SSDV/main.c

/* SSDV - Slow Scan Digital Video                                        */
/*=======================================================================*/
/* Copyright 2011-2016 Philip Heron <phil@sanslogic.co.uk>               */
/*                                                                       */
/* This program 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 3 of the License, or     */
/* (at your option) any later version.                                   */
/*                                                                       */
/* This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "ssdv.h"

void exit_usage()
{
	fprintf(stderr,
		"\n"
		"Usage: ssdv [-e|-d] [-n] [-t <percentage>] [-c <callsign>] [-i <id>] [-q <level>] [-l <length>] [<in file>] [<out file>]\n"
		"\n"
		"  -e Encode JPEG to SSDV packets.\n"
		"  -d Decode SSDV packets to JPEG.\n"
		"\n"
		"  -n Encode packets with no FEC.\n"
		"  -t For testing, drops the specified percentage of packets while decoding.\n"
		"  -c Set the callign. Accepts A-Z 0-9 and space, up to 6 characters.\n"
		"  -i Set the image ID (0-255).\n"
		"  -q Set the JPEG quality level (0 to 7, defaults to 4).\n"
		"  -l Set packet length in bytes (max: 256, default 256).\n"
		"  -v Print data for each packet decoded.\n"
		"\n"
		"Packet Length\n"
		"\n"
		"The packet length must be specified for both encoding and decoding if not\n"
		"the default 256 bytes. Smaller packets will increase overhead.\n"
		"\n");
	exit(-1);
}

int main(int argc, char *argv[])
{
	int c, i;
	FILE *fin = stdin;
	FILE *fout = stdout;
	char encode = -1;
	char type = SSDV_TYPE_NORMAL;
	int droptest = 0;
	int verbose = 0;
	int errors;
	char callsign[7];
	uint8_t image_id = 0;
	int8_t quality = 4;
	int pkt_length = SSDV_PKT_SIZE;
	ssdv_t ssdv;
	int skipped;
	
	uint8_t pkt[SSDV_PKT_SIZE], b[128], *jpeg;
	size_t jpeg_length;
	
	callsign[0] = '\0';
	
	opterr = 0;
	while((c = getopt(argc, argv, "ednc:i:q:l:t:v")) != -1)
	{
		switch(c)
		{
		case 'e': encode = 1; break;
		case 'd': encode = 0; break;
		case 'n': type = SSDV_TYPE_NOFEC; break;
		case 'c':
			if(strlen(optarg) > 6)
			{
				fprintf(stderr, "Warning: callsign cropped to 6 characters.\n");
			}
			strncpy(callsign, optarg, 6);
			callsign[6] = '\0';
			break;
		case 'i': image_id = atoi(optarg); break;
		case 'q': quality = atoi(optarg); break;
		case 'l': pkt_length = atoi(optarg); break;
		case 't': droptest = atoi(optarg); break;
		case 'v': verbose = 1; break;
		case '?': exit_usage();
		}
	}
	
	c = argc - optind;
	if(c > 2) exit_usage();
	
	for(i = 0; i < c; i++)
	{
		if(!strcmp(argv[optind + i], "-")) continue;
		
		switch(i)
		{
		case 0:
			fin = fopen(argv[optind + i], "rb");
			if(!fin)
			{
				fprintf(stderr, "Error opening '%s' for input:\n", argv[optind + i]);
				perror("fopen");
				return(-1);
			}
			break;
		
		case 1:
			fout = fopen(argv[optind + i], "wb");
			if(!fout)         
			{                 
				fprintf(stderr, "Error opening '%s' for output:\n", argv[optind + i]);
				perror("fopen");        
				return(-1);
			}
			break;
		}
	}
	
	switch(encode)
	{
	case 0: /* Decode */
		
		if(droptest > 0) fprintf(stderr, "*** NOTE: Drop test enabled: %i ***\n", droptest);
		
		if(ssdv_dec_init(&ssdv, pkt_length) != SSDV_OK)
		{
			return(-1);
		}
		
		jpeg_length = 1024 * 1024 * 4;
		jpeg = malloc(jpeg_length);
		ssdv_dec_set_buffer(&ssdv, jpeg, jpeg_length);
		
		i = 0;
		while(fread(pkt, pkt_length, 1, fin) > 0)
		{
			/* Drop % of packets */
			if(droptest && (rand() / (RAND_MAX / 100) < droptest)) continue;
			
			/* Test the packet is valid */
			skipped = 0;
			while((c = ssdv_dec_is_packet(pkt, pkt_length, &errors)) != 0)
			{
				/* Read 1 byte at a time until a new packet is found */
				memmove(&pkt[0], &pkt[1], pkt_length - 1);
				
				if(fread(&pkt[pkt_length - 1], 1, 1, fin) <= 0)
				{
					break;
				}
				
				skipped++;
			}
			
			/* No valid packet was found before EOF */
			if(c != 0) break;
			
			if(verbose)
			{
				ssdv_packet_info_t p;
				
				if(skipped > 0)
				{
					fprintf(stderr, "Skipped %d bytes.\n", skipped);
				}
				
				ssdv_dec_header(&p, pkt);
				fprintf(stderr, "Decoded image packet. Callsign: \"%s\", Image ID: %d, Resolution: %dx%d, Packet ID: %d (%d errors corrected)\n"
				                ">> Type: %d, Quality: %d, EOI: %d, MCU Mode: %d, MCU Offset: %d, MCU ID: %d/%d\n",
					p.callsign_s,
					p.image_id,
					p.width,
					p.height,
					p.packet_id,
					errors,
					p.type,
					p.quality,
					p.eoi,
					p.mcu_mode,
					p.mcu_offset,
					p.mcu_id,
					p.mcu_count
				);
			}
			
			/* Feed it to the decoder */
			ssdv_dec_feed(&ssdv, pkt);
			i++;
		}
		
		ssdv_dec_get_jpeg(&ssdv, &jpeg, &jpeg_length);
		fwrite(jpeg, 1, jpeg_length, fout);
		free(jpeg);
		
		fprintf(stderr, "Read %i packets\n", i);
		
		break;
	
	case 1: /* Encode */
		
		if(ssdv_enc_init(&ssdv, type, callsign, image_id, quality, pkt_length) != SSDV_OK)
		{
			return(-1);
		}
		
		ssdv_enc_set_buffer(&ssdv, pkt);
		
		i = 0;
		
		while(1)
		{
			while((c = ssdv_enc_get_packet(&ssdv)) == SSDV_FEED_ME)
			{
				size_t r = fread(b, 1, 128, fin);
				
				if(r <= 0)
				{
					fprintf(stderr, "Premature end of file\n");
					break;
				}
				ssdv_enc_feed(&ssdv, b, r);
			}
			
			if(c == SSDV_EOI)
			{
				fprintf(stderr, "ssdv_enc_get_packet said EOI\n");
				break;
			}
			else if(c != SSDV_OK)
			{
				fprintf(stderr, "ssdv_enc_get_packet failed: %i\n", c);
				return(-1);
			}
			
			fwrite(pkt, 1, pkt_length, fout);
			i++;
		}
		
		fprintf(stderr, "Wrote %i packets\n", i);
		
		break;
	
	default:
		fprintf(stderr, "No mode specified.\n");
		break;
	}
	
	if(fin != stdin) fclose(fin);
	if(fout != stdout) fclose(fout);
	
	return(0);
}