| /* GStreamer |
| * |
| * Copyright (C) <2014> Stian Selnes <stian@pexip.com> |
| * |
| * 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., 59 Temple Place - Suite 330, |
| * Boston, MA 02111-1307, USA. |
| */ |
| |
| /** |
| * SECTION:element-rtph261depay |
| * @see_also: rtph261pay |
| * |
| * Extract encoded H.261 video frames from RTP packets according to RFC 4587. |
| * For detailed information see: https://www.rfc-editor.org/rfc/rfc4587.txt |
| * |
| * The depayloader takes an RTP packet and extracts its H.261 stream. It |
| * aggregates the extracted stream until a complete frame is received before |
| * it pushes it downstream. |
| * |
| * <refsect2> |
| * <title>Example pipeline</title> |
| * |[ |
| * gst-launch-1.0 udpsrc caps='application/x-rtp, payload=31' ! rtph261depay ! avdec_h261 ! autovideosink |
| * ]| This example pipeline will depayload and decode an RTP H.261 video stream. |
| * Refer to the rtph261pay example to create the RTP stream. |
| * </refsect2> |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| # include "config.h" |
| #endif |
| |
| #include <string.h> |
| |
| #include <gst/rtp/gstrtpbuffer.h> |
| #include <gst/video/video.h> |
| #include "gstrtph261depay.h" |
| #include "gstrtph261pay.h" /* GstRtpH261PayHeader */ |
| #include "gstrtputils.h" |
| |
| GST_DEBUG_CATEGORY_STATIC (rtph261depay_debug); |
| #define GST_CAT_DEFAULT (rtph261depay_debug) |
| |
| static const guint8 NO_LEFTOVER = 0xFF; |
| |
| static GstStaticPadTemplate gst_rtp_h261_depay_src_template = |
| GST_STATIC_PAD_TEMPLATE ("src", |
| GST_PAD_SRC, |
| GST_PAD_ALWAYS, |
| GST_STATIC_CAPS ("video/x-h261") |
| ); |
| |
| static GstStaticPadTemplate gst_rtp_h261_depay_sink_template = |
| GST_STATIC_PAD_TEMPLATE ("sink", |
| GST_PAD_SINK, |
| GST_PAD_ALWAYS, |
| GST_STATIC_CAPS ("application/x-rtp, " |
| "media = (string) \"video\", " |
| "payload = (int) " GST_RTP_PAYLOAD_H261_STRING ", " |
| "clock-rate = (int) 90000, " "encoding-name = (string) \"H261\"; " |
| "application/x-rtp, " |
| "media = (string) \"video\", " |
| "payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", " |
| "clock-rate = (int) 90000, " "encoding-name = (string) \"H261\"") |
| ); |
| |
| G_DEFINE_TYPE (GstRtpH261Depay, gst_rtp_h261_depay, |
| GST_TYPE_RTP_BASE_DEPAYLOAD); |
| #define parent_class gst_rtp_h261_depay_parent_class |
| |
| static GstBuffer * |
| gst_rtp_h261_depay_process (GstRTPBaseDepayload * depayload, GstRTPBuffer * rtp) |
| { |
| GstRtpH261Depay *depay; |
| GstBuffer *outbuf = NULL; |
| gint payload_len; |
| guint8 *payload; |
| const guint header_len = GST_RTP_H261_PAYLOAD_HEADER_LEN; |
| gboolean marker; |
| GstRtpH261PayHeader *header; |
| |
| depay = GST_RTP_H261_DEPAY (depayload); |
| |
| if (GST_BUFFER_IS_DISCONT (rtp->buffer)) { |
| GST_DEBUG_OBJECT (depay, "Discont buffer, flushing adapter"); |
| gst_adapter_clear (depay->adapter); |
| depay->leftover = NO_LEFTOVER; |
| depay->start = FALSE; |
| } |
| |
| payload_len = gst_rtp_buffer_get_payload_len (rtp); |
| payload = gst_rtp_buffer_get_payload (rtp); |
| |
| marker = gst_rtp_buffer_get_marker (rtp); |
| |
| if (payload_len < header_len + 1) { |
| /* Must have at least one byte payload */ |
| GST_WARNING_OBJECT (depay, "Dropping packet with invalid payload length"); |
| return NULL; |
| } |
| |
| header = (GstRtpH261PayHeader *) payload; |
| |
| GST_DEBUG_OBJECT (depay, |
| "payload_len: %d, header_len: %d, sbit: %d, ebit: %d, marker %d", |
| payload_len, header_len, header->sbit, header->ebit, marker); |
| |
| payload += header_len; |
| payload_len -= header_len; |
| |
| if (!depay->start) { |
| /* Check for picture start code */ |
| guint32 bits = GST_READ_UINT32_BE (payload) << header->sbit; |
| if (payload_len > 4 && bits >> 12 == 0x10) { |
| GST_DEBUG_OBJECT (depay, "Found picture start code"); |
| depay->start = TRUE; |
| } else { |
| GST_DEBUG_OBJECT (depay, "No picture start code yet, skipping payload"); |
| goto skip; |
| } |
| } |
| |
| if (header->sbit != 0) { |
| /* Take the leftover from previous packet and merge it at the beginning */ |
| payload[0] &= 0xFF >> header->sbit; |
| if (depay->leftover != NO_LEFTOVER) { |
| /* Happens if sbit is set for first packet in frame. Then previous byte |
| * has already been flushed. */ |
| payload[0] |= depay->leftover; |
| } |
| depay->leftover = NO_LEFTOVER; |
| } |
| |
| if (header->ebit == 0) { |
| /* H.261 stream ends on byte boundary, take entire packet */ |
| gst_adapter_push (depay->adapter, |
| gst_rtp_buffer_get_payload_subbuffer (rtp, header_len, payload_len)); |
| } else { |
| /* Take the entire buffer except for the last byte, which will be kept to |
| * merge with next packet */ |
| gst_adapter_push (depay->adapter, |
| gst_rtp_buffer_get_payload_subbuffer (rtp, header_len, |
| payload_len - 1)); |
| depay->leftover = payload[payload_len - 1] & (0xFF << header->ebit); |
| } |
| |
| skip: |
| if (marker) { |
| if (depay->start) { |
| guint avail; |
| |
| if (depay->leftover != NO_LEFTOVER) { |
| GstBuffer *buf = gst_buffer_new_and_alloc (1); |
| gst_buffer_memset (buf, 0, depay->leftover, 1); |
| gst_adapter_push (depay->adapter, buf); |
| depay->leftover = NO_LEFTOVER; |
| } |
| |
| avail = gst_adapter_available (depay->adapter); |
| outbuf = gst_adapter_take_buffer (depay->adapter, avail); |
| gst_rtp_drop_non_video_meta (depay, outbuf); |
| |
| /* Note that the I flag does not mean intra frame, but that the entire |
| * stream is intra coded. */ |
| if (header->i) |
| GST_BUFFER_FLAG_UNSET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT); |
| else |
| GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT); |
| |
| GST_DEBUG_OBJECT (depay, "Pushing out a buffer of %u bytes", avail); |
| depay->start = FALSE; |
| } else { |
| depay->start = TRUE; |
| } |
| } |
| |
| return outbuf; |
| } |
| |
| static gboolean |
| gst_rtp_h261_depay_setcaps (GstRTPBaseDepayload * filter, GstCaps * caps) |
| { |
| GstCaps *srccaps; |
| |
| srccaps = gst_caps_new_empty_simple ("video/x-h261"); |
| gst_pad_set_caps (GST_RTP_BASE_DEPAYLOAD_SRCPAD (filter), srccaps); |
| gst_caps_unref (srccaps); |
| |
| return TRUE; |
| } |
| |
| static GstStateChangeReturn |
| gst_rtp_h261_depay_change_state (GstElement * element, |
| GstStateChange transition) |
| { |
| GstRtpH261Depay *depay; |
| GstStateChangeReturn ret; |
| |
| depay = GST_RTP_H261_DEPAY (element); |
| |
| switch (transition) { |
| case GST_STATE_CHANGE_NULL_TO_READY: |
| break; |
| case GST_STATE_CHANGE_READY_TO_PAUSED: |
| gst_adapter_clear (depay->adapter); |
| depay->start = FALSE; |
| break; |
| default: |
| break; |
| } |
| |
| ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition); |
| |
| switch (transition) { |
| case GST_STATE_CHANGE_READY_TO_NULL: |
| break; |
| default: |
| break; |
| } |
| return ret; |
| } |
| |
| static void |
| gst_rtp_h261_depay_dispose (GObject * object) |
| { |
| GstRtpH261Depay *depay; |
| |
| depay = GST_RTP_H261_DEPAY (object); |
| |
| if (depay->adapter) { |
| gst_object_unref (depay->adapter); |
| depay->adapter = NULL; |
| } |
| |
| G_OBJECT_CLASS (parent_class)->dispose (object); |
| } |
| |
| static void |
| gst_rtp_h261_depay_class_init (GstRtpH261DepayClass * klass) |
| { |
| GObjectClass *gobject_class; |
| GstElementClass *gstelement_class; |
| GstRTPBaseDepayloadClass *gstrtpbasedepayload_class; |
| |
| gobject_class = G_OBJECT_CLASS (klass); |
| gstelement_class = GST_ELEMENT_CLASS (klass); |
| gstrtpbasedepayload_class = GST_RTP_BASE_DEPAYLOAD_CLASS (klass); |
| |
| gst_element_class_add_static_pad_template (gstelement_class, |
| &gst_rtp_h261_depay_src_template); |
| gst_element_class_add_static_pad_template (gstelement_class, |
| &gst_rtp_h261_depay_sink_template); |
| |
| gst_element_class_set_static_metadata (gstelement_class, |
| "RTP H261 depayloader", "Codec/Depayloader/Network/RTP", |
| "Extracts H261 video from RTP packets (RFC 4587)", |
| "Stian Selnes <stian@pexip.com>"); |
| |
| gstrtpbasedepayload_class->process_rtp_packet = gst_rtp_h261_depay_process; |
| gstrtpbasedepayload_class->set_caps = gst_rtp_h261_depay_setcaps; |
| |
| gobject_class->dispose = gst_rtp_h261_depay_dispose; |
| |
| gstelement_class->change_state = gst_rtp_h261_depay_change_state; |
| |
| GST_DEBUG_CATEGORY_INIT (rtph261depay_debug, "rtph261depay", 0, |
| "H261 Video RTP Depayloader"); |
| } |
| |
| static void |
| gst_rtp_h261_depay_init (GstRtpH261Depay * depay) |
| { |
| depay->adapter = gst_adapter_new (); |
| depay->leftover = NO_LEFTOVER; |
| } |
| |
| gboolean |
| gst_rtp_h261_depay_plugin_init (GstPlugin * plugin) |
| { |
| return gst_element_register (plugin, "rtph261depay", |
| GST_RANK_SECONDARY, GST_TYPE_RTP_H261_DEPAY); |
| } |