jpegReader, h, v);
int mcus_per_line = mcus_per_row(comp);
int blocks_per_line = (int)Math.Ceiling((double)this.Width / (8 * comp.factorH));
// TODO: Explain the non-interleaved scan ------
h++; x++;
if (h == comp.factorH)
{
h = 0; mcuIndex++;
}
if ((x % mcus_per_line) == 0)
{
x = 0;
v++;
if (v == comp.factorV)
{
if (h != 0)
{
mcuIndex++; h = 0;
}
v = 0;
}
else
{
mcuIndex -= blocks_per_line;
// we were mid-block
if (h != 0)
{
mcuIndex++; h = 0;
}
}
}
// -----------------------------------------------
}
else // Components are interleaved
{
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.SetBlock(mcuTotalIndex);
for (int j = 0; j < comp.factorV; j++)
{
for (int i = 0; i < comp.factorH; i++)
{
comp.DecodeMCU(jpegReader, i, j);
}
}
}
mcuIndex++;
mcuTotalIndex++;
}
}
// We've found a marker, see if the marker is a restart
// marker or just the next marker in the stream. If
// it's the next marker in the stream break out of the
// while loop, if it's just a restart marker skip it
catch (JPEGMarkerFoundException ex)
{
marker = ex.Marker;
// Handle JPEG Restart Markers, this is where the
// count of MCU's per interval is compared with
// the count actually obtained, if it's short then
// pad on some MCU's ONLY for components that are
// greater than one. Also restart the DC prediction
// to zero.
if (marker == JPEGMarker.RST0 ||
marker == JPEGMarker.RST1 ||
marker == JPEGMarker.RST2 ||
marker == JPEGMarker.RST3 ||
marker == JPEGMarker.RST4 ||
marker == JPEGMarker.RST5 ||
marker == JPEGMarker.RST6 ||
marker == JPEGMarker.RST7)
{
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
if (compIndex > 1)
{
comp.padMCU(mcuTotalIndex, resetInterval - mcuIndex);
}
comp.resetInterval();
}
mcuTotalIndex += (resetInterval - mcuIndex);
mcuIndex = 0;
}
else
{
break; // We're at the end of our scan, exit out.
}
}
}
}
public void DecodeScanBaseline(byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
// Set the decode function for all the components
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.Decode = comp.DecodeBaseline;
}
DecodeScan(numberOfComponents, componentSelector, resetInterval, jpegReader, ref marker);
}
public void DecodeScanProgressive(byte successiveApproximation, byte startSpectralSelection, byte endSpectralSelection,
byte numberOfComponents, byte[] componentSelector, int resetInterval, JPEGBinaryReader jpegReader, ref byte marker)
{
byte successiveHigh = (byte)(successiveApproximation >> 4);
byte successiveLow = (byte)(successiveApproximation & 0x0f);
if ((startSpectralSelection > endSpectralSelection) || (endSpectralSelection > 63))
{
throw new Exception("Bad spectral selection.");
}
bool dcOnly = startSpectralSelection == 0;
bool refinementScan = (successiveHigh != 0);
if (dcOnly) // DC scan
{
if (endSpectralSelection != 0)
{
throw new Exception("Bad spectral selection for DC only scan.");
}
}
else // AC scan
{
if (numberOfComponents > 1)
{
throw new Exception("Too many components for AC scan!");
}
}
// Set the decode function for all the components
// TODO: set this for the scan and let the component figure it out
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
{
JpegComponent comp = Scan.GetComponentById(componentSelector[compIndex]);
comp.successiveLow = successiveLow;
if (dcOnly)
{
if (refinementScan) // DC refine
{
comp.Decode = comp.DecodeDCRefine;
}
else // DC first
{
comp.Decode = comp.DecodeDCFirst;
}
}
else
{
comp.spectralStart = startSpectralSelection;
comp.spectralEnd = endSpectralSelection;
if (refinementScan) // AC refine
{
comp.Decode = comp.DecodeACRefine;
}
else // AC first
{
comp.Decode = comp.DecodeACFirst;
}
}
}
DecodeScan(numberOfComponents, componentSelector, resetInterval, jpegReader, ref marker);
}
/// <summary>Figure F.16 - Reads the huffman code bit-by-bit.</summary>
public int Decode(JPEGBinaryReader JPEGStream)
{
int i = 0;
short code = (short)JPEGStream.ReadBits(1);
while (code > maxcode[i])
{
i++;
code <<= 1;
code |= (short)JPEGStream.ReadBits(1);
}
int val = huffval[code + (valptr[i])];
if (val < 0)
val = 256 + val;
return val;
}
public void DecodeBaseline(JPEGBinaryReader stream, float[] dest)
{
float dc = decode_dc_coefficient(stream);
decode_ac_coefficients(stream, dest);
dest[0] = dc;
}
