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/***************************************************************************
* Copyright (C) 2008 by Ilya Kotov *
* forkotov02@hotmail.ru *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include <QIODevice>
#include <neaacdec.h>
#include "aacfile.h"
#define MAX_CHANNELS 6
static int adts_sample_rates[] = {96000,88200,64000,48000,44100,32000,24000,22050,16000,12000,11025,8000,7350,0,0,0};
AACFile::AACFile(QIODevice *i)
{
m_length = 0;
m_bitrate = 0;
m_input = i;
parseADTS();
}
AACFile::~AACFile()
{
}
qint64 AACFile::length()
{
return m_length;
}
quint32 AACFile::bitrate()
{
return m_bitrate;
}
void AACFile::parseADTS()
{
uchar *buf = new uchar[FAAD_MIN_STREAMSIZE*MAX_CHANNELS];
qint64 buf_at = 0;
int frames, frame_length;
int t_framelength = 0;
int samplerate = 0;
float frames_per_sec, bytes_per_frame;
qint64 pos = m_input->pos();
m_input->seek(0);
buf_at = m_input->read((char *)buf, FAAD_MIN_STREAMSIZE*MAX_CHANNELS);
for (int i = 0; i < buf_at - 1; i++)
{
if (buf[i] == 0xff && (buf[i+1]&0xf6) == 0xf0)
{
memmove (buf, buf + i, buf_at - i);
buf_at -= i;
break;
}
}
/* Read all frames to ensure correct time and bitrate */
for (frames = 0; /* */; frames++)
{
//qDebug("frame header = %d", buf[0]);
buf_at += m_input->read((char *)buf + buf_at, FAAD_MIN_STREAMSIZE*MAX_CHANNELS - buf_at);
if (buf_at > 7)
{
/* check syncword */
if (!((buf[0] == 0xFF)&&((buf[1] & 0xF6) == 0xF0)))
break;
if (frames == 0)
samplerate = adts_sample_rates[(buf[2]&0x3c)>>2];
frame_length = ((((unsigned int)buf[3] & 0x3)) << 11)
| (((unsigned int)buf[4]) << 3) | (buf[5] >> 5);
t_framelength += frame_length;
if (frame_length > buf_at)
break;
buf_at -= frame_length;
memmove(buf, buf + frame_length, buf_at);
}
else
{
break;
}
}
m_input->seek(pos);
frames_per_sec = (float)samplerate/1024.0f;
if (frames != 0)
bytes_per_frame = (float)t_framelength/(float)(frames*1000);
else
bytes_per_frame = 0;
m_bitrate = (quint32)(8. * bytes_per_frame * frames_per_sec + 0.5);
if (frames_per_sec != 0)
m_length = frames/frames_per_sec;
else
m_length = 1;
}
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