alsa.zip_alsa record_alsa播放_snd

//File : sndwav_common.c //Author : Loon <sepnic@gmail.com> #include <assert.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <alsa/asoundlib.h> #include "sndwav_common.h" int SNDWAV_P_GetFormat(WAVContainer_t *wav, snd_pcm_format_t *snd_format) { if (LE_SHORT(wav->format.format) != WAV_FMT_PCM) return -1; switch (LE_SHORT(wav->format.sample_length)) { case 16: *snd_format = SND_PCM_FORMAT_S16_LE; break; case 8: *snd_format = SND_PCM_FORMAT_U8; break; default: *snd_format = SND_PCM_FORMAT_UNKNOWN; break; } return 0; } ssize_t SNDWAV_ReadPcm(SNDPCMContainer_t *sndpcm, size_t rcount) { ssize_t r; size_t result = 0; size_t count = rcount; uint8_t *data = sndpcm->data_buf; if (count != sndpcm->chunk_size) { count = sndpcm->chunk_size; } while (count > 0) { r = snd_pcm_readi(sndpcm->handle, data, count); if (r == -EAGAIN || (r >= 0 && (size_t)r < count)) { snd_pcm_wait(sndpcm->handle, 1000); } else if (r == -EPIPE) { snd_pcm_prepare(sndpcm->handle); fprintf(stderr, "<<<<<<<<<<<<<<< Buffer Underrun >>>>>>>>>>>>>>>/n"); } else if (r == -ESTRPIPE) { fprintf(stderr, "<<<<<<<<<<<<<<< Need suspend >>>>>>>>>>>>>>>/n"); } else if (r < 0) { fprintf(stderr, "Error snd_pcm_writei: [%s]", snd_strerror(r)); exit(-1); } if (r > 0) { result += r; count -= r; data += r * sndpcm->bits_per_frame / 8; } } return rcount; } ssize_t SNDWAV_WritePcm(SNDPCMContainer_t *sndpcm, size_t wcount) { ssize_t r; ssize_t result = 0; uint8_t *data = sndpcm->data_buf; if (wcount < sndpcm->chunk_size) { snd_pcm_format_set_silence(sndpcm->format, data + wcount * sndpcm->bits_per_frame / 8, (sndpcm->chunk_size - wcount) * sndpcm->channels); wcount = sndpcm->chunk_size; } while (wcount > 0) { r = snd_pcm_writei(sndpcm->handle, data, wcount); if (r == -EAGAIN || (r >= 0 && (size_t)r < wcount)) { snd_pcm_wait(sndpcm->handle, 1000); } else if (r == -EPIPE) { snd_pcm_prepare(sndpcm->handle); fprintf(stderr, "<<<<<<<<<<<<<<< Buffer Underrun >>>>>>>>>>>>>>>/n"); } else if (r == -ESTRPIPE) { fprintf(stderr, "<<<<<<<<<<<<<<< Need suspend >>>>>>>>>>>>>>>/n"); } else if (r < 0) { fprintf(stderr, "Error snd_pcm_writei: [%s]", snd_strerror(r)); exit(-1); } if (r > 0) { result += r; wcount -= r; data += r * sndpcm->bits_per_frame / 8; } } return result; } int SNDWAV_SetParams(SNDPCMContainer_t *sndpcm, WAVContainer_t *wav) { snd_pcm_hw_params_t *hwparams; snd_pcm_format_t format; uint32_t exact_rate; uint32_t buffer_time, period_time; /* Allocate the snd_pcm_hw_params_t structure on the stack. */ snd_pcm_hw_params_alloca(&hwparams); /* Init hwparams with full configuration space */ if (snd_pcm_hw_params_any(sndpcm->handle, hwparams) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_any/n"); goto ERR_SET_PARAMS; } if (snd_pcm_hw_params_set_access(sndpcm->handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_access/n"); goto ERR_SET_PARAMS; } /* Set sample format */ if (SNDWAV_P_GetFormat(wav, &format) < 0) { fprintf(stderr, "Error get_snd_pcm_format/n"); goto ERR_SET_PARAMS; } if (snd_pcm_hw_params_set_format(sndpcm->handle, hwparams, format) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_format/n"); goto ERR_SET_PARAMS; } sndpcm->format = format; /* Set number of channels */ if (snd_pcm_hw_params_set_channels(sndpcm->handle, hwparams, LE_SHORT(wav->format.channels)) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_channels/n"); goto ERR_SET_PARAMS; } sndpcm->channels = LE_SHORT(wav->format.channels); /* Set sample rate. If the exact rate is not supported */ /* by the hardware, use nearest possible rate. */ exact_rate = LE_INT(wav->format.sample_rate); if (snd_pcm_hw_params_set_rate_near(sndpcm->handle, hwparams, &exact_rate, 0) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_rate_near/n"); goto ERR_SET_PARAMS; } if (LE_INT(wav->format.sample_rate) != exact_rate) { fprintf(stderr, "The rate %d Hz is not supported by your hardware./n ==> Using %d Hz instead./n", LE_INT(wav->format.sample_rate), exact_rate); } if (snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time, 0) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_get_buffer_time_max/n"); goto ERR_SET_PARAMS; } if (buffer_time > 500000) buffer_time = 500000; period_time = buffer_time / 4; if (snd_pcm_hw_params_set_buffer_time_near(sndpcm->handle, hwparams, &buffer_time, 0) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_buffer_time_near/n"); goto ERR_SET_PARAMS; } if (snd_pcm_hw_params_set_period_time_near(sndpcm->handle, hwparams, &period_time, 0) < 0) { fprintf(stderr, "Error snd_pcm_hw_params_set_period_time_near/n"); goto ERR_SET_PARAMS; } /* Set hw params */ if (snd_pcm_hw_params(sndpcm->handle, hwparams) < 0) { fprintf(stderr, "Error snd_pcm_hw_params(handle, params)/n"); goto ERR_SET_PARAMS; } snd_pcm_hw_params_get_period_size(hwparams, &sndpcm->chunk_size, 0); snd_pcm_hw_params_get_buffer_size(hwparams, &sndpcm->buffer_size); if (sndpcm->chunk_size == sndpcm->buffer_size) { fprintf(stderr, ("Can't use period equal to buffer size (%lu == %lu)/n"), sndpcm->chunk_size, sndpcm->buffer_size); goto ERR_SET_PARAMS; } sndpcm->bits_per_sample = snd_pcm_format_physical_width(format); sndpcm->bits_per_frame = sndpcm->bits_per_sample * LE_SHORT(wav->format.channels); sndpcm->chunk_bytes = sndpcm->chunk_size * sndpcm->bits_per_frame / 8; /* Allocate audio data buffer */ sndpcm->data_buf = (uint8_t *)malloc(sndpcm->chunk_bytes); if (!sndpcm->data_buf) { fprintf(stderr, "Error malloc: [data_buf]/n"); goto ERR_SET_PARAMS; } return 0; ERR_SET_PARAMS: return -1; }