mirror of
https://github.com/alsa-project/alsa-tools.git
synced 2025-10-31 22:25:34 -04:00
97a55787e6
- added getopt_long to parse the command line options - added -D (--device) option - added -q (--quiet) option - added -I (--iec958) option - added AC3 to IEC958 encapsulation code (not tested) - addec xrun detection and restart
137 lines
3.5 KiB
C
137 lines
3.5 KiB
C
/***************************************************************************/
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/* This code has been fully inspired from various place */
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/* I will give their name later. May they be bless .... It works */
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/* */
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/* For the moment test it. */
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/* */
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/* 27-08-00 -- Ze'ev Maor -- fixed recovery from flase syncword detection */
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/* */
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/* 24-08-00 -- Ze'ev Maor -- Modified for integrtion with DXR3-OMS-plugin */
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/***************************************************************************/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <inttypes.h>
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#include <libac3/ac3.h>
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#include <libac3/ac3_internal.h>
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#include <libac3/parse.h>
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#include <libac3/crc.h>
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#include "output.h"
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void swab(const void*, void*, size_t);
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#define BLOCK_SIZE 6144
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static char buf[BLOCK_SIZE];
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static uint32_t sbuffer_size;
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static syncinfo_t syncinfo;
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static char *sbuffer;
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static int done_banner;
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static uint32_t
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buffer_syncframe(syncinfo_t *syncinfo, uint8_t **start, uint8_t *end)
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{
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uint8_t *cur = *start;
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uint16_t syncword = syncinfo->syncword;
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uint32_t ret = 0;
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//
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// Find an ac3 sync frame.
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//
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while(syncword != 0x0b77)
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{
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if(cur >= end)
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goto done;
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syncword = (syncword << 8) + *cur++;
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}
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//need the next 3 bytes to decide how big the frame is
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while(sbuffer_size < 3)
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{
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if(cur >= end)
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goto done;
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sbuffer[sbuffer_size++] = *cur++;
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}
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parse_syncinfo_data(syncinfo,sbuffer);
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while(sbuffer_size < syncinfo->frame_size * 2 - 2)
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{
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if(cur >= end)
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goto done;
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sbuffer[sbuffer_size++] = *cur++;
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}
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crc_init();
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crc_process_frame(sbuffer,syncinfo->frame_size * 2 - 2);
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if(!crc_validate())
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{
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//error_flag = 1;
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fprintf(stderr,"** CRC failed - skipping frame **\n");
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syncword = 0xffff;
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sbuffer_size = 0;
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bzero(buf,BLOCK_SIZE);
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goto done;
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}
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//
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//if we got to this point, we found a valid ac3 frame to decode
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//
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//reset the syncword for next time
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syncword = 0xffff;
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sbuffer_size = 0;
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ret = 1;
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done:
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syncinfo->syncword = syncword;
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*start = cur;
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return ret;
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}
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void
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init_spdif(void)
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{
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sbuffer_size = 0;
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sbuffer = &buf[10];
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done_banner = 0;
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}
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int
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output_spdif(uint8_t *data_start, uint8_t *data_end, int quiet)
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{
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unsigned short *sbuf = (unsigned short *)buf;
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int ret = 0, res;
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while(buffer_syncframe(&syncinfo, &data_start, data_end))
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{
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sbuf[0] = 0xf872; //spdif syncword
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sbuf[1] = 0x4e1f; // .............
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sbuf[2] = 0x0001; // AC3 data
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sbuf[3] = syncinfo.frame_size * 16;
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sbuf[4] = 0x0b77; // AC3 syncwork
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if (!done_banner) {
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fprintf(stdout,"AC3 Stream ");
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fprintf(stdout,"%2.1f KHz",syncinfo.sampling_rate * 1e-3);
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fprintf(stdout,"%4d kbps",syncinfo.bit_rate);
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fprintf(stdout,"\n");
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done_banner = 1;
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}
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// extract_ac3 seems to write swabbed data
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swab(&buf[10], &buf[10], syncinfo.frame_size * 2 - 2);
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res = output_play(sbuf, BLOCK_SIZE / 2 / 2); /* 2 channels, 16-bit samples */
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ret = ret < 0 ? ret : res;
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bzero(buf,BLOCK_SIZE);
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}
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return ret;
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}
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