Voice to text using CMU Pocketsphinx

sudo apt-get install libpulse-dev

/* Install Sphinxbase first */
cd sphinxbase-0.8/ 

./configure
make
sudo make install

/* 
** The sphinxbase will be installed in /usr/local/ folder. 
** Not every system loads libraries from this folder automatically. 
** It can be done by exporting the following environment variables:
*/
export LD_LIBRARY_PATH=/usr/local/lib
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
/*
** It's also a good idea to put it in your .bashrc
*/

/* Now install pocketpshinx */
cd ../pocketsphinx-0.8/

./configure
make
sudo make install

/*
** You have now successfully installed PocketSphinx. 
** Let's try it out by executing this command  
*/

pocketsphinx_continuous

#include <pocketsphinx.h>

int
main(int argc, char *argv[])
{
	ps_decoder_t *ps;
	cmd_ln_t *config;
	FILE *fh;
	char const *hyp, *uttid;
	int16 buf[512];
	int rv;
	int32 score;

	config = cmd_ln_init(NULL, ps_args(), TRUE,
			     "-hmm", MODELDIR "/hmm/en_US/hub4wsj_sc_8k",
			     "-lm", MODELDIR "/lm/en/turtle.DMP",
			     "-dict", MODELDIR "/lm/en/turtle.dic",
			     NULL);
/*
**  Alternatively, you can directly specify where the 'hmm', 'dict' and 'lm' files are
**  by directly writing their absolute path as I've done below. 
**  They're in the extracted pocketsphinx-0.8 folder/model/
**  What this will do is make your compilation command smaller but in return
**  you can't give it runtime locations for the hmm, lm and dict files
**
** config = cmd_ln_init(NULL, ps_args(), TRUE,               
** 			     "-hmm", "/home/anup/Stuff/pocketsphinx/pocketsphinx-0.8/model/hmm/en_US/hub4wsj_sc_8k",
** 			     "-lm", "/home/anup/Stuff/pocketsphinx/pocketsphinx-0.8/model/lm/en/turtle.DMP",
** 			     "-dict", "/home/anup/Stuff/pocketsphinx/pocketsphinx-0.8/model/lm/en/turtle.dic",
** 			     NULL);
*/
	if (config == NULL)
		return 1;
	ps = ps_init(config);
	if (ps == NULL)
		return 1;

	fh = fopen("goforward.raw", "rb");
	if (fh == NULL) {
		perror("Failed to open goforward.raw");
		return 1;
	}

	rv = ps_decode_raw(ps, fh, "goforward", -1);
	if (rv < 0)
		return 1;
	hyp = ps_get_hyp(ps, &score, &uttid);
	if (hyp == NULL)
		return 1;
	printf("Recognized: %s\n", hyp);

        fseek(fh, 0, SEEK_SET);
        rv = ps_start_utt(ps, "goforward");
	if (rv < 0)
		return 1;
        while (!feof(fh)) {
            size_t nsamp;
            nsamp = fread(buf, 2, 512, fh);
            rv = ps_process_raw(ps, buf, nsamp, FALSE, FALSE);
        }
        rv = ps_end_utt(ps);
	if (rv < 0)
		return 1;
	hyp = ps_get_hyp(ps, &score, &uttid);
	if (hyp == NULL)
		return 1;
	printf("Recognized: %s\n", hyp);

	fclose(fh);
        ps_free(ps);
	return 0;
}

/* Compile the program */
gcc -o hello_ps hello_ps.c 'pkg-config --cflags --libs pocketsphinx sphinxbase'

/*
** Execute the binary
** Make sure that the audio file 'goforward.raw' is in the same 
** directory as your program otherwise it'll fail to execute.
*/
./hello_ps

/* Your .bashrc can have these lines to make your life easier. */
export LD_LIBRARY_PATH=/usr/local/lib
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

/*
** Only if you're going to hard code the hmm, lm and dict file paths
** Like in the example
*/
gps()
{
    gcc -o $1.o $1 'pkg-config --cflags --libs pocketsphinx sphinxbase'
}

/*
** Now you can simply use the API by including the pocketsphinx header
** and compile the program using the command 'gps' 
*/
gps filename.c