Better error messages when encoder cannot be created

The vorbis encoder cannot be initialized for very low bitrates. In
these cases a meaningful error message is printed to the console.
This is still not the best solution, but better than nothing.

git-svn-id: https://svn.code.sf.net/p/aqualung/code/trunk@1291 3cd24cdc-1f22-0410-b8b1-dcf80e670293

src/encoder/enc_vorbis.c

@@ -88,8 +88,11 @@ vorbisenc_encoder_open(encoder_t * enc, encoder_mode_t * mode) {
 	       vorbis_encode_ctl(&pd->vi, OV_ECTL_RATEMANAGE2_SET, NULL) ||
 	       vorbis_encode_setup_init(&pd->vi));
 
-	if (ret)
+	if (ret) {
+		fprintf(stdout, "vorbisenc_encoder_open(): cannot setup encoding with set params (bps=%d)\n",
+			mode->bps);
 		return -1;
+	}
 
 	vorbis_comment_init(&pd->vc);
         if (mode->write_meta) {

src/encoder/file_encoder.c

@@ -76,18 +76,18 @@ file_encoder_open(file_encoder_t * fenc, encoder_mode_t * mode) {
 	encoder_t * enc;
 
 	if (mode->filename == NULL) {
-		fprintf(stderr, "Warning: filename == NULL passed to file_encoder_open()\n");
+		fprintf(stderr, "error: filename == NULL passed to file_encoder_open()\n");
 		return 1;
 	}
 
 	enc = encoder_init_v[mode->file_lib](fenc);
 	if (!enc) {
-		fprintf(stderr, "Warning: error initializing encoder %d.\n", mode->file_lib);
+		fprintf(stderr, "error initializing encoder %d.\n", mode->file_lib);
 		return 1;
 	}
 
 	if (enc->open(enc, mode) != 0) {
-		fprintf(stderr, "Warning: error opening encoder %d.\n", mode->file_lib);
+		fprintf(stderr, "error opening encoder %d.\n", mode->file_lib);
 		return 1;
 	}