format_mp3: Add MP3 write support.

This adds the ability to write in the MP3 format;
previously, MP3 data could only be read.

Resolves: asterisk#664

UserNote: Asterisk now supports natively writing
data in the MP3 format.

addons/format_mp3.c

@@ -9,7 +9,11 @@
  * Thanks to mpglib from http://www.mpg123.org/
  * and Chris Stenton [jacs@gnome.co.uk]
  * for coding the ability to play stereo and non-8khz files
-
+ *
+ * MP3 write support using LAME
+ * added by Naveen Albert <asterisk@phreaknet.org>
+ * and sponsored by Marfox Ltd.
+ *
  * See http://www.asterisk.org for more information about
  * the Asterisk project. Please do not directly contact
  * any of the maintainers of this project for assistance;
@@ -28,6 +32,7 @@
  */
 
 /*** MODULEINFO
+	<use type="external">lame</use>
 	<defaultenabled>no</defaultenabled>
 	<support_level>extended</support_level>
  ***/
@@ -37,6 +42,17 @@
 #include "mp3/mpg123.h"
 #include "mp3/mpglib.h"
 
+/* LAME (libmp3lame) is only needed for MP3 write support.
+ * This is provided by the libmp3lame-dev package on Debian. */
+#ifdef HAVE_LAME
+#define ENABLE_MP3_WRITING
+#endif
+
+#ifdef ENABLE_MP3_WRITING
+#include <stdarg.h>
+#include <lame/lame.h>
+#endif
+
 #include "asterisk/module.h"
 #include "asterisk/mod_format.h"
 #include "asterisk/logger.h"
@@ -46,6 +62,10 @@
 #define MP3_SCACHE 16384
 #define MP3_DCACHE 8192
 
+#ifdef ENABLE_MP3_WRITING
+static lame_global_flags *gfp;
+#endif
+
 struct mp3_private {
 	/*! state for the mp3 decoder */
 	struct mpstr mp;
@@ -63,6 +83,9 @@ struct mp3_private {
 	int dbufoffset;
 	int offset;
 	long seek;
+#ifdef ENABLE_MP3_WRITING
+	unsigned int wrote:1;
+#endif
 };
 
 static const char name[] = "mp3";
@@ -107,6 +130,20 @@ static void mp3_close(struct ast_filestream *s)
 {
 	struct mp3_private *p = s->_private;
 
+#ifdef ENABLE_MP3_WRITING
+	if (p->wrote) {
+		unsigned char buf[7200];
+		int wres, res;
+		ast_debug(1, "Flushing MP3 stream\n");
+		res = lame_encode_flush(gfp, buf, sizeof(buf));
+		wres = fwrite(buf, 1, res, s->f);
+		if (wres != res) {
+			ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", wres, res, strerror(errno));
+		}
+		lame_mp3_tags_fid(gfp, s->f);
+	}
+#endif
+
 	ExitMP3(&p->mp);
 	return;
 }
@@ -236,14 +273,44 @@ static struct ast_frame *mp3_read(struct ast_filestream *s, int *whennext)
 	return &s->fr;
 }
 
-
 static int mp3_write(struct ast_filestream *fs, struct ast_frame *f)
 {
-	ast_log(LOG_ERROR,"I Can't write MP3 only read them.\n");
-	return -1;
+#ifdef ENABLE_MP3_WRITING
+/* mp3buf_size in bytes = 1.25*num_samples + 7200
+ * Assuming f->datalen <= 720, 1.25 * 720 + 7200 = 8100 */
+#define MP3_BUFSIZE 8192
+	int res, wres;
+	unsigned char buf[MP3_BUFSIZE];
+	struct mp3_private *p = fs->_private;
+
+	if (!f->datalen) {
+		return -1;
+	}
 
-}
+	if (f->datalen > 720) {
+		ast_log(LOG_WARNING, "Too much data to write at once: %d\n", f->datalen);
+		return -1;
+	}
 
+	/* Since this is mono audio, we only have a L channel. R channel buffer is ignored. */
+	res = lame_encode_buffer(gfp, f->data.ptr, f->data.ptr, f->samples, buf, sizeof(buf));
+	if (res < 0) {
+		ast_log(LOG_WARNING, "LAME encode returned %d\n", res);
+		return -1;
+	}
+
+	wres = fwrite(buf, 1, res, fs->f);
+	if (wres != res) {
+		ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", wres, res, strerror(errno));
+		return -1;
+	}
+	p->wrote = 1;
+	return 0;
+#else
+	ast_log(LOG_ERROR, "I Can't write MP3 only read them.\n");
+	return -1;
+#endif
+}
 
 static int mp3_seek(struct ast_filestream *s, off_t sample_offset, int whence)
 {
@@ -274,8 +341,13 @@ static int mp3_seek(struct ast_filestream *s, off_t sample_offset, int whence)
 
 static int mp3_rewrite(struct ast_filestream *s, const char *comment)
 {
+#ifdef ENABLE_MP3_WRITING
+	/* Header gets written at the end */
+	return 0;
+#else
 	ast_log(LOG_ERROR,"I Can't write MP3 only read them.\n");
 	return -1;
+#endif
 }
 
 static int mp3_trunc(struct ast_filestream *s)
@@ -313,17 +385,64 @@ static struct ast_format_def mp3_f = {
 	.desc_size = sizeof(struct mp3_private),
 };
 
+#ifdef ENABLE_MP3_WRITING
+/* gcc suggests printf attribute but that is wrong here */
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+static void mp3_error(const char *format, va_list ap)
+{
+	ast_log_ap(AST_LOG_WARNING, format, ap);
+}
+
+static void mp3_debug(const char *format, va_list ap)
+{
+	ast_log_ap(AST_LOG_DEBUG, format, ap);
+}
+
+static void mp3_msg(const char *format, va_list ap)
+{
+	ast_log_ap(AST_LOG_NOTICE, format, ap);
+}
+#endif
 
 static int load_module(void)
 {
+#ifdef ENABLE_MP3_WRITING
+	int res;
+
+	ast_debug(1, "LAME version: %s\n", get_lame_version());
+	gfp = lame_init();
+
+	/* Set logging callbacks */
+	lame_set_errorf(gfp, mp3_error);
+	lame_set_debugf(gfp, mp3_debug);
+	lame_set_msgf(gfp, mp3_msg);
+
+	/* Override default settings */
+	lame_set_num_channels(gfp, 1); /* Mono */
+	lame_set_in_samplerate(gfp, 8000); /* 8 KHz */
+	/* Bit rate, e.g. 64 = 64kbps PCM audio */
+	lame_set_brate(gfp, 16);
+	lame_set_mode(gfp, 3); /* Mono */
+	lame_set_quality(gfp, 5); /* Medium quality */
+
+	res = lame_init_params(gfp);
+	if (res < 0) {
+		ast_log(LOG_ERROR, "Failed to initialize LAME\n");
+		return -1;
+	}
+#endif
 	mp3_f.format = ast_format_slin;
 	InitMP3Constants();
 	return ast_format_def_register(&mp3_f);
 }
 
 static int unload_module(void)
 {
-	return ast_format_def_unregister(name);
+	int res = ast_format_def_unregister(name);
+#ifdef ENABLE_MP3_WRITING
+	lame_close(gfp);
+#endif
+	return res;
 }
 
 AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "MP3 format [Any rate but 8000hz mono is optimal]");

build_tools/menuselect-deps.in

@@ -26,6 +26,7 @@ JACK=@PBX_JACK@
 JANSSON=@PBX_JANSSON@
 URIPARSER=@PBX_URIPARSER@
 KQUEUE=@PBX_KQUEUE@
+LAME=@PBX_LAME@
 LDAP=@PBX_LDAP@
 LIBEDIT=@PBX_LIBEDIT@
 LIBJWT=@PBX_LIBJWT@

configure.ac

@@ -579,6 +579,7 @@ AST_EXT_LIB_SETUP([OPUS], [Opus], [opus])
 AST_EXT_LIB_SETUP([OPUSFILE], [Opusfile], [opusfile])
 AST_EXT_LIB_SETUP([PGSQL], [PostgreSQL], [postgres])
 AST_EXT_LIB_SETUP([BEANSTALK], [Beanstalk Job Queue], [beanstalk])
+AST_EXT_LIB_SETUP([LAME], [LAME MP3], [mp3lame])
 
 if test "x${PBX_PJPROJECT}" != "x1" ; then
 AST_EXT_LIB_SETUP([PJPROJECT], [PJPROJECT], [pjproject])
@@ -1630,6 +1631,7 @@ fi
 
 # do the package library checks now
 
+AST_EXT_LIB_CHECK([LAME], [mp3lame], [get_lame_version], [lame/lame.h])
 AST_EXT_LIB_CHECK([BFD], [bfd], [bfd_openr], [bfd.h])
 # Fedora/RedHat/CentOS require extra libraries
 AST_EXT_LIB_CHECK([BFD], [bfd], [bfd_openr], [bfd.h], [-ldl -liberty])

makeopts.in

@@ -194,6 +194,9 @@ LIBJWT_CONFIGURE_OPTS=@LIBJWT_CONFIGURE_OPTS@
 URIPARSER_INCLUDE=@URIPARSER_INCLUDE@
 URIPARSER_LIB=@URIPARSER_LIB@
 
+LAME_INCLUDE=@LAME_INCLUDE@
+LAME_LIB=@LAME_LIB@
+
 LDAP_INCLUDE=@LDAP_INCLUDE@
 LDAP_LIB=@LDAP_LIB@