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/*
* mpg123.c
*
* Copyright (C) Thomas Oestreich - June 2001
* Copyright (c) 1999 Albert L Faber
*
* This file is part of transcode, a video stream processing tool
*
* transcode 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.
*
* transcode 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "transcode.h"
#include "tcinfo.h"
#include "ioaux.h"
#include "magic.h"
#include "tc.h"
#include "libtc/libtc.h"
#ifdef HAVE_LAME
#include "mpg123.h"
#define MAX_U_32_NUM 0xFFFFFFFF
#define MAX_BUF 4096
static char sbuffer[MAX_BUF];
static int fskip(FILE * fp, long offset, int whence)
{
#ifndef PIPE_BUF
char buffer[4096];
#else
char buffer[PIPE_BUF];
#endif
int read;
if (0 == fseek(fp, offset, whence))
return 0;
if (whence != SEEK_CUR || offset < 0) {
tc_log_warn(__FILE__,
"fskip problem: Mostly the return status of functions is not evaluate so it is more secure to polute <stderr>.");
return -1;
}
while (offset > 0) {
read = offset > sizeof(buffer) ? sizeof(buffer) : offset;
if ((read = fread(buffer, 1, read, fp)) <= 0)
return -1;
offset -= read;
}
return 0;
}
static int check_aid(const unsigned char *header)
{
return 0 == strncmp(header, "AiD\1", 4);
}
/*
* Please check this and don't kill me if there's a bug
* This is a (nearly?) complete header analysis for a MPEG-1/2/2.5 Layer I, II or III
* data stream
*/
static int is_syncword_mp123(const void *const headerptr)
{
const unsigned char *const p = headerptr;
static const char abl2[16] =
{ 0, 7, 7, 7, 0, 7, 0, 0, 0, 0, 0, 8, 8, 8, 8, 8 };
if ((p[0] & 0xFF) != 0xFF)
return 0; // first 8 bits must be '1'
if ((p[1] & 0xE0) != 0xE0)
return 0; // next 3 bits are also
if ((p[1] & 0x18) == 0x08)
return 0; // no MPEG-1, -2 or -2.5
if ((p[1] & 0x06) == 0x00)
return 0; // no Layer I, II and III
if ((p[2] & 0xF0) == 0xF0)
return 0; // bad bitrate
if ((p[2] & 0x0C) == 0x0C)
return 0; // no sample frequency with (32,44.1,48)/(1,2,4)
if ((p[1] & 0x06) == 0x04) // illegal Layer II bitrate/Channel Mode comb
if (abl2[p[2] >> 4] & (1 << (p[3] >> 6)))
return 0;
return 1;
}
static int is_syncword_mp3(const void *const headerptr)
{
const unsigned char *const p = headerptr;
if ((p[0] & 0xFF) != 0xFF)
return 0; // first 8 bits must be '1'
if ((p[1] & 0xE0) != 0xE0)
return 0; // next 3 bits are also
if ((p[1] & 0x18) == 0x08)
return 0; // no MPEG-1, -2 or -2.5
if ((p[1] & 0x06) != 0x02)
return 0; // no Layer III (can be merged with 'next 3 bits are also' test, but don't do this, this decreases readability)
if ((p[2] & 0xF0) == 0xF0)
return 0; // bad bitrate
if ((p[2] & 0x0C) == 0x0C)
return 0; // no sample frequency with (32,44.1,48)/(1,2,4)
return 1;
}
int lame_decode_initfile(FILE * fd, mp3data_struct * mp3data, int format)
{
// VBRTAGDATA pTagData;
// int xing_header,len2,num_frames;
#define bufsize 100
unsigned char buf[bufsize];
int ret;
int len, aid_header;
short int pcm_l[1152], pcm_r[1152];
memset(mp3data, 0, sizeof(mp3data_struct));
memset(buf, 0, bufsize);
lame_decode_init();
if (!format) format = 0x55;
len = 4;
if (fread(buf, 1, len, fd) != len)
return -1; /* failed */
aid_header = check_aid(buf);
if (aid_header) {
if (fread(buf, 2, 1, fd) != 1)
return -1; /* failed */
aid_header = (unsigned char) buf[0] + 256 * (unsigned char) buf[1];
tc_log_msg(__FILE__, "Album ID found. length=%i", aid_header);
/* skip rest of AID, except for 6 bytes we have already read */
fskip(fd, aid_header - 6, SEEK_CUR);
/* read 4 more bytes to set up buffer for MP3 header check */
len = fread(buf, 1, 4, fd);
}
/* look for valid 4 byte MPEG header */
if (len < 4)
return -1;
if (format == 0x55) {
while ( !is_syncword_mp3(buf)) {
int i;
for (i = 0; i < len - 1; i++)
buf[i] = buf[i + 1];
if (fread(buf + len - 1, 1, 1, fd) != 1)
return -1; /* failed */
}
} else if (format == 0x50) {
while ( !is_syncword_mp123(buf)) {
int i;
for (i = 0; i < len - 1; i++)
buf[i] = buf[i + 1];
if (fread(buf + len - 1, 1, 1, fd) != 1)
return -1; /* failed */
}
}
// now parse the current buffer looking for MP3 headers.
// (as of 11/00: mpglib modified so that for the first frame where
// headers are parsed, no data will be decoded.
// However, for freeformat, we need to decode an entire frame,
// so mp3data->bitrate will be 0 until we have decoded the first
// frame. Cannot decode first frame here because we are not
// yet prepared to handle the output.
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (-1 == ret)
return -1;
/* repeat until we decode a valid mp3 header. */
while (!mp3data->header_parsed) {
len = fread(buf, 1, sizeof(buf), fd);
if (len != sizeof(buf))
return -1;
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (-1 == ret)
return -1;
}
if (mp3data->bitrate==0) {
tc_log_msg(__FILE__,"Input file is freeformat.");
}
if (mp3data->totalframes > 0) {
/* mpglib found a Xing VBR header and computed nsamp & totalframes */
}
else {
/* set as unknown. Later, we will take a guess based on file size
* ant bitrate */
mp3data->nsamp = MAX_U_32_NUM;
}
return 0;
}
/*
For lame_decode_fromfile: return code
-1 error
n number of samples output. either 576 or 1152 depending on MP3 file.
For lame_decode1_headers(): return code
-1 error
0 ok, but need more data before outputing any samples
n number of samples output. either 576 or 1152 depending on MP3 file.
*/
int lame_decode_fromfile(FILE * fd, short pcm_l[], short pcm_r[],
mp3data_struct * mp3data)
{
int ret = 0, len=0;
unsigned char buf[1024];
/* first see if we still have data buffered in the decoder: */
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (ret!=0) return ret;
/* read until we get a valid output frame */
while (1) {
len = fread(buf, 1, 1024, fd);
if (len == 0) {
/* we are done reading the file, but check for buffered data */
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (ret<=0) return -1; // done with file
break;
}
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (ret == -1) return -1;
if (ret >0) break;
}
return ret;
}
static int verbose_flag;
int buf_probe_mp3(unsigned char *_buf, int len, ProbeTrackInfo *pcm)
{
// VBRTAGDATA pTagData;
// int xing_header,len2,num_frames;
char *buf;
mp3data_struct *mp3data;
int i, ret;
int format=0;
short int pcm_l[1152], pcm_r[1152];
int type;
if((mp3data = tc_zalloc(sizeof(mp3data_struct)))==NULL) {
tc_log_error(__FILE__, "out of memory");
exit(1);
}
lame_decode_init();
buf=_buf;
for (i = 0; i < len - 1; i++) {
if(is_syncword_mp123(buf)) {
// catch false positives
switch(buf[1] & 0xff) {
case 0xFD: case 0xFC: format = CODEC_MP2; break;
case 0xFB: format = CODEC_MP3; break;
}
if (format) break;
}
++buf;
}
type = buf[1] & 0xff;
ret = lame_decode1_headers(buf, len, pcm_l, pcm_r, mp3data);
if (-1 == ret) {
//tc_log_error(__FILE__, "failed to probe mp3 header (%d)", len);
return -1;
}
//copy infos:
pcm->samplerate = mp3data->samplerate;
pcm->chan = mp3data->stereo;
pcm->bits = 16;
pcm->format = CODEC_MP3;
pcm->bitrate = mp3data->bitrate;
if(verbose_flag & TC_DEBUG)
tc_log_msg(__FILE__, "channels=%d, samplerate=%d Hz, bitrate=%d kbps, (fsize=%d)", mp3data->stereo, mp3data->samplerate, mp3data->bitrate, mp3data->framesize);
switch(type) {
case 0xFD:
case 0xFC:
pcm->format = CODEC_MP2;
break;
case 0xFB:
pcm->format = CODEC_MP3;
break;
}
return 0;
}
void probe_mp3(info_t *ipipe)
{
ssize_t ret=0;
// need to find syncframe:
if((ret = tc_pread(ipipe->fd_in, sbuffer, MAX_BUF)) != MAX_BUF) {
if (!ret) {
ipipe->error=1;
return;
}
}
verbose_flag = ipipe->verbose;
//for single MP3 stream only
if(buf_probe_mp3(sbuffer, ret, &ipipe->probe_info->track[0])<0) {
ipipe->error=1;
return;
}
switch(ipipe->probe_info->track[0].format) {
case CODEC_MP2:
ipipe->probe_info->magic = TC_MAGIC_MP2;
break;
case CODEC_MP3:
ipipe->probe_info->magic = TC_MAGIC_MP3;
break;
}
++ipipe->probe_info->num_tracks;
return;
}
#else // HAVE_LAME
void probe_mp3(info_t *ipipe) {
tc_log_error(__FILE__, "no lame support available");
return;
}
#endif