summaryrefslogtreecommitdiff
path: root/ext/celt/gstceltenc.c
blob: 09cd44204fab1a03cad8e87baa6bdbd5f5f69ad5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
/* GStreamer Celt Encoder
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 * Copyright (C) <2008> Sebastian Dröge <sebastian.droege@collabora.co.uk>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Based on the celtenc element
 */

/**
 * SECTION:element-celtenc
 * @see_also: celtdec, oggmux
 *
 * This element raw audio to CELT.
 *
 * <refsect2>
 * <title>Example pipelines</title>
 * |[
 * gst-launch -v audiotestsrc wave=sine num-buffers=100 ! audioconvert ! celtenc ! oggmux ! filesink location=sine.ogg
 * ]| Encode a test sine signal to Ogg/CELT.
 * </refsect2>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <math.h>
#include <celt/celt.h>
#include <celt/celt_header.h>

#include <gst/gsttagsetter.h>
#include <gst/tag/tag.h>
#include <gst/audio/audio.h>
#include "gstceltenc.h"

GST_DEBUG_CATEGORY_STATIC (celtenc_debug);
#define GST_CAT_DEFAULT celtenc_debug

#define GST_CELT_ENC_TYPE_PREDICTION (gst_celt_enc_prediction_get_type())
static GType
gst_celt_enc_prediction_get_type (void)
{
  static const GEnumValue values[] = {
    {0, "Independent frames", "idependent"},
    {1, "Short term interframe prediction", "short-term"},
    {2, "Long term interframe prediction", "long-term"},
    {0, NULL, NULL}
  };
  static volatile GType id = 0;

  if (g_once_init_enter ((gsize *) & id)) {
    GType _id;

    _id = g_enum_register_static ("GstCeltEncPrediction", values);

    g_once_init_leave ((gsize *) & id, _id);
  }

  return id;
}

static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-raw, "
        "format = (string) " GST_AUDIO_NE (S16) ", "
        "layout = (string) interleaved, "
        "rate = (int) [ 32000, 64000 ], " "channels = (int) [ 1, 2 ]")
    );

static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-celt, "
        "rate = (int) [ 32000, 64000 ], "
        "channels = (int) [ 1, 2 ], " "frame-size = (int) [ 64, 512 ]")
    );

#define DEFAULT_BITRATE         64000
#define DEFAULT_FRAMESIZE       480
#define DEFAULT_CBR             TRUE
#define DEFAULT_COMPLEXITY      9
#define DEFAULT_MAX_BITRATE     64000
#define DEFAULT_PREDICTION      0
#define DEFAULT_START_BAND      0

enum
{
  PROP_0,
  PROP_BITRATE,
  PROP_FRAMESIZE,
  PROP_CBR,
  PROP_COMPLEXITY,
  PROP_MAX_BITRATE,
  PROP_PREDICTION,
  PROP_START_BAND
};

static void gst_celt_enc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void gst_celt_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);

static gboolean gst_celt_enc_start (GstAudioEncoder * enc);
static gboolean gst_celt_enc_stop (GstAudioEncoder * enc);
static gboolean gst_celt_enc_set_format (GstAudioEncoder * enc,
    GstAudioInfo * info);
static GstFlowReturn gst_celt_enc_handle_frame (GstAudioEncoder * enc,
    GstBuffer * in_buf);
static gboolean gst_celt_enc_sink_event (GstAudioEncoder * enc,
    GstEvent * event);
static GstFlowReturn gst_celt_enc_pre_push (GstAudioEncoder * benc,
    GstBuffer ** buffer);

#define gst_celt_enc_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstCeltEnc, gst_celt_enc, GST_TYPE_AUDIO_ENCODER,
    G_IMPLEMENT_INTERFACE (GST_TYPE_TAG_SETTER, NULL));

static void
gst_celt_enc_class_init (GstCeltEncClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;
  GstAudioEncoderClass *gstbase_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;
  gstbase_class = (GstAudioEncoderClass *) klass;

  gobject_class->set_property = gst_celt_enc_set_property;
  gobject_class->get_property = gst_celt_enc_get_property;

  gstbase_class->start = GST_DEBUG_FUNCPTR (gst_celt_enc_start);
  gstbase_class->stop = GST_DEBUG_FUNCPTR (gst_celt_enc_stop);
  gstbase_class->set_format = GST_DEBUG_FUNCPTR (gst_celt_enc_set_format);
  gstbase_class->handle_frame = GST_DEBUG_FUNCPTR (gst_celt_enc_handle_frame);
  gstbase_class->event = GST_DEBUG_FUNCPTR (gst_celt_enc_sink_event);
  gstbase_class->pre_push = GST_DEBUG_FUNCPTR (gst_celt_enc_pre_push);

  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_BITRATE,
      g_param_spec_int ("bitrate", "Encoding Bit-rate",
          "Specify an encoding bit-rate (in bps).",
          10000, 320000, DEFAULT_BITRATE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_FRAMESIZE,
      g_param_spec_int ("framesize", "Frame Size",
          "The number of samples per frame", 64, 512, DEFAULT_FRAMESIZE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_CBR,
      g_param_spec_boolean ("cbr", "Constant bit rate",
          "Constant bit rate", DEFAULT_CBR,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_COMPLEXITY,
      g_param_spec_int ("complexity", "Complexity",
          "Complexity", 0, 10, DEFAULT_COMPLEXITY,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_MAX_BITRATE,
      g_param_spec_int ("max-bitrate", "Maximum Encoding Bit-rate",
          "Specify a maximum encoding bit rate (in bps) for variable bit rate encoding.",
          10000, 320000, DEFAULT_MAX_BITRATE,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_PREDICTION,
      g_param_spec_enum ("prediction", "Interframe Prediction",
          "Controls the use of interframe prediction.",
          GST_CELT_ENC_TYPE_PREDICTION, DEFAULT_PREDICTION,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_START_BAND,
      g_param_spec_int ("start-band", "Start Band",
          "Controls the start band that should be used",
          0, G_MAXINT, DEFAULT_START_BAND,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&src_factory));
  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&sink_factory));
  gst_element_class_set_details_simple (gstelement_class, "Celt audio encoder",
      "Codec/Encoder/Audio",
      "Encodes audio in Celt format",
      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");

  GST_DEBUG_CATEGORY_INIT (celtenc_debug, "celtenc", 0, "Celt encoder");
}

static void
gst_celt_enc_init (GstCeltEnc * enc)
{
  enc->bitrate = DEFAULT_BITRATE;
  enc->frame_size = DEFAULT_FRAMESIZE;
  enc->cbr = DEFAULT_CBR;
  enc->complexity = DEFAULT_COMPLEXITY;
  enc->max_bitrate = DEFAULT_MAX_BITRATE;
  enc->prediction = DEFAULT_PREDICTION;
}

static gboolean
gst_celt_enc_start (GstAudioEncoder * benc)
{
  GstCeltEnc *enc = GST_CELT_ENC (benc);

  GST_DEBUG_OBJECT (enc, "start");
  enc->channels = -1;
  enc->rate = -1;
  enc->header_sent = FALSE;

  return TRUE;
}

static gboolean
gst_celt_enc_stop (GstAudioEncoder * benc)
{
  GstCeltEnc *enc = GST_CELT_ENC (benc);

  GST_DEBUG_OBJECT (enc, "stop");
  enc->header_sent = FALSE;
  if (enc->state) {
    celt_encoder_destroy (enc->state);
    enc->state = NULL;
  }
  if (enc->mode) {
    celt_mode_destroy (enc->mode);
    enc->mode = NULL;
  }
  memset (&enc->header, 0, sizeof (enc->header));

  g_slist_foreach (enc->headers, (GFunc) gst_buffer_unref, NULL);
  enc->headers = NULL;

  gst_tag_setter_reset_tags (GST_TAG_SETTER (enc));

  return TRUE;
}

static gboolean
gst_celt_enc_setup (GstCeltEnc * enc)
{
  gint error = CELT_OK;

#ifdef HAVE_CELT_0_7
  enc->mode = celt_mode_create (enc->rate, enc->frame_size, &error);
#else
  enc->mode =
      celt_mode_create (enc->rate, enc->channels, enc->frame_size, &error);
#endif
  if (!enc->mode)
    goto mode_initialization_failed;

#ifdef HAVE_CELT_0_11
  celt_header_init (&enc->header, enc->mode, enc->frame_size, enc->channels);
#else
#ifdef HAVE_CELT_0_7
  celt_header_init (&enc->header, enc->mode, enc->channels);
#else
  celt_header_init (&enc->header, enc->mode);
#endif
#endif
  enc->header.nb_channels = enc->channels;

#ifdef HAVE_CELT_0_8
  enc->frame_size = enc->header.frame_size;
#else
  celt_mode_info (enc->mode, CELT_GET_FRAME_SIZE, &enc->frame_size);
#endif

#ifdef HAVE_CELT_0_11
  enc->state = celt_encoder_create_custom (enc->mode, enc->channels, &error);
#else
#ifdef HAVE_CELT_0_7
  enc->state = celt_encoder_create (enc->mode, enc->channels, &error);
#else
  enc->state = celt_encoder_create (enc->mode);
#endif
#endif
  if (!enc->state)
    goto encoder_creation_failed;

#ifdef CELT_SET_VBR_RATE
  if (!enc->cbr) {
    celt_encoder_ctl (enc->state, CELT_SET_VBR_RATE (enc->bitrate / 1000), 0);
  }
#endif
#ifdef CELT_SET_COMPLEXITY
  celt_encoder_ctl (enc->state, CELT_SET_COMPLEXITY (enc->complexity), 0);
#endif
#ifdef CELT_SET_PREDICTION
  celt_encoder_ctl (enc->state, CELT_SET_PREDICTION (enc->prediction), 0);
#endif
#ifdef CELT_SET_START_BAND
  celt_encoder_ctl (enc->state, CELT_SET_START_BAND (enc->start_band), 0);
#endif

  GST_LOG_OBJECT (enc, "we have frame size %d", enc->frame_size);

  return TRUE;

mode_initialization_failed:
  GST_ERROR_OBJECT (enc, "Mode initialization failed: %d", error);
  return FALSE;

encoder_creation_failed:
#ifdef HAVE_CELT_0_7
  GST_ERROR_OBJECT (enc, "Encoder creation failed: %d", error);
#else
  GST_ERROR_OBJECT (enc, "Encoder creation failed");
#endif
  return FALSE;
}

static gint64
gst_celt_enc_get_latency (GstCeltEnc * enc)
{
  return gst_util_uint64_scale (enc->frame_size, GST_SECOND, enc->rate);
}

static gboolean
gst_celt_enc_set_format (GstAudioEncoder * benc, GstAudioInfo * info)
{
  GstCeltEnc *enc;
  GstCaps *otherpadcaps;

  enc = GST_CELT_ENC (benc);

  enc->channels = GST_AUDIO_INFO_CHANNELS (info);
  enc->rate = GST_AUDIO_INFO_RATE (info);

  /* handle reconfigure */
  if (enc->state) {
    celt_encoder_destroy (enc->state);
    enc->state = NULL;
  }
  if (enc->mode) {
    celt_mode_destroy (enc->mode);
    enc->mode = NULL;
  }
  memset (&enc->header, 0, sizeof (enc->header));

  otherpadcaps = gst_pad_get_allowed_caps (GST_AUDIO_ENCODER_SRC_PAD (enc));
  if (otherpadcaps) {
    if (!gst_caps_is_empty (otherpadcaps)) {
      GstStructure *ps = gst_caps_get_structure (otherpadcaps, 0);
      gst_structure_get_int (ps, "frame-size", &enc->frame_size);
    }
    gst_caps_unref (otherpadcaps);
  }

  if (enc->requested_frame_size > 0)
    enc->frame_size = enc->requested_frame_size;

  GST_DEBUG_OBJECT (enc, "channels=%d rate=%d frame-size=%d",
      enc->channels, enc->rate, enc->frame_size);

  if (!gst_celt_enc_setup (enc))
    return FALSE;

  /* feedback to base class */
  gst_audio_encoder_set_latency (benc,
      gst_celt_enc_get_latency (enc), gst_celt_enc_get_latency (enc));
  gst_audio_encoder_set_frame_samples_min (benc, enc->frame_size);
  gst_audio_encoder_set_frame_samples_max (benc, enc->frame_size);
  gst_audio_encoder_set_frame_max (benc, 1);

  return TRUE;
}

static gboolean
gst_celt_enc_sink_event (GstAudioEncoder * benc, GstEvent * event)
{
  GstCeltEnc *enc;

  enc = GST_CELT_ENC (benc);

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_TAG:
    {
      GstTagList *list;
      GstTagSetter *setter = GST_TAG_SETTER (enc);
      const GstTagMergeMode mode = gst_tag_setter_get_tag_merge_mode (setter);

      gst_event_parse_tag (event, &list);
      gst_tag_setter_merge_tags (setter, list, mode);
      break;
    }
    default:
      break;
  }

  /* we only peeked, let base class handle it */
  return GST_AUDIO_ENCODER_CLASS (parent_class)->event (benc, event);
}

static GstBuffer *
gst_celt_enc_create_metadata_buffer (GstCeltEnc * enc)
{
  const GstTagList *tags;
  GstTagList *empty_tags = NULL;
  GstBuffer *comments = NULL;

  tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (enc));

  GST_DEBUG_OBJECT (enc, "tags = %" GST_PTR_FORMAT, tags);

  if (tags == NULL) {
    /* FIXME: better fix chain of callers to not write metadata at all,
     * if there is none */
    empty_tags = gst_tag_list_new_empty ();
    tags = empty_tags;
  }
  comments = gst_tag_list_to_vorbiscomment_buffer (tags, NULL,
      0, "Encoded with GStreamer Celtenc");

  GST_BUFFER_OFFSET (comments) = 0;
  GST_BUFFER_OFFSET_END (comments) = 0;

  if (empty_tags)
    gst_tag_list_free (empty_tags);

  return comments;
}

static GstFlowReturn
gst_celt_enc_encode (GstCeltEnc * enc, GstBuffer * buf)
{
  GstFlowReturn ret = GST_FLOW_OK;
  gint frame_size = enc->frame_size;
  gint bytes = frame_size * 2 * enc->channels;
  gint bytes_per_packet;
  gint16 *data, *data0 = NULL;
  gint outsize, size;
  GstBuffer *outbuf;
  GstMapInfo map, omap;

  if (G_LIKELY (buf)) {
    gst_buffer_map (buf, &map, GST_MAP_READ);
    data = (gint16 *) map.data;
    size = map.size;

    if (G_UNLIKELY (map.size % bytes)) {
      GST_DEBUG_OBJECT (enc, "draining; adding silence samples");
      size = ((size / bytes) + 1) * bytes;
      data0 = g_malloc0 (size);
      memcpy (data0, data, size);
      data = data0;
    }
  } else {
    GST_DEBUG_OBJECT (enc, "nothing to drain");
    goto done;
  }

  frame_size = size / (2 * enc->channels);
  if (enc->cbr) {
    bytes_per_packet = (enc->bitrate * frame_size / enc->rate + 4) / 8;
  } else {
    bytes_per_packet = (enc->max_bitrate * frame_size / enc->rate + 4) / 8;
  }

  outbuf = gst_buffer_new_and_alloc (bytes_per_packet);
  GST_DEBUG_OBJECT (enc, "encoding %d samples (%d bytes)", frame_size, bytes);

  gst_buffer_map (outbuf, &omap, GST_MAP_WRITE);

#ifdef HAVE_CELT_0_8
  outsize =
      celt_encode (enc->state, data, frame_size, omap.data, bytes_per_packet);
#else
  outsize = celt_encode (enc->state, data, NULL, omap.data, bytes_per_packet);
#endif

  gst_buffer_unmap (outbuf, &omap);
  gst_buffer_unmap (buf, &map);

  if (outsize < 0) {
    GST_ELEMENT_ERROR (enc, STREAM, ENCODE, (NULL),
        ("encoding failed: %d", outsize));
    ret = GST_FLOW_ERROR;
    goto done;
  }

  GST_DEBUG_OBJECT (enc, "encoding %d bytes", bytes);

  ret = gst_audio_encoder_finish_frame (GST_AUDIO_ENCODER (enc),
      outbuf, frame_size);

done:
  g_free (data0);
  return ret;
}

/*
 * (really really) FIXME: move into core (dixit tpm)
 */
/**
 * _gst_caps_set_buffer_array:
 * @caps: a #GstCaps
 * @field: field in caps to set
 * @buf: header buffers
 *
 * Adds given buffers to an array of buffers set as the given @field
 * on the given @caps.  List of buffer arguments must be NULL-terminated.
 *
 * Returns: input caps with a streamheader field added, or NULL if some error
 */
static GstCaps *
_gst_caps_set_buffer_array (GstCaps * caps, const gchar * field,
    GstBuffer * buf, ...)
{
  GstStructure *structure = NULL;
  va_list va;
  GValue array = { 0 };
  GValue value = { 0 };

  g_return_val_if_fail (caps != NULL, NULL);
  g_return_val_if_fail (gst_caps_is_fixed (caps), NULL);
  g_return_val_if_fail (field != NULL, NULL);

  caps = gst_caps_make_writable (caps);
  structure = gst_caps_get_structure (caps, 0);

  g_value_init (&array, GST_TYPE_ARRAY);

  va_start (va, buf);
  /* put buffers in a fixed list */
  while (buf) {
    g_assert (gst_buffer_is_writable (buf));

    /* mark buffer */
    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_HEADER);

    g_value_init (&value, GST_TYPE_BUFFER);
    buf = gst_buffer_copy (buf);
    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_HEADER);
    gst_value_set_buffer (&value, buf);
    gst_buffer_unref (buf);
    gst_value_array_append_value (&array, &value);
    g_value_unset (&value);

    buf = va_arg (va, GstBuffer *);
  }

  gst_structure_set_value (structure, field, &array);
  g_value_unset (&array);

  return caps;
}

static GstFlowReturn
gst_celt_enc_handle_frame (GstAudioEncoder * benc, GstBuffer * buf)
{
  GstCeltEnc *enc;
  GstFlowReturn ret = GST_FLOW_OK;

  enc = GST_CELT_ENC (benc);

  if (!enc->header_sent) {
    /* Celt streams begin with two headers; the initial header (with
       most of the codec setup parameters) which is mandated by the Ogg
       bitstream spec.  The second header holds any comment fields.
       We merely need to make the headers, then pass them to libcelt 
       one at a time; libcelt handles the additional Ogg bitstream 
       constraints */
    GstBuffer *buf1, *buf2;
    GstCaps *caps;
    /* libcelt has a bug which underestimates header size by 4... */
    unsigned int header_size = enc->header.header_size + 4;
    unsigned char *data = g_malloc (header_size);

    /* create header buffer */
    int error = celt_header_to_packet (&enc->header, data, header_size);
    if (error < 0) {
      g_free (data);
      goto no_header;
    }
    buf1 = gst_buffer_new_wrapped (data, header_size);
    GST_BUFFER_OFFSET_END (buf1) = 0;
    GST_BUFFER_OFFSET (buf1) = 0;

    /* create comment buffer */
    buf2 = gst_celt_enc_create_metadata_buffer (enc);

    /* mark and put on caps */
    caps = gst_caps_new_simple ("audio/x-celt",
        "rate", G_TYPE_INT, enc->rate,
        "channels", G_TYPE_INT, enc->channels,
        "frame-size", G_TYPE_INT, enc->frame_size, NULL);
    caps = _gst_caps_set_buffer_array (caps, "streamheader", buf1, buf2, NULL);

    /* negotiate with these caps */
    GST_DEBUG_OBJECT (enc, "here are the caps: %" GST_PTR_FORMAT, caps);
    GST_LOG_OBJECT (enc, "rate=%d channels=%d frame-size=%d",
        enc->rate, enc->channels, enc->frame_size);
    gst_audio_encoder_set_output_format (GST_AUDIO_ENCODER (enc), caps);
    gst_caps_unref (caps);

    /* push out buffers */
    /* store buffers for later pre_push sending */
    g_slist_foreach (enc->headers, (GFunc) gst_buffer_unref, NULL);
    enc->headers = NULL;
    GST_DEBUG_OBJECT (enc, "storing header buffers");
    enc->headers = g_slist_prepend (enc->headers, buf2);
    enc->headers = g_slist_prepend (enc->headers, buf1);

    enc->header_sent = TRUE;
  }

  GST_DEBUG_OBJECT (enc, "received buffer %p of %u bytes", buf,
      buf ? gst_buffer_get_size (buf) : 0);

  ret = gst_celt_enc_encode (enc, buf);

done:
  return ret;

  /* ERRORS */
no_header:
  {
    GST_ELEMENT_ERROR (enc, STREAM, ENCODE, (NULL),
        ("Failed to encode header"));
    ret = GST_FLOW_ERROR;
    goto done;
  }
}

/* push out the buffer */
static GstFlowReturn
gst_celt_enc_push_buffer (GstCeltEnc * enc, GstBuffer * buffer)
{
  guint size;

  size = gst_buffer_get_size (buffer);
  GST_DEBUG_OBJECT (enc, "pushing output buffer of size %u", size);

  return gst_pad_push (GST_AUDIO_ENCODER_SRC_PAD (enc), buffer);
}

static GstFlowReturn
gst_celt_enc_pre_push (GstAudioEncoder * benc, GstBuffer ** buffer)
{
  GstCeltEnc *enc;
  GstFlowReturn ret = GST_FLOW_OK;

  enc = GST_CELT_ENC (benc);

  /* FIXME 0.11 ? get rid of this special ogg stuff and have it
   * put and use 'codec data' in caps like anything else,
   * with all the usual out-of-band advantage etc */
  if (G_UNLIKELY (enc->headers)) {
    GSList *header = enc->headers;

    /* try to push all of these, if we lose one, might as well lose all */
    while (header) {
      if (ret == GST_FLOW_OK)
        ret = gst_celt_enc_push_buffer (enc, header->data);
      else
        gst_celt_enc_push_buffer (enc, header->data);
      header = g_slist_next (header);
    }

    g_slist_free (enc->headers);
    enc->headers = NULL;
  }

  return ret;
}

static void
gst_celt_enc_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstCeltEnc *enc;

  enc = GST_CELT_ENC (object);

  switch (prop_id) {
    case PROP_BITRATE:
      g_value_set_int (value, enc->bitrate);
      break;
    case PROP_FRAMESIZE:
      g_value_set_int (value, enc->frame_size);
      break;
    case PROP_CBR:
      g_value_set_boolean (value, enc->cbr);
      break;
    case PROP_COMPLEXITY:
      g_value_set_int (value, enc->complexity);
      break;
    case PROP_MAX_BITRATE:
      g_value_set_int (value, enc->max_bitrate);
      break;
    case PROP_PREDICTION:
      g_value_set_enum (value, enc->prediction);
      break;
    case PROP_START_BAND:
      g_value_set_int (value, enc->start_band);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_celt_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstCeltEnc *enc;

  enc = GST_CELT_ENC (object);

  switch (prop_id) {
    case PROP_BITRATE:
      enc->bitrate = g_value_get_int (value);
      break;
    case PROP_FRAMESIZE:
      enc->requested_frame_size = g_value_get_int (value);
      enc->frame_size = enc->requested_frame_size;
      break;
    case PROP_CBR:
      enc->cbr = g_value_get_boolean (value);
      break;
    case PROP_COMPLEXITY:
      enc->complexity = g_value_get_int (value);
      break;
    case PROP_MAX_BITRATE:
      enc->max_bitrate = g_value_get_int (value);
      break;
    case PROP_PREDICTION:
      enc->prediction = g_value_get_enum (value);
      break;
    case PROP_START_BAND:
      enc->start_band = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}