flacdec_filter.c

   1 /*
   2  * Copyright (C) 2011-2013 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file flacdec_filter.c The flac decoder. */
   8
   9 #include <regex.h>
  10 #include <FLAC/stream_decoder.h>
  11
  12 #include "para.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "ggo.h"
  16 #include "buffer_tree.h"
  17 #include "filter.h"
  18 #include "error.h"
  19 #include "string.h"
  20
  21 struct private_flacdec_data {
  22         FLAC__StreamDecoder *decoder;
  23         bool have_more;
  24         /*
  25          * We can not consume directly what was copied by the read callback
  26          * because we might need to feed unconsumend bytes to the decoder again
  27          * after the read callback ran out of data and returned ABORT. So we
  28          * track how many bytes have been fed to libflac but are unconsumed so far.
  29          */
  30         size_t unconsumed;
  31 };
  32
  33 static FLAC__StreamDecoderReadStatus read_cb(
  34                 __a_unused const FLAC__StreamDecoder *decoder,
  35                 FLAC__byte buffer[], size_t *bytes, void *client_data)
  36 {
  37         struct filter_node *fn = client_data;
  38         struct private_flacdec_data *pfd = fn->private_data;
  39         struct btr_node *btrn = fn->btrn;
  40         char *btr_buf;
  41         size_t copy, want = *bytes, have;
  42         int ns;
  43
  44         *bytes = 0;
  45         assert(want > 0);
  46         ns = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
  47         if (ns < 0)
  48                 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
  49         for (;;) {
  50                 have = btr_next_buffer_omit(btrn, pfd->unconsumed, &btr_buf);
  51                 if (have == 0)
  52                         break;
  53                 copy = PARA_MIN(want, have);
  54                 //PARA_CRIT_LOG("want: %zu, have: %zu, unconsumed %zu\n",
  55                 //      want, have, pfd->unconsumed);
  56                 memcpy(buffer, btr_buf, copy);
  57                 pfd->unconsumed += copy;
  58                 *bytes += copy;
  59                 buffer += copy;
  60                 want -= copy;
  61                 if (want == 0)
  62                         break;
  63         }
  64         if (*bytes > 0)
  65                 return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
  66         /**
  67         * Nothing was copied. If the input queue of the btrn is smaller than
  68         * the minimal input queue size, our parent must have been gone, so
  69         * we're not going to get more input. Since our remaining data is not
  70         * sufficient do decode a single frame, we have an EOF condition.
  71         */
  72         if (btr_get_input_queue_size(btrn) < fn->min_iqs) {
  73                 assert(btr_no_parent(btrn));
  74                 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
  75         }
  76         /*
  77          * We are kind of screwed here. Returning CONTINUE with a byte count of
  78          * zero leads to an endless loop, so we must return either EOF or
  79          * ABORT. Unfortunately, both options require to flush the decoder
  80          * afterwards because libFLAC refuses to resume decoding if the decoder
  81          * is in EOF or ABORT state. But flushing implies dropping the decoder
  82          * input queue, so buffered data is lost.
  83          *
  84          * We work around this shortcoming by remembering the number of
  85          * unconsumed bytes in pfd->unconsumed. In the write/meta callbacks,
  86          * this number is decreased whenever a frame has been decoded
  87          * successfully and btr_consume() has been called to consume the bytes
  88          * corresponding to the decoded frame.  After returning ABORT here, the
  89          * decoder can be flushed, and we will feed the unconsumed bytes again.
  90          */
  91         return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
  92 }
  93
  94 /*
  95  * The exact value does not really matter. It just has to be larger than the
  96  * size of the input buffer of the bitstream reader of libflac.
  97  */
  98 #define TELL_CB_DUMMY_VAL 1000000
  99
 100 /*
 101  * FLAC__stream_decoder_get_decode_position() invokes this callback. The flac
 102  * library then gets the number of unconsumed bytes from the bitstream reader,
 103  * subtracts this number from the offset returned here and returns the
 104  * difference as the decode position.
 105  */
 106 static FLAC__StreamDecoderTellStatus tell_cb(__a_unused const FLAC__StreamDecoder *decoder,
 107                 FLAC__uint64 *absolute_byte_offset, __a_unused void *client_data)
 108 {
 109         *absolute_byte_offset = TELL_CB_DUMMY_VAL;
 110         return FLAC__STREAM_DECODER_TELL_STATUS_OK;
 111 }
 112
 113 /*
 114  * There is no API function that returns the number of unconsumed bytes
 115  * directly. The trick is to define a tell callback which always returns a
 116  * fixed dummy value and compute the number of unconsumed bytes from the return
 117  * value of FLAC__stream_decoder_get_decode_position().
 118  */
 119 static void flac_consume(struct filter_node *fn)
 120 {
 121         struct private_flacdec_data *pfd = fn->private_data;
 122         struct btr_node *btrn = fn->btrn;
 123         FLAC__uint64 x;
 124
 125         FLAC__stream_decoder_get_decode_position(pfd->decoder, &x);
 126         assert(x <= TELL_CB_DUMMY_VAL);
 127         x = TELL_CB_DUMMY_VAL - x; /* number of unconsumed bytes */
 128         assert(x <= pfd->unconsumed);
 129         btr_consume(btrn, pfd->unconsumed - x);
 130         pfd->unconsumed = x;
 131 }
 132
 133 static FLAC__StreamDecoderWriteStatus write_cb(
 134                 const FLAC__StreamDecoder *decoder,
 135                 const FLAC__Frame *frame,
 136                 const FLAC__int32 *const buffer[],
 137                 void *client_data)
 138 {
 139         struct filter_node *fn = client_data;
 140         struct btr_node *btrn = fn->btrn;
 141         size_t k, n = frame->header.blocksize;
 142         unsigned channels = FLAC__stream_decoder_get_channels(decoder);
 143         char *outbuffer = para_malloc(n * channels * 2);
 144
 145         if (channels == 1) {
 146                 for (k = 0; k < n; k++) {
 147                         int sample = buffer[0][k];
 148                         write_int16_host_endian(outbuffer + 2 * k, sample);
 149                 }
 150         } else {
 151                 for (k = 0; k < n; k++) {
 152                         int left = buffer[0][k], right = buffer[1][k];
 153                         write_int16_host_endian(outbuffer + 4 * k, left);
 154                         write_int16_host_endian(outbuffer + 4 * k + 2, right);
 155                 }
 156         }
 157         btr_add_output(outbuffer, n * channels * 2, btrn);
 158         flac_consume(fn);
 159         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 160 }
 161
 162 static void meta_cb (__a_unused const FLAC__StreamDecoder *decoder,
 163                 __a_unused const FLAC__StreamMetadata *metadata,
 164                 void *client_data)
 165 {
 166         flac_consume(client_data);
 167 }
 168
 169 static void error_cb( __a_unused const FLAC__StreamDecoder *decoder,
 170                 FLAC__StreamDecoderErrorStatus status,
 171                 __a_unused void *client_data)
 172 {
 173         PARA_ERROR_LOG("%s\n", FLAC__StreamDecoderErrorStatusString[status]);
 174 }
 175
 176 static int flacdec_init(struct filter_node *fn)
 177 {
 178         struct private_flacdec_data *pfd = fn->private_data;
 179         FLAC__StreamDecoderInitStatus init_status;
 180
 181         PARA_INFO_LOG("initializing flac decoder\n");
 182         pfd->decoder = FLAC__stream_decoder_new();
 183         if (!pfd->decoder)
 184                 return -E_FLACDEC_DECODER_ALLOC;
 185         FLAC__stream_decoder_set_metadata_respond_all(pfd->decoder);
 186         init_status = FLAC__stream_decoder_init_stream(pfd->decoder, read_cb,
 187                 NULL /* seek */, tell_cb, NULL /* length_cb */, NULL /* eof_cb */,
 188                 write_cb, meta_cb, error_cb, fn);
 189         if (init_status == FLAC__STREAM_DECODER_INIT_STATUS_OK)
 190                 return 1;
 191         FLAC__stream_decoder_delete(pfd->decoder);
 192         return -E_FLACDEC_DECODER_INIT;
 193 }
 194
 195 static int flacdec_execute(struct btr_node *btrn, const char *cmd,
 196                 char **result)
 197 {
 198         struct filter_node *fn = btr_context(btrn);
 199         struct private_flacdec_data *pfd = fn->private_data;
 200         unsigned sample_rate = FLAC__stream_decoder_get_sample_rate(pfd->decoder);
 201         unsigned channels = FLAC__stream_decoder_get_channels(pfd->decoder);
 202
 203         return decoder_execute(cmd, sample_rate, channels, result);
 204 }
 205
 206 #define FLACDEC_MAX_OUTPUT_SIZE (640 * 1024)
 207
 208 static bool output_queue_full(struct btr_node *btrn)
 209 {
 210         return btr_get_output_queue_size(btrn) > FLACDEC_MAX_OUTPUT_SIZE;
 211 }
 212
 213 static void flacdec_pre_select(struct sched *s, struct task *t)
 214 {
 215         struct filter_node *fn = container_of(t, struct filter_node, task);
 216         struct private_flacdec_data *pfd = fn->private_data;
 217         struct btr_node *btrn = fn->btrn;
 218         int ret;
 219
 220         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 221         if (ret < 0)
 222                 return sched_min_delay(s);
 223         if (output_queue_full(btrn))
 224                 return sched_request_timeout_ms(30, s);
 225         if (ret > 0 || pfd->have_more)
 226                 return sched_min_delay(s);
 227 }
 228
 229 static int flacdec_post_select(__a_unused struct sched *s, struct task *t)
 230 {
 231         struct filter_node *fn = container_of(t, struct filter_node, task);
 232         struct private_flacdec_data *pfd = fn->private_data;
 233         struct btr_node *btrn = fn->btrn;
 234         int ret;
 235         FLAC__StreamDecoderState state;
 236
 237         if (output_queue_full(btrn))
 238                 return 0;
 239         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 240         if (ret < 0 && ret != -E_BTR_EOF) /* fatal error */
 241                 goto out;
 242         if (ret <= 0 && !pfd->have_more) /* nothing to do */
 243                 goto out;
 244         if (!pfd->decoder) {
 245                 ret = flacdec_init(fn);
 246                 goto out;
 247         }
 248         if (output_queue_full(btrn)) {
 249                 pfd->have_more = true;
 250                 ret = 1;
 251                 goto out;
 252         }
 253         pfd->have_more = false;
 254         FLAC__stream_decoder_process_single(pfd->decoder);
 255         state = FLAC__stream_decoder_get_state(pfd->decoder);
 256         ret = -E_FLACDEC_EOF;
 257         if (state == FLAC__STREAM_DECODER_END_OF_STREAM)
 258                 goto out;
 259         if (state == FLAC__STREAM_DECODER_ABORTED) {
 260                 FLAC__stream_decoder_flush(pfd->decoder);
 261                 pfd->unconsumed = 0; /* feed unconsumed bytes again */
 262                 fn->min_iqs = btr_get_input_queue_size(btrn) + 1;
 263                 ret = 1;
 264                 goto out;
 265         }
 266         pfd->have_more = true;
 267         fn->min_iqs = 0;
 268         ret = 1;
 269 out:
 270         if (ret < 0)
 271                 btr_remove_node(&fn->btrn);
 272         return ret;
 273 }
 274
 275 static void flacdec_close(struct filter_node *fn)
 276 {
 277         struct private_flacdec_data *pfd;
 278
 279         if (!fn)
 280                 return;
 281         pfd = fn->private_data;
 282         if (!pfd)
 283                 return;
 284         if (pfd->decoder) {
 285                 FLAC__stream_decoder_finish(pfd->decoder);
 286                 FLAC__stream_decoder_delete(pfd->decoder);
 287         }
 288         free(pfd);
 289         fn->private_data = NULL;
 290 }
 291
 292 static void flacdec_open(struct filter_node *fn)
 293 {
 294         struct private_flacdec_data *pfd = para_calloc(sizeof(*pfd));
 295         fn->private_data = pfd;
 296         fn->min_iqs = 0;
 297 }
 298
 299 /**
 300  * The init function of the flacdec filter.
 301  *
 302  * \param f Pointer to the filter struct to initialize.
 303  *
 304  * \sa filter::init.
 305  */
 306 void flacdec_filter_init(struct filter *f)
 307 {
 308         f->open = flacdec_open;
 309         f->close = flacdec_close;
 310         f->pre_select = flacdec_pre_select;
 311         f->post_select = flacdec_post_select;
 312         f->execute = flacdec_execute;
 313 }