wav.c

   1 /*
   2  * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file wav.c a filter that inserts a wave header */
  20
  21 #include "para.h"
  22
  23 #include "list.h"
  24 #include "sched.h"
  25 #include "filter.h"
  26 #include "string.h"
  27
  28 /** size of the output buffer */
  29 #define WAV_OUTBUF_SIZE 81920
  30 /** a wav header is always 44 bytes */
  31 #define WAV_HEADER_LEN 44
  32 /** always write 16 bit header */
  33 #define BITS 16
  34
  35 /**
  36  * write a 32 bit unsigned value to a buffer
  37  *
  38  * \param buf the buffer to write to
  39  * \param x the value to write
  40  */
  41 #define WRITE_U32(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);\
  42         (buf)[1] = (unsigned char)(((x) >> 8) & 0xff);\
  43         (buf)[2] = (unsigned char)(((x) >> 16) & 0xff);\
  44         (buf)[3] = (unsigned char)(((x) >> 24) & 0xff);
  45
  46 /**
  47  * write a 16 bit unsigned value to a buffer
  48  *
  49  * \param buf the buffer to write to
  50  * \param x the value to write
  51  */
  52 #define WRITE_U16(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);
  53
  54 static void make_wav_header(int channels, int samplerate, struct filter_node *fn)
  55 {
  56
  57         char *headbuf = fn->buf;
  58         unsigned int size = 0x7fffffff;
  59         int bytespersec = channels * samplerate * BITS / 8;
  60         int align = channels * BITS / 8;
  61
  62         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  63         memset(headbuf, 0, WAV_HEADER_LEN);
  64         memcpy(headbuf, "RIFF", 4);
  65         WRITE_U32(headbuf + 4, size - 8);
  66         memcpy(headbuf + 8, "WAVE", 4);
  67         memcpy(headbuf + 12, "fmt ", 4);
  68         WRITE_U32(headbuf + 16, 16);
  69         WRITE_U16(headbuf + 20, 1);     /* format */
  70         WRITE_U16(headbuf + 22, channels);
  71         WRITE_U32(headbuf + 24, samplerate);
  72         WRITE_U32(headbuf + 28, bytespersec);
  73         WRITE_U16(headbuf + 32, align);
  74         WRITE_U16(headbuf + 34, BITS);
  75         memcpy(headbuf + 36, "data", 4);
  76         WRITE_U32(headbuf + 40, size - 44);
  77 }
  78
  79 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  80 {
  81         size_t copy;
  82         int *bof = fn->private_data;
  83
  84         if (*bof) {
  85                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  86                 fn->loaded = WAV_HEADER_LEN;
  87                 *bof = 0;
  88 //              return 0;
  89         }
  90         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  91         memmove(fn->buf + fn->loaded, inbuf, copy);
  92         fn->loaded += copy;
  93 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  94         return copy;
  95 }
  96
  97 static void wav_close(struct filter_node *fn)
  98 {
  99         free(fn->buf);
 100         fn->buf = NULL;
 101         free(fn->private_data);
 102         fn->private_data = NULL;
 103 }
 104
 105 static void wav_open(struct filter_node *fn)
 106 {
 107         int *bof;
 108
 109         fn->bufsize = WAV_OUTBUF_SIZE;
 110         fn->buf = para_malloc(fn->bufsize);
 111         fn->private_data = para_malloc(sizeof(int));
 112         bof = fn->private_data;
 113         *bof = 1;
 114         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
 115                 fn, fn->buf, fn->loaded);
 116 }
 117
 118 /**
 119  * the init function of the wav filter
 120  *
 121  * \param f struct to initialize
 122  */
 123 void wav_init(struct filter *f)
 124 {
 125         f->convert = wav_convert;
 126         f->close = wav_close;
 127         f->open = wav_open;
 128 }