| /********** |
| This library is free software; you can redistribute it and/or modify it under |
| the terms of the GNU Lesser General Public License as published by the |
| Free Software Foundation; either version 2.1 of the License, or (at your |
| option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) |
| |
| This library is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this library; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2015 Live Networks, Inc. All rights reserved. |
| // Descriptor preceding frames of 'ADU' MP3 streams (for improved loss-tolerance) |
| // Implementation |
| |
| #include "MP3ADUdescriptor.hh" |
| |
| ////////// ADUdescriptor ////////// |
| |
| //##### NOTE: For now, ignore fragmentation. Fix this later! ##### |
| |
| #define TWO_BYTE_DESCR_FLAG 0x40 |
| |
| unsigned ADUdescriptor::generateDescriptor(unsigned char*& toPtr, |
| unsigned remainingFrameSize) { |
| unsigned descriptorSize = ADUdescriptor::computeSize(remainingFrameSize); |
| switch (descriptorSize) { |
| case 1: { |
| *toPtr++ = (unsigned char)remainingFrameSize; |
| break; |
| } |
| case 2: { |
| generateTwoByteDescriptor(toPtr, remainingFrameSize); |
| break; |
| } |
| } |
| |
| return descriptorSize; |
| } |
| |
| void ADUdescriptor::generateTwoByteDescriptor(unsigned char*& toPtr, |
| unsigned remainingFrameSize) { |
| *toPtr++ = (TWO_BYTE_DESCR_FLAG|(unsigned char)(remainingFrameSize>>8)); |
| *toPtr++ = (unsigned char)(remainingFrameSize&0xFF); |
| } |
| |
| unsigned ADUdescriptor::getRemainingFrameSize(unsigned char*& fromPtr) { |
| unsigned char firstByte = *fromPtr++; |
| |
| if (firstByte&TWO_BYTE_DESCR_FLAG) { |
| // This is a 2-byte descriptor |
| unsigned char secondByte = *fromPtr++; |
| |
| return ((firstByte&0x3F)<<8) | secondByte; |
| } else { |
| // This is a 1-byte descriptor |
| return (firstByte&0x3F); |
| } |
| } |
| |