wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file wav_filter.c A filter that inserts a wave header. */
   8
   9 #include "para.h"
  10
  11 #include "list.h"
  12 #include "sched.h"
  13 #include "filter.h"
  14 #include "string.h"
  15
  16 /** size of the output buffer */
  17 #define WAV_OUTBUF_SIZE 81920
  18 /** a wav header is always 44 bytes */
  19 #define WAV_HEADER_LEN 44
  20 /** always write 16 bit header */
  21 #define BITS 16
  22
  23 /**
  24  * write a 32 bit unsigned value to a buffer
  25  *
  26  * \param buf the buffer to write to
  27  * \param x the value to write
  28  */
  29 #define WRITE_U32(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);\
  30         (buf)[1] = (unsigned char)(((x) >> 8) & 0xff);\
  31         (buf)[2] = (unsigned char)(((x) >> 16) & 0xff);\
  32         (buf)[3] = (unsigned char)(((x) >> 24) & 0xff);
  33
  34 /**
  35  * write a 16 bit unsigned value to a buffer
  36  *
  37  * \param buf the buffer to write to
  38  * \param x the value to write
  39  */
  40 #define WRITE_U16(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);
  41
  42 static void make_wav_header(unsigned int channels, unsigned int samplerate,
  43                 struct filter_node *fn)
  44 {
  45
  46         char *headbuf = fn->buf;
  47         unsigned int size = 0x7fffffff;
  48         int bytespersec = channels * samplerate * BITS / 8;
  49         int align = channels * BITS / 8;
  50
  51         assert(channels);
  52         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  53         memset(headbuf, 0, WAV_HEADER_LEN);
  54         memcpy(headbuf, "RIFF", 4);
  55         WRITE_U32(headbuf + 4, size - 8);
  56         memcpy(headbuf + 8, "WAVE", 4);
  57         memcpy(headbuf + 12, "fmt ", 4);
  58         WRITE_U32(headbuf + 16, 16);
  59         WRITE_U16(headbuf + 20, 1);     /* format */
  60         WRITE_U16(headbuf + 22, channels);
  61         WRITE_U32(headbuf + 24, samplerate);
  62         WRITE_U32(headbuf + 28, bytespersec);
  63         WRITE_U16(headbuf + 32, align);
  64         WRITE_U16(headbuf + 34, BITS);
  65         memcpy(headbuf + 36, "data", 4);
  66         WRITE_U32(headbuf + 40, size - 44);
  67 }
  68
  69 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  70 {
  71         size_t copy;
  72         int *bof = fn->private_data;
  73
  74         if (*bof) {
  75                 if (!len)
  76                         return 0;
  77                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  78                 fn->loaded = WAV_HEADER_LEN;
  79                 *bof = 0;
  80 //              return 0;
  81         }
  82         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  83         memmove(fn->buf + fn->loaded, inbuf, copy);
  84         fn->loaded += copy;
  85 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  86         return copy;
  87 }
  88
  89 static void wav_close(struct filter_node *fn)
  90 {
  91         free(fn->buf);
  92         fn->buf = NULL;
  93         free(fn->private_data);
  94         fn->private_data = NULL;
  95 }
  96
  97 static void wav_open(struct filter_node *fn)
  98 {
  99         int *bof;
 100
 101         fn->bufsize = WAV_OUTBUF_SIZE;
 102         fn->buf = para_malloc(fn->bufsize);
 103         fn->private_data = para_malloc(sizeof(int));
 104         bof = fn->private_data;
 105         fn->loaded = 0;
 106         *bof = 1;
 107         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
 108                 fn, fn->buf, fn->loaded);
 109 }
 110
 111 /**
 112  * the init function of the wav filter
 113  *
 114  * \param f struct to initialize
 115  */
 116 void wav_filter_init(struct filter *f)
 117 {
 118         f->convert = wav_convert;
 119         f->close = wav_close;
 120         f->open = wav_open;
 121 }