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 <mad.h>
  10 #include <regex.h>
  11
  12 #include "para.h"
  13 #include "mp3dec_filter.cmdline.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "ggo.h"
  17 #include "filter.h"
  18 #include "error.h"
  19 #include "string.h"
  20
  21 /** Convert a sample value from libmad to a signed short. */
  22 #define MAD_TO_SHORT(f) (f) >= MAD_F_ONE? SHRT_MAX :\
  23         (f) <= -MAD_F_ONE? -SHRT_MAX : (signed short) ((f) >> (MAD_F_FRACBITS - 15))
  24
  25 /** State of the decoding process. */
  26 enum mp3dec_flags {
  27         /** Bad main_data_begin pointer encounterd. */
  28         MP3DEC_FLAG_BAD_DATA = 1,
  29         /** Some output has already been produced. */
  30         MP3DEC_FLAG_DECODE_STARTED = 2,
  31 };
  32
  33 /** Data specific to the mp3dec filter. */
  34 struct private_mp3dec_data {
  35         /** Information on the current mp3 stream. */
  36         struct mad_stream stream;
  37         /** Information about the frame which is currently decoded. */
  38         struct mad_frame frame;
  39         /** Contains the PCM output. */
  40         struct mad_synth synth;
  41         /** See \ref mp3dec_flags. */
  42         unsigned flags;
  43         /** Defer decoding until this time. */
  44         struct timeval stream_start_barrier;
  45         /** Wait until this many input bytes are available. */
  46         size_t input_len_barrier;
  47 };
  48
  49 static int need_bad_data_delay(struct private_mp3dec_data *pmd,
  50                 size_t bytes_available)
  51 {
  52         if (!(pmd->flags & MP3DEC_FLAG_BAD_DATA))
  53                 return 0;
  54         if (pmd->flags & MP3DEC_FLAG_DECODE_STARTED)
  55                 return 0;
  56         if (bytes_available >= pmd->input_len_barrier)
  57                 return 0;
  58         if (tv_diff(now, &pmd->stream_start_barrier, NULL) > 0)
  59                 return 0;
  60         return 1;
  61 }
  62
  63 /*
  64  * Returns negative on serious errors, zero if the error should be ignored and
  65  * positive on bad data pointer errors at stream start.
  66  */
  67 static int handle_decode_error(struct private_mp3dec_data *pmd, size_t len)
  68 {
  69         if (!MAD_RECOVERABLE(pmd->stream.error)
  70                         && pmd->stream.error != MAD_ERROR_BUFLEN) {
  71                 PARA_ERROR_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  72                 return -E_MAD_FRAME_DECODE;
  73         }
  74         PARA_DEBUG_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  75         if (pmd->stream.error != MAD_ERROR_BADDATAPTR)
  76                 return 0;
  77         if (pmd->flags & MP3DEC_FLAG_DECODE_STARTED)
  78                 return 0;
  79         /*
  80          * Bad data pointer at stream start. Defer decoding until the amount of
  81          * data we are about to skip is available again, but wait at most 60ms.
  82          */
  83         pmd->flags |= MP3DEC_FLAG_BAD_DATA;
  84         pmd->input_len_barrier = len;
  85         tv_add(now, &(struct timeval){0, 60 * 1000},
  86                 &pmd->stream_start_barrier);
  87         return 1;
  88 }
  89
  90 static ssize_t mp3dec(char *inbuffer, size_t len, struct filter_node *fn)
  91 {
  92         int i, ret;
  93         struct private_mp3dec_data *pmd = fn->private_data;
  94         size_t copy = PARA_MIN(len, (size_t)4096);
  95
  96         if (fn->loaded + 16384 > fn->bufsize)
  97                 return 0;
  98         if (need_bad_data_delay(pmd, len))
  99                 return 0;
 100         mad_stream_buffer(&pmd->stream, (unsigned char *) inbuffer, copy);
 101         pmd->stream.error = 0;
 102 next_frame:
 103         ret = mad_header_decode(&pmd->frame.header, &pmd->stream);
 104         if (ret < 0) {
 105                 if (pmd->stream.error != MAD_ERROR_BUFLEN &&
 106                         pmd->stream.error != MAD_ERROR_LOSTSYNC)
 107                         PARA_DEBUG_LOG("header decode: %s\n",
 108                                 mad_stream_errorstr(&pmd->stream));
 109                 goto out;
 110         }
 111         fn->fc->samplerate = pmd->frame.header.samplerate;
 112         fn->fc->channels = MAD_NCHANNELS(&pmd->frame.header);
 113         ret = mad_frame_decode(&pmd->frame, &pmd->stream);
 114         if (ret != 0) {
 115                 ret = handle_decode_error(pmd, len);
 116                 if (ret < 0)
 117                         return ret;
 118                 if (ret == 0)
 119                         goto out;
 120                 ret = copy - (pmd->stream.bufend - pmd->stream.next_frame);
 121                 PARA_NOTICE_LOG("skipping %d input bytes\n", ret);
 122                 return ret;
 123         }
 124         mad_synth_frame(&pmd->synth, &pmd->frame);
 125         pmd->flags |= MP3DEC_FLAG_DECODE_STARTED;
 126
 127         for (i = 0; i < pmd->synth.pcm.length; i++) {
 128                 int s = MAD_TO_SHORT(pmd->synth.pcm.samples[0][i]);
 129                 write_int16_host_endian(fn->buf + fn->loaded, s);
 130                 fn->loaded += 2;
 131                 if (MAD_NCHANNELS(&pmd->frame.header) == 2) { /* stereo */
 132                         s = MAD_TO_SHORT(pmd->synth.pcm.samples[1][i]);
 133                         write_int16_host_endian(fn->buf + fn->loaded, s);
 134                         fn->loaded += 2;
 135                 }
 136                 if (fn->loaded != fn->bufsize) /* output buffer not full */
 137                         continue;
 138                 PARA_ERROR_LOG("output buffer full: %zd\n", fn->loaded);
 139                         return -E_MP3DEC_OVERRUN;
 140         }
 141         if (fn->loaded + 16384 <= fn->bufsize)
 142                 goto next_frame;
 143 out:
 144         if (pmd->stream.next_frame) { /* we still have some data */
 145                 size_t off = pmd->stream.bufend - pmd->stream.next_frame;
 146                 if (fn->loaded + 16384 <= fn->bufsize && off > 2048)
 147                         goto next_frame;
 148                 return copy - off;
 149         }
 150         return copy;
 151 }
 152
 153 static void mp3dec_close(struct filter_node *fn)
 154 {
 155         struct private_mp3dec_data *pmd = fn->private_data;
 156
 157         mad_synth_finish(&pmd->synth);
 158         mad_frame_finish(&pmd->frame);
 159         mad_stream_finish(&pmd->stream);
 160
 161         free(fn->buf);
 162         fn->buf = NULL;
 163         free(pmd);
 164         fn->private_data = NULL;
 165 }
 166
 167 static void mp3dec_open(struct filter_node *fn)
 168 {
 169         struct private_mp3dec_data *pmd = para_calloc(sizeof(*pmd));
 170         struct mp3dec_filter_args_info *mp3_conf = fn->conf;
 171
 172         fn->private_data = pmd;
 173         mad_stream_init(&pmd->stream);
 174         mad_frame_init(&pmd->frame);
 175         mad_synth_init(&pmd->synth);
 176         fn->loaded = 0;
 177         fn->bufsize = mp3_conf->bufsize_arg * 1024;
 178         fn->buf = para_calloc(fn->bufsize);
 179         if (mp3_conf->ignore_crc_given)
 180                 mad_stream_options(&pmd->stream, MAD_OPTION_IGNORECRC);
 181 }
 182
 183 static int mp3dec_parse_config(int argc, char **argv, void **config)
 184 {
 185         int ret;
 186         struct mp3dec_filter_args_info *mp3_conf;
 187
 188         mp3_conf = para_calloc(sizeof(*mp3_conf));
 189         ret = -E_MP3DEC_SYNTAX;
 190         if (mp3dec_cmdline_parser(argc, argv, mp3_conf))
 191                 goto err;
 192         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 193         if (mp3_conf->bufsize_arg < 32)
 194                 goto err;
 195         if (mp3_conf->bufsize_arg >= INT_MAX / 1024)
 196                 goto err;
 197         *config = mp3_conf;
 198         return 1;
 199 err:
 200         free(mp3_conf);
 201         return ret;
 202 }
 203
 204 /**
 205  * The init function of the mp3dec filter.
 206  *
 207  * \param f Pointer to the filter struct to initialize.
 208  *
 209  * \sa filter::init.
 210  */
 211 void mp3dec_filter_init(struct filter *f)
 212 {
 213         struct mp3dec_filter_args_info dummy;
 214
 215         mp3dec_cmdline_parser_init(&dummy);
 216         f->open = mp3dec_open;
 217         f->convert = mp3dec;
 218         f->close = mp3dec_close;
 219         f->parse_config = mp3dec_parse_config;
 220         f->help = (struct ggo_help) {
 221                 .short_help = mp3dec_filter_args_info_help,
 222                 .detailed_help = mp3dec_filter_args_info_detailed_help
 223         };
 224 }