mp3dec_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 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 "ggo.h"
  14 #include "filter.h"
  15 #include "error.h"
  16 #include <mad.h>
  17 #include "string.h"
  18
  19 /** Convert a sample value from libmad to a signed short. */
  20 #define MAD_TO_SHORT(f) (f) >= MAD_F_ONE? SHRT_MAX :\
  21         (f) <= -MAD_F_ONE? -SHRT_MAX : (signed short) ((f) >> (MAD_F_FRACBITS - 15))
  22
  23 /** Data specific to the mp3dec filter. */
  24 struct private_mp3dec_data {
  25         /** Information on the current mp3 stream. */
  26         struct mad_stream stream;
  27         /** Information about the frame which is currently decoded. */
  28         struct mad_frame frame;
  29         /** Contains the PCM output. */
  30         struct mad_synth synth;
  31 };
  32
  33 static ssize_t mp3dec(char *inbuffer, size_t len, struct filter_node *fn)
  34 {
  35         int i, ret;
  36         struct private_mp3dec_data *pmd = fn->private_data;
  37         size_t copy = PARA_MIN(len, (size_t)4096);
  38
  39         if (fn->loaded + 16384 > fn->bufsize)
  40                 return 0;
  41         mad_stream_buffer(&pmd->stream, (unsigned char *) inbuffer, copy);
  42         pmd->stream.error = 0;
  43 next_frame:
  44         ret = mad_header_decode(&pmd->frame.header, &pmd->stream);
  45         if (ret < 0) {
  46                 if (pmd->stream.error != MAD_ERROR_BUFLEN &&
  47                         pmd->stream.error != MAD_ERROR_LOSTSYNC)
  48                         PARA_DEBUG_LOG("header decode: %s\n",
  49                                 mad_stream_errorstr(&pmd->stream));
  50                 goto out;
  51         }
  52         fn->fc->samplerate = pmd->frame.header.samplerate;
  53         fn->fc->channels = MAD_NCHANNELS(&pmd->frame.header);
  54         ret = mad_frame_decode(&pmd->frame, &pmd->stream);
  55         if (ret) {
  56                 if (MAD_RECOVERABLE(pmd->stream.error) ||
  57                         pmd->stream.error == MAD_ERROR_BUFLEN) {
  58                         PARA_DEBUG_LOG("frame decode: %s\n",
  59                                 mad_stream_errorstr(&pmd->stream));
  60                         goto out;
  61                 }
  62                 PARA_ERROR_LOG("frame decode: %s\n",
  63                         mad_stream_errorstr(&pmd->stream));
  64                 return -E_MAD_FRAME_DECODE;
  65         }
  66         mad_synth_frame(&pmd->synth, &pmd->frame);
  67
  68         for (i = 0; i < pmd->synth.pcm.length; i++) {
  69                 int s = MAD_TO_SHORT(pmd->synth.pcm.samples[0][i]);
  70                 write_int16_host_endian(fn->buf + fn->loaded, s);
  71                 fn->loaded += 2;
  72                 if (MAD_NCHANNELS(&pmd->frame.header) == 2) { /* stereo */
  73                         s = MAD_TO_SHORT(pmd->synth.pcm.samples[1][i]);
  74                         write_int16_host_endian(fn->buf + fn->loaded, s);
  75                         fn->loaded += 2;
  76                 }
  77                 if (fn->loaded != fn->bufsize) /* output buffer not full */
  78                         continue;
  79                 PARA_ERROR_LOG("output buffer full: %zd\n", fn->loaded);
  80                         return -E_MP3DEC_OVERRUN;
  81         }
  82         if (fn->loaded + 16384 <= fn->bufsize)
  83                 goto next_frame;
  84 out:
  85         if (pmd->stream.next_frame) { /* we still have some data */
  86                 size_t off = pmd->stream.bufend - pmd->stream.next_frame;
  87                 if (fn->loaded + 16384 <= fn->bufsize && off > 2048)
  88                         goto next_frame;
  89                 return copy - off;
  90         }
  91         return copy;
  92 }
  93
  94 static void mp3dec_close(struct filter_node *fn)
  95 {
  96         struct private_mp3dec_data *pmd = fn->private_data;
  97
  98         mad_synth_finish(&pmd->synth);
  99         mad_frame_finish(&pmd->frame);
 100         mad_stream_finish(&pmd->stream);
 101
 102         free(fn->buf);
 103         fn->buf = NULL;
 104         free(pmd);
 105         fn->private_data = NULL;
 106 }
 107
 108 static void mp3dec_open(struct filter_node *fn)
 109 {
 110         struct private_mp3dec_data *pmd = para_calloc(sizeof(*pmd));
 111         struct mp3dec_filter_args_info *mp3_conf = fn->conf;
 112
 113         fn->private_data = pmd;
 114         mad_stream_init(&pmd->stream);
 115         mad_frame_init(&pmd->frame);
 116         mad_synth_init(&pmd->synth);
 117         fn->loaded = 0;
 118         fn->bufsize = mp3_conf->bufsize_arg * 1024;
 119         fn->buf = para_calloc(fn->bufsize);
 120         if (mp3_conf->ignore_crc_given)
 121                 mad_stream_options(&pmd->stream, MAD_OPTION_IGNORECRC);
 122 }
 123
 124 static int mp3dec_parse_config(int argc, char **argv, void **config)
 125 {
 126         int ret;
 127         struct mp3dec_filter_args_info *mp3_conf;
 128
 129         mp3_conf = para_calloc(sizeof(*mp3_conf));
 130         ret = -E_MP3DEC_SYNTAX;
 131         if (mp3dec_cmdline_parser(argc, argv, mp3_conf))
 132                 goto err;
 133         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 134         if (mp3_conf->bufsize_arg < 32)
 135                 goto err;
 136         if (mp3_conf->bufsize_arg >= INT_MAX / 1024)
 137                 goto err;
 138         *config = mp3_conf;
 139         return 1;
 140 err:
 141         free(mp3_conf);
 142         return ret;
 143 }
 144
 145 /**
 146  * The init function of the mp3dec filter.
 147  *
 148  * \param f Pointer to the filter struct to initialize.
 149  *
 150  * \sa filter::init.
 151  */
 152 void mp3dec_filter_init(struct filter *f)
 153 {
 154         struct mp3dec_filter_args_info dummy;
 155
 156         mp3dec_cmdline_parser_init(&dummy);
 157         f->open = mp3dec_open;
 158         f->convert = mp3dec;
 159         f->close = mp3dec_close;
 160         f->parse_config = mp3dec_parse_config;
 161         f->help = (struct ggo_help) {
 162                 .short_help = mp3dec_filter_args_info_help,
 163                 .detailed_help = mp3dec_filter_args_info_detailed_help
 164         };
 165 }