/* 2004.02.01 first released source code for IOMP */ /* * Copyright (C) 2000-2002 the xine project * * This file is part of xine, a free video player. * * xine is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * xine 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA * * Logarithmic PCM Decoder * This audio decoder handles the mu-law and A-law logarithmic coding * standards. * * mu-law -> PCM conversion routine found at this site: * http://www.speech.cs.cmu.edu/comp.speech/Section2/Q2.7.html * and credited to this person: * Craig Reese: IDA/Supercomputing Research Center * * A-law -> PCM conversion routine lifted from SoX Sound eXchange: * http://sox.sourceforge.net/ * which listed the code as being lifted from Sun Microsystems. * * $Id: logpcm.c,v 1.2 2003/11/25 04:26:04 georgedon Exp $ * */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include "buffer.h" #include "xine_internal.h" #include "video_out.h" #include "audio_out.h" #include "xineutils.h" #include "bswap.h" #define AUDIOBUFSIZE 128*1024 #define LOGPCM_BITS_PER_SAMPLE 16 typedef struct { audio_decoder_class_t decoder_class; } logpcm_class_t; typedef struct logpcm_decoder_s { audio_decoder_t audio_decoder; xine_stream_t *stream; int64_t pts; int output_open; int output_channels; int samplerate; unsigned char *buf; int bufsize; int size; short logtable[256]; } logpcm_decoder_t; /* ** This routine converts from ulaw to 16 bit linear. ** ** Craig Reese: IDA/Supercomputing Research Center ** 29 September 1989 ** ** References: ** 1) CCITT Recommendation G.711 (very difficult to follow) ** 2) MIL-STD-188-113,"Interoperability and Performance Standards ** for Analog-to_Digital Conversion Techniques," ** 17 February 1987 ** ** Input: 8 bit ulaw sample ** Output: signed 16 bit linear sample */ static int mulaw2linear(unsigned char mulawbyte) { static int exp_lut[8] = {0,132,396,924,1980,4092,8316,16764}; int sign, exponent, mantissa, sample; mulawbyte = ~mulawbyte; sign = (mulawbyte & 0x80); exponent = (mulawbyte >> 4) & 0x07; mantissa = mulawbyte & 0x0F; sample = exp_lut[exponent] + (mantissa << (exponent + 3)); if (sign != 0) sample = -sample; return(sample); } /* * The following A-law -> PCM conversion function came from SoX which in * turn came from Sun Microsystems. */ #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */ #define QUANT_MASK (0xf) /* Quantization field mask. */ #define SEG_SHIFT (4) /* Left shift for segment number. */ #define SEG_MASK (0x70) /* Segment field mask. */ /* * alaw2linear() - Convert an A-law value to 16-bit signed linear PCM * */ static int alaw2linear(unsigned char a_val) { int t; int seg; a_val ^= 0x55; t = (a_val & QUANT_MASK) << 4; seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; switch (seg) { case 0: t += 8; break; case 1: t += 0x108; break; default: t += 0x108; t <<= seg - 1; } return ((a_val & SIGN_BIT) ? t : -t); } static void logpcm_decode_data (audio_decoder_t *this_gen, buf_element_t *buf) { logpcm_decoder_t *this = (logpcm_decoder_t *) this_gen; audio_buffer_t *audio_buffer; int in; int i; int bytes_to_send; if (buf->decoder_flags & BUF_FLAG_HEADER) { this->samplerate = buf->decoder_info[1]; this->output_channels = buf->decoder_info[3]; this->buf = xine_xmalloc(AUDIOBUFSIZE); this->bufsize = AUDIOBUFSIZE; this->size = 0; /* stream/meta info */ this->stream->meta_info[XINE_META_INFO_AUDIOCODEC] = (buf->type == BUF_AUDIO_MULAW) ? strdup("mu-law log PCM") : strdup("A-law log PCM"); /* pre-calculate the possible log values */ if (buf->type == BUF_AUDIO_MULAW) for (i = 0; i < 256; i++) this->logtable[i] = (short)mulaw2linear(i); else if (buf->type == BUF_AUDIO_ALAW) for (i = 0; i < 256; i++) this->logtable[i] = (short)alaw2linear(i); return; } if (!this->output_open) { this->output_open = this->stream->audio_out->open(this->stream->audio_out, this->stream, LOGPCM_BITS_PER_SAMPLE, this->samplerate, (this->output_channels == 2) ? AO_CAP_MODE_STEREO : AO_CAP_MODE_MONO); } /* if the audio still isn't open, bail */ if (!this->output_open) return; if( this->size + buf->size > this->bufsize ) { this->bufsize = this->size + 2 * buf->size; printf("logpcm: increasing source buffer to %d to avoid overflow.\n", this->bufsize); this->buf = realloc( this->buf, this->bufsize ); } xine_fast_memcpy (&this->buf[this->size], buf->content, buf->size); this->size += buf->size; if (buf->decoder_flags & BUF_FLAG_FRAME_END) { /* time to decode a frame */ /* iterate through each 8-bit sample in the input buffer */ in = 0; while (in < this->size) { audio_buffer = this->stream->audio_out->get_buffer (this->stream->audio_out); if (audio_buffer->mem_size == 0) { printf ("logpcm: Help! Allocated audio buffer with nothing in it!\n"); return; } /* this->size and in are sample counts, mem_size is a byte count */ if ((this->size - in) > (audio_buffer->mem_size / 2)) bytes_to_send = audio_buffer->mem_size / 2; else bytes_to_send = this->size - in; /* fill up this buffer */ for (i = 0; i < bytes_to_send; i++) audio_buffer->mem[i] = this->logtable[this->buf[in++]]; audio_buffer->num_frames = bytes_to_send / this->output_channels; audio_buffer->vpts = buf->pts; buf->pts = 0; /* only first buffer gets the real pts */ this->stream->audio_out->put_buffer (this->stream->audio_out, audio_buffer, this->stream); } /* reset internal accumulation buffer */ this->size = 0; } } static void logpcm_reset (audio_decoder_t *this_gen) { } static void logpcm_discontinuity (audio_decoder_t *this_gen) { logpcm_decoder_t *this = (logpcm_decoder_t *) this_gen; this->pts = 0; } static void logpcm_dispose (audio_decoder_t *this_gen) { logpcm_decoder_t *this = (logpcm_decoder_t *) this_gen; if (this->output_open) this->stream->audio_out->close (this->stream->audio_out, this->stream); this->output_open = 0; if (this->buf) free(this->buf); free (this_gen); } static audio_decoder_t *open_plugin (audio_decoder_class_t *class_gen, xine_stream_t *stream) { logpcm_decoder_t *this ; this = (logpcm_decoder_t *) malloc (sizeof (logpcm_decoder_t)); this->audio_decoder.decode_data = logpcm_decode_data; this->audio_decoder.reset = logpcm_reset; this->audio_decoder.discontinuity = logpcm_discontinuity; this->audio_decoder.dispose = logpcm_dispose; this->output_open = 0; this->output_channels = 0; this->stream = stream; this->buf = NULL; this->size = 0; return &this->audio_decoder; } static char *get_identifier (audio_decoder_class_t *this) { return "Log PCM"; } static char *get_description (audio_decoder_class_t *this) { return "Logarithmic PCM audio format decoder plugin"; } static void dispose_class (audio_decoder_class_t *this) { free (this); } static void *init_plugin (xine_t *xine, void *data) { logpcm_class_t *this ; this = (logpcm_class_t *) malloc (sizeof (logpcm_class_t)); this->decoder_class.open_plugin = open_plugin; this->decoder_class.get_identifier = get_identifier; this->decoder_class.get_description = get_description; this->decoder_class.dispose = dispose_class; return this; } static uint32_t audio_types[] = { BUF_AUDIO_MULAW, BUF_AUDIO_ALAW, 0 }; static decoder_info_t dec_info_audio = { audio_types, /* supported types */ 9 /* priority */ }; plugin_info_t xine_plugin_info[] = { /* type, API, "name", version, special_info, init_function */ { PLUGIN_AUDIO_DECODER, 13, "logpcm", XINE_VERSION_CODE, &dec_info_audio, &init_plugin }, { PLUGIN_NONE, 0, "", 0, NULL, NULL } };