Added ac3dec 0.6.1 with native ALSA driver.

2025-11-02 09:01:48 -05:00 · 2001-04-17 19:31:03 +00:00 · 2001-04-17 19:31:03 +00:00 · 28ff64db0a
commit 28ff64db0a
parent f2d80b5b5d
50 changed files with 6094 additions and 0 deletions
--- a/ac3dec/libac3/decode.c
+++ b/ac3dec/libac3/decode.c
@ -0,0 +1,149 @@
+/* 
+ *    decode.c
+ *
+ *	Copyright (C) Aaron Holtzman - May 1999
+ *
+ *  This file is part of ac3dec, a free Dolby AC-3 stream decoder.
+ *	
+ *  ac3dec 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.
+ *   
+ *  ac3dec 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. 
+ *
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif 
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/time.h>
+#include "ac3.h"
+#include "ac3_internal.h"
+#include "bitstream.h"
+#include "imdct.h"
+#include "exponent.h"
+#include "coeff.h"
+#include "bit_allocate.h"
+#include "parse.h"
+#include "crc.h"
+#include "stats.h"
+#include "rematrix.h"
+#include "sanity_check.h"
+#include "downmix.h"
+#include "debug.h"
+
+//our global config structure
+ac3_config_t ac3_config;
+uint_32 error_flag = 0;
+
+static audblk_t audblk;
+static bsi_t bsi;
+static syncinfo_t syncinfo;
+static uint_32 frame_count = 0;
+static uint_32 done_banner;
+static ac3_frame_t frame;
+
+//the floating point samples for one audblk
+static stream_samples_t samples;
+
+//the integer samples for the entire frame (with enough space for 2 ch out)
+//if this size change, be sure to change the size when muting
+static sint_16 s16_samples[6 * 6 * 256];
+
+void
+ac3_init(ac3_config_t *config)
+{
+	memcpy(&ac3_config,config,sizeof(ac3_config_t));
+
+	bitstream_init(config->fill_buffer_callback);
+	imdct_init();
+	sanity_check_init(&syncinfo,&bsi,&audblk);
+
+	frame.audio_data = s16_samples;
+}
+
+ac3_frame_t*
+ac3_decode_frame(void)
+{
+	uint_32 i;
+
+	//find a syncframe and parse
+	parse_syncinfo(&syncinfo);
+	if(error_flag)
+		goto error;
+
+	dprintf("(decode) begin frame %d\n",frame_count++);
+	frame.sampling_rate = syncinfo.sampling_rate;
+
+	parse_bsi(&bsi);
+
+	if(!done_banner)
+	{
+		stats_print_banner(&syncinfo,&bsi);
+		done_banner = 1;
+	}
+
+	for(i=0; i < 6; i++)
+	{
+		//Initialize freq/time sample storage
+		memset(samples,0,sizeof(float) * 256 * (bsi.nfchans + bsi.lfeon));
+
+		// Extract most of the audblk info from the bitstream
+		// (minus the mantissas 
+		parse_audblk(&bsi,&audblk);
+
+		// Take the differential exponent data and turn it into
+		// absolute exponents 
+		exponent_unpack(&bsi,&audblk); 
+		if(error_flag)
+			goto error;
+
+		// Figure out how many bits per mantissa 
+		bit_allocate(syncinfo.fscod,&bsi,&audblk);
+
+		// Extract the mantissas from the stream and
+		// generate floating point frequency coefficients
+		coeff_unpack(&bsi,&audblk,samples);
+		if(error_flag)
+			goto error;
+
+		if(bsi.acmod == 0x2)
+			rematrix(&audblk,samples);
+
+		// Convert the frequency samples into time samples 
+		imdct(&bsi,&audblk,samples);
+
+		// Downmix into the requested number of channels
+		// and convert floating point to sint_16
+		downmix(&bsi,samples,&s16_samples[i * ac3_config.num_output_ch * 256]);
+
+		sanity_check(&syncinfo,&bsi,&audblk);
+		if(error_flag)
+			goto error;
+	}
+	parse_auxdata(&syncinfo);
+
+	return &frame;	
+
+error:
+	//mute the frame
+	memset(s16_samples,0,sizeof(sint_16) * 256 * 2 * 6);
+
+	error_flag = 0;
+	return &frame;	
+
+}