1 /* GStreamer AC3 parser
2 * Copyright (C) 2009 Tim-Philipp Müller <tim centricular net>
3 * Copyright (C) 2009 Mark Nauwelaerts <mnauw users sf net>
4 * Copyright (C) 2009 Nokia Corporation. All rights reserved.
5 * Contact: Stefan Kost <stefan.kost@nokia.com>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
23 * SECTION:element-ac3parse
24 * @short_description: AC3 parser
25 * @see_also: #GstAmrParse, #GstAACParse
27 * This is an AC3 parser.
30 * <title>Example launch line</title>
32 * gst-launch-1.0 filesrc location=abc.ac3 ! ac3parse ! a52dec ! audioresample ! audioconvert ! autoaudiosink
38 * - audio/ac3 to audio/x-private1-ac3 is not implemented (done in the muxer)
39 * - should accept framed and unframed input (needs decodebin fixes first)
48 #include "gstac3parse.h"
49 #include <gst/base/base.h>
50 #include <gst/pbutils/pbutils.h>
52 GST_DEBUG_CATEGORY_STATIC (ac3_parse_debug);
53 #define GST_CAT_DEFAULT ac3_parse_debug
57 const guint bit_rate; /* nominal bit rate */
58 const guint frame_size[3]; /* frame size for 32kHz, 44kHz, and 48kHz */
59 } frmsizcod_table[38] = {
126 1024, 1114, 1536}}, {
128 1024, 1115, 1536}}, {
130 1152, 1253, 1728}}, {
132 1152, 1254, 1728}}, {
134 1280, 1393, 1920}}, {
139 static const guint fscod_rates[4] = { 48000, 44100, 32000, 0 };
140 static const guint acmod_chans[8] = { 2, 1, 2, 3, 3, 4, 4, 5 };
141 static const guint numblks[4] = { 1, 2, 3, 6 };
143 static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
146 GST_STATIC_CAPS ("audio/x-ac3, framed = (boolean) true, "
147 " channels = (int) [ 1, 6 ], rate = (int) [ 8000, 48000 ], "
148 " alignment = (string) { iec61937, frame}; "
149 "audio/x-eac3, framed = (boolean) true, "
150 " channels = (int) [ 1, 6 ], rate = (int) [ 8000, 48000 ], "
151 " alignment = (string) { iec61937, frame}; "));
153 static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
156 GST_STATIC_CAPS ("audio/x-ac3; " "audio/x-eac3; " "audio/ac3; "
157 "audio/x-private1-ac3"));
159 static void gst_ac3_parse_finalize (GObject * object);
161 static gboolean gst_ac3_parse_start (GstBaseParse * parse);
162 static gboolean gst_ac3_parse_stop (GstBaseParse * parse);
163 static GstFlowReturn gst_ac3_parse_handle_frame (GstBaseParse * parse,
164 GstBaseParseFrame * frame, gint * skipsize);
165 static GstFlowReturn gst_ac3_parse_pre_push_frame (GstBaseParse * parse,
166 GstBaseParseFrame * frame);
167 static gboolean gst_ac3_parse_src_event (GstBaseParse * parse,
169 static GstCaps *gst_ac3_parse_get_sink_caps (GstBaseParse * parse,
171 static gboolean gst_ac3_parse_set_sink_caps (GstBaseParse * parse,
174 #define gst_ac3_parse_parent_class parent_class
175 G_DEFINE_TYPE (GstAc3Parse, gst_ac3_parse, GST_TYPE_BASE_PARSE);
178 gst_ac3_parse_class_init (GstAc3ParseClass * klass)
180 GObjectClass *object_class = G_OBJECT_CLASS (klass);
181 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
182 GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
184 GST_DEBUG_CATEGORY_INIT (ac3_parse_debug, "ac3parse", 0,
185 "AC3 audio stream parser");
187 object_class->finalize = gst_ac3_parse_finalize;
189 gst_element_class_add_static_pad_template (element_class, &sink_template);
190 gst_element_class_add_static_pad_template (element_class, &src_template);
192 gst_element_class_set_static_metadata (element_class,
193 "AC3 audio stream parser", "Codec/Parser/Converter/Audio",
194 "AC3 parser", "Tim-Philipp Müller <tim centricular net>");
196 parse_class->start = GST_DEBUG_FUNCPTR (gst_ac3_parse_start);
197 parse_class->stop = GST_DEBUG_FUNCPTR (gst_ac3_parse_stop);
198 parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_ac3_parse_handle_frame);
199 parse_class->pre_push_frame =
200 GST_DEBUG_FUNCPTR (gst_ac3_parse_pre_push_frame);
201 parse_class->src_event = GST_DEBUG_FUNCPTR (gst_ac3_parse_src_event);
202 parse_class->get_sink_caps = GST_DEBUG_FUNCPTR (gst_ac3_parse_get_sink_caps);
203 parse_class->set_sink_caps = GST_DEBUG_FUNCPTR (gst_ac3_parse_set_sink_caps);
207 gst_ac3_parse_reset (GstAc3Parse * ac3parse)
209 ac3parse->channels = -1;
210 ac3parse->sample_rate = -1;
211 ac3parse->blocks = -1;
212 ac3parse->eac = FALSE;
213 ac3parse->sent_codec_tag = FALSE;
214 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_NONE);
218 gst_ac3_parse_init (GstAc3Parse * ac3parse)
220 gst_base_parse_set_min_frame_size (GST_BASE_PARSE (ac3parse), 8);
221 gst_ac3_parse_reset (ac3parse);
222 ac3parse->baseparse_chainfunc =
223 GST_BASE_PARSE_SINK_PAD (GST_BASE_PARSE (ac3parse))->chainfunc;
224 GST_PAD_SET_ACCEPT_INTERSECT (GST_BASE_PARSE_SINK_PAD (ac3parse));
225 GST_PAD_SET_ACCEPT_TEMPLATE (GST_BASE_PARSE_SINK_PAD (ac3parse));
229 gst_ac3_parse_finalize (GObject * object)
231 G_OBJECT_CLASS (parent_class)->finalize (object);
235 gst_ac3_parse_start (GstBaseParse * parse)
237 GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
239 GST_DEBUG_OBJECT (parse, "starting");
241 gst_ac3_parse_reset (ac3parse);
247 gst_ac3_parse_stop (GstBaseParse * parse)
249 GST_DEBUG_OBJECT (parse, "stopping");
255 gst_ac3_parse_set_alignment (GstAc3Parse * ac3parse, gboolean eac)
259 const gchar *str = NULL;
265 caps = gst_pad_get_allowed_caps (GST_BASE_PARSE_SRC_PAD (ac3parse));
270 for (i = 0; i < gst_caps_get_size (caps); i++) {
271 st = gst_caps_get_structure (caps, i);
273 if (!g_str_equal (gst_structure_get_name (st), "audio/x-eac3"))
276 if ((str = gst_structure_get_string (st, "alignment"))) {
277 if (g_str_equal (str, "iec61937")) {
278 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_IEC61937);
279 GST_DEBUG_OBJECT (ac3parse, "picked iec61937 alignment");
280 } else if (g_str_equal (str, "frame") == 0) {
281 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_FRAME);
282 GST_DEBUG_OBJECT (ac3parse, "picked frame alignment");
284 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_FRAME);
285 GST_WARNING_OBJECT (ac3parse, "unknown alignment: %s", str);
292 gst_caps_unref (caps);
296 if (ac3parse->align == GST_AC3_PARSE_ALIGN_NONE) {
297 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_FRAME);
298 GST_DEBUG_OBJECT (ac3parse, "picked syncframe alignment");
303 gst_ac3_parse_frame_header_ac3 (GstAc3Parse * ac3parse, GstBuffer * buf,
304 gint skip, guint * frame_size, guint * rate, guint * chans, guint * blks,
309 guint8 fscod, frmsizcod, bsid, acmod, lfe_on, rate_scale;
310 gboolean ret = FALSE;
312 GST_LOG_OBJECT (ac3parse, "parsing ac3");
314 gst_buffer_map (buf, &map, GST_MAP_READ);
315 gst_bit_reader_init (&bits, map.data, map.size);
316 gst_bit_reader_skip_unchecked (&bits, skip * 8);
318 gst_bit_reader_skip_unchecked (&bits, 16 + 16);
319 fscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2);
320 frmsizcod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 6);
322 if (G_UNLIKELY (fscod == 3 || frmsizcod >= G_N_ELEMENTS (frmsizcod_table))) {
323 GST_DEBUG_OBJECT (ac3parse, "bad fscod=%d frmsizcod=%d", fscod, frmsizcod);
327 bsid = gst_bit_reader_get_bits_uint8_unchecked (&bits, 5);
328 gst_bit_reader_skip_unchecked (&bits, 3); /* bsmod */
329 acmod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3);
331 /* spec not quite clear here: decoder should decode if less than 8,
332 * but seemingly only defines 6 and 8 cases */
333 /* Files with 9 and 10 happen, and seem to comply with the <= 8
334 format, so let them through. The spec says nothing about 9 and 10 */
336 GST_DEBUG_OBJECT (ac3parse, "unexpected bsid=%d", bsid);
338 } else if (bsid != 8 && bsid != 6) {
339 GST_DEBUG_OBJECT (ac3parse, "undefined bsid=%d", bsid);
342 if ((acmod & 0x1) && (acmod != 0x1)) /* 3 front channels */
343 gst_bit_reader_skip_unchecked (&bits, 2);
344 if ((acmod & 0x4)) /* if a surround channel exists */
345 gst_bit_reader_skip_unchecked (&bits, 2);
346 if (acmod == 0x2) /* if in 2/0 mode */
347 gst_bit_reader_skip_unchecked (&bits, 2);
349 lfe_on = gst_bit_reader_get_bits_uint8_unchecked (&bits, 1);
351 /* 6/8->0, 9->1, 10->2,
352 see http://matroska.org/technical/specs/codecid/index.html */
353 rate_scale = (CLAMP (bsid, 8, 10) - 8);
356 *frame_size = frmsizcod_table[frmsizcod].frame_size[fscod] * 2;
358 *rate = fscod_rates[fscod] >> rate_scale;
360 *chans = acmod_chans[acmod] + lfe_on;
369 gst_buffer_unmap (buf, &map);
375 gst_ac3_parse_frame_header_eac3 (GstAc3Parse * ac3parse, GstBuffer * buf,
376 gint skip, guint * frame_size, guint * rate, guint * chans, guint * blks,
381 guint16 frmsiz, sample_rate, blocks;
382 guint8 strmtyp, fscod, fscod2, acmod, lfe_on, strmid, numblkscod;
383 gboolean ret = FALSE;
385 GST_LOG_OBJECT (ac3parse, "parsing e-ac3");
387 gst_buffer_map (buf, &map, GST_MAP_READ);
388 gst_bit_reader_init (&bits, map.data, map.size);
389 gst_bit_reader_skip_unchecked (&bits, skip * 8);
391 gst_bit_reader_skip_unchecked (&bits, 16);
392 strmtyp = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* strmtyp */
393 if (G_UNLIKELY (strmtyp == 3)) {
394 GST_DEBUG_OBJECT (ac3parse, "bad strmtyp %d", strmtyp);
398 strmid = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3); /* substreamid */
399 frmsiz = gst_bit_reader_get_bits_uint16_unchecked (&bits, 11); /* frmsiz */
400 fscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* fscod */
402 fscod2 = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* fscod2 */
403 if (G_UNLIKELY (fscod2 == 3)) {
404 GST_DEBUG_OBJECT (ac3parse, "invalid fscod2");
407 sample_rate = fscod_rates[fscod2] / 2;
410 numblkscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* numblkscod */
411 sample_rate = fscod_rates[fscod];
412 blocks = numblks[numblkscod];
415 acmod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3); /* acmod */
416 lfe_on = gst_bit_reader_get_bits_uint8_unchecked (&bits, 1); /* lfeon */
418 gst_bit_reader_skip_unchecked (&bits, 5); /* bsid */
421 *frame_size = (frmsiz + 1) * 2;
425 *chans = acmod_chans[acmod] + lfe_on;
429 *sid = (strmtyp & 0x1) << 3 | strmid;
434 gst_buffer_unmap (buf, &map);
440 gst_ac3_parse_frame_header (GstAc3Parse * parse, GstBuffer * buf, gint skip,
441 guint * framesize, guint * rate, guint * chans, guint * blocks,
442 guint * sid, gboolean * eac)
448 gboolean ret = FALSE;
450 gst_buffer_map (buf, &map, GST_MAP_READ);
451 gst_bit_reader_init (&bits, map.data, map.size);
453 GST_MEMDUMP_OBJECT (parse, "AC3 frame sync", map.data, MIN (map.size, 16));
455 gst_bit_reader_skip_unchecked (&bits, skip * 8);
457 sync = gst_bit_reader_get_bits_uint16_unchecked (&bits, 16);
458 gst_bit_reader_skip_unchecked (&bits, 16 + 8);
459 bsid = gst_bit_reader_peek_bits_uint8_unchecked (&bits, 5);
461 if (G_UNLIKELY (sync != 0x0b77))
464 GST_LOG_OBJECT (parse, "bsid = %d", bsid);
469 ret = gst_ac3_parse_frame_header_ac3 (parse, buf, skip, framesize, rate,
472 } else if (bsid <= 16) {
475 ret = gst_ac3_parse_frame_header_eac3 (parse, buf, skip, framesize, rate,
479 GST_DEBUG_OBJECT (parse, "unexpected bsid %d", bsid);
484 GST_DEBUG_OBJECT (parse, "unexpected bsid %d", bsid);
487 gst_buffer_unmap (buf, &map);
493 gst_ac3_parse_handle_frame (GstBaseParse * parse,
494 GstBaseParseFrame * frame, gint * skipsize)
496 GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
497 GstBuffer *buf = frame->buffer;
498 GstByteReader reader;
500 gboolean lost_sync, draining, eac, more = FALSE;
501 guint frmsiz, blocks, sid;
503 gboolean update_rate = FALSE;
505 gint have_blocks = 0;
507 gboolean ret = FALSE;
508 GstFlowReturn res = GST_FLOW_OK;
510 gst_buffer_map (buf, &map, GST_MAP_READ);
512 if (G_UNLIKELY (map.size < 8)) {
517 gst_byte_reader_init (&reader, map.data, map.size);
518 off = gst_byte_reader_masked_scan_uint32 (&reader, 0xffff0000, 0x0b770000,
521 GST_LOG_OBJECT (parse, "possible sync at buffer offset %d", off);
523 /* didn't find anything that looks like a sync word, skip */
525 *skipsize = map.size - 3;
529 /* possible frame header, but not at offset 0? skip bytes before sync */
535 /* make sure the values in the frame header look sane */
536 if (!gst_ac3_parse_frame_header (ac3parse, buf, 0, &frmsiz, &rate, &chans,
537 &blocks, &sid, &eac)) {
542 GST_LOG_OBJECT (parse, "size: %u, blocks: %u, rate: %u, chans: %u", frmsiz,
543 blocks, rate, chans);
547 if (G_UNLIKELY (g_atomic_int_get (&ac3parse->align) ==
548 GST_AC3_PARSE_ALIGN_NONE))
549 gst_ac3_parse_set_alignment (ac3parse, eac);
551 GST_LOG_OBJECT (parse, "got frame");
553 lost_sync = GST_BASE_PARSE_LOST_SYNC (parse);
554 draining = GST_BASE_PARSE_DRAINING (parse);
556 if (g_atomic_int_get (&ac3parse->align) == GST_AC3_PARSE_ALIGN_IEC61937) {
557 /* We need 6 audio blocks from each substream, so we keep going forwards
560 g_assert (blocks > 0);
561 GST_LOG_OBJECT (ac3parse, "Need %d frames before pushing", 6 / blocks);
564 /* We need the first substream to be the one with id 0 */
565 GST_LOG_OBJECT (ac3parse, "Skipping till we find sid 0");
572 /* Loop till we have 6 blocks per substream */
573 for (have_blocks = 0; !more && have_blocks < 6; have_blocks += blocks) {
574 /* Loop till we get one frame from each substream */
578 if (!gst_byte_reader_skip (&reader, frmsiz)
579 || map.size < (framesize + 6)) {
584 if (!gst_ac3_parse_frame_header (ac3parse, buf, framesize, &frmsiz,
585 NULL, NULL, NULL, &sid, &eac)) {
592 /* We're now at the next frame, so no need to skip if resyncing */
596 if (lost_sync && !draining) {
599 GST_DEBUG_OBJECT (ac3parse, "resyncing; checking next frame syncword");
601 if (more || !gst_byte_reader_skip (&reader, frmsiz) ||
602 !gst_byte_reader_get_uint16_be (&reader, &word)) {
603 GST_DEBUG_OBJECT (ac3parse, "... but not sufficient data");
604 gst_base_parse_set_min_frame_size (parse, framesize + 8);
608 if (word != 0x0b77) {
609 GST_DEBUG_OBJECT (ac3parse, "0x%x not OK", word);
613 /* ok, got sync now, let's assume constant frame size */
614 gst_base_parse_set_min_frame_size (parse, framesize);
619 /* expect to have found a frame here */
620 g_assert (framesize);
623 /* arrange for metadata setup */
624 if (G_UNLIKELY (sid)) {
625 /* dependent frame, no need to (ac)count for or consider further */
626 GST_LOG_OBJECT (parse, "sid: %d", sid);
627 frame->flags |= GST_BASE_PARSE_FRAME_FLAG_NO_FRAME;
628 /* TODO maybe also mark as DELTA_UNIT,
629 * if that does not surprise baseparse elsewhere */
630 /* occupies same time space as previous base frame */
631 if (G_LIKELY (GST_BUFFER_TIMESTAMP (buf) >= GST_BUFFER_DURATION (buf)))
632 GST_BUFFER_TIMESTAMP (buf) -= GST_BUFFER_DURATION (buf);
633 /* only shortcut if we already arranged for caps */
634 if (G_LIKELY (ac3parse->sample_rate > 0))
638 if (G_UNLIKELY (ac3parse->sample_rate != rate || ac3parse->channels != chans
639 || ac3parse->eac != eac)) {
640 GstCaps *caps = gst_caps_new_simple (eac ? "audio/x-eac3" : "audio/x-ac3",
641 "framed", G_TYPE_BOOLEAN, TRUE, "rate", G_TYPE_INT, rate,
642 "channels", G_TYPE_INT, chans, NULL);
643 gst_caps_set_simple (caps, "alignment", G_TYPE_STRING,
644 g_atomic_int_get (&ac3parse->align) == GST_AC3_PARSE_ALIGN_IEC61937 ?
645 "iec61937" : "frame", NULL);
646 gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (parse), caps);
647 gst_caps_unref (caps);
649 ac3parse->sample_rate = rate;
650 ac3parse->channels = chans;
656 if (G_UNLIKELY (ac3parse->blocks != blocks)) {
657 ac3parse->blocks = blocks;
662 if (G_UNLIKELY (update_rate))
663 gst_base_parse_set_frame_rate (parse, rate, 256 * blocks, 2, 2);
666 gst_buffer_unmap (buf, &map);
668 if (ret && framesize <= map.size) {
669 res = gst_base_parse_finish_frame (parse, frame, framesize);
677 * MPEG-PS private1 streams add a 2 bytes "Audio Substream Headers" for each
678 * buffer (not each frame) with the offset of the next frame's start.
681 * -------------------------------------------
682 * |firstAccUnit|AC3SyncWord|xxxxxxxxxxxxxxxxx
683 * -------------------------------------------
685 * -------------------------------------------
686 * |firstAccUnit|xxxxxx|AC3SyncWord|xxxxxxxxxx
687 * -------------------------------------------
689 * These 2 bytes can be dropped safely as they do not include any timing
690 * information, only the offset to the start of the next frame.
692 * From http://stnsoft.com/DVD/ass-hdr.html:
693 * "FirstAccUnit offset to frame which corresponds to PTS value offset 0 is the
694 * last byte of FirstAccUnit, ie add the offset of byte 2 to get the AU's offset
695 * The value 0000 indicates there is no first access unit"
699 gst_ac3_parse_chain_priv (GstPad * pad, GstObject * parent, GstBuffer * buf)
701 GstAc3Parse *ac3parse = GST_AC3_PARSE (parent);
710 size = gst_buffer_get_size (buf);
712 goto not_enough_data;
714 gst_buffer_extract (buf, 0, data, 2);
715 first_access = (data[0] << 8) | data[1];
717 /* Skip the first_access header */
720 if (first_access > 1) {
721 /* Length of data before first_access */
722 len = first_access - 1;
724 if (len <= 0 || offset + len > size)
725 goto bad_first_access_parameter;
727 subbuf = gst_buffer_copy_region (buf, GST_BUFFER_COPY_ALL, offset, len);
728 GST_BUFFER_DTS (subbuf) = GST_CLOCK_TIME_NONE;
729 GST_BUFFER_PTS (subbuf) = GST_CLOCK_TIME_NONE;
730 ret = ac3parse->baseparse_chainfunc (pad, parent, subbuf);
731 if (ret != GST_FLOW_OK && ret != GST_FLOW_NOT_LINKED) {
732 gst_buffer_unref (buf);
740 subbuf = gst_buffer_copy_region (buf, GST_BUFFER_COPY_ALL, offset, len);
741 GST_BUFFER_PTS (subbuf) = GST_BUFFER_PTS (buf);
742 GST_BUFFER_DTS (subbuf) = GST_BUFFER_DTS (buf);
744 ret = ac3parse->baseparse_chainfunc (pad, parent, subbuf);
746 gst_buffer_unref (buf);
748 /* first_access = 0 or 1, so if there's a timestamp it applies to the first byte */
750 gst_buffer_copy_region (buf, GST_BUFFER_COPY_ALL, offset,
752 GST_BUFFER_PTS (subbuf) = GST_BUFFER_PTS (buf);
753 GST_BUFFER_DTS (subbuf) = GST_BUFFER_DTS (buf);
754 gst_buffer_unref (buf);
755 ret = ac3parse->baseparse_chainfunc (pad, parent, subbuf);
764 GST_ELEMENT_ERROR (GST_ELEMENT (ac3parse), STREAM, FORMAT, (NULL),
765 ("Insufficient data in buffer. Can't determine first_acess"));
766 gst_buffer_unref (buf);
767 return GST_FLOW_ERROR;
769 bad_first_access_parameter:
771 GST_ELEMENT_ERROR (GST_ELEMENT (ac3parse), STREAM, FORMAT, (NULL),
772 ("Bad first_access parameter (%d) in buffer", first_access));
773 gst_buffer_unref (buf);
774 return GST_FLOW_ERROR;
779 gst_ac3_parse_pre_push_frame (GstBaseParse * parse, GstBaseParseFrame * frame)
781 GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
783 if (!ac3parse->sent_codec_tag) {
788 caps = gst_pad_get_current_caps (GST_BASE_PARSE_SRC_PAD (parse));
789 if (G_UNLIKELY (caps == NULL)) {
790 if (GST_PAD_IS_FLUSHING (GST_BASE_PARSE_SRC_PAD (parse))) {
791 GST_INFO_OBJECT (parse, "Src pad is flushing");
792 return GST_FLOW_FLUSHING;
794 GST_INFO_OBJECT (parse, "Src pad is not negotiated!");
795 return GST_FLOW_NOT_NEGOTIATED;
799 taglist = gst_tag_list_new_empty ();
800 gst_pb_utils_add_codec_description_to_tag_list (taglist,
801 GST_TAG_AUDIO_CODEC, caps);
802 gst_caps_unref (caps);
804 gst_base_parse_merge_tags (parse, taglist, GST_TAG_MERGE_REPLACE);
805 gst_tag_list_unref (taglist);
807 /* also signals the end of first-frame processing */
808 ac3parse->sent_codec_tag = TRUE;
815 gst_ac3_parse_src_event (GstBaseParse * parse, GstEvent * event)
817 GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
819 if (G_UNLIKELY (GST_EVENT_TYPE (event) == GST_EVENT_CUSTOM_UPSTREAM) &&
820 gst_event_has_name (event, "ac3parse-set-alignment")) {
821 const GstStructure *st = gst_event_get_structure (event);
822 const gchar *align = gst_structure_get_string (st, "alignment");
824 if (g_str_equal (align, "iec61937")) {
825 GST_DEBUG_OBJECT (ac3parse, "Switching to iec61937 alignment");
826 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_IEC61937);
827 } else if (g_str_equal (align, "frame")) {
828 GST_DEBUG_OBJECT (ac3parse, "Switching to frame alignment");
829 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_FRAME);
831 g_atomic_int_set (&ac3parse->align, GST_AC3_PARSE_ALIGN_FRAME);
832 GST_WARNING_OBJECT (ac3parse, "Got unknown alignment request (%s) "
833 "reverting to frame alignment.",
834 gst_structure_get_string (st, "alignment"));
837 gst_event_unref (event);
841 return GST_BASE_PARSE_CLASS (parent_class)->src_event (parse, event);
845 remove_fields (GstCaps * caps)
849 n = gst_caps_get_size (caps);
850 for (i = 0; i < n; i++) {
851 GstStructure *s = gst_caps_get_structure (caps, i);
853 gst_structure_remove_field (s, "framed");
854 gst_structure_remove_field (s, "alignment");
859 extend_caps (GstCaps * caps, gboolean add_private)
862 GstCaps *ncaps = gst_caps_new_empty ();
864 n = gst_caps_get_size (caps);
865 for (i = 0; i < n; i++) {
866 GstStructure *s = gst_caps_get_structure (caps, i);
868 if (add_private && !gst_structure_has_name (s, "audio/x-private1-ac3")) {
869 GstStructure *ns = gst_structure_copy (s);
870 gst_structure_set_name (ns, "audio/x-private1-ac3");
871 gst_caps_append_structure (ncaps, ns);
872 } else if (!add_private &&
873 gst_structure_has_name (s, "audio/x-private1-ac3")) {
874 GstStructure *ns = gst_structure_copy (s);
875 gst_structure_set_name (ns, "audio/x-ac3");
876 gst_caps_append_structure (ncaps, ns);
877 ns = gst_structure_copy (s);
878 gst_structure_set_name (ns, "audio/x-eac3");
879 gst_caps_append_structure (ncaps, ns);
880 } else if (!add_private) {
881 gst_caps_append_structure (ncaps, gst_structure_copy (s));
886 gst_caps_append (caps, ncaps);
888 gst_caps_unref (caps);
896 gst_ac3_parse_get_sink_caps (GstBaseParse * parse, GstCaps * filter)
898 GstCaps *peercaps, *templ;
901 templ = gst_pad_get_pad_template_caps (GST_BASE_PARSE_SINK_PAD (parse));
903 GstCaps *fcopy = gst_caps_copy (filter);
904 /* Remove the fields we convert */
905 remove_fields (fcopy);
906 /* we do not ask downstream to handle x-private1-ac3 */
907 fcopy = extend_caps (fcopy, FALSE);
908 peercaps = gst_pad_peer_query_caps (GST_BASE_PARSE_SRC_PAD (parse), fcopy);
909 gst_caps_unref (fcopy);
911 peercaps = gst_pad_peer_query_caps (GST_BASE_PARSE_SRC_PAD (parse), NULL);
914 /* Remove the framed and alignment field. We can convert
915 * between different alignments. */
916 peercaps = gst_caps_make_writable (peercaps);
917 remove_fields (peercaps);
918 /* also allow for x-private1-ac3 input */
919 peercaps = extend_caps (peercaps, TRUE);
921 res = gst_caps_intersect_full (peercaps, templ, GST_CAPS_INTERSECT_FIRST);
922 gst_caps_unref (peercaps);
923 gst_caps_unref (templ);
929 GstCaps *intersection;
932 gst_caps_intersect_full (filter, res, GST_CAPS_INTERSECT_FIRST);
933 gst_caps_unref (res);
941 gst_ac3_parse_set_sink_caps (GstBaseParse * parse, GstCaps * caps)
944 GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
946 s = gst_caps_get_structure (caps, 0);
947 if (gst_structure_has_name (s, "audio/x-private1-ac3")) {
948 gst_pad_set_chain_function (parse->sinkpad, gst_ac3_parse_chain_priv);
950 gst_pad_set_chain_function (parse->sinkpad, ac3parse->baseparse_chainfunc);