Alsa pcm voice Program

# Include "ALSA/asoundlib. H"

// 11 kHz support, longer audible time, slower sonic speed
# Define sample_rate 48000
// # Define sample_rate 11000

// It is indeed a two-channel Interaction
# Define Channels 1
// # Define channels 2

// If latency is too small, it will cause snd_pcm_writei () to lose voice data, resulting in the short write Phenomenon
# Define latency (1000000) // 1sec

# Define nblocks 16
# Define block_size 1024
Unsigned char buffer [nblocks * block_size];/* here: some random da

Ta: Future: user layer sound data */

Static char * Device = "default";/* playback device */

# Define random_play 1
# Define common_play 2

Static unsigned char * get_user_layer_pcm_data (INT flag)
{
Int I;
For (I = 0; I <sizeof (buffer); I ++ ){
If (flag = random_play)
Buffer [I] = random () & 0xff;
Else
Buffer [I] = I & 0xff;
}
Return buffer;
}

Int main (INT argc, char ** argv)
{
Int I;
Int err, ret_code = 0;
Snd_pcm_t * handle;
Snd_pcm_sframes_t frames;

If (argc = 2)
Get_user_layer_pcm_data (random_play); // here future to get PCM data from user layer
Else
Get_user_layer_pcm_data (common_play); // here future to get PCM data from user layer

If (ERR = snd_pcm_open (& handle, device, snd_pcm_stream_playback, 0) <0 ){
Printf ("playback open error: % s/n", snd_strerror (ERR ));
Exit (exit_failure );
}

If (ERR = snd_pcm_set_params (handle,
Snd_pcm_format_u8,
Snd_pcm_access_rw_interleaved,/* snd_pcm_readi/snd_pcm_writei access */
Channels, // Channels
Sample_rate, // sample rate in Hz
1, // soft_resample
Latency) <0) {/* latency: US 0.5sec */
Printf ("playback open error: % s/n", snd_strerror (ERR ));
Exit (exit_failure );
}

For (I = 0; I <10; I ++) {// play 10 times, every play 16kb snd size
Frames = snd_pcm_writei (handle, buffer, sizeof (buffer ));
If (frames <0)
Frames = snd_pcm_recover (handle, frames, 0 );
If (frames <0 ){
Printf ("snd_pcm_writei failed: % s/n", snd_strerror (ERR ));
Ret_code =-1;
Break;
}
If (frames> 0 & frames <(long) sizeof (buffer ))
Printf ("short write (expected % Li, wrote % Li)/n", (long) sizeof (buffer), frames );
}

Snd_pcm_close (handle );

Return ret_code;
}
======================================
Makefile:
# Usage:
# Make ==> arm compile
# Make arch = arm ==> same as abve
# Make rebuild ==> make clean + Make arch = arm
# Make arch = arm rebuild

# Make arch = i386 ==> x86 compile
# Make arch = i386 rebuild ==> make clean + Make arch = i386

# Default to compile on ARM platform
Arch = arm
Cross_compile = arm-
Bin_ext =
Libdir =/Pavo/library/lib
Include_dir =/Pavo/library/include

Ifeq ("$ (origin arch)", "command line ")
Arch = $ (ARCH)
Endif

Ifeq ($ (ARCH), i386)
Cross_compile =
Bin_ext0000.exe
Libdir =/usr/lib
Include_dir =/usr/include
Endif

Ifeq ($ (ARCH), arm)
Cross_compile = arm-
Bin_ext =
Libdir =/Pavo/library/lib
Include_dir =/Pavo/library/include
Endif

Cc = $ (cross_compile) GCC
CPP = $ (CC)-e
LD = $ (cross_compile) GCC
As = $ (cross_compile)
AR = $ (cross_compile) Ar
Nm = $ (cross_compile) nm
Strip = $ (cross_compile) strip
Objcopy = $ (cross_compile) objcopy
Objdump = $ (cross_compile) objdump
Ranlib = $ (cross_compile) ranlib

Target = pcm_play $ (bin_ext)
Sources = pcm_play.c
Objs = pcm_play.o

Del_files: = $ (objs)
Del_files + = pcm_play
Del_files **pcm_play.exe

Cflags =-I $ (include_dir)
Ldflags =-L $ (libdir)

Libs = $ (ldflags)-lasound-lm-LDL-lpthread

ALL:
@ Echo compiling $ @...
$ (CC)-C $ (sources) $ (cflags)-o $ (objs)
$ (LD) $ (objs)-o $ (target) $ (libs) $ (cflags)

Clean:
@ Echo "make clean"
@ For F in $ (del_files); Do/
If test-F $ F; then/
Echo "$ f exist, RM it ";/
Rm-F $ F ;/
FI ;/
Done;

Rebuild: clean
Make all