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/*---- DXhead.c --------------------------------------------
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mod 12/7/98 add vbr scale
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Copyright 1998 Xing Technology Corp.
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-----------------------------------------------------------*/
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#include "mpg123/mpg123.h"
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/*-------------------------------------------------------------*/
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static int ExtractI4(unsigned char *buf)
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/* big endian extract */
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/*-------------------------------------------------------------*/
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int mpg123_get_xing_header(XHEADDATA * X, unsigned char *buf)
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int h_id, h_mode, h_sr_index;
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static int sr_table[4] =
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{44100, 48000, 32000, 99999};
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/* get Xing header data */
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X->flags = 0; /* clear to null incase fail */
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/* get selected MPEG header data */
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h_id = (buf[1] >> 3) & 1;
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h_sr_index = (buf[2] >> 2) & 3;
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h_mode = (buf[3] >> 6) & 3;
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/* determine offset of header */
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return 0; /* header not found */
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X->samprate = sr_table[h_sr_index];
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head_flags = X->flags = ExtractI4(buf);
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buf += 4; /* get flags */
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if (head_flags & FRAMES_FLAG)
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X->frames = ExtractI4(buf);
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if (head_flags & BYTES_FLAG)
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X->bytes = ExtractI4(buf);
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if (head_flags & TOC_FLAG)
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X->toc = malloc(100);
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for (i = 0; i < 100; i++)
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if (head_flags & VBR_SCALE_FLAG)
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X->vbr_scale = ExtractI4(buf);
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/*if( X->toc != NULL ) {
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*for(i=0;i<100;i++) {
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* if( (i%10) == 0 ) printf("\n");
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* printf(" %3d", (int)(X->toc[i]));
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return 1; /* success */
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/*-------------------------------------------------------------*/
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int mpg123_seek_point(unsigned char TOC[100], int file_bytes, float percent)
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/* interpolate in TOC to get file seek point in bytes */
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if (percent > 100.0f)
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fx = fa + (fb - fa) * (percent - a);
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seekpoint = (int) ((1.0f / 256.0f) * fx * file_bytes);
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/*-------------------------------------------------------------*/
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int mpg123_stream_check_for_xing_header(struct frame *fr, XHEADDATA * xhead)
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unsigned char *head_data;
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lseek(rd->filept, -(fr->framesize + 4), SEEK_CUR);
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head_data = malloc(fr->framesize + 4);
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read(rd->filept,head_data, fr->framesize +4); /* now read the rest */
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ret = mpg123_get_xing_header(xhead, head_data);