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90f5ae8f45
ULP FEC, as defined in RFC 5109, has the protected and protection packets sharing the same ssrc, and a different payload type, and implies rewriting the seqnums of the protected stream when encoding the protection packets. This has the unfortunate drawback of not being able to tell whether a lost packet was a protection packet. rtpbasedepayload relies on gaps in the seqnums to set the DISCONT flag on buffers it outputs. Before that commit, this created two problems: * The protection packets don't make it as far as the depayloader, which means it will mark buffers as DISCONT every time the previous packets were protected * While we could work around the previous issue by looking at the protection packets ignored and dropped in rtpptdemux, we would still mark buffers as DISCONT when a FEC packet was lost, as we cannot know that it was indeed a FEC packet, even though this should have no impact on the decoding of the stream With this commit, we consider that when using ULPFEC, gaps in the seqnums are not a reliable indicator of whether buffers should be marked as DISCONT or not, and thus rewrite the seqnums on the decoding side as well to form a perfect sequence, this obviously doesn't prevent the jitterbuffer from doing its job as the ulpfec decoder is downstream from it. https://bugzilla.gnome.org/show_bug.cgi?id=794909
85 lines
2.4 KiB
C
85 lines
2.4 KiB
C
/* GStreamer plugin for forward error correction
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* Copyright (C) 2017 Pexip
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Author: Mikhail Fludkov <misha@pexip.com>
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*/
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#ifndef __GST_RTP_ULPFEC_DEC_H__
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#define __GST_RTP_ULPFEC_DEC_H__
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#include <gst/gst.h>
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#include "rtpstorage.h"
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G_BEGIN_DECLS
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#define GST_TYPE_RTP_ULPFEC_DEC \
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(gst_rtp_ulpfec_dec_get_type())
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#define GST_RTP_ULPFEC_DEC(obj) \
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(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_RTP_ULPFEC_DEC,GstRtpUlpFecDec))
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#define GST_RTP_ULPFEC_DEC_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_RTP_ULPFEC_DEC,GstRtpUlpFecDecClass))
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#define GST_IS_RTP_ULPFEC_DEC(obj) \
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(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_RTP_ULPFEC_DEC))
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#define GST_IS_RTP_ULPFEC_DEC_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_RTP_ULPFEC_DEC))
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typedef struct _GstRtpUlpFecDec GstRtpUlpFecDec;
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typedef struct _GstRtpUlpFecDecClass GstRtpUlpFecDecClass;
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struct _GstRtpUlpFecDecClass {
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GstElementClass parent_class;
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};
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struct _GstRtpUlpFecDec {
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GstElement parent;
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GstPad *srcpad;
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GstPad *sinkpad;
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/* properties */
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guint8 fec_pt;
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RtpStorage *storage;
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gsize packets_recovered;
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gsize packets_unrecovered;
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/* internal stuff */
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GstFlowReturn chain_return_val;
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gboolean unset_discont_flag;
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gboolean have_caps_ssrc;
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gboolean have_caps_pt;
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guint32 caps_ssrc;
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guint8 caps_pt;
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GList *info_media;
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GPtrArray *info_fec;
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GArray *info_arr;
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GArray *scratch_buf;
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gboolean lost_packet_from_storage;
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gboolean lost_packet_returned;
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guint16 next_seqnum;
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/* stats */
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gsize fec_packets_received;
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gsize fec_packets_rejected;
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gsize packets_rejected;
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};
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GType gst_rtp_ulpfec_dec_get_type (void);
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G_END_DECLS
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#endif /* __GST_RTP_ULPFEC_DEC_H__ */
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