[vlc-commits] [Git][videolan/vlc][master] 3 commits: rtp: add audio/ac3 payload parser
Rémi Denis-Courmont (@Courmisch)
gitlab at videolan.org
Fri Dec 3 07:57:07 UTC 2021
Rémi Denis-Courmont pushed to branch master at VideoLAN / VLC
Commits:
091c8500 by Rémi Denis-Courmont at 2021-12-03T07:43:07+00:00
rtp: add audio/ac3 payload parser
- - - - -
a368e7c6 by Rémi Denis-Courmont at 2021-12-03T07:43:07+00:00
rtp/ac3: add a private structure
- - - - -
fcb3359d by Rémi Denis-Courmont at 2021-12-03T07:43:07+00:00
rtp/ac3: add support for E-AC-3 (audio/eac3)
- - - - -
2 changed files:
- modules/access/rtp/Makefile.am
- + modules/access/rtp/ac3.c
Changes:
=====================================
modules/access/rtp/Makefile.am
=====================================
@@ -31,10 +31,12 @@ endif
# RTP payload parser plugins
rtpparsedir = $(accessdir)/rtp
rtpparse_LTLIBRARIES = \
+ librtp_ac3_plugin.la \
librtp_mpeg12_plugin.la \
librtp_pcm_plugin.la \
librtp_xiph_plugin.la
+librtp_ac3_plugin_la_SOURCES = access/rtp/ac3.c
librtp_mpeg12_plugin_la_SOURCES = access/rtp/mpeg12.c
librtp_pcm_plugin_la_SOURCES = access/rtp/pcm.c
=====================================
modules/access/rtp/ac3.c
=====================================
@@ -0,0 +1,252 @@
+/**
+ * @file ac3.c
+ * @brief RTP AC-3 and E-AC-3 payload format parser
+ */
+/*****************************************************************************
+ * Copyright © 2021 Rémi Denis-Courmont
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ ****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <vlc_common.h>
+#include <vlc_block.h>
+#include <vlc_es.h>
+#include <vlc_plugin.h>
+#include <vlc_strings.h>
+
+#include "rtp.h"
+#include "../../packetizer/a52.h"
+
+struct rtp_ac3 {
+ struct vlc_logger *logger;
+ bool enhanced;
+};
+
+struct rtp_ac3_source {
+ block_t *frags;
+ block_t **frag_end;
+ unsigned char missing;
+ struct vlc_rtp_es *es;
+};
+
+static void *rtp_ac3_begin(struct vlc_rtp_pt *pt)
+{
+ struct rtp_ac3 *sys = pt->opaque;
+ struct rtp_ac3_source *src = malloc(sizeof (*src));
+ if (unlikely(src == NULL))
+ return NULL;
+
+ src->frags = NULL;
+ src->frag_end = &src->frags;
+
+ es_format_t fmt;
+
+ es_format_Init(&fmt, AUDIO_ES, sys->enhanced ? VLC_CODEC_EAC3
+ : VLC_CODEC_A52);
+ fmt.audio.i_rate = pt->frequency;
+ if (!sys->enhanced)
+ fmt.audio.i_channels = pt->channel_count ? pt->channel_count : 6;
+ src->es = vlc_rtp_pt_request_es(pt, &fmt);
+ return src;
+}
+
+static void rtp_ac3_end(struct vlc_rtp_pt *pt, void *data)
+{
+ struct rtp_ac3_source *src = data;
+
+ if (unlikely(src == NULL))
+ return;
+
+ vlc_rtp_es_destroy(src->es);
+ block_ChainRelease(src->frags);
+ free(src);
+ (void) pt;
+}
+
+static void rtp_ac3_decode_compound(struct vlc_logger *log, bool enhanced,
+ struct rtp_ac3_source *src,
+ block_t *block, unsigned int frames)
+{
+ vlc_a52_header_t hdr;
+
+ if (frames == 0) {
+ block_Release(block);
+ return;
+ }
+
+ while (frames > 1) {
+ if (vlc_a52_header_Parse(&hdr, block->p_buffer, block->i_buffer)
+ || (hdr.b_eac3 && !enhanced)
+ || hdr.i_size > block->i_buffer) {
+ vlc_warning(log, "corrupt packet: %u frames, %zu bytes remaining",
+ frames, block->i_buffer);
+ block_Release(block);
+ return;
+ }
+
+ block_t *frame = block_Alloc(hdr.i_size);
+
+ if (likely(frame != NULL)) {
+ memcpy(frame->p_buffer, block->p_buffer, hdr.i_size);
+ frame->i_pts = block->i_pts;
+ vlc_rtp_es_send(src->es, frame);
+ }
+
+ block->p_buffer += hdr.i_size;
+ block->i_buffer -= hdr.i_size;
+ block->i_pts = VLC_TICK_INVALID;
+ frames--;
+ }
+
+ /* Send the last frame, no need to copy */
+ vlc_rtp_es_send(src->es, block);
+}
+
+static void rtp_ac3_send(struct rtp_ac3_source *src)
+{
+ block_t *frags = src->frags;
+ block_t *frame = block_ChainGather(frags);
+
+ if (likely(frame != NULL))
+ vlc_rtp_es_send(src->es, frame);
+ else
+ block_ChainRelease(frags);
+
+ src->frags = NULL;
+ src->frag_end = &src->frags;
+}
+
+static void rtp_ac3_decode(struct vlc_rtp_pt *pt, void *data, block_t *block,
+ const struct vlc_rtp_pktinfo *restrict info)
+{
+ struct rtp_ac3 *sys = pt->opaque;
+ struct rtp_ac3_source *src = data;
+ struct vlc_logger *log = sys->logger;
+
+ if (unlikely(src == NULL)) {
+drop: block_Release(block);
+ return;
+ }
+
+ if (block->i_buffer < 2) {
+ vlc_warning(log, "corrupt packet (%zu bytes)", block->i_buffer);
+ goto drop;
+ }
+
+ /* Payload header: 2 bytes, AC-3 (RFC4184 §4.1.1), E-AC-3 (RFC4598 §4.1) */
+ uint_fast8_t ftmask = sys->enhanced ? 1 : 3;
+ uint_fast8_t frametype = block->p_buffer[0] & ftmask;
+ uint_fast8_t framenum = block->p_buffer[1];
+
+ block->p_buffer += 2;
+ block->i_buffer -= 2;
+
+ if (src->frags != NULL && (frametype != ftmask || src->missing == 0)) {
+ /* Missed end of previous frame. */
+ src->frags->i_flags |= BLOCK_FLAG_CORRUPTED;
+ rtp_ac3_send(src);
+ vlc_warning(log, "reassembly error: %hhu missing fragments",
+ src->missing);
+ }
+
+ if (frametype == 0) {
+ rtp_ac3_decode_compound(log, sys->enhanced, src, block, framenum);
+ return;
+ }
+
+ if (src->frags == NULL) {
+ if (frametype == 3) {
+ /* Missed start of current frame. Not much to do without header. */
+ assert(!sys->enhanced);
+ block_Release(block);
+ vlc_warning(log, "reassembly error: missing initial fragment");
+ return;
+ }
+
+ /* Initial fragment of a new frame */
+ if (framenum == 0) {
+ block_Release(block);
+ return;
+ }
+
+ src->missing = framenum;
+ }
+
+ assert(src->missing > 0);
+ src->missing--;
+ *src->frag_end = block;
+ src->frag_end = &block->p_next;
+
+ if (info->m) {
+ if (src->missing != 0) {
+ src->frags->i_flags |= BLOCK_FLAG_CORRUPTED;
+ vlc_warning(log, "reassembly error: %hhu missing fragments",
+ src->missing);
+ }
+ rtp_ac3_send(src);
+ }
+}
+
+static void rtp_ac3_destroy(struct vlc_rtp_pt *pt)
+{
+ struct rtp_ac3 *sys = pt->opaque;
+
+ free(sys);
+}
+
+static const struct vlc_rtp_pt_operations rtp_ac3_ops = {
+ rtp_ac3_destroy, rtp_ac3_begin, rtp_ac3_end, rtp_ac3_decode,
+};
+
+
+static int rtp_ac3_open(vlc_object_t *obj, struct vlc_rtp_pt *pt,
+ const struct vlc_sdp_pt *desc)
+{
+ bool enhanced;
+
+ if (vlc_ascii_strcasecmp(desc->name, "ac3") == 0) /* RFC4184 */
+ enhanced = false;
+ else
+ if (vlc_ascii_strcasecmp(desc->name, "eac3") == 0) /* RFC4598 */
+ enhanced = true;
+ else
+ return VLC_ENOTSUP;
+
+ struct rtp_ac3 *sys = malloc(sizeof (*sys));
+ if (unlikely(sys == NULL))
+ return VLC_ENOMEM;
+
+ sys->logger = vlc_object_logger(obj);
+ sys->enhanced = enhanced;
+ pt->opaque = sys;
+ pt->ops = &rtp_ac3_ops;
+ return VLC_SUCCESS;
+}
+
+vlc_module_begin()
+ set_shortname(N_("RTP AC3"))
+ set_description(N_("RTP AC-3 payload parser"))
+ set_category(CAT_INPUT)
+ set_subcategory(SUBCAT_INPUT_DEMUX)
+ set_rtp_parser_callback(rtp_ac3_open)
+ add_shortcut("audio/ac3", "audio/eac3")
+vlc_module_end()
View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/08891a8df34c2be265678843d23b3cb3ae23c7c2...fcb3359d5eeffb97b648a7e9ccea9b585e702185
--
View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/08891a8df34c2be265678843d23b3cb3ae23c7c2...fcb3359d5eeffb97b648a7e9ccea9b585e702185
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