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/*
* Copyright (C) 2005-2013 Team XBMC
* http://www.xbmc.org
*
* 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, 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 XBMC; see the file COPYING. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include "ES_MPEGAudio.h"
#include "bitstream.h"
using namespace TSDemux;
const uint16_t FrequencyTable[3] = { 44100, 48000, 32000 };
const uint16_t BitrateTable[2][3][15] =
{
{
{0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448 },
{0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384 },
{0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 }
},
{
{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160}
}
};
ES_MPEG2Audio::ES_MPEG2Audio(uint16_t pid)
: ElementaryStream(pid)
{
m_PTS = 0;
m_DTS = 0;
m_FrameSize = 0;
m_SampleRate = 0;
m_Channels = 0;
m_BitRate = 0;
es_alloc_init = 2048;
}
ES_MPEG2Audio::~ES_MPEG2Audio()
{
}
void ES_MPEG2Audio::Parse(STREAM_PKT* pkt)
{
int p = es_parsed;
int l;
while ((l = es_len - p) > 3)
{
if (FindHeaders(es_buf + p, l) < 0)
break;
p++;
}
es_parsed = p;
if (es_found_frame && l >= m_FrameSize)
{
bool streamChange = SetAudioInformation(m_Channels, m_SampleRate, m_BitRate, 0, 0);
pkt->pid = pid;
pkt->data = &es_buf[p];
pkt->size = m_FrameSize;
pkt->duration = 90000 * 1152 / m_SampleRate;
pkt->dts = m_DTS;
pkt->pts = m_PTS;
pkt->streamChange = streamChange;
es_consumed = p + m_FrameSize;
es_parsed = es_consumed;
es_found_frame = false;
}
}
int ES_MPEG2Audio::FindHeaders(uint8_t *buf, int buf_size)
{
if (es_found_frame)
return -1;
if (buf_size < 4)
return -1;
uint8_t *buf_ptr = buf;
if ((buf_ptr[0] == 0xFF && (buf_ptr[1] & 0xE0) == 0xE0))
{
CBitstream bs(buf_ptr, 4 * 8);
bs.skipBits(11); // syncword
int audioVersion = bs.readBits(2);
if (audioVersion == 1)
return 0;
int mpeg2 = !(audioVersion & 1);
int mpeg25 = !(audioVersion & 3);
int layer = bs.readBits(2);
if (layer == 0)
return 0;
layer = 4 - layer;
bs.skipBits(1); // protetion bit
int bitrate_index = bs.readBits(4);
if (bitrate_index == 15 || bitrate_index == 0)
return 0;
m_BitRate = BitrateTable[mpeg2][layer - 1][bitrate_index] * 1000;
int sample_rate_index = bs.readBits(2);
if (sample_rate_index == 3)
return 0;
m_SampleRate = FrequencyTable[sample_rate_index] >> (mpeg2 + mpeg25);
int padding = bs.readBits1();
bs.skipBits(1); // private bit
int channel_mode = bs.readBits(2);
if (channel_mode == 11)
m_Channels = 1;
else
m_Channels = 2;
if (layer == 1)
m_FrameSize = (12 * m_BitRate / m_SampleRate + padding) * 4;
else
m_FrameSize = 144 * m_BitRate / m_SampleRate + padding;
es_found_frame = true;
m_DTS = c_pts;
m_PTS = c_pts;
c_pts += 90000 * 1152 / m_SampleRate;
return -1;
}
return 0;
}
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