make experiment with ALSA capture

CMakeLists.txt

@@ -38,6 +38,10 @@ target_link_libraries(${PROJECT_NAME} ${V4L2WRAPPER_LIBRARY})
 find_package (Threads)
 target_link_libraries (${PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT}) 
 
+#ALSA
+find_package(ALSA)
+target_link_libraries (${PROJECT_NAME} ${ALSA_LIBRARY}) 
+
 # LOG4CPP
 find_path(LOG4CPP_INCLUDE_DIR log4cpp/Category.hh)
 if (NOT LOG4CPP_INCLUDE_DIR)

inc/ALSACapture.h

@@ -0,0 +1,82 @@
+/* ---------------------------------------------------------------------------
+** This software is in the public domain, furnished "as is", without technical
+** support, and with no warranty, express or implied, as to its usefulness for
+** any purpose.
+**
+** ALSACapture.cpp
+** 
+** V4L2 RTSP streamer                                                                 
+**                                                                                    
+** ALSA capture overide of V4l2Capture
+**                                                                                    
+** -------------------------------------------------------------------------*/
+
+#include <alsa/asoundlib.h>
+
+class ALSACapture : public V4l2Capture
+{
+	public:
+		static ALSACapture* createNew(V4L2DeviceParameters params) { return new ALSACapture(params); }
+		virtual ~ALSACapture()
+		{
+			if (m_pcm != NULL)
+			{
+				snd_pcm_close (m_pcm);
+			}
+		}
+	
+	protected:
+		ALSACapture(V4L2DeviceParameters params) : V4l2Device(params,V4L2_BUF_TYPE_VIDEO_CAPTURE), V4l2Capture(params), m_pcm(NULL)
+		{
+			snd_pcm_hw_params_t *hw_params = NULL;
+			int err = 0;
+			unsigned int rate = 44100;
+
+			// open PCM device
+			if ((err = snd_pcm_open (&m_pcm, params.m_devName.c_str(), SND_PCM_STREAM_CAPTURE, 0)) < 0) {
+				fprintf (stderr, "cannot open audio device %s (%s)\n", params.m_devName.c_str(), snd_strerror (err));
+			}
+						
+			// configure hw_params
+			else if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
+				fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n", snd_strerror (err));
+			}
+			else if ((err = snd_pcm_hw_params_any (m_pcm, hw_params)) < 0) {
+				fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n", snd_strerror (err));
+			}			
+			else if ((err = snd_pcm_hw_params_set_access (m_pcm, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
+				fprintf (stderr, "cannot set access type (%s)\n", snd_strerror (err));
+			}
+			else if ((err = snd_pcm_hw_params_set_format (m_pcm, hw_params, SND_PCM_FORMAT_S16_BE)) < 0) {
+				fprintf (stderr, "cannot set sample format (%s)\n", snd_strerror (err));
+			}
+			else if ((err = snd_pcm_hw_params_set_rate_near (m_pcm, hw_params, &rate, 0)) < 0) {
+				fprintf (stderr, "cannot set sample rate (%s)\n", snd_strerror (err));
+			}
+			else if ((err = snd_pcm_hw_params_set_channels (m_pcm, hw_params, 2)) < 0) {
+				fprintf (stderr, "cannot set channel count (%s)\n", snd_strerror (err));
+			}
+			else if ((err = snd_pcm_hw_params (m_pcm, hw_params)) < 0) {
+				fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror (err));
+			}
+			// start capture
+			else if ((err = snd_pcm_prepare (m_pcm)) < 0) {
+				fprintf (stderr, "cannot prepare audio interface for use (%s)\n", snd_strerror (err));
+			}			
+		}
+			
+	public:
+		virtual size_t read(char* buffer, size_t bufferSize)
+		{
+			size_t ret = snd_pcm_readi (m_pcm, buffer, bufferSize);
+			fprintf (stderr, "snd_pcm_readi size:%ld\n", ret);
+			return ret;
+		}
+		
+		virtual bool isReady() { return (m_pcm != NULL); };
+		
+	private:
+		snd_pcm_t* m_pcm;
+	
+};
+

src/ServerMediaSubsession.cpp

@@ -63,6 +63,10 @@ RTPSink*  BaseServerMediaSubsession::createSink(UsageEnvironment& env, Groupsock
 	{
 		videoSink = JPEGVideoRTPSink::createNew (env, rtpGroupsock); 
 	}
+	else if (format == "audio/L16")
+	{
+		videoSink = SimpleRTPSink::createNew(env, rtpGroupsock,rtpPayloadTypeIfDynamic, 44100, "audio", "L16", 2, True, False); 
+	}
 	return videoSink;
 }