wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2009 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 "ggo.h"
  14 #include "filter.h"
  15 #include "string.h"
  16 #include "portable_io.h"
  17
  18 /** size of the output buffer */
  19 #define WAV_OUTBUF_SIZE 81920
  20 /** a wav header is always 44 bytes */
  21 #define WAV_HEADER_LEN 44
  22 /** always write 16 bit header */
  23 #define BITS 16
  24
  25 static void make_wav_header(unsigned int channels, unsigned int samplerate,
  26                 struct filter_node *fn)
  27 {
  28
  29         char *headbuf = fn->buf;
  30         unsigned int size = 0x7fffffff;
  31         int bytespersec = channels * samplerate * BITS / 8;
  32         int align = channels * BITS / 8;
  33
  34         assert(channels);
  35         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
  36         memset(headbuf, 0, WAV_HEADER_LEN);
  37         memcpy(headbuf, "RIFF", 4);
  38         write_u32(headbuf + 4, size - 8);
  39         memcpy(headbuf + 8, "WAVE", 4);
  40         memcpy(headbuf + 12, "fmt ", 4);
  41         write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
  42         write_u16(headbuf + 20, 1);     /* format (1 == PCM/uncompressed) */
  43         write_u16(headbuf + 22, channels);
  44         write_u32(headbuf + 24, samplerate);
  45         write_u32(headbuf + 28, bytespersec);
  46         write_u16(headbuf + 32, align); /* number of bytes per sample slice */
  47         write_u16(headbuf + 34, BITS); /* significant bits per sample */
  48         memcpy(headbuf + 36, "data", 4); /* chunk ID */
  49         write_u32(headbuf + 40, size - 44); /* chunk size */
  50 }
  51
  52 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)
  53 {
  54         size_t copy;
  55         int *bof = fn->private_data;
  56
  57         if (*bof) {
  58                 if (!len)
  59                         return 0;
  60                 make_wav_header(fn->fc->channels, fn->fc->samplerate, fn);
  61                 fn->loaded = WAV_HEADER_LEN;
  62                 *bof = 0;
  63 //              return 0;
  64         }
  65         copy = PARA_MIN(len, fn->bufsize - fn->loaded);
  66         memmove(fn->buf + fn->loaded, inbuf, copy);
  67         fn->loaded += copy;
  68 //      PARA_DEBUG_LOG("len = %d, copy = %d\n", len, copy);
  69         return copy;
  70 }
  71
  72 static void wav_close(struct filter_node *fn)
  73 {
  74         free(fn->buf);
  75         fn->buf = NULL;
  76         free(fn->private_data);
  77         fn->private_data = NULL;
  78 }
  79
  80 static void wav_open(struct filter_node *fn)
  81 {
  82         int *bof;
  83
  84         fn->bufsize = WAV_OUTBUF_SIZE;
  85         fn->buf = para_malloc(fn->bufsize);
  86         fn->private_data = para_malloc(sizeof(int));
  87         bof = fn->private_data;
  88         fn->loaded = 0;
  89         *bof = 1;
  90         PARA_INFO_LOG("wav filter node: %p, output buffer: %p, loaded: %zd\n",
  91                 fn, fn->buf, fn->loaded);
  92 }
  93
  94 /**
  95  * the init function of the wav filter
  96  *
  97  * \param f struct to initialize
  98  */
  99 void wav_filter_init(struct filter *f)
 100 {
 101         f->convert = wav_convert;
 102         f->close = wav_close;
 103         f->open = wav_open;
 104 }