wav.c

   1 /*
   2  * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file wav.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         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  52         memset(headbuf, 0, WAV_HEADER_LEN);
  53         memcpy(headbuf, "RIFF", 4);
  54         WRITE_U32(headbuf + 4, size - 8);
  55         memcpy(headbuf + 8, "WAVE", 4);
  56         memcpy(headbuf + 12, "fmt ", 4);
  57         WRITE_U32(headbuf + 16, 16);
  58         WRITE_U16(headbuf + 20, 1);     /* format */
  59         WRITE_U16(headbuf + 22, channels);
  60         WRITE_U32(headbuf + 24, samplerate);
  61         WRITE_U32(headbuf + 28, bytespersec);
  62         WRITE_U16(headbuf + 32, align);
  63         WRITE_U16(headbuf + 34, BITS);
  64         memcpy(headbuf + 36, "data", 4);
  65         WRITE_U32(headbuf + 40, size - 44);
  66 }
  67
  68 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  69 {
  70         size_t copy;
  71         int *bof = fn->private_data;
  72
  73         if (*bof) {
  74                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  75                 fn->loaded = WAV_HEADER_LEN;
  76                 *bof = 0;
  77 //              return 0;
  78         }
  79         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  80         memmove(fn->buf + fn->loaded, inbuf, copy);
  81         fn->loaded += copy;
  82 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  83         return copy;
  84 }
  85
  86 static void wav_close(struct filter_node *fn)
  87 {
  88         free(fn->buf);
  89         fn->buf = NULL;
  90         free(fn->private_data);
  91         fn->private_data = NULL;
  92 }
  93
  94 static void wav_open(struct filter_node *fn)
  95 {
  96         int *bof;
  97
  98         fn->bufsize = WAV_OUTBUF_SIZE;
  99         fn->buf = para_malloc(fn->bufsize);
 100         fn->private_data = para_malloc(sizeof(int));
 101         bof = fn->private_data;
 102         *bof = 1;
 103         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
 104                 fn, fn->buf, fn->loaded);
 105 }
 106
 107 /**
 108  * the init function of the wav filter
 109  *
 110  * \param f struct to initialize
 111  */
 112 void wav_init(struct filter *f)
 113 {
 114         f->convert = wav_convert;
 115         f->close = wav_close;
 116         f->open = wav_open;
 117 }