gstreamer/gst/encoding/gstencodebin.c
Thibault Saunier 5aa5faecf0 encodebin: Split implementation into a base class
Create EncodeBaseBin as a base class for the existing
encodebin to allow other implementations.

Co-authored with Jan Schmidt <jan@centricular.com>
2020-11-30 15:44:53 -03:00

128 lines
5.1 KiB
C

/* GStreamer encoding bin
* Copyright (C) 2009 Edward Hervey <edward.hervey@collabora.co.uk>
* (C) 2009 Nokia Corporation
* Copyright (C) 2020 Thibault Saunier <tsaunier@igalia.com>
* (C) 2020 Igalia S.L
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-encodebin
* @title: encodebin
*
* EncodeBin provides a bin for encoding/muxing various streams according to
* a specified #GstEncodingProfile.
*
* Based on the profile that was set (via the #GstEncodeBaseBin:profile property),
* EncodeBin will internally select and configure the required elements
* (encoders, muxers, but also audio and video converters) so that you can
* provide it raw or pre-encoded streams of data in input and have your
* encoded/muxed/converted stream in output.
*
* ## Features
*
* * Automatic encoder and muxer selection based on elements available on the
* system.
*
* * Conversion of raw audio/video streams (scaling, framerate conversion,
* colorspace conversion, samplerate conversion) to conform to the profile
* output format.
*
* * Variable number of streams. If the presence property for a stream encoding
* profile is 0, you can request any number of sink pads for it via the
* standard request pad gstreamer API or the #GstEncodeBaseBin::request-pad action
* signal.
*
* * Avoid reencoding (passthrough). If the input stream is already encoded and is
* compatible with what the #GstEncodingProfile expects, then the stream won't
* be re-encoded but just passed through downstream to the muxer or the output.
*
* * Mix pre-encoded and raw streams as input. In addition to the passthrough
* feature above, you can feed both raw audio/video *AND* already-encoded data
* to a pad. #GstEncodeBaseBin will take care of passing through the compatible
* segments and re-encoding the segments of media that need encoding.
*
* * Standard behaviour is to use a #GstEncodingContainerProfile to have both
* encoding and muxing performed. But you can also provide a single stream
* profile (like #GstEncodingAudioProfile) to only have the encoding done and
* handle the encoded output yourself.
*
* * Audio imperfection corrections. Incoming audio streams can have non perfect
* timestamps (jitter), like the streams coming from ASF files. #GstEncodeBaseBin
* will automatically fix those imperfections for you. See
* #GstEncodeBaseBin:audio-jitter-tolerance for more details.
*
* * Variable or Constant video framerate. If your #GstEncodingVideoProfile has
* the variableframerate property deactivated (default), then the incoming
* raw video stream will be retimestampped in order to produce a constant
* framerate.
*
* * Cross-boundary re-encoding. When feeding compatible pre-encoded streams that
* fall on segment boundaries, and for supported formats (right now only H263),
* the GOP will be decoded/reencoded when needed to produce an encoded output
* that fits exactly within the request GstSegment.
*
* * Missing plugin support. If a #GstElement is missing to encode/mux to the
* request profile formats, a missing-plugin #GstMessage will be posted on the
* #GstBus, allowing systems that support the missing-plugin system to offer the
* user a way to install the missing element.
*
*/
#include "gstencodebin.h"
struct _GstEncodeBin
{
GstEncodeBaseBin parent;
};
G_DEFINE_TYPE (GstEncodeBin, gst_encode_bin, GST_TYPE_ENCODE_BASE_BIN);
static GstStaticPadTemplate muxer_src_template =
GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static void
gst_encode_bin_class_init (GstEncodeBinClass * klass)
{
GstElementClass *gstelement_klass = (GstElementClass *) klass;
gst_element_class_add_static_pad_template (gstelement_klass,
&muxer_src_template);
gst_element_class_set_static_metadata (gstelement_klass,
"Encoder Bin",
"Generic/Bin/Encoder",
"Convenience encoding/muxing element",
"Edward Hervey <edward.hervey@collabora.co.uk>");
}
static void
gst_encode_bin_init (GstEncodeBin * encode_bin)
{
GstEncodeBaseBin *encode_base_bin = (GstEncodeBaseBin *) (encode_bin);
GstPadTemplate *tmpl;
tmpl = gst_static_pad_template_get (&muxer_src_template);
encode_base_bin->srcpad =
gst_ghost_pad_new_no_target_from_template ("src", tmpl);
gst_object_unref (tmpl);
gst_pad_set_active (encode_base_bin->srcpad, TRUE);
gst_element_add_pad (GST_ELEMENT_CAST (encode_base_bin),
encode_base_bin->srcpad);
}