mpv/libmpdemux/aac_hdr.c

48 lines
1.6 KiB
C

/*
* Copyright (C) 2005 Nico Sabbi
*
* This file is part of MPlayer.
*
* MPlayer 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.
*
* MPlayer 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 MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdint.h>
#include "aac_hdr.h"
#include "libavutil/attributes.h"
/// \param srate (out) sample rate
/// \param num (out) number of audio frames in this ADTS frame
/// \return size of the ADTS frame in bytes
/// aac_parse_frames needs a buffer at least 8 bytes long
int aac_parse_frame(uint8_t *buf, int *srate, int *num)
{
int i = 0, sr, fl = 0, id av_unused;
static int srates[] = {96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 0, 0, 0};
if((buf[i] != 0xFF) || ((buf[i+1] & 0xF6) != 0xF0))
return 0;
id = (buf[i+1] >> 3) & 0x01; //id=1 mpeg2, 0: mpeg4
sr = (buf[i+2] >> 2) & 0x0F;
if(sr > 11)
return 0;
*srate = srates[sr];
fl = ((buf[i+3] & 0x03) << 11) | (buf[i+4] << 3) | ((buf[i+5] >> 5) & 0x07);
*num = (buf[i+6] & 0x02) + 1;
return fl;
}