mp3dec_filter.c

   1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file mp3dec_filter.c Paraslash's mp3 decoder. */
   4
   5 #include <mad.h>
   6 #include <regex.h>
   7 #include <lopsub.h>
   8
   9 #include "filter_cmd.lsg.h"
  10 #include "para.h"
  11 #include "list.h"
  12 #include "sched.h"
  13 #include "buffer_tree.h"
  14 #include "filter.h"
  15 #include "error.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         /** The number of channels of the current stream. */
  31         unsigned int channels;
  32         /** Current sample rate in Hz. */
  33         unsigned int sample_rate;
  34 };
  35
  36 /* Returns negative on serious errors. */
  37 static int handle_decode_error(struct private_mp3dec_data *pmd)
  38 {
  39         if (!MAD_RECOVERABLE(pmd->stream.error)
  40                         && pmd->stream.error != MAD_ERROR_BUFLEN) {
  41                 PARA_ERROR_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  42                 return -E_MAD_FRAME_DECODE;
  43         }
  44         PARA_DEBUG_LOG("%s\n", mad_stream_errorstr(&pmd->stream));
  45         return 0;
  46 }
  47
  48 static void mp3dec_consume(struct btr_node *btrn, struct mad_stream *s,
  49                 size_t max)
  50 {
  51         size_t used;
  52
  53         if (!s->next_frame)
  54                 used = max;
  55         else { /* we still have some data */
  56                 used = s->next_frame - s->buffer;
  57                 assert(used <= max);
  58         }
  59         btr_consume(btrn, used);
  60 }
  61
  62 static void mp3dec_close(struct filter_node *fn)
  63 {
  64         struct private_mp3dec_data *pmd = fn->private_data;
  65
  66         mad_synth_finish(&pmd->synth);
  67         mad_frame_finish(&pmd->frame);
  68         mad_stream_finish(&pmd->stream);
  69
  70         free(pmd);
  71         fn->private_data = NULL;
  72 }
  73
  74 #define MP3DEC_MAX_FRAME 8192
  75
  76 static int mp3dec_post_select(__a_unused struct sched *s, void *context)
  77 {
  78         struct filter_node *fn = context;
  79         int i, ret;
  80         struct private_mp3dec_data *pmd = fn->private_data;
  81         struct btr_node *btrn = fn->btrn;
  82         size_t loaded = 0, len, iqs;
  83         char *inbuffer, *outbuffer;
  84
  85 next_buffer:
  86         pmd->stream.error = 0;
  87         iqs = btr_get_input_queue_size(btrn);
  88         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
  89         if (ret < 0)
  90                 goto err;
  91         if (ret == 0)
  92                 return 0;
  93         btr_merge(btrn, fn->min_iqs);
  94         len = btr_next_buffer(btrn, &inbuffer);
  95         /*
  96          * Decode at most 8K in one go to give the post_select() functions of
  97          * other buffer tree nodes a chance to run. This is necessary to avoid
  98          * buffer underruns on slow machines.
  99          */
 100         len = PARA_MIN(len, (size_t)MP3DEC_MAX_FRAME);
 101         mad_stream_buffer(&pmd->stream, (unsigned char *)inbuffer, len);
 102 next_frame:
 103         ret = mad_header_decode(&pmd->frame.header, &pmd->stream);
 104         if (ret < 0) {
 105                 mp3dec_consume(btrn, &pmd->stream, len);
 106                 if (pmd->stream.error == MAD_ERROR_BUFLEN) {
 107                         if (len == iqs && btr_no_parent(btrn)) {
 108                                 ret = -E_MP3DEC_EOF;
 109                                 goto err;
 110                         }
 111                         fn->min_iqs += 100;
 112                         ret = -E_MP3DEC_CORRUPT;
 113                         if (fn->min_iqs > MP3DEC_MAX_FRAME)
 114                                 goto err;
 115                 }
 116                 if (loaded == 0)
 117                         goto next_buffer;
 118                 return 0;
 119         }
 120         pmd->sample_rate = pmd->frame.header.samplerate;
 121         pmd->channels = MAD_NCHANNELS(&pmd->frame.header);
 122 decode:
 123         ret = mad_frame_decode(&pmd->frame, &pmd->stream);
 124         if (ret != 0) {
 125                 ret = handle_decode_error(pmd);
 126                 if (ret < 0)
 127                         goto err;
 128                 mad_stream_sync(&pmd->stream);
 129                 if (pmd->stream.error == MAD_ERROR_BUFLEN) {
 130                         ret = -E_MP3DEC_EOF;
 131                         if (len == iqs && btr_no_parent(btrn))
 132                                 goto err;
 133                         fn->min_iqs += 100;
 134                         ret = -E_MP3DEC_CORRUPT;
 135                         if (fn->min_iqs > MP3DEC_MAX_FRAME)
 136                                 goto err;
 137                         mp3dec_consume(btrn, &pmd->stream, len);
 138                         return 0;
 139                 }
 140                 if (pmd->stream.error != MAD_ERROR_BADDATAPTR)
 141                         goto decode;
 142                 mp3dec_consume(btrn, &pmd->stream, len);
 143                 return 0;
 144         }
 145         fn->min_iqs = 0;
 146         mad_synth_frame(&pmd->synth, &pmd->frame);
 147         outbuffer = para_malloc(pmd->synth.pcm.length * 2 * pmd->channels);
 148         loaded = 0;
 149         for (i = 0; i < pmd->synth.pcm.length; i++) {
 150                 int sample = MAD_TO_SHORT(pmd->synth.pcm.samples[0][i]);
 151                 write_int16_host_endian(outbuffer + loaded, sample);
 152                 loaded += 2;
 153                 if (pmd->channels == 2) { /* stereo */
 154                         sample = MAD_TO_SHORT(pmd->synth.pcm.samples[1][i]);
 155                         write_int16_host_endian(outbuffer + loaded, sample);
 156                         loaded += 2;
 157                 }
 158         }
 159         btr_add_output(outbuffer, loaded, btrn);
 160         goto next_frame;
 161 err:
 162         assert(ret < 0);
 163         btr_remove_node(&fn->btrn);
 164         return ret;
 165 }
 166
 167 static void mp3dec_open(struct filter_node *fn)
 168 {
 169         struct private_mp3dec_data *pmd = para_calloc(sizeof(*pmd));
 170
 171         fn->private_data = pmd;
 172         mad_stream_init(&pmd->stream);
 173         mad_frame_init(&pmd->frame);
 174         mad_synth_init(&pmd->synth);
 175         if (FILTER_CMD_OPT_GIVEN(MP3DEC, IGNORE_CRC, fn->lpr))
 176                 mad_stream_options(&pmd->stream, MAD_OPTION_IGNORECRC);
 177 }
 178
 179 static int mp3dec_execute(struct btr_node *btrn, const char *cmd, char **result)
 180 {
 181         struct filter_node *fn = btr_context(btrn);
 182         struct private_mp3dec_data *pmd = fn->private_data;
 183
 184         return decoder_execute(cmd, pmd->sample_rate, pmd->channels, result);
 185 }
 186
 187 const struct filter lsg_filter_cmd_com_mp3dec_user_data = {
 188         .open = mp3dec_open,
 189         .close = mp3dec_close,
 190         .pre_select = generic_filter_pre_select,
 191         .post_select = mp3dec_post_select,
 192         .execute = mp3dec_execute,
 193 };