gstreamer/ext/avtp/gstavtpaafpay.h
Andre Guedes 1e985f02f4 avtp: Introduce AAF payloader element
This patch introduces the AVTP Audio Format (AAF) payloader element from
the AVTP plugin. The element inputs audio raw data and outputs AVTP
packets (aka AVTPDUs), implementing a typical protocol payloader element
from GStreamer.

AAF is one of the available formats to transport audio data in an AVTP
system. AAF is specified in IEEE 1722-2016 section 7 and provides two
encapsulation mode: PCM and AES3. This patch implements PCM
encapsulation mode only.

The AAF payloader working mechanism consists of building the AAF header,
prepending it to the GstBuffer received on the sink pad, and pushing the
buffer downstream. Payloader parameters such as stream ID, maximum
transit time, time uncertainty, and timestamping mode are passed via
element properties. AAF doesn't support all possible sample format and
sampling rate values so the sink pad caps template from the payloader is
a subset of audio/x-raw. Additionally, this patch implements only
"normal" timestamping mode from AAF. "Sparse" mode should be implemented
in future.

Upcoming patches will introduce other AVTP payloader elements that will
have some common code. For that reason, this patch introduces the
GstAvtpBasePayload abstract class that implements common payloader
functionalities, and the GstAvtpAafPay class that extends the
GstAvtpBasePayload class, implementing AAF-specific functionalities.

The AAF payloader element is most likely to be used with the AVTP sink
element (to be introduced by a later patch) but it could also be used
with UDP sink element to implement AVTP over UDP as described in IEEE
1722-2016 Annex J.

This element was inspired by RTP payloader elements.
2019-07-03 09:59:35 -07:00

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2 KiB
C

/*
* GStreamer AVTP Plugin
* Copyright (C) 2019 Intel Corporation
*
* 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 Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
#ifndef __GST_AVTP_AAF_PAY_H__
#define __GST_AVTP_AAF_PAY_H__
#include <gst/gst.h>
#include "gstavtpbasepayload.h"
G_BEGIN_DECLS
#define GST_TYPE_AVTP_AAF_PAY (gst_avtp_aaf_pay_get_type())
#define GST_AVTP_AAF_PAY(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AVTP_AAF_PAY,GstAvtpAafPay))
#define GST_AVTP_AAF_PAY_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AVTP_AAF_PAY,GstAvtpAafPayClass))
#define GST_IS_AVTP_AAF_PAY(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AVTP_AAF_PAY))
#define GST_IS_AVTP_AAF_PAY_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AVTP_AAF_PAY))
typedef struct _GstAvtpAafPay GstAvtpAafPay;
typedef struct _GstAvtpAafPayClass GstAvtpAafPayClass;
typedef enum _GstAvtpAafTstampMode GstAvtpAafTstampMode;
enum _GstAvtpAafTstampMode {
GST_AVTP_AAF_TSTAMP_MODE_NORMAL,
GST_AVTP_AAF_TSTAMP_MODE_SPARSE,
};
struct _GstAvtpAafPay
{
GstAvtpBasePayload payload;
GstAvtpAafTstampMode tstamp_mode;
GstMemory *header;
gint channels;
gint depth;
gint rate;
gint format;
};
struct _GstAvtpAafPayClass
{
GstAvtpBasePayloadClass parent_class;
};
GType gst_avtp_aaf_pay_get_type (void);
gboolean gst_avtp_aaf_pay_plugin_init (GstPlugin * plugin);
G_END_DECLS
#endif /* __GST_AVTP_AAF_PAY_H__ */