shout: introduce pluggable encoder API

I've perhaps gone a bit overboard, but here's the current rundown:

Both Ogg and MP3 use the "shout" audio output plugin.  The shout audio
output plugin itself has two new plugins, one for the Ogg encoder,
and another for the MP3 (LAME) encoder.

Configuration for an Ogg stream doesn't change.  For an MP3 stream,
configuration is the same as Ogg, with two exceptions.  First, you must
specify the optional "encoding" parameter, which should be set to "mp3".
See mpd.conf(5) for more details.  Second, the "quality" parameter is
reversed for LAME, such that 1 is high quality for LAME, whereas 10 is
high quality for Ogg.

I've decomposed the code so that all libshout related operations
are done in audioOutput_shout.c, all Ogg specific functions are in
audioOutput_shout_ogg.c, and of course then all LAME specific functions
are handled in audioOutput_shout_mp3.c.

To develop encoder plugins for the shout audio output plugin, I basically
just mimicked the plugin system used for audio outputs.  This might be
overkill, but hopefully if anyone ever wants to support some other sort
of stream, like maybe AAC, FLAC, or WMA (hey it could happen), they will
hopefully be all set.

The Ogg encoder is slightly less optimal under this configuration.
It used to send shout data directly out of its ogg_page structures.  Now,
in the interest of encapsulation, it copies the data from its ogg_page
structures into a buffer provided by the shout audio output plugin (see
audioOutput_shout_ogg.c, line 77.)  I suspect the performance impact
is negligible.

As for metadata, I'm pretty sure they'll both work.  I wrote up a test
scaffold that would create a fake tag, and tell the plugin to send it
out to the stream every few seconds.  It seemed to work fine.  Of course,
if something does break, I'll be glad to fix it.

Lastly, I've renamed lots of things into snake_case, in keeping with
normalperson's wishes in that regard.

[mk: moved the MP3 patch after this one.  Splitted this patch into
several parts; the others were already applied before this one.  Fixed
a bunch GCC warnings and wrong whitespace modifications.  Made it
compile with mpd-mk by adapting to its prototypes]

1 files changed, 74 insertions, 19 deletions

diff --git a/src/audioOutputs/audioOutput_shout_ogg.c b/src/audioOutputs/audioOutput_shout_ogg.c
index d0d1b6880..5e0adf4d0 100644
--- a/src/audioOutputs/audioOutput_shout_ogg.c
+++ b/src/audioOutputs/audioOutput_shout_ogg.c
@@ -18,9 +18,24 @@
 
 #include "audioOutput_shout.h"
 
-#ifdef HAVE_SHOUT
+#ifdef HAVE_SHOUT_OGG
 
 #include "../utils.h"
+#include <vorbis/vorbisenc.h>
+
+typedef struct _ogg_vorbis_data {
+	ogg_stream_state os;
+	ogg_page og;
+	ogg_packet op;
+	ogg_packet header_main;
+	ogg_packet header_comments;
+	ogg_packet header_codebooks;
+
+	vorbis_dsp_state vd;
+	vorbis_block vb;
+	vorbis_info vi;
+	vorbis_comment vc;
+} ogg_vorbis_data;
 
 static void add_tag(ogg_vorbis_data *od, const char *name, char *value)
 {
@@ -31,9 +46,9 @@ static void add_tag(ogg_vorbis_data *od, const char *name, char *value)
 	}
 }
 
-void copy_tag_to_vorbis_comment(struct shout_data *sd)
+static void copy_tag_to_vorbis_comment(struct shout_data *sd)
 {
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 
 	if (sd->tag) {
 		int i;
@@ -49,6 +64,7 @@ void copy_tag_to_vorbis_comment(struct shout_data *sd)
 			case TAG_ITEM_TITLE:
 				add_tag(od, "TITLE", sd->tag->items[i]->value);
 				break;
+
 			default:
 				break;
 			}
@@ -83,7 +99,7 @@ static int copy_ogg_buffer_to_shout_buffer(ogg_page *og,
 static int flush_ogg_buffer(struct shout_data *sd)
 {
 	shout_buffer *buf = &sd->buf;
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 	int ret = 0;
 
 	if (ogg_stream_flush(&od->os, &od->og))
@@ -92,9 +108,9 @@ static int flush_ogg_buffer(struct shout_data *sd)
 	return ret;
 }
 
-int send_ogg_vorbis_header(struct shout_data *sd)
+static int send_ogg_vorbis_header(struct shout_data *sd)
 {
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 
 	vorbis_analysis_headerout(&od->vd, &od->vc,
 				  &od->header_main,
@@ -121,9 +137,9 @@ static void finish_encoder(ogg_vorbis_data *od)
 	}
 }
 
-int shout_ogg_encoder_clear_encoder(struct shout_data *sd)
+static int shout_ogg_encoder_clear_encoder(struct shout_data *sd)
 {
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 	int ret;
 
 	finish_encoder(od);
@@ -139,9 +155,30 @@ int shout_ogg_encoder_clear_encoder(struct shout_data *sd)
 	return ret;
 }
 
+static void shout_ogg_encoder_finish(struct shout_data *sd)
+{
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
+
+	if (od) {
+		free(od);
+		sd->encoder_data = NULL;
+	}
+}
+
+static int shout_ogg_encoder_init(struct shout_data *sd)
+{
+	ogg_vorbis_data *od;
+
+	if (NULL == (od = xmalloc(sizeof(ogg_vorbis_data))))
+		FATAL("error initializing ogg vorbis encoder data\n");
+	sd->encoder_data = od;
+
+	return 0;
+}
+
 static int reinit_encoder(struct shout_data *sd)
 {
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 
 	vorbis_info_init(&od->vi);
 
@@ -150,7 +187,7 @@ static int reinit_encoder(struct shout_data *sd)
 						sd->audio_format.channels,
 						sd->audio_format.sampleRate,
 						sd->quality * 0.1)) {
-			ERROR("problem setting up vorbis encoder for shout\n");
+			ERROR("error initializing vorbis vbr\n");
 			vorbis_info_clear(&od->vi);
 			return -1;
 		}
@@ -159,7 +196,7 @@ static int reinit_encoder(struct shout_data *sd)
 					    sd->audio_format.channels,
 					    sd->audio_format.sampleRate, -1.0,
 					    sd->bitrate * 1000, -1.0)) {
-			ERROR("problem setting up vorbis encoder for shout\n");
+			ERROR("error initializing vorbis encoder\n");
 			vorbis_info_clear(&od->vi);
 			return -1;
 		}
@@ -173,7 +210,7 @@ static int reinit_encoder(struct shout_data *sd)
 	return 0;
 }
 
-int init_encoder(struct shout_data *sd)
+static int shout_ogg_encoder_init_encoder(struct shout_data *sd)
 {
 	if (reinit_encoder(sd))
 		return -1;
@@ -186,11 +223,11 @@ int init_encoder(struct shout_data *sd)
 	return 0;
 }
 
-int shout_ogg_encoder_send_metadata(struct shout_data * sd,
-				    mpd_unused char * song,
-				    mpd_unused size_t size)
+static int shout_ogg_encoder_send_metadata(struct shout_data *sd,
+					   mpd_unused char * song,
+					   mpd_unused size_t size)
 {
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 
 	shout_ogg_encoder_clear_encoder(sd);
 	if (reinit_encoder(sd))
@@ -212,8 +249,8 @@ int shout_ogg_encoder_send_metadata(struct shout_data * sd,
 	return 0;
 }
 
-void shout_ogg_encoder_encode(struct shout_data *sd,
-			      const char *chunk, size_t size)
+static int shout_ogg_encoder_encode(struct shout_data *sd,
+				    const char *chunk, size_t size)
 {
 	shout_buffer *buf = &sd->buf;
 	unsigned int i;
@@ -221,7 +258,7 @@ void shout_ogg_encoder_encode(struct shout_data *sd,
 	float **vorbbuf;
 	unsigned int samples;
 	int bytes = sd->audio_format.bits / 8;
-	ogg_vorbis_data *od = &sd->od;
+	ogg_vorbis_data *od = (ogg_vorbis_data *)sd->encoder_data;
 
 	samples = size / (bytes * sd->audio_format.channels);
 	vorbbuf = vorbis_analysis_buffer(&od->vd, samples);
@@ -248,6 +285,24 @@ void shout_ogg_encoder_encode(struct shout_data *sd,
 
 	if (ogg_stream_pageout(&od->os, &od->og))
 		copy_ogg_buffer_to_shout_buffer(&od->og, buf);
+
+	return 0;
 }
 
+shout_encoder_plugin shout_ogg_encoder = {
+	"ogg",
+	SHOUT_FORMAT_VORBIS,
+
+	shout_ogg_encoder_clear_encoder,
+	shout_ogg_encoder_encode,
+	shout_ogg_encoder_finish,
+	shout_ogg_encoder_init,
+	shout_ogg_encoder_init_encoder,
+	shout_ogg_encoder_send_metadata,
+};
+
+#else
+
+DISABLED_SHOUT_ENCODER_PLUGIN(shout_ogg_encoder);
+
 #endif