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# seq_decompress.cpp

    00001 /* ***** BEGIN LICENSE BLOCK *****
    00002 *
    00003 * $Id: seq_decompress.cpp,v 1.3 2005/01/30 05:11:41 gabest Exp $ $Name:  $
    00004 *
    00005 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
    00006 *
    00007 * The contents of this file are subject to the Mozilla Public License
    00008 * Version 1.1 (the "License"); you may not use this file except in compliance
    00009 * with the License. You may obtain a copy of the License at
    00010 * http://www.mozilla.org/MPL/
    00011 *
    00012 * Software distributed under the License is distributed on an "AS IS" basis,
    00013 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
    00014 * the specific language governing rights and limitations under the License.
    00015 *
    00016 * The Original Code is BBC Research and Development code.
    00017 *
    00018 * The Initial Developer of the Original Code is the British Broadcasting
    00019 * Corporation.
    00020 * Portions created by the Initial Developer are Copyright (C) 2004.
    00021 * All Rights Reserved.
    00022 *
    00023 * Contributor(s): Thomas Davies (Original Author),
    00024 *                 Anuradha Suraparaju
    00025 *
    00026 * Alternatively, the contents of this file may be used under the terms of
    00027 * the GNU General Public License Version 2 (the "GPL"), or the GNU Lesser
    00028 * Public License Version 2.1 (the "LGPL"), in which case the provisions of
    00029 * the GPL or the LGPL are applicable instead of those above. If you wish to
    00030 * allow use of your version of this file only under the terms of the either
    00031 * the GPL or LGPL and not to allow others to use your version of this file
    00032 * under the MPL, indicate your decision by deleting the provisions above
    00033 * and replace them with the notice and other provisions required by the GPL
    00034 * or LGPL. If you do not delete the provisions above, a recipient may use
    00035 * your version of this file under the terms of any one of the MPL, the GPL
    00036 * or the LGPL.
    00037 * ***** END LICENSE BLOCK ***** */
    00038
    00039
    00041 //---------------------------------------//
    00042 //Class to manage decompressing sequences//
    00043 //---------------------------------------//
    00045
    00046 #include <libdirac_common/dirac_assertions.h>
    00047 #include <libdirac_decoder/seq_decompress.h>
    00048 #include <libdirac_common/common.h>
    00049 #include <libdirac_common/golomb.h>
    00050 #include <libdirac_common/frame_buffer.h>
    00051 #include <libdirac_decoder/frame_decompress.h>
    00052 using namespace dirac;
    00053
    00054 SequenceDecompressor::SequenceDecompressor(std::istream* ip,bool verbosity)
    00055 :
    00056 m_all_done(false),
    00057 m_infile(ip),
    00058 m_current_code_fnum(0),
    00059 m_delay(1),
    00060 m_last_frame_read(-1),
    00061 m_show_fnum(-1)
    00062 {
    00063     m_decparams.SetBitsIn( new BitInputManager(m_infile) );
    00064     m_decparams.SetVerbose( verbosity );
    00065     ReadStreamHeader();
    00066
    00067     //Amount of horizontal padding for Y,U and V components
    00068     int xpad_luma,xpad_chroma;
    00069
    00070     //Amount of vertical padding for Y,U and V components
    00071     int ypad_luma,ypad_chroma;
    00072
    00073     //scaling factors for chroma based on chroma format
    00074     int x_chroma_fac,y_chroma_fac;
    00075
    00076     //First, we need to have sufficient padding to take account of the blocksizes.
    00077     //It's sufficient to check for chroma
    00078
    00079     if ( m_sparams.CFormat() == format411 )
    00080     {
    00081         x_chroma_fac = 4;
    00082         y_chroma_fac = 1;
    00083     }
    00084     else if ( m_sparams.CFormat() == format420 )
    00085     {
    00086         x_chroma_fac = 2;
    00087         y_chroma_fac = 2;
    00088     }
    00089     else if ( m_sparams.CFormat() == format422 )
    00090     {
    00091         x_chroma_fac = 2;
    00092         y_chroma_fac = 1;
    00093     }
    00094     else
    00095     {
    00096         x_chroma_fac = 1;
    00097         y_chroma_fac = 1;
    00098     }
    00099
    00100     int xl_chroma=m_sparams.Xl() / x_chroma_fac;
    00101     int yl_chroma=m_sparams.Yl() / y_chroma_fac;
    00102
    00103     //make sure we have enough macroblocks to cover the pictures
    00104     m_decparams.SetXNumMB( m_sparams.Xl() / m_decparams.LumaBParams(0).Xbsep() );
    00105     m_decparams.SetYNumMB( m_sparams.Yl() / m_decparams.LumaBParams(0).Ybsep() );
    00106     if ( m_decparams.XNumMB() * m_decparams.ChromaBParams(0).Xbsep() < xl_chroma )
    00107     {
    00108         m_decparams.SetXNumMB( m_decparams.XNumMB() + 1 );
    00109         xpad_chroma = m_decparams.XNumMB() * m_decparams.ChromaBParams(0).Xbsep() - xl_chroma;
    00110     }
    00111     else
    00112         xpad_chroma=0;
    00113
    00114     if (m_decparams.YNumMB()*m_decparams.ChromaBParams(0).Ybsep()<yl_chroma)
    00115     {
    00116         m_decparams.SetYNumMB( m_decparams.YNumMB() + 1 );
    00117         ypad_chroma=m_decparams.YNumMB()*m_decparams.ChromaBParams(0).Ybsep()-yl_chroma;
    00118     }
    00119     else
    00120         ypad_chroma=0;
    00121
    00122     //Now we have an integral number of macroblocks in a picture and we set the number of blocks
    00123     m_decparams.SetXNumBlocks( 4*m_decparams.XNumMB() );
    00124     m_decparams.SetYNumBlocks( 4*m_decparams.YNumMB() );
    00125
    00126     //Next we work out the additional padding due to the wavelet transform
    00127     //For the moment, we'll fix the transform depth to be 4, so we need divisibility by 16.
    00128     //In the future we'll want arbitrary transform depths. It's sufficient to check for
    00129     //chroma only
    00130
    00131     int xpad_len = xl_chroma+xpad_chroma;
    00132     int ypad_len = yl_chroma+ypad_chroma;
    00133
    00134     if ( xpad_len%16 != 0 )
    00135         xpad_chroma=( ( xpad_len/16 ) + 1 )*16 - xl_chroma;
    00136     if ( ypad_len%16 != 0)
    00137         ypad_chroma = ( ( ypad_len/16 ) + 1 )*16 - yl_chroma;
    00138
    00139     xpad_luma = xpad_chroma*x_chroma_fac;
    00140     ypad_luma = ypad_chroma*y_chroma_fac;
    00141
    00142     //set up padded picture sizes, based on original picture sizes, the block parameters and the wavelet transform depth
    00143     m_fbuffer= new FrameBuffer( m_sparams.CFormat() , m_sparams.Xl() + xpad_luma , m_sparams.Yl() + ypad_luma );
    00144
    00145     m_fdecoder = new FrameDecompressor (m_decparams , m_sparams.CFormat() );
    00146 }
    00147
    00148 SequenceDecompressor::~SequenceDecompressor()
    00149 {
    00150     delete m_fbuffer;
    00151     delete m_fdecoder;
    00152     delete &m_decparams.BitsIn();
    00153 }
    00154
    00155 bool SequenceDecompressor::ReadNextFrameHeader()
    00156 {
    00157     return m_fdecoder->ReadFrameHeader(*m_fbuffer);
    00158 }
    00159
    00160 const FrameParams& SequenceDecompressor::GetNextFrameParams() const
    00161 {
    00162     return m_fdecoder->GetFrameParams();
    00163 }
    00164
    00165 Frame& SequenceDecompressor::DecompressNextFrame(bool skip /* = false */)
    00166 {
    00167     //this function decodes the next frame in coding order and returns the next frame in display order
    00168     //In general these will differ, and because of re-ordering there is a m_delay which needs to be imposed.
    00169     //This creates problems at the start and at the end of the sequence which must be dealt with.
    00170     //At the start we just keep outputting frame 0. At the end you will need to loop for longer to get all
    00171     //the frames out. It's up to the calling function to do something with the decoded frames as they
    00172     //come out - write them to screen or to file, as required.
    00173
    00174     TEST (m_fdecoder != NULL);
    00175
    00176     if (m_current_code_fnum!=0){
    00177         //if we're not at the beginning, clean the buffer of frames that can be discarded
    00178         m_fbuffer->Clean(m_show_fnum);
    00179     }
    00180
    00181     bool new_frame_to_display=false;
    00182
    00183     if (!skip)
    00184        new_frame_to_display = m_fdecoder->Decompress(*m_fbuffer);
    00185
    00186     //if we've exited with success, there's a new frame to display, so increment
    00187     //the counters. Otherwise, freeze on the last frame shown
    00188     m_show_fnum=std::max(m_current_code_fnum-m_delay,0);
    00189     if (new_frame_to_display || skip)
    00190     {
    00191         m_current_code_fnum++;
    00192     }
    00193
    00194     return m_fbuffer->GetFrame(m_show_fnum);
    00195 }
    00196
    00197 Frame& SequenceDecompressor::GetNextFrame()
    00198 {
    00199     return m_fbuffer->GetFrame(m_show_fnum);
    00200 }
    00201
    00202 void SequenceDecompressor::ReadStreamHeader()
    00203 {    //called from constructor
    00204
    00205     //read the stream header parameters
    00206     //begin with the identifying string
    00207     OLBParams bparams;
    00208     //char kwname[9];
    00209     //for (int i=0; i<8; ++i)
    00210     //{
    00211     //    kwname[i]=m_decparams.BitsIn().InputByte();
    00212     //}
    00213     //kwname[8]='\0';
    00214
    00215     char seq_start[5];
    00216     for (int i=0;i<5;++i)
    00217     {
    00218         seq_start[i]=m_decparams.BitsIn().InputByte();
    00219     }
    00220     //TBC: test that kwname="KW-DIRAC"
    00221
    00222     //bit stream version
    00223     m_sparams.SetBitstreamVersion( m_decparams.BitsIn().InputByte() );
    00224
    00225     // TODO: test if this bit stream version is supported. Report an error
    00226     // otherwise
    00227     TESTM (m_sparams.BitstreamVersion() == BITSTREAM_VERSION, "Bitstream version match");
    00228
    00229     //picture dimensions
    00230     m_sparams.SetXl( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00231     m_sparams.SetYl( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00232
    00233     //picture rate
    00234     m_sparams.SetFrameRate( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00235
    00236      //block parameters
    00237     bparams.SetXblen( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00238     bparams.SetYblen( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00239     bparams.SetXbsep( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00240     bparams.SetYbsep( int(UnsignedGolombDecode( m_decparams.BitsIn() )) );
    00241
    00242     //dimensions of block arrays (remember there may need to be padding for some block and picture sizes)
    00243     m_decparams.SetXNumBlocks( int(UnsignedGolombDecode( m_decparams.BitsIn())) );
    00244     m_decparams.SetYNumBlocks( int(UnsignedGolombDecode( m_decparams.BitsIn())) );
    00245     m_decparams.SetXNumMB( m_decparams.XNumBlocks()/4 );
    00246     m_decparams.SetYNumMB( m_decparams.YNumBlocks()/4 );
    00247
    00248     //chroma format
    00249     m_sparams.SetCFormat( ChromaFormat(UnsignedGolombDecode( m_decparams.BitsIn())) );
    00250     m_decparams.SetBlockSizes( bparams , m_sparams.CFormat() );
    00251
    00252      //interlace marker
    00253     m_decparams.SetInterlace( m_decparams.BitsIn().InputBit() );
    00254     m_sparams.SetInterlace( m_decparams.Interlace() );
    00255
    00256     //Flush the input to the end of the header
    00257     m_decparams.BitsIn().FlushInput();
    00258 }