diff --git a/src/main.c b/src/main.c
index 3503bab..7ce1dbf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -17,7 +17,411 @@
  * along with gapk.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
+
+#include <gapk/codecs.h>
+#include <gapk/formats.h>
+#include <gapk/procqueue.h>
+
+
+struct gapk_options
+{
+	const char *fname_in;
+	const struct format_desc *fmt_in;
+
+	const char *fname_out;
+	const struct format_desc *fmt_out;
+};
+
+struct gapk_state
+{
+	struct gapk_options opts;
+
+	struct pq *pq;
+
+	FILE *fh_in;
+	FILE *fh_out;
+};
+
+
+static void
+print_help(char *progname)
+{
+	int i;
+
+	/* Header */
+	fprintf(stdout, "Usage: %s [options]\n", progname);
+	fprintf(stdout, "\n");
+	fprintf(stdout, "Options:\n");
+	fprintf(stdout, "  -i, --input-file=FILE\t\tInput file\n");
+	fprintf(stdout, "  -o, --output-file=FILE\tOutput file\n");
+	fprintf(stdout, "  -f, --input-format=FMT\tInput format (see below)\n");
+	fprintf(stdout, "  -g, --output-format=FMT\tOutput format (see below)\n");
+	fprintf(stdout, "\n");
+
+	/* Print all codecs */
+	fprintf(stdout, "Supported codecs:\n");
+	fprintf(stdout, " name\tfmt enc dec\tdescription\n");
+
+	for (i=CODEC_INVALID+1; i<_CODEC_MAX; i++) {
+		const struct codec_desc *codec = codec_get_from_type(i);
+		fprintf(stdout, " %s\t %c   %c   %c\t%s\n",
+			codec->name,
+			'*',
+			codec->codec_encode ? '*' : ' ',
+			codec->codec_decode ? '*' : ' ',
+			codec->description
+		);
+	}
+
+	fprintf(stdout, "\n");
+
+	/* Print all formats */
+	fprintf(stdout, "Supported formats:\n");
+	
+	for (i=FMT_INVALID+1; i<_FMT_MAX; i++) {
+		const struct format_desc *fmt = fmt_get_from_type(i);
+		fprintf(stdout, " %s%s%s\t%s\n",
+			fmt->name,
+			strlen(fmt->name) <  7 ? "\t" : "",
+			strlen(fmt->name) < 15 ? "\t" : "",
+			fmt->description
+		);
+	}
+
+	fprintf(stdout, "\n");
+}
+
+static int
+parse_options(struct gapk_state *state, int argc, char *argv[])
+{
+	const struct option long_options[] = {
+		{"input-file", 1, 0, 'i'},
+		{"output-file", 1, 0, 'o'},
+		{"input-format", 1, 0, 'f'},
+		{"output-format", 1, 0, 'g'},
+		{"help", 0, 0, 'h'},
+	};
+	const char *short_options = "i:o:f:g:h";
+
+	struct gapk_options *opt = &state->opts;
+
+	/* Set some defaults */
+	memset(opt, 0x00, sizeof(*opt));
+
+	/* Parse */
+	while (1) {
+		int c;
+		int opt_idx;
+
+		c = getopt_long(
+			argc, argv, short_options, long_options, &opt_idx);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'i':
+			opt->fname_in = optarg;
+			break;
+
+		case 'o':
+			opt->fname_out = optarg;
+			break;
+
+		case 'f':
+			opt->fmt_in = fmt_get_from_name(optarg);
+			if (!opt->fmt_in) {
+				fprintf(stderr, "[!] Unsupported format: %s\n", optarg);
+				return -EINVAL;
+			}
+			break;
+
+		case 'g':
+			opt->fmt_out = fmt_get_from_name(optarg);
+			if (!opt->fmt_out) {
+				fprintf(stderr, "[!] Unsupported format: %s\n", optarg);
+				return -EINVAL;
+			}
+			break;
+
+		case 'h':
+			return 1;
+
+		default:
+			fprintf(stderr, "[+] Unknown option\n");
+			return -EINVAL;
+
+		}
+	}
+
+	return 0;
+}
+
+static int
+check_options(struct gapk_state *gs)
+{
+	/* Required formats */
+	if (!gs->opts.fmt_in || !gs->opts.fmt_out) {
+		fprintf(stderr, "[!] Input and output formats are required arguments !\n");
+		return -EINVAL;
+	}
+
+	/* Transcoding */
+	if (gs->opts.fmt_in->codec_type != gs->opts.fmt_out->codec_type) {
+		const struct codec_desc *codec;
+
+		/* Check source codec */
+		codec = codec_get_from_type(gs->opts.fmt_in->codec_type);
+		if (!codec) {
+			fprintf(stderr, "[!] Internal error: bad codec reference\n");
+			return -EINVAL;
+		}
+		if ((codec->type != CODEC_PCM) && !codec->codec_decode) {
+			fprintf(stderr, "[!] Decoding from '%s' codec is unsupported\n", codec->name);
+			return -ENOTSUP;
+		}
+
+		/* Check destination codec */
+		codec = codec_get_from_type(gs->opts.fmt_out->codec_type);
+		if (!codec) {
+			fprintf(stderr, "[!] Internal error: bad codec reference\n");
+			return -EINVAL;
+		}
+		if ((codec->type != CODEC_PCM) && !codec->codec_encode) {
+			fprintf(stderr, "[!] Encoding to '%s' codec is unsupported\n", codec->name);
+			return -ENOTSUP;
+		}
+	}
+
+	return 0;
+}
+
+static int
+files_open(struct gapk_state *gs)
+{
+	if (gs->opts.fname_in) {
+		gs->fh_in = fopen(gs->opts.fname_in, "rb");
+		if (!gs->fh_in) {
+			fprintf(stderr, "[!] Error while opening input file for reading\n");
+			perror("fopen");
+			return -errno;
+		}
+	} else
+		gs->fh_in = stdin;
+
+	if (gs->opts.fname_out) {
+		gs->fh_out = fopen(gs->opts.fname_out, "wb");
+		if (!gs->fh_out) {
+			fprintf(stderr, "[!] Error while opening output file for writing\n");
+			perror("fopen");
+			return -errno;
+		}
+	} else
+		gs->fh_out = stdout;
+
+	return 0;
+}
+
+static void
+files_close(struct gapk_state *gs)
+{
+	if (gs->fh_in && gs->fh_in != stdin)
+		fclose(gs->fh_in);
+	if (gs->fh_out && gs->fh_out != stdout)
+		fclose(gs->fh_out);
+}
+
+static int
+handle_headers(struct gapk_state *gs)
+{
+	int rv;
+	unsigned int len;
+
+	/* Input file header (remove & check it) */
+	len = gs->opts.fmt_in->header_len;
+	if (len) {
+		uint8_t *buf;
+		
+		buf = malloc(len);
+		if (!buf)
+			return -ENOMEM;
+
+		rv = fread(buf, len, 1, gs->fh_in);
+		if ((rv != 1) ||
+		    memcmp(buf, gs->opts.fmt_in->header, len))
+		{
+			free(buf);
+			fprintf(stderr, "[!] Invalid header in input file");
+			return -EINVAL;
+		}
+
+		free(buf);
+	}
+
+	/* Output file header (write it) */
+	len = gs->opts.fmt_out->header_len;
+	if (len) {
+		rv = fwrite(gs->opts.fmt_out->header, len, 1, gs->fh_out);
+		if (rv != 1)
+			return -ENOSPC;
+	}
+
+	return 0;
+}
+
+static int
+make_processing_chain(struct gapk_state *gs)
+{
+	const struct format_desc *fmt_in, *fmt_out;
+	const struct codec_desc *codec_in, *codec_out;
+
+	int need_dec, need_enc;
+
+	fmt_in  = gs->opts.fmt_in;
+	fmt_out = gs->opts.fmt_out;
+
+	codec_in  = codec_get_from_type(fmt_in->codec_type);
+	codec_out = codec_get_from_type(fmt_out->codec_type);
+
+	need_dec = (fmt_in->codec_type != CODEC_PCM) &&
+	           (fmt_in->codec_type != fmt_out->codec_type);
+	need_enc = (fmt_out->codec_type != CODEC_PCM) &&
+	           (fmt_out->codec_type != fmt_in->codec_type);
+
+	/* File read */
+	pq_queue_file_input(gs->pq, gs->fh_in, fmt_in->frame_len);
+
+	/* Decoding to PCM ? */
+	if (need_dec)
+	{
+		/* Convert input to decoder input fmt */
+		if (fmt_in->type != codec_in->codec_dec_format_type)
+		{
+			const struct format_desc *fmt_dec;
+
+			fmt_dec = fmt_get_from_type(codec_in->codec_dec_format_type);
+			if (!fmt_dec)
+				return -EINVAL;
+
+			pq_queue_fmt_convert(gs->pq, fmt_in, 0);
+			pq_queue_fmt_convert(gs->pq, fmt_dec, 1);
+		}
+
+		/* Do decoding */
+		pq_queue_codec(gs->pq, codec_in, 0);
+	}
+	else if (fmt_in->type != fmt_out->type)
+	{
+		/* Convert input to canonical fmt */
+		pq_queue_fmt_convert(gs->pq, fmt_in, 0);
+	}
+
+	/* Encoding from PCM ? */
+	if (need_enc)
+	{
+		/* Do encoding */
+		pq_queue_codec(gs->pq, codec_out, 1);
+
+		/* Convert encoder output to output fmt */
+		if (fmt_out->type != codec_out->codec_enc_format_type)
+		{
+			const struct format_desc *fmt_enc;
+
+			fmt_enc = fmt_get_from_type(codec_out->codec_enc_format_type);
+			if (!fmt_enc)
+				return -EINVAL;
+
+			pq_queue_fmt_convert(gs->pq, fmt_enc, 0);
+			pq_queue_fmt_convert(gs->pq, fmt_out, 1);
+		}
+	}
+	else if (fmt_in->type != fmt_out->type)
+	{
+		/* Convert canonical to output fmt */
+		pq_queue_fmt_convert(gs->pq, fmt_out, 1);
+	}
+
+	/* File write */
+	pq_queue_file_output(gs->pq, gs->fh_out, fmt_out->frame_len);
+
+	return 0;
+}
+
+static int
+run(struct gapk_state *gs)
+{
+	int rv, frames;
+
+	rv = pq_prepare(gs->pq);
+	if (rv)
+		return rv;
+
+	for (frames=0; !(rv = pq_execute(gs->pq)); frames++);
+
+	fprintf(stderr, "[+] Processed %d frames\n", frames);
+
+	return frames > 0 ? 0 : rv;
+}
+
 int main(int argc, char *argv[])
 {
-	return 0;
+	struct gapk_state _gs, *gs = &_gs;
+	int rv;
+
+	/* Clear state */
+	memset(gs, 0x00, sizeof(struct gapk_state));
+
+	/* Parse / check options */
+	rv = parse_options(gs, argc, argv);
+	if (rv > 0) {
+		print_help(argv[0]);
+		return 0;
+	}
+	if (rv < 0)
+		return rv;
+
+	/* Check request */
+	rv = check_options(gs);
+	if (rv)
+		return rv;
+
+	/* Create processing queue */
+	gs->pq = pq_create();
+	if (!gs->pq) {
+		rv = -ENOMEM;
+		goto error;
+	}
+
+	/* Open source / destination files */
+	rv = files_open(gs);
+	if (rv)
+		goto error;
+
+	/* Handle input/output headers */
+	rv = handle_headers(gs);
+	if (rv)
+		goto error;
+
+	/* Make processing chain */
+	rv = make_processing_chain(gs);
+	if (rv)
+		goto error;
+
+	/* Run the processing queue */
+	rv = run(gs);
+
+error:
+	/* Close source / destination files */
+	files_close(gs);
+
+	/* Release processing queue */
+	pq_destroy(gs->pq);
+	
+	return rv;
 }