mp3dec_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 mp3dec_filter.c Paraslash's mp3 decoder. */
   8
   9 #include "para.h"
  10 #include "mp3dec_filter.cmdline.h"
  11 #include "list.h"
  12 #include "sched.h"
  13 #include "filter.h"
  14 #include "error.h"
  15 #include <mad.h>
  16 #include "string.h"
  17
  18 /** Convert a sample value from libmad to a signed short. */
  19 #define MAD_TO_SHORT(f) (f) >= MAD_F_ONE? SHRT_MAX :\
  20         (f) <= -MAD_F_ONE? -SHRT_MAX : (signed short) ((f) >> (MAD_F_FRACBITS - 15))
  21
  22 /** Data specific to the mp3dec filter. */
  23 struct private_mp3dec_data {
  24         /** Information on the current mp3 stream. */
  25         struct mad_stream stream;
  26         /** Information about the frame which is currently decoded. */
  27         struct mad_frame frame;
  28         /** Contains the PCM output. */
  29         struct mad_synth synth;
  30 };
  31
  32 static ssize_t mp3dec(char *inbuffer, size_t len, struct filter_node *fn)
  33 {
  34         int i, ret;
  35         struct private_mp3dec_data *pmd = fn->private_data;
  36         size_t copy = PARA_MIN(len, 4096);
  37
  38         if (fn->loaded > fn->bufsize * 4 / 5)
  39                 return 0;
  40         mad_stream_buffer(&pmd->stream, (unsigned char *) inbuffer, copy);
  41         pmd->stream.error = 0;
  42 next_frame:
  43         ret = mad_header_decode(&pmd->frame.header, &pmd->stream);
  44         if (ret < 0) {
  45                 if (pmd->stream.error != MAD_ERROR_BUFLEN &&
  46                         pmd->stream.error != MAD_ERROR_LOSTSYNC)
  47                         PARA_DEBUG_LOG("header decode: %s\n",
  48                                 mad_stream_errorstr(&pmd->stream));
  49                 goto out;
  50         }
  51         fn->fc->samplerate = pmd->frame.header.samplerate;
  52         fn->fc->channels = MAD_NCHANNELS(&pmd->frame.header);
  53         ret = mad_frame_decode(&pmd->frame, &pmd->stream);
  54         if (ret) {
  55                 if (MAD_RECOVERABLE(pmd->stream.error) ||
  56                         pmd->stream.error == MAD_ERROR_BUFLEN) {
  57                         PARA_DEBUG_LOG("frame decode: %s\n",
  58                                 mad_stream_errorstr(&pmd->stream));
  59                         goto out;
  60                 }
  61                 PARA_ERROR_LOG("frame decode: %s\n",
  62                         mad_stream_errorstr(&pmd->stream));
  63                 return -E_MAD_FRAME_DECODE;
  64         }
  65         mad_synth_frame(&pmd->synth, &pmd->frame);
  66
  67         for (i = 0; i < pmd->synth.pcm.length; i++) {
  68                 int s = MAD_TO_SHORT(pmd->synth.pcm.samples[0][i]);
  69                 write_int16_host_endian(fn->buf + fn->loaded, s);
  70                 fn->loaded += 2;
  71                 if (MAD_NCHANNELS(&pmd->frame.header) == 2) { /* stereo */
  72                         s = MAD_TO_SHORT(pmd->synth.pcm.samples[1][i]);
  73                         write_int16_host_endian(fn->buf + fn->loaded, s);
  74                         fn->loaded += 2;
  75                 }
  76                 if (fn->loaded != fn->bufsize) /* output buffer not full */
  77                         continue;
  78                 PARA_ERROR_LOG("output buffer full: %zd\n", fn->loaded);
  79                         return -E_MP3DEC_OVERRUN;
  80         }
  81         if (fn->loaded <= fn->bufsize * 4 / 5)
  82                 goto next_frame;
  83 out:
  84         if (pmd->stream.next_frame) { /* we still have some data */
  85                 size_t off = pmd->stream.bufend - pmd->stream.next_frame;
  86 //              PARA_INFO_LOG("off: %zd, rate: %u, returning %zd\n", off,
  87 //                      fn->fc->samplerate, copy - off);
  88                 return copy - off;
  89         }
  90         return copy;
  91 }
  92
  93 static void mp3dec_close(struct filter_node *fn)
  94 {
  95         struct private_mp3dec_data *pmd = fn->private_data;
  96
  97         mad_synth_finish(&pmd->synth);
  98         mad_frame_finish(&pmd->frame);
  99         mad_stream_finish(&pmd->stream);
 100
 101         free(fn->buf);
 102         fn->buf = NULL;
 103         free(pmd);
 104         fn->private_data = NULL;
 105 }
 106
 107 static void mp3dec_open(struct filter_node *fn)
 108 {
 109         struct private_mp3dec_data *pmd = para_calloc(sizeof(*pmd));
 110         struct mp3dec_filter_args_info *mp3_conf = fn->conf;
 111
 112         fn->private_data = pmd;
 113         mad_stream_init(&pmd->stream);
 114         mad_frame_init(&pmd->frame);
 115         mad_synth_init(&pmd->synth);
 116         fn->loaded = 0;
 117         fn->bufsize = mp3_conf->bufsize_arg * 1024;
 118         fn->buf = para_calloc(fn->bufsize);
 119         if (mp3_conf->ignore_crc_given)
 120                 mad_stream_options(&pmd->stream, MAD_OPTION_IGNORECRC);
 121 }
 122
 123 static int mp3dec_parse_config(int argc, char **argv, void **config)
 124 {
 125         int ret;
 126         struct mp3dec_filter_args_info *mp3_conf;
 127
 128         mp3_conf = para_calloc(sizeof(*mp3_conf));
 129         ret = -E_MP3DEC_SYNTAX;
 130         if (mp3dec_cmdline_parser(argc, argv, mp3_conf))
 131                 goto err;
 132         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 133         if (mp3_conf->bufsize_arg < 32)
 134                 goto err;
 135         if (mp3_conf->bufsize_arg >= INT_MAX / 1024)
 136                 goto err;
 137         *config = mp3_conf;
 138         return 1;
 139 err:
 140         free(mp3_conf);
 141         return ret;
 142 }
 143
 144 /**
 145  * The init function of the mp3dec filter.
 146  *
 147  * \param f Pointer to the filter struct to initialize.
 148  *
 149  * \sa filter::init.
 150  */
 151 void mp3dec_filter_init(struct filter *f)
 152 {
 153         f->open = mp3dec_open;
 154         f->convert = mp3dec;
 155         f->close = mp3dec_close;
 156         f->parse_config = mp3dec_parse_config;
 157 }