TheoraDecoder.cpp

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00001 //===========================================================================
00002 //Copyright (C) 2003, 2004 Zentaro Kavanagh
00003 //
00004 //Redistribution and use in source and binary forms, with or without
00005 //modification, are permitted provided that the following conditions
00006 //are met:
00007 //
00008 //- Redistributions of source code must retain the above copyright
00009 //  notice, this list of conditions and the following disclaimer.
00010 //
00011 //- Redistributions in binary form must reproduce the above copyright
00012 //  notice, this list of conditions and the following disclaimer in the
00013 //  documentation and/or other materials provided with the distribution.
00014 //
00015 //- Neither the name of Zentaro Kavanagh nor the names of contributors 
00016 //  may be used to endorse or promote products derived from this software 
00017 //  without specific prior written permission.
00018 //
00019 //THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00020 //``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00021 //LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
00022 //PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ORGANISATION OR
00023 //CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00024 //EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00025 //PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00026 //PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00027 //LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00028 //NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00029 //SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030 //===========================================================================
00031 
00032 #include "stdafx.h"
00033 #include "theoradecoder.h"
00034 
00035 TheoraDecoder::TheoraDecoder(void)
00036         : mFirstPacket(true)
00037         , mFirstHeader(true)
00038         , mPacketCount(0)
00039 {
00040 }
00041 
00042 TheoraDecoder::~TheoraDecoder(void)
00043 {
00044 }
00045 
00046 bool TheoraDecoder::initCodec() 
00047 {
00048         theora_comment_init(&mTheoraComment);
00049         theora_info_init(&mTheoraInfo);
00050         
00051         return true;
00052  }
00053 
00054 
00055 
00056 yuv_buffer* TheoraDecoder::decodeTheora(StampedOggPacket* inPacket) {           //Accepts packet and deletes it.
00057 
00058         if (mPacketCount < 3) {
00059                 decodeHeader(inPacket);         //Accepts header and deletes it.
00060                 
00061                 return NULL;
00062         } else {
00063                 if (mFirstPacket) {
00064                         theora_decode_init(&mTheoraState, &mTheoraInfo);
00065                         mFirstPacket = false;
00066                 }
00067                         ogg_packet* locOldPack = simulateOldOggPacket(inPacket);                //Accepts the packet and deletes it.
00068                         theora_decode_packetin(&mTheoraState, locOldPack);
00069                         delete locOldPack->packet;
00070                         delete locOldPack;
00071                         
00072                         //Ignore return value... always returns 0 (or crashes :)
00073                         theora_decode_YUVout(&mTheoraState, &mYUVBuffer);
00074                         
00075                         return &mYUVBuffer;
00076         }
00077 
00078 }
00079 
00080 ogg_packet* TheoraDecoder::simulateOldOggPacket(StampedOggPacket* inPacket) {           //inPacket is accepted and deleted.
00081         const unsigned char NOT_USED = 0;
00082         ogg_packet* locOldPacket = new ogg_packet;              //Returns this... the caller is responsible for it.
00083         if (mFirstHeader) {
00084                 locOldPacket->b_o_s = 1;
00085                 mFirstHeader = false;
00086         } else {
00087                 locOldPacket->b_o_s = NOT_USED;
00088         }
00089         locOldPacket->e_o_s = NOT_USED;
00090         locOldPacket->bytes = inPacket->packetSize();
00091         locOldPacket->granulepos = inPacket->endTime();
00092         locOldPacket->packet = inPacket->packetData();
00093         locOldPacket->packetno = NOT_USED;
00094         
00095         //Set this to NULL do it doesn't get deleted by the destructor we are about invoke.
00096         inPacket->setPacketData(NULL);
00097         delete inPacket;
00098 
00099         return locOldPacket;            //Gives a poitner to the caller.
00100 }
00101 
00102 bool TheoraDecoder::isKeyFrame(StampedOggPacket* inPacket)
00103 {
00104         const unsigned char KEY_FRAME_FLAG = 0x40;
00105         if ((inPacket->packetSize() > 0) && (inPacket->packetData() != NULL)) {
00106                 return ((inPacket->packetData()[0] & KEY_FRAME_FLAG) == KEY_FRAME_FLAG) ? false : true;
00107         } else {
00108                 return false;
00109         }
00110 }
00111 bool TheoraDecoder::decodeHeader(StampedOggPacket* inHeaderPacket) {            //inHeaderPacket is accepted and deleted.
00112 
00113         ogg_packet* locOldPack = simulateOldOggPacket(inHeaderPacket);          //Accepts packet and deletes it.
00114         theora_decode_header(&mTheoraInfo, &mTheoraComment, locOldPack);
00115 
00116         delete locOldPack->packet;
00117         delete locOldPack;
00118         mPacketCount++;
00119         return true;
00120 }

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