2 * Copyright (C) 2011 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file flacdec_filter.c The flac decoder. */
11 #include <FLAC/stream_decoder.h>
17 #include "buffer_tree.h"
22 struct private_flacdec_data
{
23 FLAC__StreamDecoder
*decoder
;
26 * We can not consume directly what was copied by the read callback
27 * because we might need to feed unconsumend bytes to the decoder again
28 * after the read callback ran out of data and returned ABORT. So we
29 * track how many bytes are unconsumed so far.
34 static FLAC__StreamDecoderReadStatus
read_cb(
35 __a_unused
const FLAC__StreamDecoder
*decoder
,
36 FLAC__byte buffer
[], size_t *bytes
, void *client_data
)
38 struct filter_node
*fn
= client_data
;
39 struct private_flacdec_data
*pfd
= fn
->private_data
;
40 struct btr_node
*btrn
= fn
->btrn
;
42 size_t copy
, want
= *bytes
, have
;
47 ns
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
49 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM
;
51 have
= btr_next_buffer_omit(btrn
, pfd
->unconsumed
, &btr_buf
);
54 copy
= PARA_MIN(want
, have
);
55 //PARA_CRIT_LOG("want: %zu, have: %zu, unconsumed %zu\n",
56 // want, have, pfd->unconsumed);
57 memcpy(buffer
, btr_buf
, copy
);
58 pfd
->unconsumed
+= copy
;
66 return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE
;
68 * We are kind of screwed here. Returning CONTINUE with a byte count of
69 * zero leads to an endless loop, so we must return either EOF or
70 * ABORT. Unfortunately, both options require to flush the decoder
71 * afterwards because libFLAC refuses to resume decoding if the decoder
72 * is in EOF or ABORT state. But flushing implies dropping the decoder
73 * input queue, so buffered data is lost.
75 * We work around this shortcoming by remembering the number of
76 * unconsumed bytes in pfd->unconsumed. In the write/meta callbacks,
77 * this number is decreased whenever a frame has been decoded
78 * successfully and btr_consume() has been called to consume the bytes
79 * corresponding to the decoded frame. After returning ABORT here, the
80 * decoder can be flushed, and we will feed the unconsumed bytes again.
82 return FLAC__STREAM_DECODER_READ_STATUS_ABORT
;
86 * The exact value does not really matter. It just has to be larger than the
87 * size of the input buffer of the bitstream reader of libflac.
89 #define TELL_CB_DUMMY_VAL 1000000
92 * FLAC__stream_decoder_get_decode_position() invokes this callback. The flac
93 * library then gets the number of unconsumed bytes from the bitstream reader,
94 * subtracts this number from the offset returned here and returns the
95 * difference as the decode position.
97 static FLAC__StreamDecoderTellStatus
tell_cb(__a_unused
const FLAC__StreamDecoder
*decoder
,
98 FLAC__uint64
*absolute_byte_offset
, __a_unused
void *client_data
)
100 *absolute_byte_offset
= TELL_CB_DUMMY_VAL
;
101 return FLAC__STREAM_DECODER_TELL_STATUS_OK
;
105 * There is no API function that returns the number of unconsumed bytes
106 * directly. The trick is to define a tell callback which always returns a
107 * fixed dummy value and compute the number of unconsumed bytes from the return
108 * value of FLAC__stream_decoder_get_decode_position().
110 static void flac_consume(struct filter_node
*fn
)
112 struct private_flacdec_data
*pfd
= fn
->private_data
;
113 struct btr_node
*btrn
= fn
->btrn
;
116 FLAC__stream_decoder_get_decode_position(pfd
->decoder
, &x
);
117 assert(x
<= TELL_CB_DUMMY_VAL
);
118 x
= TELL_CB_DUMMY_VAL
- x
; /* number of unconsumed bytes */
119 assert(x
<= pfd
->unconsumed
);
120 btr_consume(btrn
, pfd
->unconsumed
- x
);
124 static FLAC__StreamDecoderWriteStatus
write_cb(
125 const FLAC__StreamDecoder
*decoder
,
126 const FLAC__Frame
*frame
,
127 const FLAC__int32
*const buffer
[],
130 struct filter_node
*fn
= client_data
;
131 struct btr_node
*btrn
= fn
->btrn
;
132 size_t k
, n
= frame
->header
.blocksize
;
133 unsigned channels
= FLAC__stream_decoder_get_channels(decoder
);
134 char *outbuffer
= para_malloc(n
* channels
* 2);
137 for (k
= 0; k
< n
; k
++) {
138 int sample
= buffer
[0][k
];
139 write_int16_host_endian(outbuffer
+ 2 * k
, sample
);
142 for (k
= 0; k
< n
; k
++) {
143 int left
= buffer
[0][k
], right
= buffer
[1][k
];
144 write_int16_host_endian(outbuffer
+ 4 * k
, left
);
145 write_int16_host_endian(outbuffer
+ 4 * k
+ 2, right
);
148 btr_add_output(outbuffer
, n
* 4, btrn
);
150 return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE
;
153 static void meta_cb (__a_unused
const FLAC__StreamDecoder
*decoder
,
154 __a_unused
const FLAC__StreamMetadata
*metadata
,
157 flac_consume(client_data
);
160 static void error_cb( __a_unused
const FLAC__StreamDecoder
*decoder
,
161 FLAC__StreamDecoderErrorStatus status
,
162 __a_unused
void *client_data
)
164 PARA_ERROR_LOG("%s\n", FLAC__StreamDecoderErrorStatusString
[status
]);
167 static int flacdec_init(struct filter_node
*fn
)
169 struct private_flacdec_data
*pfd
= fn
->private_data
;
170 FLAC__StreamDecoderInitStatus init_status
;
172 PARA_INFO_LOG("initializing flac decoder\n");
173 pfd
->decoder
= FLAC__stream_decoder_new();
175 return -E_FLACDEC_DECODER_ALLOC
;
176 FLAC__stream_decoder_set_metadata_respond_all(pfd
->decoder
);
177 init_status
= FLAC__stream_decoder_init_stream(pfd
->decoder
, read_cb
,
178 NULL
/* seek */, tell_cb
, NULL
/* length_cb */, NULL
/* eof_cb */,
179 write_cb
, meta_cb
, error_cb
, fn
);
180 if (init_status
== FLAC__STREAM_DECODER_INIT_STATUS_OK
)
182 FLAC__stream_decoder_delete(pfd
->decoder
);
183 return -E_FLACDEC_DECODER_INIT
;
186 static int flacdec_execute(struct btr_node
*btrn
, const char *cmd
,
189 struct filter_node
*fn
= btr_context(btrn
);
190 struct private_flacdec_data
*pfd
= fn
->private_data
;
191 unsigned sample_rate
= FLAC__stream_decoder_get_sample_rate(pfd
->decoder
);
192 unsigned channels
= FLAC__stream_decoder_get_channels(pfd
->decoder
);
194 return decoder_execute(cmd
, sample_rate
, channels
, result
);
197 #define FLACDEC_MAX_OUTPUT_SIZE (640 * 1024)
199 static bool output_queue_full(struct btr_node
*btrn
)
201 return btr_get_output_queue_size(btrn
) > FLACDEC_MAX_OUTPUT_SIZE
;
204 static void flacdec_pre_select(struct sched
*s
, struct task
*t
)
206 struct filter_node
*fn
= container_of(t
, struct filter_node
, task
);
207 struct private_flacdec_data
*pfd
= fn
->private_data
;
208 struct btr_node
*btrn
= fn
->btrn
;
211 ret
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
213 return sched_min_delay(s
);
214 if (output_queue_full(btrn
))
215 return sched_request_timeout_ms(30, s
);
216 if (ret
> 0 || pfd
->have_more
)
217 return sched_min_delay(s
);
220 static void flacdec_post_select(__a_unused
struct sched
*s
, struct task
*t
)
222 struct filter_node
*fn
= container_of(t
, struct filter_node
, task
);
223 struct private_flacdec_data
*pfd
= fn
->private_data
;
224 struct btr_node
*btrn
= fn
->btrn
;
227 if (output_queue_full(btrn
))
229 ret
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
230 if (ret
< 0 && ret
!= -E_BTR_EOF
) /* fatal error */
232 if (ret
<= 0 && !pfd
->have_more
) /* nothing to do */
235 ret
= flacdec_init(fn
);
240 if (output_queue_full(btrn
)) {
241 pfd
->have_more
= true;
244 pfd
->have_more
= false;
245 FLAC__StreamDecoderState state
;
246 FLAC__stream_decoder_process_single(pfd
->decoder
);
247 state
= FLAC__stream_decoder_get_state(pfd
->decoder
);
248 //PARA_CRIT_LOG("state: %s\n", FLAC__stream_decoder_get_resolved_state_string(pfd->decoder));
249 ret
= -E_FLACDEC_EOF
;
250 if (state
== FLAC__STREAM_DECODER_END_OF_STREAM
)
252 if (state
== FLAC__STREAM_DECODER_ABORTED
) {
253 FLAC__stream_decoder_flush(pfd
->decoder
);
254 fn
->min_iqs
= pfd
->unconsumed
+ 1;
263 btr_remove_node(btrn
);
266 static void flacdec_close(struct filter_node
*fn
)
268 struct private_flacdec_data
*pfd
= fn
->private_data
;
270 FLAC__stream_decoder_finish(pfd
->decoder
);
271 FLAC__stream_decoder_delete(pfd
->decoder
);
273 fn
->private_data
= NULL
;
276 static void flacdec_open(struct filter_node
*fn
)
278 struct private_flacdec_data
*pfd
= para_calloc(sizeof(*pfd
));
279 fn
->private_data
= pfd
;
284 * The init function of the flacdec filter.
286 * \param f Pointer to the filter struct to initialize.
290 void flacdec_filter_init(struct filter
*f
)
292 f
->open
= flacdec_open
;
293 f
->close
= flacdec_close
;
294 f
->pre_select
= flacdec_pre_select
;
295 f
->post_select
= flacdec_post_select
;
296 f
->execute
= flacdec_execute
;