/// <summary>
/// Release resources for garbage collection
/// </summary>
public void CloseEncoder()
{
_YEncoder = null;
_CbEncoder = null;
_CrEncoder = null;
Close();
}
/// <summary>
/// Encodes one data chunk into output stream. Settings parameter controls
/// how much data is generated.The chunk data is written to Stream
/// with no IFF header. Successive calls to EncodeChunk encode
/// successive chunks.You must call CloseCodec after encoding the last
/// chunk of a file.
/// </summary>
/// <param name="stream"></param>
/// <param name="settings"></param>
/// <returns></returns>
public int EncodeChunk(Stream stream, InterWaveEncoderSettings settings)
{
// Check
if (settings.Slices == 0 && settings.Bytes == 0 && settings.Decibels == 0)
{
throw new DjvuArgumentException("Encoder needs stop condition", nameof(settings));
}
if (_YMap == null)
{
throw new DjvuInvalidOperationException($"Cannot encode! Target encoder map is null {nameof(_YMap)}");
}
// Open
if (_YEncoder == null)
{
_CSlices = _CSerial = _CBytes = 0;
_YEncoder = new InterWaveEncoder(_YMap);
if (_CrMap != null && _CbMap != null)
{
_CbEncoder = new InterWaveEncoder(_CbMap);
_CrEncoder = new InterWaveEncoder(_CrMap);
}
}
// Prepare zcodec slices
int flag = 1;
int nslices = 0;
using (MemoryStream coderStream = new MemoryStream())
{
float estdb = -1.0f;
ZPCodec zp = new ZPCodec(coderStream, true, true);
while (flag != 0)
{
if (settings.Decibels > 0 && estdb >= settings.Decibels)
{
break;
}
if (settings.Bytes > 0 && coderStream.Position + _CBytes >= settings.Bytes)
{
break;
}
if (settings.Slices > 0 && nslices + _CSlices >= settings.Slices)
{
break;
}
flag = _YEncoder.CodeSlice(zp);
if (flag != 0 && settings.Decibels > 0)
{
if (_YEncoder._CurrentBand == 0 || estdb >= settings.Decibels - DecibelPrune)
{
estdb = _YEncoder.EstimateDecibel(_dBFrac);
}
}
if (_CrEncoder != null && _CbEncoder != null && _CSlices + nslices >= _CrCbDelay)
{
flag |= _CbEncoder.CodeSlice(zp);
flag |= _CrEncoder.CodeSlice(zp);
}
nslices++;
}
zp.Flush();
// Write primary header
stream.WriteByte((byte)_CSerial);
stream.WriteByte((byte)(nslices));
// Write extended header
if (_CSerial == 0)
{
byte major = InterWaveCodec.MajorVersion;
if (!(_CrMap != null && _CbMap != null))
{
major |= 0x80;
}
stream.WriteByte(major);
stream.WriteByte(InterWaveCodec.MinorVersion);
byte xhi = (byte)((_YMap.Width >> 8) & 0xff);
byte xlo = (byte)(_YMap.Width & 0xff);
byte yhi = (byte)((_YMap.Height >> 8) & 0xff);
byte ylo = (byte)(_YMap.Height & 0xff);
byte crCbDelay = (byte)(_CrCbHalf ? 0x00 : 0x80);
crCbDelay |= (byte)(_CrCbDelay >= 0 ? _CrCbDelay : 0x00);
stream.WriteByte(xhi);
stream.WriteByte(xlo);
stream.WriteByte(yhi);
stream.WriteByte(ylo);
stream.WriteByte(crCbDelay);
}
byte[] buffer = coderStream.GetBuffer();
stream.Write(buffer, 0, (int)coderStream.Position);
_CBytes += (int)coderStream.Position;
}
_CSlices += nslices;
_CSerial += 1;
return(flag);
}