mp3dec_filter.c

   1 /*
   2  * Copyright (C) 2005-2011 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 #include <stdbool.h>
  12
  13 #include "para.h"
  14 #include "mp3dec_filter.cmdline.h"
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "ggo.h"
  18 #include "buffer_tree.h"
  19 #include "filter.h"
  20 #include "error.h"
  21 #include "string.h"
  22
  23 /** Convert a sample value from libmad to a signed short. */
  24 #define MAD_TO_SHORT(f) (f) >= MAD_F_ONE? SHRT_MAX :\
  25         (f) <= -MAD_F_ONE? -SHRT_MAX : (signed short) ((f) >> (MAD_F_FRACBITS - 15))
  26
  27 /** State of the decoding process. */
  28 enum mp3dec_flags {
  29         /** Bad main_data_begin pointer encounterd. */
  30         MP3DEC_FLAG_BAD_DATA = 1,
  31         /** Some output has already been produced. */
  32         MP3DEC_FLAG_DECODE_STARTED = 2,
  33         MP3DEC_FLAG_NEED_MORE = 4,
  34 };
  35
  36 /** Data specific to the mp3dec filter. */
  37 struct private_mp3dec_data {
  38         /** Information on the current mp3 stream. */
  39         struct mad_stream stream;
  40         /** Information about the frame which is currently decoded. */
  41         struct mad_frame frame;
  42         /** Contains the PCM output. */
  43         struct mad_synth synth;
  44         /** See \ref mp3dec_flags. */
  45         unsigned flags;
  46         /** Defer decoding until this time. */
  47         struct timeval stream_start_barrier;
  48         /** Wait until this many input bytes are available. */
  49         size_t input_len_barrier;
  50         /** The number of channels of the current stream. */
  51         unsigned int channels;
  52         /** Current sample rate in Hz. */
  53         unsigned int sample_rate;
  54 };
  55
  56 static int need_bad_data_delay(struct private_mp3dec_data *pmd,
  57                 size_t bytes_available)
  58 {
  59         if (!(pmd->flags & MP3DEC_FLAG_BAD_DATA))
  60                 return 0;
  61         if (pmd->flags & MP3DEC_FLAG_DECODE_STARTED)
  62                 return 0;
  63         if (bytes_available >= pmd->input_len_barrier)
  64                 return 0;
  65         if (tv_diff(now, &pmd->stream_start_barrier, NULL) > 0)
  66                 return 0;
  67         return 1;
  68 }
  69
  70 /*
  71  * Returns negative on serious errors, zero if the error should be ignored and
  72  * positive on bad data pointer errors at stream start.
  73  */
  74 static int handle_decode_error(struct private_mp3dec_data *pmd, size_t len)
  75 {
  76         const struct timeval delay = {0, 60 * 1000};
  77         if (!MAD_RECOVERABLE(pmd->stream.error)
  78                         && pmd->stream.error != MAD_ERROR_BUFLEN) {
  79                 PARA_ERROR_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  80                 return -E_MAD_FRAME_DECODE;
  81         }
  82         PARA_DEBUG_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  83         if (pmd->stream.error != MAD_ERROR_BADDATAPTR)
  84                 return 0;
  85         if (pmd->flags & MP3DEC_FLAG_DECODE_STARTED)
  86                 return 0;
  87         /*
  88          * Bad data pointer at stream start. Defer decoding until the amount of
  89          * data we are about to skip is available again, but wait at most 60ms.
  90          */
  91         pmd->flags |= MP3DEC_FLAG_BAD_DATA;
  92         pmd->input_len_barrier = len;
  93         tv_add(now, &delay, &pmd->stream_start_barrier);
  94         return 1;
  95 }
  96
  97 static size_t used_mad_buffer_bytes(struct mad_stream *s, size_t max)
  98 {
  99         size_t rv;
 100
 101         if (!s->next_frame)
 102                 return max;
 103         /* we still have some data */
 104         rv = s->next_frame - s->buffer;
 105         assert(rv <= max);
 106         return rv;
 107 }
 108
 109 static void mp3dec_close(struct filter_node *fn)
 110 {
 111         struct private_mp3dec_data *pmd = fn->private_data;
 112
 113         mad_synth_finish(&pmd->synth);
 114         mad_frame_finish(&pmd->frame);
 115         mad_stream_finish(&pmd->stream);
 116
 117         free(pmd);
 118         fn->private_data = NULL;
 119 }
 120
 121 static void mp3dec_post_select(__a_unused struct sched *s, struct task *t)
 122 {
 123         struct filter_node *fn = container_of(t, struct filter_node, task);
 124         int i, ret;
 125         struct private_mp3dec_data *pmd = fn->private_data;
 126         struct btr_node *btrn = fn->btrn;
 127         size_t loaded, used, len, iqs;
 128         char *inbuffer, *outbuffer;
 129
 130 next_buffer:
 131         pmd->stream.error = 0;
 132         t->error = 0;
 133         iqs = btr_get_input_queue_size(btrn);
 134         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 135         if (ret < 0)
 136                 goto err;
 137         if (need_bad_data_delay(pmd, iqs))
 138                 return;
 139         if (ret == 0)
 140                 return;
 141         btr_merge(btrn, fn->min_iqs);
 142         len = btr_next_buffer(btrn, &inbuffer);
 143         /*
 144          * Decode at most 8K in one go to give the post_select() functions of
 145          * other buffer tree nodes a chance to run. This is necessary to avoid
 146          * buffer underruns on slow machines.
 147          */
 148         len = PARA_MIN(len, (size_t)8192);
 149         mad_stream_buffer(&pmd->stream, (unsigned char *)inbuffer, len);
 150 next_frame:
 151         ret = mad_header_decode(&pmd->frame.header, &pmd->stream);
 152         if (ret < 0) {
 153                 used = used_mad_buffer_bytes(&pmd->stream, len);
 154                 btr_consume(btrn, used);
 155                 if (pmd->stream.error == MAD_ERROR_BUFLEN) {
 156                         if (len == iqs && btr_no_parent(btrn)) {
 157                                 ret = -E_MP3DEC_EOF;
 158                                 goto err;
 159                         }
 160                         fn->min_iqs += 100;
 161                         goto next_buffer;
 162                 } else if (pmd->stream.error != MAD_ERROR_LOSTSYNC)
 163                         PARA_DEBUG_LOG("header decode: %s\n",
 164                                 mad_stream_errorstr(&pmd->stream));
 165                 goto next_buffer;
 166         }
 167         fn->min_iqs = 0;
 168         pmd->sample_rate = pmd->frame.header.samplerate;
 169         pmd->channels = MAD_NCHANNELS(&pmd->frame.header);
 170         ret = mad_frame_decode(&pmd->frame, &pmd->stream);
 171         if (ret != 0) {
 172                 PARA_INFO_LOG("frame decode: %s\n", mad_stream_errorstr(&pmd->stream));
 173                 used = used_mad_buffer_bytes(&pmd->stream, len);
 174                 ret = handle_decode_error(pmd, used);
 175                 btr_consume(btrn, used);
 176                 if (ret < 0)
 177                         goto err;
 178                 if (ret == 0)
 179                         goto next_buffer;
 180                 return;
 181         }
 182         mad_synth_frame(&pmd->synth, &pmd->frame);
 183         pmd->flags |= MP3DEC_FLAG_DECODE_STARTED;
 184
 185         outbuffer = para_malloc(pmd->synth.pcm.length * 4);
 186         loaded = 0;
 187         for (i = 0; i < pmd->synth.pcm.length; i++) {
 188                 int sample = MAD_TO_SHORT(pmd->synth.pcm.samples[0][i]);
 189                 write_int16_host_endian(outbuffer + loaded, sample);
 190                 loaded += 2;
 191                 if (MAD_NCHANNELS(&pmd->frame.header) == 2) { /* stereo */
 192                         sample = MAD_TO_SHORT(pmd->synth.pcm.samples[1][i]);
 193                         write_int16_host_endian(outbuffer + loaded, sample);
 194                         loaded += 2;
 195                 }
 196         }
 197         btr_add_output(outbuffer, loaded, btrn);
 198         goto next_frame;
 199 err:
 200         assert(ret < 0);
 201         t->error = ret;
 202         btr_remove_node(btrn);
 203 }
 204
 205 static void mp3dec_open(struct filter_node *fn)
 206 {
 207         struct private_mp3dec_data *pmd = para_calloc(sizeof(*pmd));
 208         struct mp3dec_filter_args_info *mp3_conf = fn->conf;
 209
 210         fn->private_data = pmd;
 211         mad_stream_init(&pmd->stream);
 212         mad_frame_init(&pmd->frame);
 213         mad_synth_init(&pmd->synth);
 214         if (mp3_conf->ignore_crc_given)
 215                 mad_stream_options(&pmd->stream, MAD_OPTION_IGNORECRC);
 216 }
 217
 218 static int mp3dec_parse_config(int argc, char **argv, void **config)
 219 {
 220         int ret;
 221         struct mp3dec_filter_args_info *mp3_conf;
 222
 223         mp3_conf = para_calloc(sizeof(*mp3_conf));
 224         ret = -E_MP3DEC_SYNTAX;
 225         if (mp3dec_cmdline_parser(argc, argv, mp3_conf))
 226                 goto err;
 227         *config = mp3_conf;
 228         return 1;
 229 err:
 230         free(mp3_conf);
 231         return ret;
 232 }
 233
 234 static int mp3dec_execute(struct btr_node *btrn, const char *cmd, char **result)
 235 {
 236         struct filter_node *fn = btr_context(btrn);
 237         struct private_mp3dec_data *pmd = fn->private_data;
 238
 239         return decoder_execute(cmd, pmd->sample_rate, pmd->channels, result);
 240 }
 241
 242 static void mp3dec_free_config(void *conf)
 243 {
 244         mp3dec_cmdline_parser_free(conf);
 245 }
 246 /**
 247  * The init function of the mp3dec filter.
 248  *
 249  * \param f Pointer to the filter struct to initialize.
 250  *
 251  * \sa filter::init.
 252  */
 253 void mp3dec_filter_init(struct filter *f)
 254 {
 255         struct mp3dec_filter_args_info dummy;
 256
 257         mp3dec_cmdline_parser_init(&dummy);
 258         f->open = mp3dec_open;
 259         f->close = mp3dec_close;
 260         f->parse_config = mp3dec_parse_config;
 261         f->free_config = mp3dec_free_config;
 262         f->pre_select = generic_filter_pre_select;
 263         f->post_select = mp3dec_post_select;
 264         f->execute = mp3dec_execute;
 265         f->help = (struct ggo_help) {
 266                 .short_help = mp3dec_filter_args_info_help,
 267                 .detailed_help = mp3dec_filter_args_info_detailed_help
 268         };
 269 }