/* * PCM - A-Law conversion * Copyright (c) 2000 by Abramo Bagnara * * * This library is free software; you can redistribute it and/or modify * it under the terms of the GNU Library General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include #include "pcm_local.h" #include "pcm_plugin.h" typedef void (*alaw_f)(const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset, const snd_pcm_channel_area_t *src_areas, snd_pcm_uframes_t src_offset, unsigned int channels, snd_pcm_uframes_t frames, int getputidx); typedef struct { /* This field need to be the first */ snd_pcm_plugin_t plug; int getput_idx; alaw_f func; snd_pcm_format_t sformat; } snd_pcm_alaw_t; static inline int val_seg(int val) { int r = 1; val >>= 8; if (val & 0xf0) { val >>= 4; r += 4; } if (val & 0x0c) { val >>= 2; r += 2; } if (val & 0x02) r += 1; return r; } /* * s16_to_alaw() - Convert a 16-bit linear PCM value to 8-bit A-law * * s16_to_alaw() accepts an 16-bit integer and encodes it as A-law data. * * Linear Input Code Compressed Code * ------------------------ --------------- * 0000000wxyza 000wxyz * 0000001wxyza 001wxyz * 000001wxyzab 010wxyz * 00001wxyzabc 011wxyz * 0001wxyzabcd 100wxyz * 001wxyzabcde 101wxyz * 01wxyzabcdef 110wxyz * 1wxyzabcdefg 111wxyz * * For further information see John C. Bellamy's Digital Telephony, 1982, * John Wiley & Sons, pps 98-111 and 472-476. */ static unsigned char s16_to_alaw(int pcm_val) { int mask; int seg; unsigned char aval; if (pcm_val >= 0) { mask = 0xD5; } else { mask = 0x55; pcm_val = -pcm_val; if (pcm_val > 0x7fff) pcm_val = 0x7fff; } if (pcm_val < 256) aval = pcm_val >> 4; else { /* Convert the scaled magnitude to segment number. */ seg = val_seg(pcm_val); aval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0x0f); } return aval ^ mask; } /* * alaw_to_s16() - Convert an A-law value to 16-bit linear PCM * */ static int alaw_to_s16(unsigned char a_val) { int t; int seg; a_val ^= 0x55; t = a_val & 0x7f; if (t < 16) t = (t << 4) + 8; else { seg = (t >> 4) & 0x07; t = ((t & 0x0f) << 4) + 0x108; t <<= seg -1; } return ((a_val & 0x80) ? t : -t); } void snd_pcm_alaw_decode(const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset, const snd_pcm_channel_area_t *src_areas, snd_pcm_uframes_t src_offset, unsigned int channels, snd_pcm_uframes_t frames, int putidx) { #define PUT16_LABELS #include "plugin_ops.h" #undef PUT16_LABELS void *put = put16_labels[putidx]; unsigned int channel; for (channel = 0; channel < channels; ++channel) { const char *src; char *dst; int src_step, dst_step; snd_pcm_uframes_t frames1; const snd_pcm_channel_area_t *src_area = &src_areas[channel]; const snd_pcm_channel_area_t *dst_area = &dst_areas[channel]; #if 0 if (!src_area->enabled) { if (dst_area->wanted) snd_pcm_area_silence(&dst_areas[channel], dst_offset, frames, dst_sfmt); dst_area->enabled = 0; continue; } dst_area->enabled = 1; #endif src = snd_pcm_channel_area_addr(src_area, src_offset); dst = snd_pcm_channel_area_addr(dst_area, dst_offset); src_step = snd_pcm_channel_area_step(src_area); dst_step = snd_pcm_channel_area_step(dst_area); frames1 = frames; while (frames1-- > 0) { int16_t sample = alaw_to_s16(*src); goto *put; #define PUT16_END after #include "plugin_ops.h" #undef PUT16_END after: src += src_step; dst += dst_step; } } } void snd_pcm_alaw_encode(const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset, const snd_pcm_channel_area_t *src_areas, snd_pcm_uframes_t src_offset, unsigned int channels, snd_pcm_uframes_t frames, int getidx) { #define GET16_LABELS #include "plugin_ops.h" #undef GET16_LABELS void *get = get16_labels[getidx]; unsigned int channel; int16_t sample = 0; for (channel = 0; channel < channels; ++channel) { const char *src; char *dst; int src_step, dst_step; snd_pcm_uframes_t frames1; const snd_pcm_channel_area_t *src_area = &src_areas[channel]; const snd_pcm_channel_area_t *dst_area = &dst_areas[channel]; #if 0 if (!src_area->enabled) { if (dst_area->wanted) snd_pcm_area_silence(&dst_area->area, 0, frames, dst_sfmt); dst_area->enabled = 0; continue; } dst_area->enabled = 1; #endif src = snd_pcm_channel_area_addr(src_area, src_offset); dst = snd_pcm_channel_area_addr(dst_area, dst_offset); src_step = snd_pcm_channel_area_step(src_area); dst_step = snd_pcm_channel_area_step(dst_area); frames1 = frames; while (frames1-- > 0) { goto *get; #define GET16_END after #include "plugin_ops.h" #undef GET16_END after: *dst = s16_to_alaw(sample); src += src_step; dst += dst_step; } } } static int snd_pcm_alaw_hw_refine_cprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *params) { snd_pcm_alaw_t *alaw = pcm->private_data; int err; snd_pcm_access_mask_t access_mask = { SND_PCM_ACCBIT_PLUGIN }; err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_ACCESS, &access_mask); if (err < 0) return err; if (alaw->sformat == SND_PCM_FORMAT_A_LAW) { snd_pcm_format_mask_t format_mask = { SND_PCM_FMTBIT_LINEAR }; err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_FORMAT, &format_mask); } else { err = _snd_pcm_hw_params_set_format(params, SND_PCM_FORMAT_A_LAW); } if (err < 0) return err; err = _snd_pcm_hw_params_set_subformat(params, SND_PCM_SUBFORMAT_STD); if (err < 0) return err; params->info &= ~(SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID); return 0; } static int snd_pcm_alaw_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *sparams) { snd_pcm_alaw_t *alaw = pcm->private_data; snd_pcm_access_mask_t saccess_mask = { SND_PCM_ACCBIT_MMAP }; _snd_pcm_hw_params_any(sparams); _snd_pcm_hw_param_set_mask(sparams, SND_PCM_HW_PARAM_ACCESS, &saccess_mask); _snd_pcm_hw_params_set_format(sparams, alaw->sformat); _snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD); return 0; } static int snd_pcm_alaw_hw_refine_schange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params, snd_pcm_hw_params_t *sparams) { int err; unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS | SND_PCM_HW_PARBIT_RATE | SND_PCM_HW_PARBIT_PERIOD_SIZE | SND_PCM_HW_PARBIT_BUFFER_SIZE | SND_PCM_HW_PARBIT_PERIODS | SND_PCM_HW_PARBIT_PERIOD_TIME | SND_PCM_HW_PARBIT_BUFFER_TIME | SND_PCM_HW_PARBIT_TICK_TIME); err = _snd_pcm_hw_params_refine(sparams, links, params); if (err < 0) return err; return 0; } static int snd_pcm_alaw_hw_refine_cchange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params, snd_pcm_hw_params_t *sparams) { int err; unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS | SND_PCM_HW_PARBIT_RATE | SND_PCM_HW_PARBIT_PERIOD_SIZE | SND_PCM_HW_PARBIT_BUFFER_SIZE | SND_PCM_HW_PARBIT_PERIODS | SND_PCM_HW_PARBIT_PERIOD_TIME | SND_PCM_HW_PARBIT_BUFFER_TIME | SND_PCM_HW_PARBIT_TICK_TIME); err = _snd_pcm_hw_params_refine(params, links, sparams); if (err < 0) return err; return 0; } static int snd_pcm_alaw_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params) { return snd_pcm_hw_refine_slave(pcm, params, snd_pcm_alaw_hw_refine_cprepare, snd_pcm_alaw_hw_refine_cchange, snd_pcm_alaw_hw_refine_sprepare, snd_pcm_alaw_hw_refine_schange, snd_pcm_plugin_hw_refine_slave); } static int snd_pcm_alaw_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params) { snd_pcm_alaw_t *alaw = pcm->private_data; int err = snd_pcm_hw_params_slave(pcm, params, snd_pcm_alaw_hw_refine_cchange, snd_pcm_alaw_hw_refine_sprepare, snd_pcm_alaw_hw_refine_schange, snd_pcm_plugin_hw_params_slave); if (err < 0) return err; if (pcm->stream == SND_PCM_STREAM_PLAYBACK) { if (alaw->sformat == SND_PCM_FORMAT_A_LAW) { alaw->getput_idx = snd_pcm_linear_get_index(snd_pcm_hw_params_get_format(params), SND_PCM_FORMAT_S16); alaw->func = snd_pcm_alaw_encode; } else { alaw->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, alaw->sformat); alaw->func = snd_pcm_alaw_decode; } } else { if (alaw->sformat == SND_PCM_FORMAT_A_LAW) { alaw->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, snd_pcm_hw_params_get_format(params)); alaw->func = snd_pcm_alaw_decode; } else { alaw->getput_idx = snd_pcm_linear_get_index(alaw->sformat, SND_PCM_FORMAT_S16); alaw->func = snd_pcm_alaw_encode; } } return 0; } static snd_pcm_sframes_t snd_pcm_alaw_write_areas(snd_pcm_t *pcm, const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t size, snd_pcm_uframes_t *slave_sizep) { snd_pcm_alaw_t *alaw = pcm->private_data; snd_pcm_t *slave = alaw->plug.slave; snd_pcm_uframes_t xfer = 0; snd_pcm_sframes_t err = 0; if (slave_sizep && *slave_sizep < size) size = *slave_sizep; assert(size > 0); while (xfer < size) { snd_pcm_uframes_t frames = snd_pcm_mmap_playback_xfer(slave, size - xfer); alaw->func(snd_pcm_mmap_areas(slave), snd_pcm_mmap_offset(slave), areas, offset, pcm->channels, frames, alaw->getput_idx); err = snd_pcm_mmap_forward(slave, frames); if (err < 0) break; assert((snd_pcm_uframes_t)err == frames); offset += err; xfer += err; snd_pcm_mmap_hw_forward(pcm, err); } if (xfer > 0) { if (slave_sizep) *slave_sizep = xfer; return xfer; } return err; } static snd_pcm_sframes_t snd_pcm_alaw_read_areas(snd_pcm_t *pcm, const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t size, snd_pcm_uframes_t *slave_sizep) { snd_pcm_alaw_t *alaw = pcm->private_data; snd_pcm_t *slave = alaw->plug.slave; snd_pcm_uframes_t xfer = 0; snd_pcm_sframes_t err = 0; if (slave_sizep && *slave_sizep < size) size = *slave_sizep; assert(size > 0); while (xfer < size) { snd_pcm_uframes_t frames = snd_pcm_mmap_capture_xfer(slave, size - xfer); alaw->func(areas, offset, snd_pcm_mmap_areas(slave), snd_pcm_mmap_offset(slave), pcm->channels, frames, alaw->getput_idx); err = snd_pcm_mmap_forward(slave, frames); if (err < 0) break; assert((snd_pcm_uframes_t)err == frames); offset += err; xfer += err; snd_pcm_mmap_hw_forward(pcm, err); } if (xfer > 0) { if (slave_sizep) *slave_sizep = xfer; return xfer; } return err; } static void snd_pcm_alaw_dump(snd_pcm_t *pcm, snd_output_t *out) { snd_pcm_alaw_t *alaw = pcm->private_data; snd_output_printf(out, "A-Law conversion PCM (%s)\n", snd_pcm_format_name(alaw->sformat)); if (pcm->setup) { snd_output_printf(out, "Its setup is:\n"); snd_pcm_dump_setup(pcm, out); } snd_output_printf(out, "Slave: "); snd_pcm_dump(alaw->plug.slave, out); } snd_pcm_ops_t snd_pcm_alaw_ops = { close: snd_pcm_plugin_close, info: snd_pcm_plugin_info, hw_refine: snd_pcm_alaw_hw_refine, hw_params: snd_pcm_alaw_hw_params, hw_free: snd_pcm_plugin_hw_free, sw_params: snd_pcm_plugin_sw_params, channel_info: snd_pcm_plugin_channel_info, dump: snd_pcm_alaw_dump, nonblock: snd_pcm_plugin_nonblock, async: snd_pcm_plugin_async, mmap: snd_pcm_plugin_mmap, munmap: snd_pcm_plugin_munmap, }; int snd_pcm_alaw_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sformat, snd_pcm_t *slave, int close_slave) { snd_pcm_t *pcm; snd_pcm_alaw_t *alaw; assert(pcmp && slave); if (snd_pcm_format_linear(sformat) != 1 && sformat != SND_PCM_FORMAT_A_LAW) return -EINVAL; alaw = calloc(1, sizeof(snd_pcm_alaw_t)); if (!alaw) { return -ENOMEM; } alaw->sformat = sformat; alaw->plug.read = snd_pcm_alaw_read_areas; alaw->plug.write = snd_pcm_alaw_write_areas; alaw->plug.slave = slave; alaw->plug.close_slave = close_slave; pcm = calloc(1, sizeof(snd_pcm_t)); if (!pcm) { free(alaw); return -ENOMEM; } if (name) pcm->name = strdup(name); pcm->type = SND_PCM_TYPE_ALAW; pcm->stream = slave->stream; pcm->mode = slave->mode; pcm->ops = &snd_pcm_alaw_ops; pcm->op_arg = pcm; pcm->fast_ops = &snd_pcm_plugin_fast_ops; pcm->fast_op_arg = pcm; pcm->private_data = alaw; pcm->poll_fd = slave->poll_fd; pcm->hw_ptr = &alaw->plug.hw_ptr; pcm->appl_ptr = &alaw->plug.appl_ptr; *pcmp = pcm; return 0; } int _snd_pcm_alaw_open(snd_pcm_t **pcmp, const char *name, snd_config_t *conf, snd_pcm_stream_t stream, int mode) { snd_config_iterator_t i, next; const char *sname = NULL; int err; snd_pcm_t *spcm; snd_pcm_format_t sformat = SND_PCM_FORMAT_UNKNOWN; snd_config_for_each(i, next, conf) { snd_config_t *n = snd_config_iterator_entry(i); const char *id = snd_config_get_id(n); if (strcmp(id, "comment") == 0) continue; if (strcmp(id, "type") == 0) continue; if (strcmp(id, "sname") == 0) { err = snd_config_get_string(n, &sname); if (err < 0) { ERR("Invalid type for %s", id); return -EINVAL; } continue; } if (strcmp(id, "sformat") == 0) { const char *f; err = snd_config_get_string(n, &f); if (err < 0) { ERR("Invalid type for %s", id); return -EINVAL; } sformat = snd_pcm_format_value(f); if (sformat == SND_PCM_FORMAT_UNKNOWN) { ERR("Unknown sformat"); return -EINVAL; } if (snd_pcm_format_linear(sformat) != 1 && sformat != SND_PCM_FORMAT_A_LAW) { ERR("Invalid sformat"); return -EINVAL; } continue; } ERR("Unknown field %s", id); return -EINVAL; } if (!sname) { ERR("sname is not defined"); return -EINVAL; } if (sformat == SND_PCM_FORMAT_UNKNOWN) { ERR("sformat is not defined"); return -EINVAL; } /* This is needed cause snd_config_update may destroy config */ sname = strdup(sname); if (!sname) return -ENOMEM; err = snd_pcm_open(&spcm, sname, stream, mode); free((void *) sname); if (err < 0) return err; err = snd_pcm_alaw_open(pcmp, name, sformat, spcm, 1); if (err < 0) snd_pcm_close(spcm); return err; }