print meaningful error messages if something goes wrong in main/pq

3 files changed, 34 insertions, 10 deletions

diff --git a/src/main.c b/src/main.c
index d3affbf..60a3bab 100644
--- a/src/main.c
+++ b/src/main.c
@@ -440,8 +440,10 @@ make_processing_chain(struct gapk_state *gs)
 	else if (gs->opts.alsa_in)
 		pq_queue_alsa_input(gs->pq, gs->opts.alsa_in, fmt_in->frame_len);
 #endif
-	else
+	else {
+		fprintf(stderr, "Unknown/invalid input\n");
 		return -1;
+	}
 
 	/* Decoding to PCM ? */
 	if (need_dec)
@@ -452,8 +454,11 @@ make_processing_chain(struct gapk_state *gs)
 			const struct format_desc *fmt_dec;
 
 			fmt_dec = fmt_get_from_type(codec_in->codec_dec_format_type);
-			if (!fmt_dec)
+			if (!fmt_dec) {
+				fprintf(stderr, "Cannot determine decoder input format for codec %s\n",
+					codec_in->name);
 				return -EINVAL;
+			}
 
 			pq_queue_fmt_convert(gs->pq, fmt_in, 0);
 			pq_queue_fmt_convert(gs->pq, fmt_dec, 1);
@@ -480,8 +485,11 @@ make_processing_chain(struct gapk_state *gs)
 			const struct format_desc *fmt_enc;
 
 			fmt_enc = fmt_get_from_type(codec_out->codec_enc_format_type);
-			if (!fmt_enc)
+			if (!fmt_enc) {
+				fprintf(stderr, "Cannot determine encoder output format for codec %s\n",
+					codec_out->name);
 				return -EINVAL;
+			}
 
 			pq_queue_fmt_convert(gs->pq, fmt_enc, 0);
 			pq_queue_fmt_convert(gs->pq, fmt_out, 1);
@@ -502,8 +510,10 @@ make_processing_chain(struct gapk_state *gs)
 	else if (gs->opts.alsa_out)
 		pq_queue_alsa_output(gs->pq, gs->opts.alsa_out, fmt_out->frame_len);
 #endif
-	else
+	else {
+		fprintf(stderr, "Unknown/invalid output\n");
 		return -1;
+	}
 
 	return 0;
 }
@@ -569,23 +579,30 @@ int main(int argc, char *argv[])
 	gs->pq = pq_create();
 	if (!gs->pq) {
 		rv = -ENOMEM;
+		fprintf(stderr, "Error creating processing queue\n");
 		goto error;
 	}
 
 	/* Open source / destination files */
 	rv = files_open(gs);
-	if (rv)
+	if (rv) {
+		fprintf(stderr, "Error opening file(s)\n");
 		goto error;
+	}
 
 	/* Handle input/output headers */
 	rv = handle_headers(gs);
-	if (rv)
+	if (rv) {
+		fprintf(stderr, "Error handling header(s)\n");
 		goto error;
+	}
 
 	/* Make processing chain */
 	rv = make_processing_chain(gs);
-	if (rv)
+	if (rv) {
+		fprintf(stderr, "Error making processing chain\n");
 		goto error;
+	}
 
 	signal(SIGINT, &signal_handler);
 
diff --git a/src/pq_format.c b/src/pq_format.c
index 2089218..590dfd8 100644
--- a/src/pq_format.c
+++ b/src/pq_format.c
@@ -42,7 +42,8 @@ pq_queue_fmt_convert(struct pq *pq, const struct format_desc *fmt, int to_from_n
 	struct pq_item *item;
 	const struct codec_desc *codec = codec_get_from_type(fmt->codec_type);
 
-	if (!codec)
+	if (!codec) {
+		fprintf(stderr, "Cannot determine codec from format %s\n", fmt->name);
 		return -EINVAL;
 
 	item = pq_add_item(pq);
diff --git a/src/procqueue.c b/src/procqueue.c
index 66c2967..b61be89 100644
--- a/src/procqueue.c
+++ b/src/procqueue.c
@@ -72,8 +72,11 @@ pq_add_item(struct pq *pq)
 {
 	struct pq_item *item;
 
-	if (pq->n_items == MAX_PQ_ITEMS)
+	if (pq->n_items == MAX_PQ_ITEMS) {
+		fprintf(stderr, "Processing Queue cannot handle more than %u items\n",
+			MAX_PQ_ITEMS);
 		return NULL;
+	}
 
 	item = calloc(1, sizeof(struct pq_item));
 	if (!item)
@@ -98,8 +101,11 @@ pq_prepare(struct pq *pq)
 	for (i=0; i<pq->n_items; i++) {
 		struct pq_item *item = pq->items[i];
 
-		if (item->len_in && item->len_in != len_prev)
+		if (item->len_in && item->len_in != len_prev) {
+			fprintf(stderr, "PQ item requires input size %u, but previous output is %u\n",
+				item->len_in, len_prev);
 			return -EINVAL;
+		}
 
 		if (i < (pq->n_items-1)) {
 			unsigned int buf_size = item->len_out;