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mirror of https://github.com/mpv-player/mpv synced 2024-12-23 15:22:09 +00:00
mpv/demux/mp3_hdr.c
wm4 4873b32c59 Rename directories, move files (step 2 of 2)
Finish renaming directories and moving files. Adjust all include
statements to make the previous commit compile.

The two commits are separate, because git is bad at tracking renames
and content changes at the same time.

Also take this as an opportunity to remove the separation between
"common" and "mplayer" sources in the Makefile. ("common" used to be
shared between mplayer and mencoder.)
2012-11-12 20:08:18 +01:00

145 lines
4.3 KiB
C

/*
* 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 <stdio.h>
#include "config.h"
#include "mp3_hdr.h"
#include "core/mp_msg.h"
//----------------------- mp3 audio frame header parser -----------------------
static int tabsel_123[2][3][16] = {
{ {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0},
{0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,0},
{0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,0} },
{ {0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,0},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,0},
{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,0} }
};
static long freqs[9] = { 44100, 48000, 32000, // MPEG 1.0
22050, 24000, 16000, // MPEG 2.0
11025, 12000, 8000}; // MPEG 2.5
/*
* return frame size or -1 (bad frame)
*/
int mp_get_mp3_header(unsigned char* hbuf,int* chans, int* srate, int* spf, int* mpa_layer, int* br){
int stereo,ssize,lsf,framesize,padding,bitrate_index,sampling_frequency, divisor;
int bitrate;
int layer, mult[3] = { 12000, 144000, 144000 };
unsigned long newhead =
hbuf[0] << 24 |
hbuf[1] << 16 |
hbuf[2] << 8 |
hbuf[3];
// printf("head=0x%08X\n",newhead);
// head_check:
if( (newhead & 0xffe00000) != 0xffe00000 ){
mp_msg(MSGT_DEMUXER,MSGL_DBG2,"head_check failed\n");
return -1;
}
layer = 4-((newhead>>17)&3);
if(layer==4){
mp_msg(MSGT_DEMUXER,MSGL_DBG2,"not layer-1/2/3\n");
return -1;
}
sampling_frequency = ((newhead>>10)&0x3); // valid: 0..2
if(sampling_frequency==3){
mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid sampling_frequency\n");
return -1;
}
if( newhead & ((long)1<<20) ) {
// MPEG 1.0 (lsf==0) or MPEG 2.0 (lsf==1)
lsf = (newhead & ((long)1<<19)) ? 0x0 : 0x1;
sampling_frequency += (lsf*3);
} else {
// MPEG 2.5
lsf = 1;
sampling_frequency += 6;
}
// crc = ((newhead>>16)&0x1)^0x1;
bitrate_index = ((newhead>>12)&0xf); // valid: 1..14
padding = ((newhead>>9)&0x1);
// fr->extension = ((newhead>>8)&0x1);
// fr->mode = ((newhead>>6)&0x3);
// fr->mode_ext = ((newhead>>4)&0x3);
// fr->copyright = ((newhead>>3)&0x1);
// fr->original = ((newhead>>2)&0x1);
// fr->emphasis = newhead & 0x3;
stereo = ( (((newhead>>6)&0x3)) == 3) ? 1 : 2;
// !checked later through tabsel_123[]!
// if(!bitrate_index || bitrate_index==15){
// mp_msg(MSGT_DEMUXER,MSGL_DBG2,"Free format not supported.\n");
// return -1;
// }
if(lsf)
ssize = (stereo == 1) ? 9 : 17;
else
ssize = (stereo == 1) ? 17 : 32;
if(!((newhead>>16)&0x1)) ssize += 2; // CRC
bitrate = tabsel_123[lsf][layer-1][bitrate_index];
framesize = bitrate * mult[layer-1];
mp_msg(MSGT_DEMUXER,MSGL_DBG2,"FRAMESIZE: %d, layer: %d, bitrate: %d, mult: %d\n",
framesize, layer, tabsel_123[lsf][layer-1][bitrate_index], mult[layer-1]);
if(!framesize){
mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid framesize/bitrate_index\n");
return -1;
}
divisor = (layer == 3 ? (freqs[sampling_frequency] << lsf) : freqs[sampling_frequency]);
framesize /= divisor;
if(layer==1)
framesize = (framesize+padding)*4;
else
framesize += padding;
// if(framesize<=0 || framesize>MAXFRAMESIZE) return FALSE;
if(srate) {
*srate = freqs[sampling_frequency];
if(spf) {
if(layer == 1)
*spf = 384;
else if(layer == 2)
*spf = 1152;
else if(*srate < 32000)
*spf = 576;
else
*spf = 1152;
}
}
if(mpa_layer) *mpa_layer = layer;
if(chans) *chans = stereo;
if(br) *br = bitrate;
return framesize;
}