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/* $Id: interface.c,v 1.46 2004/03/10 00:50:54 robert Exp $ */
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#include "interface.h"
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#include "decode_i386.h"
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BOOL InitMP3( PMPSTR mp)
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memset(mp,0,sizeof(MPSTR));
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mp->old_free_format=0;
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mp->head = mp->tail = NULL;
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wordpointer = mp->bsspace[mp->bsnum] + 512;
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mp->sync_bitstream = 1;
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make_decode_tables(32767);
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void ExitMP3( PMPSTR mp)
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static struct buf *addbuf( PMPSTR mp, unsigned char *buf,int size)
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nbuf = (struct buf*) malloc( sizeof(struct buf) );
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fprintf(stderr,"Out of memory!\n");
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nbuf->pnt = (unsigned char*) malloc((size_t)size);
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memcpy(nbuf->pnt,buf,(size_t)size);
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nbuf->prev = mp->head;
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mp->head->next = nbuf;
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void remove_buf(PMPSTR mp)
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struct buf *buf = mp->tail;
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mp->tail = buf->next;
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mp->tail->prev = NULL;
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mp->tail = mp->head = NULL;
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static int read_buf_byte(PMPSTR mp)
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while(pos >= mp->tail->size) {
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fprintf(stderr,"Fatal error! tried to read past mp buffer\n");
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b = mp->tail->pnt[pos];
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static void read_head(PMPSTR mp)
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head = read_buf_byte(mp);
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head |= read_buf_byte(mp);
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head |= read_buf_byte(mp);
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head |= read_buf_byte(mp);
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void copy_mp(PMPSTR mp,int size,unsigned char *ptr)
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while(len < size && mp->tail) {
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int blen = mp->tail->size - mp->tail->pos;
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if( (size - len) <= blen) {
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memcpy(ptr+len,mp->tail->pnt+mp->tail->pos,(size_t)nlen);
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mp->tail->pos += nlen;
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if(mp->tail->pos == mp->tail->size) {
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/* number of bytes needed by GetVbrTag to parse header */
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#define XING_HEADER_SIZE 194
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/* traverse mp data structure without changing it */
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/* (just like sync_buffer) */
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/* pull out Xing bytes */
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/* call vbr header check code from LAME */
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/* if we find a header, parse it and also compute the VBR header size */
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/* if no header, do nothing. */
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/* bytes = number of bytes before MPEG header. skip this many bytes */
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/* before starting to read */
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/* return value: number of bytes in VBR header, including syncword */
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int check_vbr_header(PMPSTR mp,int bytes)
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int sync_buffer(PMPSTR mp,int free_match)
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/* traverse mp structure without modifing pointers, looking
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* for a frame valid header.
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* if free_format, valid header must also have the same
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* return number of bytes in mp, before the header
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* return -1 if header is not found
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unsigned int b[4]={0,0,0,0};
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struct buf *buf=mp->tail;
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for (i=0; i<mp->bsize; i++) {
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b[0]=b[1]; b[1]=b[2]; b[2]=b[3];
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while(pos >= buf->size) {
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/* not enough data to read 4 bytes */
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b[3] = buf->pnt[pos];
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struct frame *fr = &mp->fr;
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h = head_check(head,fr->lay);
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if (h && free_match) {
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/* just to be even more thorough, match the sample rate */
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int mode,stereo,sampling_frequency,mpeg25,lsf;
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if( head & (1<<20) ) {
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lsf = (head & (1<<19)) ? 0x0 : 0x1;
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mode = ((head>>6)&0x3);
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stereo = (mode == MPG_MD_MONO) ? 1 : 2;
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sampling_frequency = 6 + ((head>>10)&0x3);
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sampling_frequency = ((head>>10)&0x3) + (lsf*3);
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h = ((stereo==fr->stereo) && (lsf==fr->lsf) && (mpeg25==fr->mpeg25) &&
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(sampling_frequency == fr->sampling_frequency));
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int decodeMP3_clipchoice( PMPSTR mp,unsigned char *in,int isize,char *out,
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int (*synth_1to1_mono_ptr)(PMPSTR,real *,unsigned char *,int *),
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int (*synth_1to1_ptr)(PMPSTR,real *,int,unsigned char *, int *) )
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int i,iret,bits,bytes;
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if (in && isize && addbuf(mp,in,isize) == NULL)
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/* First decode header */
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if(!mp->header_parsed) {
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if (mp->fsizeold==-1 || mp->sync_bitstream) {
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mp->sync_bitstream=0;
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/* This is the very first call. sync with anything */
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/* bytes= number of bytes before header */
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bytes=sync_buffer(mp,0);
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/* now look for Xing VBR header */
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if (mp->bsize >= bytes+XING_HEADER_SIZE ) {
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/* vbrbytes = number of bytes in entire vbr header */
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vbrbytes=check_vbr_header(mp,bytes);
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/* not enough data to look for Xing header */
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return MP3_NEED_MORE;
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if (mp->vbr_header) {
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/* do we have enough data to parse entire Xing header? */
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if (bytes+vbrbytes > mp->bsize) return MP3_NEED_MORE;
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/* read in Xing header. Buffer data in case it
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* is used by a non zero main_data_begin for the next
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* frame, but otherwise dont decode Xing header */
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/*fprintf(stderr,"found xing header, skipping %i bytes\n",vbrbytes+bytes);*/
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for (i=0; i<vbrbytes+bytes; ++i) read_buf_byte(mp);
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/* now we need to find another syncword */
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/* just return and make user send in more data */
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return MP3_NEED_MORE;
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/* match channels, samplerate, etc, when syncing */
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bytes=sync_buffer(mp,1);
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if (bytes<0) return MP3_NEED_MORE;
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/* there were some extra bytes in front of header.
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* bitstream problem, but we are now resynced
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* should try to buffer previous data in case new
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* frame has nonzero main_data_begin, but we need
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* to make sure we do not overflow buffer
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// fprintf(stderr,"bitstream problem: resyncing...\n");
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mp->old_free_format=0;
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mp->sync_bitstream=1;
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/* skip some bytes, buffer the rest */
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size = (int) (wordpointer - (mp->bsspace[mp->bsnum]+512));
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if (size > MAXFRAMESIZE) {
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/* wordpointer buffer is trashed. probably cant recover, but try anyway */
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fprintf(stderr,"mpglib: wordpointer trashed. size=%i (%i) bytes=%i \n",
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size,MAXFRAMESIZE,bytes);
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wordpointer = mp->bsspace[mp->bsnum]+512;
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/* buffer contains 'size' data right now
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we want to add 'bytes' worth of data, but do not
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exceed MAXFRAMESIZE, so we through away 'i' bytes */
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i = (size+bytes)-MAXFRAMESIZE;
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copy_mp(mp,bytes,wordpointer);
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mp->fsizeold += bytes;
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decode_header(&mp->fr,mp->header);
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mp->framesize = mp->fr.framesize;
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mp->free_format = (mp->framesize==0);
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mp->ssize = (mp->fr.stereo == 1) ? 9 : 17;
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mp->ssize = (mp->fr.stereo == 1) ? 17 : 32;
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if (mp->fr.error_protection)
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mp->bsnum = 1-mp->bsnum; /* toggle buffer */
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wordpointer = mp->bsspace[mp->bsnum] + 512;
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/* for very first header, never parse rest of data */
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if (mp->fsizeold==-1)
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return MP3_NEED_MORE;
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/* now decode side information */
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if (!mp->side_parsed) {
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if (mp->bsize < mp->ssize)
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return MP3_NEED_MORE;
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copy_mp(mp,mp->ssize,wordpointer);
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if(mp->fr.error_protection)
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bits=do_layer3_sideinfo(&mp->fr);
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/* bits = actual number of bits needed to parse this frame */
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/* can be negative, if all bits needed are in the reservoir */
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/* read just as many bytes as necessary before decoding */
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mp->dsize = (bits+7)/8;
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/* this will force mpglib to read entire frame before decoding */
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/* mp->dsize= mp->framesize - mp->ssize;*/
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/* check if there is enough input data */
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if(mp->fr.framesize > mp->bsize)
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return MP3_NEED_MORE;
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/* takes care that the right amount of data is copied into wordpointer */
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mp->dsize=mp->fr.framesize;
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/* now decode main data */
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if (!mp->data_parsed ) {
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if(mp->dsize > mp->bsize) {
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return MP3_NEED_MORE;
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copy_mp(mp,mp->dsize,wordpointer);
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/*do_layer3(&mp->fr,(unsigned char *) out,done); */
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if(mp->fr.error_protection)
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do_layer1(mp,(unsigned char *) out,done);
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if(mp->fr.error_protection)
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do_layer2(mp,(unsigned char *) out,done);
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do_layer3(mp,(unsigned char *) out,done, synth_1to1_mono_ptr, synth_1to1_ptr);
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// fprintf(stderr,"invalid layer %d\n",mp->fr.lay);
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wordpointer = mp->bsspace[mp->bsnum] + 512 + mp->ssize + mp->dsize;
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/* remaining bits are ancillary data, or reservoir for next frame
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* If free format, scan stream looking for next frame to determine
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if (mp->free_format) {
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if (mp->old_free_format) {
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/* free format. bitrate must not vary */
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mp->framesize=mp->fsizeold_nopadding + (mp->fr.padding);
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bytes=sync_buffer(mp,1);
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if (bytes<0) return iret;
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mp->framesize = bytes + mp->ssize+mp->dsize;
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mp->fsizeold_nopadding= mp->framesize - mp->fr.padding;
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fprintf(stderr,"freeformat bitstream: estimated bitrate=%ikbs \n",
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8*(4+mp->framesize)*freqs[mp->fr.sampling_frequency]/
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(1000*576*(2-mp->fr.lsf)));
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/* buffer the ancillary data and reservoir for next frame */
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bytes = mp->framesize-(mp->ssize+mp->dsize);
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if (bytes > mp->bsize) {
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copy_mp(mp,bytes,wordpointer);
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wordpointer += bytes;
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size = (int) (wordpointer - (mp->bsspace[mp->bsnum]+512));
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if (size > MAXFRAMESIZE) {
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fprintf(stderr,"fatal error. MAXFRAMESIZE not large enough.\n");
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/* the above frame is completey parsed. start looking for next frame */
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mp->fsizeold = mp->framesize;
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mp->old_free_format = mp->free_format;
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int decodeMP3( PMPSTR mp,unsigned char *in,int isize,char *out,
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// fprintf(stderr,"To less out space\n");
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/* passing pointers to the functions which clip the samples */
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return decodeMP3_clipchoice(mp, in, isize, out, osize, done, synth_1to1_mono, synth_1to1);
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int decodeMP3_unclipped( PMPSTR mp,unsigned char *in,int isize,char *out,
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/* we forbid input with more than 1152 samples per channel for output in unclipped mode */
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if(osize < 1152 * 2 * sizeof(real) ) {
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// fprintf(stderr,"To less out space\n");
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/* passing pointers to the functions which don't clip the samples */
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return decodeMP3_clipchoice(mp, in, isize, out, osize, done, synth_1to1_mono_unclipped, synth_1to1_unclipped);
added
removed
src/transcode/mpglib/mpglib/interface.c
