rxrx/sdp: set actual audio specs

Instead of deducing from audio parameters, defer the creation until we
receive some audio data.

This complements identical change for RTSP in the commit 41b0388
(2024-08-13).

src/audio/audio.cpp

@@ -263,13 +263,6 @@ sdp_send_change_address_message(struct module           *root,
         free_response(resp);
 }
 
-static void
-sdp_change_address_callback(void *udata, const char *address)
-{
-        enum module_class path_sender[] = { MODULE_CLASS_AUDIO, MODULE_CLASS_SENDER, MODULE_CLASS_NONE };
-        sdp_send_change_address_message((module*) udata, path_sender, address);
-}
-
 /**
  * take care that addrs can also be comma-separated list of addresses !
  * @retval  0 state succesfully initialized
@@ -417,20 +410,6 @@ int audio_init(struct state_audio **ret,
                                    &s->audio_network_device, &len);
         }
 
-        if ((s->audio_tx_mode & MODE_SENDER) && strcasecmp(opt->proto, "sdp") == 0) {
-                const audio_codec_params params =
-                    parse_audio_codec_params(opt->codec_cfg);
-                if (sdp_add_audio(rtp_is_ipv6(s->audio_network_device),
-                                  opt->send_port,
-                                  IF_NOT_NULL_ELSE(params.sample_rate, kHz48),
-                                  audio_capture_channels, params.codec,
-                                  sdp_change_address_callback,
-                                  get_root_module(common->parent)) != 0) {
-                        MSG(ERROR,"Cannot add audio to SDP!\n");
-                        goto error;
-                }
-        }
-
         if ((s->audio_tx_mode & MODE_SENDER) != 0U || "help"s == opt->codec_cfg) {
                 if ((s->audio_encoder = audio_codec_init_cfg(opt->codec_cfg, AUDIO_CODER)) == nullptr) {
                         goto error;
@@ -1070,7 +1049,7 @@ static int find_codec_sample_rate(int sample_rate, const int *supported) {
 
 static void
 set_audio_spec_to_vrxtx(struct video_rxtx *vrxtx, audio_frame2 *compressed_frm,
-                        struct rtp *netdev, bool *audio_spec_to_vrxtx_set)
+                        struct rtp *netdev, int tx_port, bool *audio_spec_to_vrxtx_set)
 {
         if (*audio_spec_to_vrxtx_set) {
                 return;
@@ -1085,7 +1064,7 @@ set_audio_spec_to_vrxtx(struct video_rxtx *vrxtx, audio_frame2 *compressed_frm,
             audio_desc_to_cstring(desc), rx_port);
 
         assert(vrxtx != nullptr);
-        vrxtx->set_audio_spec(&desc, rx_port);
+        vrxtx->set_audio_spec(&desc, rx_port, tx_port, rtp_is_ipv6(netdev));
 }
 
 static void *audio_sender_thread(void *arg)
@@ -1181,6 +1160,7 @@ static void *audio_sender_thread(void *arg)
                                     set_audio_spec_to_vrxtx(
                                         s->vrxtx, &compressed,
                                         s->audio_network_device,
+                                        s->audio_network_parameters.send_port,
                                         &audio_spec_to_vrxtx_set);
                             }
                         }

src/video_rxtx.cpp

@@ -223,7 +223,8 @@ void video_rxtx::list(bool full)
 
 void
 video_rxtx::set_audio_spec(const struct audio_desc * /* desc */,
-                           int /* audio_rx_port */)
+                           int /* audio_rx_port */, int /* audio_tx_port */,
+                           bool /* ipv6 */)
 {
         MSG(INFO, "video RXTX not h264_rtp, not setting audio...\n");
 }

src/video_rxtx.hpp

@@ -92,7 +92,9 @@ struct video_rxtx {
         virtual void join();
         static video_rxtx *create(std::string const & name, std::map<std::string, param_u> const &);
         static void list(bool full);
-        virtual void set_audio_spec(const struct audio_desc *desc, int audio_rx_port);
+        virtual void set_audio_spec(const struct audio_desc *desc,
+                                    int audio_rx_port, int audio_tx_port,
+                                    bool ipv6);
         std::string m_port_id;
 protected:
         video_rxtx(std::map<std::string, param_u> const &);

src/video_rxtx/h264_rtp.cpp

@@ -147,7 +147,8 @@ void h264_rtp_video_rxtx::join()
 
 void
 h264_rtp_video_rxtx::set_audio_spec(const struct audio_desc *desc,
-                                    int                      audio_rx_port)
+                                    int  audio_rx_port, int /* audio_tx_port */,
+                                    bool /* ipv6 */)
 {
         rtsp_params.adesc = *desc;
         rtsp_params.rtp_port_audio = audio_rx_port;

src/video_rxtx/h264_rtp.hpp

@@ -58,7 +58,9 @@ class h264_rtp_video_rxtx : public rtp_video_rxtx {
         h264_rtp_video_rxtx(std::map<std::string, param_u> const &, int);
         virtual ~h264_rtp_video_rxtx();
         void join() override;
-        void set_audio_spec(const struct audio_desc *desc, int audio_rx_port) override;
+        void set_audio_spec(const struct audio_desc *desc, int audio_rx_port,
+                            int audio_tx_port, bool ipv6) override;
+
 private:
         virtual void send_frame(std::shared_ptr<video_frame>) noexcept override;
         virtual void *(*get_receiver_thread() noexcept)(void *arg) override {

src/video_rxtx/h264_sdp.cpp

@@ -63,6 +63,7 @@
 #include "video_rxtx.hpp"
 
 #define DEFAULT_SDP_COMPRESSION "lavc:codec=MJPEG:safe"
+#define MOD_NAME "[vrxtx/sdp] "
 
 using std::cout;
 using std::exception;
@@ -169,10 +170,26 @@ h264_sdp_video_rxtx::send_frame(shared_ptr<video_frame> tx_frame) noexcept
         }
 }
 
+static void
+sdp_change_address_callback(void *udata, const char *address)
+{
+        const enum module_class path_sender[] = { MODULE_CLASS_AUDIO,
+                                                  MODULE_CLASS_SENDER,
+                                                  MODULE_CLASS_NONE };
+        sdp_send_change_address_message((module *) udata, path_sender, address);
+}
+
 void
-h264_sdp_video_rxtx::set_audio_spec(const struct audio_desc * /* desc */,
-                                    int /* audio_rx_port */)
+h264_sdp_video_rxtx::set_audio_spec(const struct audio_desc *desc,
+                                    int /* audio_rx_port */, int audio_tx_port, bool ipv6)
 {
+        if (sdp_add_audio(ipv6, audio_tx_port,
+                          desc->sample_rate,
+                          desc->ch_count, desc->codec,
+                          sdp_change_address_callback,
+                          get_root_module(m_common.parent)) != 0) {
+                MSG(ERROR, "Cannot add audio to SDP!\n");
+        }
 }
 
 static video_rxtx *create_video_rxtx_h264_sdp(std::map<std::string, param_u> const &params)

src/video_rxtx/h264_sdp.hpp

@@ -60,7 +60,8 @@ class h264_sdp_video_rxtx : public rtp_video_rxtx {
         virtual void *(*get_receiver_thread() noexcept)(void *arg) override {
                 return nullptr;
         }
-        void set_audio_spec(const struct audio_desc *desc, int audio_rx_port) override;
+        void set_audio_spec(const struct audio_desc *desc, int audio_rx_port,
+                            int audio_tx_port, bool ipv6) override;
         void sdp_add_video(codec_t codec);
         codec_t m_sdp_configured_codec = VIDEO_CODEC_NONE;
         int m_saved_tx_port;