Add support for the Opus codec

.github/workflows/main.yml

@@ -10,6 +10,7 @@ env:
     -DWITH_ALSA=ON
     -DWITH_DIAMONDCARD=ON
     -DWITH_GSM=ON
+    -DWITH_OPUS=ON
     -DWITH_SPEEX=ON
     -DWITH_ZRTP=OFF
   # Essential packages required by all builds
@@ -19,6 +20,7 @@ env:
     flex
     libccrtp-dev
     libmagic-dev
+    libopus-dev
     libreadline-dev
     libsndfile1-dev
     libucommon-dev
@@ -78,6 +80,7 @@ jobs:
               -DWITH_QT5=OFF
               -DWITH_ALSA=OFF
               -DWITH_GSM=OFF
+              -DWITH_OPUS=OFF
               -DWITH_SPEEX=OFF
               -DWITH_ZRTP=OFF
             # The empty string would evaluate to false and fail to override

CMakeLists.txt

@@ -14,6 +14,7 @@ include(CMakeDependentOption)
 
 OPTION(WITH_ZRTP		"Enable ZRTP encrypted calls" OFF)
 OPTION(WITH_SPEEX		"Enable the Speex codec" OFF)
+OPTION(WITH_OPUS		"Enable the Opus codec" OFF)
 OPTION(WITH_ILBC		"Enable the iLBC codec" OFF)
 OPTION(WITH_ALSA		"Enable ALSA support" ON)
 CMAKE_DEPENDENT_OPTION(WITH_DIAMONDCARD	"Enable Diamondcard integration" ON "WITH_QT5" OFF)
@@ -40,6 +41,8 @@ include (CMakePushCheckState)
 include (CheckCXXSourceCompiles)
 include (TestBigEndian)
 
+find_package(PkgConfig REQUIRED)
+
 find_package(LibXml2 REQUIRED)
 find_package(LibMagic REQUIRED)
 find_package(LibSndfile REQUIRED)
@@ -110,6 +113,12 @@ if (WITH_SPEEX)
 	endif (SPEEX_FOUND)
 endif (WITH_SPEEX)
 
+if (WITH_OPUS)
+	pkg_check_modules(Opus REQUIRED opus)
+	set(HAVE_OPUS TRUE)
+	include_directories(${Opus_INCLUDE_DIRS})
+endif (WITH_OPUS)
+
 if (WITH_ILBC)
 	find_package(Ilbc)
 

README.md

@@ -32,6 +32,7 @@ The following tools are also required:
 * libzrtpcpp (version >= 0.9.0) [ZRTP library, ccRTP support must be enabled](https://www.gnu.org/software/ccrtp/zrtp.html)
 * bcg729 [G.729A codec library](http://www.linphone.org/technical-corner/bcg729)
 * Speex and SpeexDSP [Speex codec library](http://www.speex.org/)
+* libopus [Opus codec library](http://opus-codec.org/)
 * iLBC [iLBC codec library](http://www.ilbcfreeware.org/)
 * [Akonadi](https://community.kde.org/KDE_PIM/Akonadi) (specifically, the `core` library) and [KContacts](https://cgit.kde.org/kcontacts.git)
 
@@ -47,6 +48,7 @@ All possible options are:
 * ZRTP support: `-DWITH_ZRTP=On`
 * G.729A codec support: `-DWITH_G729=On`
 * Speex codec support: `-DWITH_SPEEX=On`
+* Opus codec support: `-DWITH_OPUS=On`
 * iLBC codec support: `-DWITH_ILBC=On`
 * Diamondcard support: `-DWITH_DIAMONDCARD=On`
 * Akonadi support: `-DWITH_AKONADI=On` (requires `WITH_QT5`)

src/CMakeLists.txt

@@ -100,6 +100,9 @@ set(twinkle_LIBS
 if (WITH_GSM)
 	list(APPEND twinkle_LIBS ${GSM_LIBRARY})
 endif (WITH_GSM)
+if (WITH_OPUS)
+	list(APPEND twinkle_LIBS ${Opus_LIBRARIES})
+endif (WITH_OPUS)
 
 if (WITH_QT5)
 	add_subdirectory(gui)

src/audio/audio_codecs.cpp

@@ -16,7 +16,9 @@
 */
 
 #include <cstdlib>
+#include <sstream>
 #include "audio_codecs.h"
+#include "userintf.h"
 
 unsigned short audio_sample_rate(t_audio_codec codec) {
 	switch(codec) {
@@ -37,6 +39,8 @@ unsigned short audio_sample_rate(t_audio_codec codec) {
 		return 16000;
 	case CODEC_SPEEX_UWB:
 		return 32000;
+	case CODEC_OPUS:
+		return 48000;
 	default:
 		// Use 8000 as default rate
 		return 8000;
@@ -112,3 +116,38 @@ short mix_linear_pcm(short pcm1, short pcm2) {
 
 	return short(mixed_sample);
 }
+
+#ifdef HAVE_OPUS
+unsigned short opus_adjusted_ptime(unsigned short ptime) {
+	if (ptime <= 10) {
+		return 10;
+	} else if (ptime <= 20) {
+		return 20;
+	} else if (ptime <= 40) {
+		return 40;
+	} else if (ptime <= 60) {
+		return 60;
+	} else {
+		// Maximum duration of an Opus frame
+		// (Although libopus v1.2+ allows for values up to 120 ms, it
+		// merely encodes multiple frames into a single Opus packet)
+		return 60;
+	}
+}
+
+void log_opus_error(
+		const std::string &func_name,
+		const std::string &msg,
+		int opus_error,
+		bool display_msg)
+{
+	std::stringstream ss;
+	ss << "Opus error: " << msg << ": " << opus_strerror(opus_error);
+	std::string s = ss.str();
+
+	log_file->write_report(s, func_name, LOG_NORMAL, LOG_CRITICAL);
+	if (display_msg) {
+		ui->cb_display_msg(s, MSG_CRITICAL);
+	}
+}
+#endif

src/audio/audio_codecs.h

@@ -18,8 +18,11 @@
 #ifndef _AUDIO_CODECS_H
 #define _AUDIO_CODECS_H
 
+#include <string>
+#include "twinkle_config.h"
 #include "g711.h"
 #include "g72x.h"
+#include "log.h"
 
 // Audio codecs
 enum t_audio_codec {
@@ -31,6 +34,7 @@ enum t_audio_codec {
 	CODEC_SPEEX_NB,
 	CODEC_SPEEX_WB,
 	CODEC_SPEEX_UWB,
+	CODEC_OPUS,
 	CODEC_ILBC,
 	CODEC_G722,
 	CODEC_G726_16,
@@ -41,13 +45,34 @@ enum t_audio_codec {
 	CODEC_G729A
 };
 
+enum t_opus_bandwidth_sample_rate {
+	OPUS_SAMPLE_RATE_NB  =  8000,
+	OPUS_SAMPLE_RATE_MB  = 12000,
+	OPUS_SAMPLE_RATE_WB  = 16000,
+	OPUS_SAMPLE_RATE_SWB = 24000,
+	OPUS_SAMPLE_RATE_FB  = 48000,
+};
+
+// Format specific parameters, received on a "a=fmtp:" line during the SDP
+// negotiation, to be passed to the corresponding encoder/decoder
+struct t_codec_sdp_params {
+#ifdef HAVE_OPUS
+	bool			opus_cbr = 0;
+	unsigned int		opus_maxplaybackrate = 0;
+	unsigned int		opus_maxaveragebitrate = 0;
+	bool			opus_useinbandfec = 0;
+	bool			opus_usedtx = 0;
+#endif
+};
+
 // Default ptime values (ms) for audio codecs
 #define PTIME_G711_ALAW		20
 #define PTIME_G711_ULAW		20
 #define PTIME_G722		20
 #define PTIME_G726		20
 #define PTIME_GSM		20
 #define PTIME_SPEEX		20
+#define PTIME_OPUS		20
 #define MIN_PTIME		10
 #define MAX_PTIME		80
 
@@ -111,4 +136,16 @@ int resample(short *input_buf, int input_len, int input_sample_rate,
 // Mix 2 16 bits signed linear PCM values
 short mix_linear_pcm(short pcm1, short pcm2);
 
+#ifdef HAVE_OPUS
+// Bump an arbitrary ptime to the next value allowed by the Opus codec
+unsigned short opus_adjusted_ptime(unsigned short ptime);
+
+// Log an Opus error
+void log_opus_error(
+		const std::string &func_name,
+		const std::string &msg,
+		int opus_error,
+		bool display_msg = true);
+#endif
+
 #endif

src/audio/audio_decoder.cpp

@@ -253,6 +253,80 @@ bool t_speex_audio_decoder::valid_payload_size(uint16 payload_size, uint16 sampl
 }
 #endif
 
+#ifdef HAVE_OPUS
+//////////////////////////////////////////
+// class t_opus_audio_decoder
+//////////////////////////////////////////
+
+t_opus_audio_decoder::t_opus_audio_decoder(uint16 default_ptime, t_user *user_config) :
+	t_audio_decoder(default_ptime, true, user_config)
+{
+	_codec = CODEC_OPUS;
+	if (_default_ptime == 0) {
+		_default_ptime = PTIME_OPUS;
+	}
+	_frame_size = audio_sample_rate(_codec) * _default_ptime / 1000;
+
+	int error;
+	dec = opus_decoder_create(audio_sample_rate(_codec), 1, &error);
+	if (error != OPUS_OK) {
+		log_opus_error("t_opus_audio_decoder::t_opus_audio_decoder",
+				"Cannot create decoder", error);
+		dec = NULL;
+		return;
+	}
+}
+
+t_opus_audio_decoder::~t_opus_audio_decoder() {
+	if (dec) {
+		opus_decoder_destroy(dec);
+	}
+}
+
+uint16 t_opus_audio_decoder::get_ptime(uint16 payload_size) const {
+	return get_default_ptime();
+}
+
+uint16 t_opus_audio_decoder::decode(uint8 *payload, uint16 payload_size,
+		int16 *pcm_buf, uint16 pcm_buf_size)
+{
+	if (!dec) return 0;
+
+	assert(pcm_buf_size >= _frame_size);
+
+	int nsamples = opus_decode(dec, payload, payload_size, pcm_buf, pcm_buf_size, 0);
+
+	if (nsamples < 0) {
+		log_opus_error("t_opus_audio_decoder::decode",
+				"Error while decoding", nsamples);
+		return 0;
+	}
+
+	return nsamples;
+}
+
+uint16 t_opus_audio_decoder::conceal(int16 *pcm_buf, uint16 pcm_buf_size) {
+	if (!dec) return 0;
+
+	assert(pcm_buf_size >= _frame_size);
+
+	int nsamples = opus_decode(dec, NULL, 0, pcm_buf, _frame_size, 0);
+
+	if (nsamples < 0) {
+		log_opus_error("t_opus_audio_decoder::conceal",
+				"Error while concealing missing frame", nsamples);
+		return 0;
+	}
+
+	return nsamples;
+}
+
+bool t_opus_audio_decoder::valid_payload_size(uint16 payload_size, uint16 sample_buf_size) const
+{
+	return true;
+}
+#endif
+
 #ifdef HAVE_ILBC
 //////////////////////////////////////////
 // class t_ilbc_audio_decoder

src/audio/audio_decoder.h

@@ -37,6 +37,10 @@ extern "C" {
 #include <speex/speex_preprocess.h> 
 #endif
 
+#ifdef HAVE_OPUS
+#include <opus/opus.h>
+#endif
+
 extern "C" {
 #	include "g722.h"
 #	include "g722_local.h"
@@ -157,6 +161,25 @@ class t_speex_audio_decoder : public t_audio_decoder {
 };
 #endif
 
+#ifdef HAVE_OPUS
+// Opus
+class t_opus_audio_decoder : public t_audio_decoder {
+private:
+	OpusDecoder	*dec;
+	unsigned short	_frame_size;  // Number of samples per frame
+
+public:
+	t_opus_audio_decoder(uint16 default_ptime, t_user *user_config);
+	virtual ~t_opus_audio_decoder();
+
+	virtual uint16 get_ptime(uint16 payload_size) const;
+	virtual uint16 decode(uint8 *payload, uint16 payload_size,
+			int16 *pcm_buf, uint16 pcm_buf_size);
+	virtual uint16 conceal(int16 *pcm_buf, uint16 pcm_buf_size);
+	virtual bool valid_payload_size(uint16 payload_size, uint16 sample_buf_size) const;
+};
+#endif
+
 #ifdef HAVE_ILBC
 // iLBC
 class t_ilbc_audio_decoder : public t_audio_decoder {