add interface to get audio format list

inc/ALSACapture.h

@@ -46,13 +46,15 @@ class ALSACapture  : public DeviceInterface
 		int configureFormat(snd_pcm_hw_params_t *hw_params);
 			
 	public:
-		virtual size_t read(char* buffer, size_t bufferSize);		
-		virtual int getFd();
-		virtual unsigned long getBufferSize()   { return m_bufferSize;          }	
+		virtual size_t         read(char* buffer, size_t bufferSize);		
+		virtual int            getFd();
+		virtual unsigned long  getBufferSize()      { return m_bufferSize;          }	
 		
-		virtual unsigned long getSampleRate()   { return m_params.m_sampleRate; }
-		virtual unsigned long getChannels  ()   { return m_params.m_channels;   }
-		virtual int           getAudioFormat () { return m_fmt;                 }
+		virtual unsigned long  getSampleRate()      { return m_params.m_sampleRate; }
+		virtual unsigned long  getChannels  ()      { return m_params.m_channels;   }
+		virtual int            getAudioFormat ()    { return m_fmt;                 }
+		virtual std::list<int> getAudioFormatList() { return m_fmtList;             }
+
 		
 	private:
 		snd_pcm_t*            m_pcm;
@@ -60,6 +62,7 @@ class ALSACapture  : public DeviceInterface
 		unsigned long         m_periodSize;
 		ALSACaptureParameters m_params;
 		snd_pcm_format_t      m_fmt;
+		std::list<int>        m_fmtList;
 };
 
 

inc/DeviceInterface.h

@@ -9,7 +9,7 @@
 
 
 #pragma once
-
+#include <list>
 
 // ---------------------------------
 // Device Interface
@@ -19,14 +19,16 @@ class DeviceInterface
 	public:
 		virtual size_t read(char* buffer, size_t bufferSize) = 0;	
 		virtual int getFd()                                  = 0;	
-		virtual unsigned long getBufferSize()                = 0;
-		virtual int getWidth()                               { return -1; }	
-		virtual int getHeight()                              { return -1; }
-		virtual int getVideoFormat()                         { return -1; }
-		virtual unsigned long getSampleRate()                { return -1; }
-		virtual unsigned long getChannels()                  { return -1; }
-		virtual int           getAudioFormat()               { return -1; }				
-		virtual ~DeviceInterface() {};
+		virtual unsigned long  getBufferSize()               = 0;
+		virtual int            getWidth()                    { return -1; }	
+		virtual int            getHeight()                   { return -1; }
+		virtual int            getVideoFormat()              { return -1; }
+		virtual std::list<int> getVideoFormatList()          { return std::list<int>(); }
+		virtual unsigned long  getSampleRate()               { return -1; }
+		virtual unsigned long  getChannels()                 { return -1; }
+		virtual int            getAudioFormat()              { return -1; }				
+		virtual std::list<int> getAudioFormatList()          { return std::list<int>(); }
+		virtual ~DeviceInterface()                           {};
 };
 
 

src/ALSACapture.cpp

@@ -15,6 +15,46 @@
 
 #include "ALSACapture.h"
 
+static const snd_pcm_format_t formats[] = {
+	SND_PCM_FORMAT_S8,
+	SND_PCM_FORMAT_U8,
+	SND_PCM_FORMAT_S16_LE,
+	SND_PCM_FORMAT_S16_BE,
+	SND_PCM_FORMAT_U16_LE,
+	SND_PCM_FORMAT_U16_BE,
+	SND_PCM_FORMAT_S24_LE,
+	SND_PCM_FORMAT_S24_BE,
+	SND_PCM_FORMAT_U24_LE,
+	SND_PCM_FORMAT_U24_BE,
+	SND_PCM_FORMAT_S32_LE,
+	SND_PCM_FORMAT_S32_BE,
+	SND_PCM_FORMAT_U32_LE,
+	SND_PCM_FORMAT_U32_BE,
+	SND_PCM_FORMAT_FLOAT_LE,
+	SND_PCM_FORMAT_FLOAT_BE,
+	SND_PCM_FORMAT_FLOAT64_LE,
+	SND_PCM_FORMAT_FLOAT64_BE,
+	SND_PCM_FORMAT_IEC958_SUBFRAME_LE,
+	SND_PCM_FORMAT_IEC958_SUBFRAME_BE,
+	SND_PCM_FORMAT_MU_LAW,
+	SND_PCM_FORMAT_A_LAW,
+	SND_PCM_FORMAT_IMA_ADPCM,
+	SND_PCM_FORMAT_MPEG,
+	SND_PCM_FORMAT_GSM,
+	SND_PCM_FORMAT_SPECIAL,
+	SND_PCM_FORMAT_S24_3LE,
+	SND_PCM_FORMAT_S24_3BE,
+	SND_PCM_FORMAT_U24_3LE,
+	SND_PCM_FORMAT_U24_3BE,
+	SND_PCM_FORMAT_S20_3LE,
+	SND_PCM_FORMAT_S20_3BE,
+	SND_PCM_FORMAT_U20_3LE,
+	SND_PCM_FORMAT_U20_3BE,
+	SND_PCM_FORMAT_S18_3LE,
+	SND_PCM_FORMAT_S18_3BE,
+	SND_PCM_FORMAT_U18_3LE,
+	SND_PCM_FORMAT_U18_3BE,
+};
 
 ALSACapture* ALSACapture::createNew(const ALSACaptureParameters & params) 
 { 
@@ -101,6 +141,15 @@ ALSACapture::ALSACapture(const ALSACaptureParameters & params) : m_pcm(NULL), m_
 		this->close();
 	}			
 	
+	if (!err) {
+		// get supported format
+		for (int i = 0; i < sizeof(formats)/sizeof(formats[0]); ++i) {
+			if (!snd_pcm_hw_params_test_format(m_pcm, hw_params, formats[i])) {
+				m_fmtList.push_back(formats[i]);
+			}
+		}	
+	}
+
 	LOG(NOTICE) << "ALSA device: \"" << m_params.m_devName << "\" buffer_size:" << m_bufferSize << " period_size:" << m_periodSize << " rate:" << m_params.m_sampleRate;
 }