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gstreamer/gst/rtp/gstrtph264depay.c
Mark Nauwelaerts 4c368242c0 rtph264depay: determine output h264 layout using caps negotiation 
... thereby (partially) deprecating properties currently controlling whether
or not byte-stream output or NAL/AU alignment (though properties still determine
fallback if nothing specified in caps).

Fixes #606662.
2010-12-17 15:38:27 +01:00

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/* GStreamer
* Copyright (C) <2006> Wim Taymans <wim.taymans@gmail.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.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <string.h>
#include <gst/rtp/gstrtpbuffer.h>
#include "gstrtph264depay.h"
GST_DEBUG_CATEGORY_STATIC (rtph264depay_debug);
#define GST_CAT_DEFAULT (rtph264depay_debug)
#define DEFAULT_BYTE_STREAM TRUE
#define DEFAULT_ACCESS_UNIT FALSE
enum
{
PROP_0,
PROP_BYTE_STREAM,
PROP_ACCESS_UNIT,
PROP_LAST
};
/* 3 zero bytes syncword */
static const guint8 sync_bytes[] = { 0, 0, 0, 1 };
static GstStaticPadTemplate gst_rtp_h264_depay_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/x-h264")
);
static GstStaticPadTemplate gst_rtp_h264_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_DYNAMIC_STRING ", "
"clock-rate = (int) 90000, " "encoding-name = (string) \"H264\"")
/** optional parameters **/
/* "profile-level-id = (string) ANY, " */
/* "max-mbps = (string) ANY, " */
/* "max-fs = (string) ANY, " */
/* "max-cpb = (string) ANY, " */
/* "max-dpb = (string) ANY, " */
/* "max-br = (string) ANY, " */
/* "redundant-pic-cap = (string) { \"0\", \"1\" }, " */
/* "sprop-parameter-sets = (string) ANY, " */
/* "parameter-add = (string) { \"0\", \"1\" }, " */
/* "packetization-mode = (string) { \"0\", \"1\", \"2\" }, " */
/* "sprop-interleaving-depth = (string) ANY, " */
/* "sprop-deint-buf-req = (string) ANY, " */
/* "deint-buf-cap = (string) ANY, " */
/* "sprop-init-buf-time = (string) ANY, " */
/* "sprop-max-don-diff = (string) ANY, " */
/* "max-rcmd-nalu-size = (string) ANY " */
);
GST_BOILERPLATE (GstRtpH264Depay, gst_rtp_h264_depay, GstBaseRTPDepayload,
GST_TYPE_BASE_RTP_DEPAYLOAD);
static void gst_rtp_h264_depay_finalize (GObject * object);
static void gst_rtp_h264_depay_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_rtp_h264_depay_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstStateChangeReturn gst_rtp_h264_depay_change_state (GstElement *
element, GstStateChange transition);
static GstBuffer *gst_rtp_h264_depay_process (GstBaseRTPDepayload * depayload,
GstBuffer * buf);
static gboolean gst_rtp_h264_depay_setcaps (GstBaseRTPDepayload * filter,
GstCaps * caps);
static void
gst_rtp_h264_depay_base_init (gpointer klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&gst_rtp_h264_depay_src_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&gst_rtp_h264_depay_sink_template));
gst_element_class_set_details_simple (element_class, "RTP H264 depayloader",
"Codec/Depayloader/Network",
"Extracts H264 video from RTP packets (RFC 3984)",
"Wim Taymans <wim.taymans@gmail.com>");
}
static void
gst_rtp_h264_depay_class_init (GstRtpH264DepayClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
GstBaseRTPDepayloadClass *gstbasertpdepayload_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gstbasertpdepayload_class = (GstBaseRTPDepayloadClass *) klass;
gobject_class->finalize = gst_rtp_h264_depay_finalize;
gobject_class->set_property = gst_rtp_h264_depay_set_property;
gobject_class->get_property = gst_rtp_h264_depay_get_property;
g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_BYTE_STREAM,
g_param_spec_boolean ("byte-stream", "Byte Stream",
"Generate byte stream format of NALU (deprecated; use caps)",
DEFAULT_BYTE_STREAM, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_ACCESS_UNIT,
g_param_spec_boolean ("access-unit", "Access Unit",
"Merge NALU into AU (picture) (deprecated; use caps)",
DEFAULT_ACCESS_UNIT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gstelement_class->change_state = gst_rtp_h264_depay_change_state;
gstbasertpdepayload_class->process = gst_rtp_h264_depay_process;
gstbasertpdepayload_class->set_caps = gst_rtp_h264_depay_setcaps;
GST_DEBUG_CATEGORY_INIT (rtph264depay_debug, "rtph264depay", 0,
"H264 Video RTP Depayloader");
}
static void
gst_rtp_h264_depay_init (GstRtpH264Depay * rtph264depay,
GstRtpH264DepayClass * klass)
{
rtph264depay->adapter = gst_adapter_new ();
rtph264depay->picture_adapter = gst_adapter_new ();
rtph264depay->byte_stream = DEFAULT_BYTE_STREAM;
rtph264depay->merge = DEFAULT_ACCESS_UNIT;
}
static void
gst_rtp_h264_depay_finalize (GObject * object)
{
GstRtpH264Depay *rtph264depay;
rtph264depay = GST_RTP_H264_DEPAY (object);
if (rtph264depay->codec_data)
gst_buffer_unref (rtph264depay->codec_data);
g_object_unref (rtph264depay->adapter);
g_object_unref (rtph264depay->picture_adapter);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_rtp_h264_depay_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstRtpH264Depay *rtph264depay;
rtph264depay = GST_RTP_H264_DEPAY (object);
switch (prop_id) {
case PROP_BYTE_STREAM:
rtph264depay->byte_stream = g_value_get_boolean (value);
break;
case PROP_ACCESS_UNIT:
rtph264depay->merge = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_rtp_h264_depay_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstRtpH264Depay *rtph264depay;
rtph264depay = GST_RTP_H264_DEPAY (object);
switch (prop_id) {
case PROP_BYTE_STREAM:
g_value_set_boolean (value, rtph264depay->byte_stream);
break;
case PROP_ACCESS_UNIT:
g_value_set_boolean (value, rtph264depay->merge);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_rtp_h264_depay_negotiate (GstRtpH264Depay * rtph264depay)
{
GstCaps *caps;
gint byte_stream = -1;
gint merge = -1;
caps =
gst_pad_get_allowed_caps (GST_BASE_RTP_DEPAYLOAD_SRCPAD (rtph264depay));
GST_DEBUG_OBJECT (rtph264depay, "allowed caps: %" GST_PTR_FORMAT, caps);
if (caps) {
if (gst_caps_get_size (caps) > 0) {
GstStructure *s = gst_caps_get_structure (caps, 0);
const gchar *str = NULL;
if ((str = gst_structure_get_string (s, "stream-format"))) {
if (strcmp (str, "avc") == 0) {
byte_stream = FALSE;
} else if (strcmp (str, "byte-stream") == 0) {
byte_stream = TRUE;
} else {
GST_DEBUG_OBJECT (rtph264depay, "unknown stream-format: %s", str);
}
}
if ((str = gst_structure_get_string (s, "alignment"))) {
if (strcmp (str, "au") == 0) {
merge = TRUE;
} else if (strcmp (str, "nal") == 0) {
merge = FALSE;
} else {
GST_DEBUG_OBJECT (rtph264depay, "unknown alignment: %s", str);
}
}
}
gst_caps_unref (caps);
}
if (byte_stream >= 0) {
GST_DEBUG_OBJECT (rtph264depay, "downstream requires byte-stream %d",
byte_stream);
if (rtph264depay->byte_stream != byte_stream) {
GST_WARNING_OBJECT (rtph264depay,
"overriding property setting based on caps");
rtph264depay->byte_stream = byte_stream;
}
}
if (merge >= 0) {
GST_DEBUG_OBJECT (rtph264depay, "downstream requires merge %d", merge);
if (rtph264depay->merge != merge) {
GST_WARNING_OBJECT (rtph264depay,
"overriding property setting based on caps");
rtph264depay->merge = merge;
}
}
}
static gboolean
gst_rtp_h264_depay_setcaps (GstBaseRTPDepayload * depayload, GstCaps * caps)
{
GstCaps *srccaps;
gint clock_rate;
GstStructure *structure = gst_caps_get_structure (caps, 0);
GstRtpH264Depay *rtph264depay;
const gchar *ps, *profile;
GstBuffer *codec_data;
guint8 *b64;
gboolean res;
rtph264depay = GST_RTP_H264_DEPAY (depayload);
if (!gst_structure_get_int (structure, "clock-rate", &clock_rate))
clock_rate = 90000;
depayload->clock_rate = clock_rate;
srccaps = gst_caps_new_simple ("video/x-h264", NULL);
/* Base64 encoded, comma separated config NALs */
ps = gst_structure_get_string (structure, "sprop-parameter-sets");
/* hex: AVCProfileIndication:8 | profile_compat:8 | AVCLevelIndication:8 */
profile = gst_structure_get_string (structure, "profile-level-id");
/* negotiate with downstream w.r.t. output format and alignment */
gst_rtp_h264_depay_negotiate (rtph264depay);
if (rtph264depay->byte_stream && ps != NULL) {
/* for bytestream we only need the parameter sets but we don't error out
* when they are not there, we assume they are in the stream. */
gchar **params;
guint len, total;
gint i;
params = g_strsplit (ps, ",", 0);
/* count total number of bytes in base64. Also include the sync bytes in
* front of the params. */
len = 0;
for (i = 0; params[i]; i++) {
len += strlen (params[i]);
len += sizeof (sync_bytes);
}
/* we seriously overshoot the length, but it's fine. */
codec_data = gst_buffer_new_and_alloc (len);
b64 = GST_BUFFER_DATA (codec_data);
total = 0;
for (i = 0; params[i]; i++) {
guint save = 0;
gint state = 0;
GST_DEBUG_OBJECT (depayload, "decoding param %d (%s)", i, params[i]);
memcpy (b64, sync_bytes, sizeof (sync_bytes));
b64 += sizeof (sync_bytes);
len =
g_base64_decode_step (params[i], strlen (params[i]), b64, &state,
&save);
GST_DEBUG_OBJECT (depayload, "decoded %d bytes", len);
total += len + sizeof (sync_bytes);
b64 += len;
}
GST_BUFFER_SIZE (codec_data) = total;
g_strfreev (params);
/* keep the codec_data, we need to send it as the first buffer. We cannot
* push it in the adapter because the adapter might be flushed on discont.
*/
if (rtph264depay->codec_data)
gst_buffer_unref (rtph264depay->codec_data);
rtph264depay->codec_data = codec_data;
} else if (!rtph264depay->byte_stream) {
gchar **params;
guint8 **sps, **pps;
guint len, num_sps, num_pps;
gint i;
guint8 *data;
if (ps == NULL)
goto incomplete_caps;
params = g_strsplit (ps, ",", 0);
len = g_strv_length (params);
GST_DEBUG_OBJECT (depayload, "we have %d params", len);
sps = g_new0 (guint8 *, len + 1);
pps = g_new0 (guint8 *, len + 1);
num_sps = num_pps = 0;
/* start with 7 bytes header */
len = 7;
for (i = 0; params[i]; i++) {
gsize nal_len;
guint8 *nalp;
guint save = 0;
gint state = 0;
nal_len = strlen (params[i]);
nalp = g_malloc (nal_len + 2);
nal_len =
g_base64_decode_step (params[i], nal_len, nalp + 2, &state, &save);
nalp[0] = (nal_len >> 8) & 0xff;
nalp[1] = nal_len & 0xff;
len += nal_len + 2;
/* copy to the right list */
if ((nalp[2] & 0x1f) == 7) {
GST_DEBUG_OBJECT (depayload, "adding param %d as SPS %d", i, num_sps);
sps[num_sps++] = nalp;
} else {
GST_DEBUG_OBJECT (depayload, "adding param %d as PPS %d", i, num_pps);
pps[num_pps++] = nalp;
}
}
g_strfreev (params);
if (num_sps == 0 || (GST_READ_UINT16_BE (sps[0]) < 3) || num_pps == 0) {
g_strfreev ((gchar **) pps);
g_strfreev ((gchar **) sps);
goto incomplete_caps;
}
codec_data = gst_buffer_new_and_alloc (len);
data = GST_BUFFER_DATA (codec_data);
/* 8 bits version == 1 */
*data++ = 1;
if (profile) {
guint32 profile_id;
/* hex: AVCProfileIndication:8 | profile_compat:8 | AVCLevelIndication:8 */
sscanf (profile, "%6x", &profile_id);
*data++ = (profile_id >> 16) & 0xff;
*data++ = (profile_id >> 8) & 0xff;
*data++ = profile_id & 0xff;
} else {
/* extract from SPS */
*data++ = sps[0][3];
*data++ = sps[0][4];
*data++ = sps[0][5];
}
/* 6 bits reserved | 2 bits lengthSizeMinusOn */
*data++ = 0xff;
/* 3 bits reserved | 5 bits numOfSequenceParameterSets */
*data++ = 0xe0 | (num_sps & 0x1f);
/* copy all SPS */
for (i = 0; sps[i]; i++) {
len = ((sps[i][0] << 8) | sps[i][1]) + 2;
GST_DEBUG_OBJECT (depayload, "copy SPS %d of length %d", i, len);
memcpy (data, sps[i], len);
g_free (sps[i]);
data += len;
}
g_free (sps);
/* 8 bits numOfPictureParameterSets */
*data++ = num_pps;
/* copy all PPS */
for (i = 0; pps[i]; i++) {
len = ((pps[i][0] << 8) | pps[i][1]) + 2;
GST_DEBUG_OBJECT (depayload, "copy PPS %d of length %d", i, len);
memcpy (data, pps[i], len);
g_free (pps[i]);
data += len;
}
g_free (pps);
GST_BUFFER_SIZE (codec_data) = data - GST_BUFFER_DATA (codec_data);
gst_caps_set_simple (srccaps,
"codec_data", GST_TYPE_BUFFER, codec_data, NULL);
}
gst_caps_set_simple (srccaps, "stream-format", G_TYPE_STRING,
rtph264depay->byte_stream ? "byte-stream" : "avc",
"alignment", G_TYPE_STRING, rtph264depay->merge ? "au" : "nal", NULL);
res = gst_pad_set_caps (depayload->srcpad, srccaps);
gst_caps_unref (srccaps);
return res;
/* ERRORS */
incomplete_caps:
{
GST_DEBUG_OBJECT (depayload, "we have incomplete caps");
gst_caps_unref (srccaps);
return FALSE;
}
}
/* SPS/PPS/IDR considered key, all others DELTA;
* so downstream waiting for keyframe can pick up at SPS/PPS/IDR */
#define NAL_TYPE_IS_KEY(nt) (((nt) == 5) || ((nt) == 7) || ((nt) == 8))
static gboolean
gst_rtp_h264_depay_handle_nal (GstRtpH264Depay * rtph264depay, GstBuffer * nal,
GstClockTime in_timestamp)
{
GstBaseRTPDepayload *depayload = GST_BASE_RTP_DEPAYLOAD (rtph264depay);
gint nal_type;
guint size;
guint8 *data;
GstBuffer *outbuf = NULL;
GstClockTime out_timestamp;
gboolean keyframe, out_keyframe;
size = GST_BUFFER_SIZE (nal);
if (G_UNLIKELY (size < 5))
goto short_nal;
data = GST_BUFFER_DATA (nal);
nal_type = data[4] & 0x1f;
GST_DEBUG_OBJECT (rtph264depay, "handle NAL type %d", nal_type);
keyframe = NAL_TYPE_IS_KEY (nal_type);
out_keyframe = keyframe;
out_timestamp = in_timestamp;
if (rtph264depay->merge) {
gboolean start = FALSE, complete = FALSE;
/* consider a coded slices (IDR or not) to start a picture,
* (so ending the previous one) if first_mb_in_slice == 0
* (non-0 is part of previous one) */
/* NOTE this is not entirely according to Access Unit specs in 7.4.1.2.4,
* but in practice it works in sane cases, needs not much parsing,
* and also works with broken frame_num in NAL (where spec-wise would fail) */
if (nal_type == 1 || nal_type == 2 || nal_type == 5) {
/* we have a picture start */
start = TRUE;
if (data[5] & 0x80) {
/* first_mb_in_slice == 0 completes a picture */
complete = TRUE;
}
} else if (nal_type >= 6 && nal_type <= 9) {
/* SEI, SPS, PPS, AU terminate picture */
complete = TRUE;
}
GST_DEBUG_OBJECT (depayload, "start %d, complete %d", start, complete);
if (complete && rtph264depay->picture_start) {
guint outsize;
/* we had a picture in the adapter and we completed it */
GST_DEBUG_OBJECT (depayload, "taking completed AU");
outsize = gst_adapter_available (rtph264depay->picture_adapter);
outbuf = gst_adapter_take_buffer (rtph264depay->picture_adapter, outsize);
out_timestamp = rtph264depay->last_ts;
out_keyframe = rtph264depay->last_keyframe;
rtph264depay->last_keyframe = FALSE;
rtph264depay->picture_start = FALSE;
}
/* add to adapter */
GST_DEBUG_OBJECT (depayload, "adding NAL to picture adapter");
gst_adapter_push (rtph264depay->picture_adapter, nal);
rtph264depay->last_ts = in_timestamp;
rtph264depay->last_keyframe |= keyframe;
rtph264depay->picture_start |= start;
} else {
/* no merge, output is input nal */
GST_DEBUG_OBJECT (depayload, "using NAL as output");
outbuf = nal;
}
if (outbuf) {
/* prepend codec_data */
if (rtph264depay->codec_data) {
GST_DEBUG_OBJECT (depayload, "prepending codec_data");
outbuf = gst_buffer_join (rtph264depay->codec_data, outbuf);
rtph264depay->codec_data = NULL;
out_keyframe = TRUE;
}
outbuf = gst_buffer_make_metadata_writable (outbuf);
GST_BUFFER_TIMESTAMP (outbuf) = out_timestamp;
if (out_keyframe)
GST_BUFFER_FLAG_UNSET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT);
else
GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT);
gst_buffer_set_caps (outbuf, GST_PAD_CAPS (depayload->srcpad));
gst_base_rtp_depayload_push (depayload, outbuf);
}
return TRUE;
/* ERRORS */
short_nal:
{
GST_WARNING_OBJECT (depayload, "dropping short NAL");
gst_buffer_unref (nal);
return FALSE;
}
}
static GstBuffer *
gst_rtp_h264_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
{
GstRtpH264Depay *rtph264depay;
GstBuffer *outbuf;
guint8 nal_unit_type;
rtph264depay = GST_RTP_H264_DEPAY (depayload);
/* flush remaining data on discont */
if (GST_BUFFER_IS_DISCONT (buf)) {
gst_adapter_clear (rtph264depay->adapter);
rtph264depay->wait_start = TRUE;
}
{
gint payload_len;
guint8 *payload;
guint header_len;
guint8 nal_ref_idc;
guint8 *outdata;
guint outsize, nalu_size;
GstClockTime timestamp;
timestamp = GST_BUFFER_TIMESTAMP (buf);
payload_len = gst_rtp_buffer_get_payload_len (buf);
payload = gst_rtp_buffer_get_payload (buf);
GST_DEBUG_OBJECT (rtph264depay, "receiving %d bytes", payload_len);
if (payload_len == 0)
return NULL;
/* +---------------+
* |0|1|2|3|4|5|6|7|
* +-+-+-+-+-+-+-+-+
* |F|NRI| Type |
* +---------------+
*
* F must be 0.
*/
nal_ref_idc = (payload[0] & 0x60) >> 5;
nal_unit_type = payload[0] & 0x1f;
/* at least one byte header with type */
header_len = 1;
GST_DEBUG_OBJECT (rtph264depay, "NRI %d, Type %d", nal_ref_idc,
nal_unit_type);
switch (nal_unit_type) {
case 0:
case 30:
case 31:
/* undefined */
goto undefined_type;
case 25:
/* STAP-B Single-time aggregation packet 5.7.1 */
/* 2 byte extra header for DON */
header_len += 2;
/* fallthrough */
case 24:
{
/* strip headers */
payload += header_len;
payload_len -= header_len;
rtph264depay->wait_start = FALSE;
/* STAP-A Single-time aggregation packet 5.7.1 */
while (payload_len > 2) {
/* 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | NALU Size |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
nalu_size = (payload[0] << 8) | payload[1];
if (nalu_size > payload_len)
nalu_size = payload_len;
outsize = nalu_size + sizeof (sync_bytes);
outbuf = gst_buffer_new_and_alloc (outsize);
outdata = GST_BUFFER_DATA (outbuf);
if (rtph264depay->byte_stream) {
memcpy (outdata, sync_bytes, sizeof (sync_bytes));
} else {
outdata[0] = outdata[1] = 0;
outdata[2] = payload[0];
outdata[3] = payload[1];
}
/* strip NALU size */
payload += 2;
payload_len -= 2;
outdata += sizeof (sync_bytes);
memcpy (outdata, payload, nalu_size);
gst_adapter_push (rtph264depay->adapter, outbuf);
payload += nalu_size;
payload_len -= nalu_size;
}
outsize = gst_adapter_available (rtph264depay->adapter);
outbuf = gst_adapter_take_buffer (rtph264depay->adapter, outsize);
gst_rtp_h264_depay_handle_nal (rtph264depay, outbuf, timestamp);
break;
}
case 26:
/* MTAP16 Multi-time aggregation packet 5.7.2 */
header_len = 5;
/* fallthrough, not implemented */
case 27:
/* MTAP24 Multi-time aggregation packet 5.7.2 */
header_len = 6;
goto not_implemented;
break;
case 28:
case 29:
{
/* FU-A Fragmentation unit 5.8 */
/* FU-B Fragmentation unit 5.8 */
gboolean S, E;
/* +---------------+
* |0|1|2|3|4|5|6|7|
* +-+-+-+-+-+-+-+-+
* |S|E|R| Type |
* +---------------+
*
* R is reserved and always 0
*/
S = (payload[1] & 0x80) == 0x80;
E = (payload[1] & 0x40) == 0x40;
GST_DEBUG_OBJECT (rtph264depay, "S %d, E %d", S, E);
if (rtph264depay->wait_start && !S)
goto waiting_start;
if (S) {
/* NAL unit starts here */
guint8 nal_header;
rtph264depay->wait_start = FALSE;
/* reconstruct NAL header */
nal_header = (payload[0] & 0xe0) | (payload[1] & 0x1f);
/* strip type header, keep FU header, we'll reuse it to reconstruct
* the NAL header. */
payload += 1;
payload_len -= 1;
nalu_size = payload_len;
outsize = nalu_size + sizeof (sync_bytes);
outbuf = gst_buffer_new_and_alloc (outsize);
outdata = GST_BUFFER_DATA (outbuf);
outdata += sizeof (sync_bytes);
memcpy (outdata, payload, nalu_size);
outdata[0] = nal_header;
GST_DEBUG_OBJECT (rtph264depay, "queueing %d bytes", outsize);
/* and assemble in the adapter */
gst_adapter_push (rtph264depay->adapter, outbuf);
} else {
/* strip off FU indicator and FU header bytes */
payload += 2;
payload_len -= 2;
outsize = payload_len;
outbuf = gst_buffer_new_and_alloc (outsize);
outdata = GST_BUFFER_DATA (outbuf);
memcpy (outdata, payload, outsize);
GST_DEBUG_OBJECT (rtph264depay, "queueing %d bytes", outsize);
/* and assemble in the adapter */
gst_adapter_push (rtph264depay->adapter, outbuf);
}
/* if NAL unit ends, flush the adapter */
if (E) {
GST_DEBUG_OBJECT (rtph264depay, "output %d bytes", outsize);
outsize = gst_adapter_available (rtph264depay->adapter);
outbuf = gst_adapter_take_buffer (rtph264depay->adapter, outsize);
outdata = GST_BUFFER_DATA (outbuf);
if (rtph264depay->byte_stream) {
memcpy (outdata, sync_bytes, sizeof (sync_bytes));
} else {
outsize -= 4;
outdata[0] = (outsize >> 24);
outdata[1] = (outsize >> 16);
outdata[2] = (outsize >> 8);
outdata[3] = (outsize);
}
gst_rtp_h264_depay_handle_nal (rtph264depay, outbuf, timestamp);
}
break;
}
default:
{
rtph264depay->wait_start = FALSE;
/* 1-23 NAL unit Single NAL unit packet per H.264 5.6 */
/* the entire payload is the output buffer */
nalu_size = payload_len;
outsize = nalu_size + sizeof (sync_bytes);
outbuf = gst_buffer_new_and_alloc (outsize);
outdata = GST_BUFFER_DATA (outbuf);
if (rtph264depay->byte_stream) {
memcpy (outdata, sync_bytes, sizeof (sync_bytes));
} else {
outdata[0] = outdata[1] = 0;
outdata[2] = nalu_size >> 8;
outdata[3] = nalu_size & 0xff;
}
outdata += sizeof (sync_bytes);
memcpy (outdata, payload, nalu_size);
gst_rtp_h264_depay_handle_nal (rtph264depay, outbuf, timestamp);
break;
}
}
}
return NULL;
/* ERRORS */
undefined_type:
{
GST_ELEMENT_WARNING (rtph264depay, STREAM, DECODE,
(NULL), ("Undefined packet type"));
return NULL;
}
waiting_start:
{
GST_DEBUG_OBJECT (rtph264depay, "waiting for start");
return NULL;
}
not_implemented:
{
GST_ELEMENT_ERROR (rtph264depay, STREAM, FORMAT,
(NULL), ("NAL unit type %d not supported yet", nal_unit_type));
return NULL;
}
}
static GstStateChangeReturn
gst_rtp_h264_depay_change_state (GstElement * element,
GstStateChange transition)
{
GstRtpH264Depay *rtph264depay;
GstStateChangeReturn ret;
rtph264depay = GST_RTP_H264_DEPAY (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
gst_adapter_clear (rtph264depay->adapter);
rtph264depay->wait_start = TRUE;
gst_adapter_clear (rtph264depay->picture_adapter);
rtph264depay->picture_start = FALSE;
rtph264depay->last_keyframe = 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;
}
gboolean
gst_rtp_h264_depay_plugin_init (GstPlugin * plugin)
{
return gst_element_register (plugin, "rtph264depay",
GST_RANK_MARGINAL, GST_TYPE_RTP_H264_DEPAY);
}
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