2 * Copyright (C) 2011-2012 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file flacdec_filter.c The flac decoder. */
10 #include <FLAC/stream_decoder.h>
16 #include "buffer_tree.h"
21 struct private_flacdec_data
{
22 FLAC__StreamDecoder
*decoder
;
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.
33 static FLAC__StreamDecoderReadStatus
read_cb(
34 __a_unused
const FLAC__StreamDecoder
*decoder
,
35 FLAC__byte buffer
[], size_t *bytes
, void *client_data
)
37 struct filter_node
*fn
= client_data
;
38 struct private_flacdec_data
*pfd
= fn
->private_data
;
39 struct btr_node
*btrn
= fn
->btrn
;
41 size_t copy
, want
= *bytes
, have
;
46 ns
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
48 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM
;
50 have
= btr_next_buffer_omit(btrn
, pfd
->unconsumed
, &btr_buf
);
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
;
65 return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE
;
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.
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.
81 return FLAC__STREAM_DECODER_READ_STATUS_ABORT
;
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.
88 #define TELL_CB_DUMMY_VAL 1000000
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.
96 static FLAC__StreamDecoderTellStatus
tell_cb(__a_unused
const FLAC__StreamDecoder
*decoder
,
97 FLAC__uint64
*absolute_byte_offset
, __a_unused
void *client_data
)
99 *absolute_byte_offset
= TELL_CB_DUMMY_VAL
;
100 return FLAC__STREAM_DECODER_TELL_STATUS_OK
;
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().
109 static void flac_consume(struct filter_node
*fn
)
111 struct private_flacdec_data
*pfd
= fn
->private_data
;
112 struct btr_node
*btrn
= fn
->btrn
;
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
);
123 static FLAC__StreamDecoderWriteStatus
write_cb(
124 const FLAC__StreamDecoder
*decoder
,
125 const FLAC__Frame
*frame
,
126 const FLAC__int32
*const buffer
[],
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);
136 for (k
= 0; k
< n
; k
++) {
137 int sample
= buffer
[0][k
];
138 write_int16_host_endian(outbuffer
+ 2 * k
, sample
);
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
);
147 btr_add_output(outbuffer
, n
* 4, btrn
);
149 return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE
;
152 static void meta_cb (__a_unused
const FLAC__StreamDecoder
*decoder
,
153 __a_unused
const FLAC__StreamMetadata
*metadata
,
156 flac_consume(client_data
);
159 static void error_cb( __a_unused
const FLAC__StreamDecoder
*decoder
,
160 FLAC__StreamDecoderErrorStatus status
,
161 __a_unused
void *client_data
)
163 PARA_ERROR_LOG("%s\n", FLAC__StreamDecoderErrorStatusString
[status
]);
166 static int flacdec_init(struct filter_node
*fn
)
168 struct private_flacdec_data
*pfd
= fn
->private_data
;
169 FLAC__StreamDecoderInitStatus init_status
;
171 PARA_INFO_LOG("initializing flac decoder\n");
172 pfd
->decoder
= FLAC__stream_decoder_new();
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
)
181 FLAC__stream_decoder_delete(pfd
->decoder
);
182 return -E_FLACDEC_DECODER_INIT
;
185 static int flacdec_execute(struct btr_node
*btrn
, const char *cmd
,
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
);
193 return decoder_execute(cmd
, sample_rate
, channels
, result
);
196 #define FLACDEC_MAX_OUTPUT_SIZE (640 * 1024)
198 static bool output_queue_full(struct btr_node
*btrn
)
200 return btr_get_output_queue_size(btrn
) > FLACDEC_MAX_OUTPUT_SIZE
;
203 static void flacdec_pre_select(struct sched
*s
, struct task
*t
)
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
;
210 ret
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
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
);
219 static void flacdec_post_select(__a_unused
struct sched
*s
, struct task
*t
)
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
;
226 if (output_queue_full(btrn
))
228 ret
= btr_node_status(btrn
, fn
->min_iqs
, BTR_NT_INTERNAL
);
229 if (ret
< 0 && ret
!= -E_BTR_EOF
) /* fatal error */
231 if (ret
<= 0 && !pfd
->have_more
) /* nothing to do */
234 ret
= flacdec_init(fn
);
239 if (output_queue_full(btrn
)) {
240 pfd
->have_more
= true;
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
)
251 if (state
== FLAC__STREAM_DECODER_ABORTED
) {
252 FLAC__stream_decoder_flush(pfd
->decoder
);
253 fn
->min_iqs
= pfd
->unconsumed
+ 1;
262 btr_remove_node(btrn
);
265 static void flacdec_close(struct filter_node
*fn
)
267 struct private_flacdec_data
*pfd
= fn
->private_data
;
269 FLAC__stream_decoder_finish(pfd
->decoder
);
270 FLAC__stream_decoder_delete(pfd
->decoder
);
272 fn
->private_data
= NULL
;
275 static void flacdec_open(struct filter_node
*fn
)
277 struct private_flacdec_data
*pfd
= para_calloc(sizeof(*pfd
));
278 fn
->private_data
= pfd
;
283 * The init function of the flacdec filter.
285 * \param f Pointer to the filter struct to initialize.
289 void flacdec_filter_init(struct filter
*f
)
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
;