flacdec_filter.c

   1 /*
   2  * Copyright (C) 2011-2012 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 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          * We are kind of screwed here. Returning CONTINUE with a byte count of
  68          * zero leads to an endless loop, so we must return either EOF or
  69          * ABORT. Unfortunately, both options require to flush the decoder
  70          * afterwards because libFLAC refuses to resume decoding if the decoder
  71          * is in EOF or ABORT state. But flushing implies dropping the decoder
  72          * input queue, so buffered data is lost.
  73          *
  74          * We work around this shortcoming by remembering the number of
  75          * unconsumed bytes in pfd->unconsumed. In the write/meta callbacks,
  76          * this number is decreased whenever a frame has been decoded
  77          * successfully and btr_consume() has been called to consume the bytes
  78          * corresponding to the decoded frame.  After returning ABORT here, the
  79          * decoder can be flushed, and we will feed the unconsumed bytes again.
  80          */
  81         return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
  82 }
  83
  84 /*
  85  * The exact value does not really matter. It just has to be larger than the
  86  * size of the input buffer of the bitstream reader of libflac.
  87  */
  88 #define TELL_CB_DUMMY_VAL 1000000
  89
  90 /*
  91  * FLAC__stream_decoder_get_decode_position() invokes this callback. The flac
  92  * library then gets the number of unconsumed bytes from the bitstream reader,
  93  * subtracts this number from the offset returned here and returns the
  94  * difference as the decode position.
  95  */
  96 static FLAC__StreamDecoderTellStatus tell_cb(__a_unused const FLAC__StreamDecoder *decoder,
  97                 FLAC__uint64 *absolute_byte_offset, __a_unused void *client_data)
  98 {
  99         *absolute_byte_offset = TELL_CB_DUMMY_VAL;
 100         return FLAC__STREAM_DECODER_TELL_STATUS_OK;
 101 }
 102
 103 /*
 104  * There is no API function that returns the number of unconsumed bytes
 105  * directly. The trick is to define a tell callback which always returns a
 106  * fixed dummy value and compute the number of unconsumed bytes from the return
 107  * value of FLAC__stream_decoder_get_decode_position().
 108  */
 109 static void flac_consume(struct filter_node *fn)
 110 {
 111         struct private_flacdec_data *pfd = fn->private_data;
 112         struct btr_node *btrn = fn->btrn;
 113         FLAC__uint64 x;
 114
 115         FLAC__stream_decoder_get_decode_position(pfd->decoder, &x);
 116         assert(x <= TELL_CB_DUMMY_VAL);
 117         x = TELL_CB_DUMMY_VAL - x; /* number of unconsumed bytes */
 118         assert(x <= pfd->unconsumed);
 119         btr_consume(btrn, pfd->unconsumed - x);
 120         pfd->unconsumed = x;
 121 }
 122
 123 static FLAC__StreamDecoderWriteStatus write_cb(
 124                 const FLAC__StreamDecoder *decoder,
 125                 const FLAC__Frame *frame,
 126                 const FLAC__int32 *const buffer[],
 127                 void *client_data)
 128 {
 129         struct filter_node *fn = client_data;
 130         struct btr_node *btrn = fn->btrn;
 131         size_t k, n = frame->header.blocksize;
 132         unsigned channels = FLAC__stream_decoder_get_channels(decoder);
 133         char *outbuffer = para_malloc(n * channels * 2);
 134
 135         if (channels == 1) {
 136                 for (k = 0; k < n; k++) {
 137                         int sample = buffer[0][k];
 138                         write_int16_host_endian(outbuffer + 2 * k, sample);
 139                 }
 140         } else {
 141                 for (k = 0; k < n; k++) {
 142                         int left = buffer[0][k], right = buffer[1][k];
 143                         write_int16_host_endian(outbuffer + 4 * k, left);
 144                         write_int16_host_endian(outbuffer + 4 * k + 2, right);
 145                 }
 146         }
 147         btr_add_output(outbuffer, n * 4, btrn);
 148         flac_consume(fn);
 149         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 150 }
 151
 152 static void meta_cb (__a_unused const FLAC__StreamDecoder *decoder,
 153                 __a_unused const FLAC__StreamMetadata *metadata,
 154                 void *client_data)
 155 {
 156         flac_consume(client_data);
 157 }
 158
 159 static void error_cb( __a_unused const FLAC__StreamDecoder *decoder,
 160                 FLAC__StreamDecoderErrorStatus status,
 161                 __a_unused void *client_data)
 162 {
 163         PARA_ERROR_LOG("%s\n", FLAC__StreamDecoderErrorStatusString[status]);
 164 }
 165
 166 static int flacdec_init(struct filter_node *fn)
 167 {
 168         struct private_flacdec_data *pfd = fn->private_data;
 169         FLAC__StreamDecoderInitStatus init_status;
 170
 171         PARA_INFO_LOG("initializing flac decoder\n");
 172         pfd->decoder = FLAC__stream_decoder_new();
 173         if (!pfd->decoder)
 174                 return -E_FLACDEC_DECODER_ALLOC;
 175         FLAC__stream_decoder_set_metadata_respond_all(pfd->decoder);
 176         init_status = FLAC__stream_decoder_init_stream(pfd->decoder, read_cb,
 177                 NULL /* seek */, tell_cb, NULL /* length_cb */, NULL /* eof_cb */,
 178                 write_cb, meta_cb, error_cb, fn);
 179         if (init_status == FLAC__STREAM_DECODER_INIT_STATUS_OK)
 180                 return 1;
 181         FLAC__stream_decoder_delete(pfd->decoder);
 182         return -E_FLACDEC_DECODER_INIT;
 183 }
 184
 185 static int flacdec_execute(struct btr_node *btrn, const char *cmd,
 186                 char **result)
 187 {
 188         struct filter_node *fn = btr_context(btrn);
 189         struct private_flacdec_data *pfd = fn->private_data;
 190         unsigned sample_rate = FLAC__stream_decoder_get_sample_rate(pfd->decoder);
 191         unsigned channels = FLAC__stream_decoder_get_channels(pfd->decoder);
 192
 193         return decoder_execute(cmd, sample_rate, channels, result);
 194 }
 195
 196 #define FLACDEC_MAX_OUTPUT_SIZE (640 * 1024)
 197
 198 static bool output_queue_full(struct btr_node *btrn)
 199 {
 200         return btr_get_output_queue_size(btrn) > FLACDEC_MAX_OUTPUT_SIZE;
 201 }
 202
 203 static void flacdec_pre_select(struct sched *s, struct task *t)
 204 {
 205         struct filter_node *fn = container_of(t, struct filter_node, task);
 206         struct private_flacdec_data *pfd = fn->private_data;
 207         struct btr_node *btrn = fn->btrn;
 208         int ret;
 209
 210         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 211         if (ret < 0)
 212                 return sched_min_delay(s);
 213         if (output_queue_full(btrn))
 214                 return sched_request_timeout_ms(30, s);
 215         if (ret > 0 || pfd->have_more)
 216                 return sched_min_delay(s);
 217 }
 218
 219 static void flacdec_post_select(__a_unused struct sched *s, struct task *t)
 220 {
 221         struct filter_node *fn = container_of(t, struct filter_node, task);
 222         struct private_flacdec_data *pfd = fn->private_data;
 223         struct btr_node *btrn = fn->btrn;
 224         int ret;
 225
 226         if (output_queue_full(btrn))
 227                 return;
 228         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 229         if (ret < 0 && ret != -E_BTR_EOF) /* fatal error */
 230                 goto out;
 231         if (ret <= 0 && !pfd->have_more) /* nothing to do */
 232                 goto out;
 233         if (!pfd->decoder) {
 234                 ret = flacdec_init(fn);
 235                 goto out;
 236         }
 237         pfd->unconsumed = 0;
 238         for (;;) {
 239                 if (output_queue_full(btrn)) {
 240                         pfd->have_more = true;
 241                         break;
 242                 }
 243                 pfd->have_more = false;
 244                 FLAC__StreamDecoderState state;
 245                 FLAC__stream_decoder_process_single(pfd->decoder);
 246                 state = FLAC__stream_decoder_get_state(pfd->decoder);
 247                 //PARA_CRIT_LOG("state: %s\n", FLAC__stream_decoder_get_resolved_state_string(pfd->decoder));
 248                 ret = -E_FLACDEC_EOF;
 249                 if (state == FLAC__STREAM_DECODER_END_OF_STREAM)
 250                         goto out;
 251                 if (state == FLAC__STREAM_DECODER_ABORTED) {
 252                         FLAC__stream_decoder_flush(pfd->decoder);
 253                         fn->min_iqs = pfd->unconsumed + 1;
 254                         break;
 255                 }
 256                 fn->min_iqs = 0;
 257         }
 258         ret = 1;
 259 out:
 260         t->error = ret;
 261         if (ret < 0)
 262                 btr_remove_node(btrn);
 263 }
 264
 265 static void flacdec_close(struct filter_node *fn)
 266 {
 267         struct private_flacdec_data *pfd = fn->private_data;
 268
 269         FLAC__stream_decoder_finish(pfd->decoder);
 270         FLAC__stream_decoder_delete(pfd->decoder);
 271         free(pfd);
 272         fn->private_data = NULL;
 273 }
 274
 275 static void flacdec_open(struct filter_node *fn)
 276 {
 277         struct private_flacdec_data *pfd = para_calloc(sizeof(*pfd));
 278         fn->private_data = pfd;
 279         fn->min_iqs = 0;
 280 }
 281
 282 /**
 283  * The init function of the flacdec filter.
 284  *
 285  * \param f Pointer to the filter struct to initialize.
 286  *
 287  * \sa filter::init.
 288  */
 289 void flacdec_filter_init(struct filter *f)
 290 {
 291         f->open = flacdec_open;
 292         f->close = flacdec_close;
 293         f->pre_select = flacdec_pre_select;
 294         f->post_select = flacdec_post_select;
 295         f->execute = flacdec_execute;
 296 }