1 /* Farsight
2 * Copyright (C) 2006 Marcel Moreaux <marcelm@spacelabs.nl>
3 * (C) 2008 Wim Taymans <wim.taymans@gmail.com>
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 */
20
21 /*
22 * RTP DV depayloader.
23 *
24 * Important note for NTSC-users:
25 *
26 * Because the author uses PAL video, and he does not have proper DV
27 * documentation (the DV format specification is not freely available),
28 * this code may very well contain PAL-specific assumptions.
29 */
30
31 #include <stdlib.h>
32 #include <string.h>
33 #include <gst/gst.h>
34
35 #include "gstrtpdvdepay.h"
36 #include "gstrtputils.h"
37
38 GST_DEBUG_CATEGORY (rtpdvdepay_debug);
39 #define GST_CAT_DEFAULT (rtpdvdepay_debug)
40 /* Filter signals and args */
41 enum
42 {
43 /* FILL ME */
44 LAST_SIGNAL
45 };
46
47 enum
48 {
49 PROP_0,
50 };
51
52 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
53 GST_PAD_SRC,
54 GST_PAD_ALWAYS,
55 GST_STATIC_CAPS ("video/x-dv")
56 );
57
58 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
59 GST_PAD_SINK,
60 GST_PAD_ALWAYS,
61 GST_STATIC_CAPS ("application/x-rtp, "
62 "media = (string) { \"video\", \"audio\" },"
63 "encoding-name = (string) \"DV\", "
64 "clock-rate = (int) 90000,"
65 "encode = (string) { \"SD-VCR/525-60\", \"SD-VCR/625-50\", \"HD-VCR/1125-60\","
66 "\"HD-VCR/1250-50\", \"SDL-VCR/525-60\", \"SDL-VCR/625-50\","
67 "\"306M/525-60\", \"306M/625-50\", \"314M-25/525-60\","
68 "\"314M-25/625-50\", \"314M-50/525-60\", \"314M-50/625-50\" }"
69 /* optional parameters can't go in the template
70 * "audio = (string) { \"bundled\", \"none\" }"
71 */
72 )
73 );
74
75 static GstStateChangeReturn
76 gst_rtp_dv_depay_change_state (GstElement * element, GstStateChange transition);
77
78 static GstBuffer *gst_rtp_dv_depay_process (GstRTPBaseDepayload * base,
79 GstRTPBuffer * rtp);
80 static gboolean gst_rtp_dv_depay_setcaps (GstRTPBaseDepayload * depayload,
81 GstCaps * caps);
82
83 #define gst_rtp_dv_depay_parent_class parent_class
84 G_DEFINE_TYPE (GstRTPDVDepay, gst_rtp_dv_depay, GST_TYPE_RTP_BASE_DEPAYLOAD);
85
86
87 static void
gst_rtp_dv_depay_class_init(GstRTPDVDepayClass * klass)88 gst_rtp_dv_depay_class_init (GstRTPDVDepayClass * klass)
89 {
90 GstElementClass *gstelement_class = (GstElementClass *) klass;
91 GstRTPBaseDepayloadClass *gstrtpbasedepayload_class =
92 (GstRTPBaseDepayloadClass *) klass;
93
94 GST_DEBUG_CATEGORY_INIT (rtpdvdepay_debug, "rtpdvdepay", 0,
95 "DV RTP Depayloader");
96
97 gstelement_class->change_state =
98 GST_DEBUG_FUNCPTR (gst_rtp_dv_depay_change_state);
99
100 gst_element_class_add_static_pad_template (gstelement_class, &src_factory);
101 gst_element_class_add_static_pad_template (gstelement_class, &sink_factory);
102
103 gst_element_class_set_static_metadata (gstelement_class, "RTP DV Depayloader",
104 "Codec/Depayloader/Network/RTP",
105 "Depayloads DV from RTP packets (RFC 3189)",
106 "Marcel Moreaux <marcelm@spacelabs.nl>, Wim Taymans <wim.taymans@gmail.com>");
107
108 gstrtpbasedepayload_class->process_rtp_packet =
109 GST_DEBUG_FUNCPTR (gst_rtp_dv_depay_process);
110 gstrtpbasedepayload_class->set_caps =
111 GST_DEBUG_FUNCPTR (gst_rtp_dv_depay_setcaps);
112 }
113
114 /* initialize the new element
115 * instantiate pads and add them to element
116 * set functions
117 * initialize structure
118 */
119 static void
gst_rtp_dv_depay_init(GstRTPDVDepay * filter)120 gst_rtp_dv_depay_init (GstRTPDVDepay * filter)
121 {
122 }
123
124 static gboolean
parse_encode(GstRTPDVDepay * rtpdvdepay,const gchar * encode)125 parse_encode (GstRTPDVDepay * rtpdvdepay, const gchar * encode)
126 {
127 rtpdvdepay->width = 720;
128 if (!strcmp (encode, "314M-25/525-60")) {
129 rtpdvdepay->frame_size = 240000;
130 rtpdvdepay->height = 480;
131 rtpdvdepay->rate_num = 30000;
132 rtpdvdepay->rate_denom = 1001;
133 } else if (!strcmp (encode, "SD-VCR/525-60")) {
134 rtpdvdepay->frame_size = 120000;
135 rtpdvdepay->height = 480;
136 rtpdvdepay->rate_num = 30000;
137 rtpdvdepay->rate_denom = 1001;
138 } else if (!strcmp (encode, "314M-50/625-50")) {
139 rtpdvdepay->frame_size = 288000;
140 rtpdvdepay->height = 576;
141 rtpdvdepay->rate_num = 25;
142 rtpdvdepay->rate_denom = 1;
143 } else if (!strcmp (encode, "SD-VCR/625-50")) {
144 rtpdvdepay->frame_size = 144000;
145 rtpdvdepay->height = 576;
146 rtpdvdepay->rate_num = 25;
147 rtpdvdepay->rate_denom = 1;
148 } else if (!strcmp (encode, "314M-25/625-50")) {
149 rtpdvdepay->frame_size = 144000;
150 rtpdvdepay->height = 576;
151 rtpdvdepay->rate_num = 25;
152 rtpdvdepay->rate_denom = 1;
153 } else
154 rtpdvdepay->frame_size = -1;
155
156 return rtpdvdepay->frame_size != -1;
157 }
158
159 static gboolean
gst_rtp_dv_depay_setcaps(GstRTPBaseDepayload * depayload,GstCaps * caps)160 gst_rtp_dv_depay_setcaps (GstRTPBaseDepayload * depayload, GstCaps * caps)
161 {
162 GstStructure *structure;
163 GstRTPDVDepay *rtpdvdepay;
164 GstCaps *srccaps;
165 gint clock_rate;
166 gboolean systemstream, ret;
167 const gchar *encode, *media;
168
169 rtpdvdepay = GST_RTP_DV_DEPAY (depayload);
170
171 structure = gst_caps_get_structure (caps, 0);
172
173 if (!gst_structure_get_int (structure, "clock-rate", &clock_rate))
174 clock_rate = 90000; /* default */
175 depayload->clock_rate = clock_rate;
176
177 /* we really need the encode property to figure out the frame size, it's also
178 * required by the spec */
179 if (!(encode = gst_structure_get_string (structure, "encode")))
180 goto no_encode;
181
182 /* figure out the size of one frame */
183 if (!parse_encode (rtpdvdepay, encode))
184 goto unknown_encode;
185
186 /* check the media, this tells us that the stream has video or not */
187 if (!(media = gst_structure_get_string (structure, "media")))
188 goto no_media;
189
190 systemstream = FALSE;
191
192 if (!strcmp (media, "audio")) {
193 /* we need a demuxer for audio only */
194 systemstream = TRUE;
195 } else if (!strcmp (media, "video")) {
196 const gchar *audio;
197
198 /* check the optional audio field, if it's present and set to bundled, we
199 * are dealing with a system stream. */
200 if ((audio = gst_structure_get_string (structure, "audio"))) {
201 if (!strcmp (audio, "bundled"))
202 systemstream = TRUE;
203 }
204 }
205
206 /* allocate accumulator */
207 rtpdvdepay->acc = gst_buffer_new_and_alloc (rtpdvdepay->frame_size);
208
209 /* Initialize the new accumulator frame.
210 * If the previous frame exists, copy that into the accumulator frame.
211 * This way, missing packets in the stream won't show up badly. */
212 gst_buffer_memset (rtpdvdepay->acc, 0, 0, rtpdvdepay->frame_size);
213
214 srccaps = gst_caps_new_simple ("video/x-dv",
215 "systemstream", G_TYPE_BOOLEAN, systemstream,
216 "width", G_TYPE_INT, rtpdvdepay->width,
217 "height", G_TYPE_INT, rtpdvdepay->height,
218 "framerate", GST_TYPE_FRACTION, rtpdvdepay->rate_num,
219 rtpdvdepay->rate_denom, NULL);
220 ret = gst_pad_set_caps (depayload->srcpad, srccaps);
221 gst_caps_unref (srccaps);
222
223 return ret;
224
225 /* ERRORS */
226 no_encode:
227 {
228 GST_ERROR_OBJECT (rtpdvdepay, "required encode property not found in caps");
229 return FALSE;
230 }
231 unknown_encode:
232 {
233 GST_ERROR_OBJECT (rtpdvdepay, "unknown encode property %s found", encode);
234 return FALSE;
235 }
236 no_media:
237 {
238 GST_ERROR_OBJECT (rtpdvdepay, "required media property not found in caps");
239 return FALSE;
240 }
241 }
242
243 /* A DV frame consists of a bunch of 80-byte DIF blocks.
244 * Each DIF block contains a 3-byte header telling where in the DV frame the
245 * DIF block should go. We use this information to calculate its position.
246 */
247 static guint
calculate_difblock_location(guint8 * block)248 calculate_difblock_location (guint8 * block)
249 {
250 gint block_type, dif_sequence, dif_block;
251 guint location;
252
253 block_type = block[0] >> 5;
254 dif_sequence = block[1] >> 4;
255 dif_block = block[2];
256
257 location = dif_sequence * 150;
258
259 switch (block_type) {
260 case 0: /* Header block, no offset */
261 break;
262 case 1: /* Subcode block */
263 location += (1 + dif_block);
264 break;
265 case 2: /* VAUX block */
266 location += (3 + dif_block);
267 break;
268 case 3: /* Audio block */
269 location += (6 + dif_block * 16);
270 break;
271 case 4: /* Video block */
272 location += (7 + (dif_block / 15) + dif_block);
273 break;
274 default: /* Something bogus */
275 GST_DEBUG ("UNKNOWN BLOCK");
276 location = -1;
277 break;
278 }
279 return location;
280 }
281
282 static gboolean
foreach_metadata_drop(GstBuffer * inbuf,GstMeta ** meta,gpointer user_data)283 foreach_metadata_drop (GstBuffer * inbuf, GstMeta ** meta, gpointer user_data)
284 {
285 *meta = NULL;
286 return TRUE;
287 }
288
289 /* Process one RTP packet. Accumulate RTP payload in the proper place in a DV
290 * frame, and return that frame if we detect a new frame, or NULL otherwise.
291 * We assume a DV frame is 144000 bytes. That should accomodate PAL as well as
292 * NTSC.
293 */
294 static GstBuffer *
gst_rtp_dv_depay_process(GstRTPBaseDepayload * base,GstRTPBuffer * rtp)295 gst_rtp_dv_depay_process (GstRTPBaseDepayload * base, GstRTPBuffer * rtp)
296 {
297 GstBuffer *out = NULL;
298 guint8 *payload;
299 guint32 rtp_ts;
300 guint payload_len, location;
301 GstRTPDVDepay *dvdepay = GST_RTP_DV_DEPAY (base);
302 gboolean marker;
303 GstMapInfo map;
304
305 marker = gst_rtp_buffer_get_marker (rtp);
306
307 /* Check if the received packet contains (the start of) a new frame, we do
308 * this by checking the RTP timestamp. */
309 rtp_ts = gst_rtp_buffer_get_timestamp (rtp);
310
311 /* we cannot copy the packet yet if the marker is set, we will do that below
312 * after taking out the data */
313 if (dvdepay->prev_ts != -1 && rtp_ts != dvdepay->prev_ts && !marker) {
314 /* the timestamp changed */
315 GST_DEBUG_OBJECT (dvdepay, "new frame with ts %u, old ts %u", rtp_ts,
316 dvdepay->prev_ts);
317
318 /* return copy of accumulator. */
319 out = gst_buffer_copy (dvdepay->acc);
320 gst_buffer_foreach_meta (dvdepay->acc, foreach_metadata_drop, NULL);
321 }
322
323 /* Extract the payload */
324 payload_len = gst_rtp_buffer_get_payload_len (rtp);
325 payload = gst_rtp_buffer_get_payload (rtp);
326
327 /* copy all DIF chunks in their place. */
328 gst_buffer_map (dvdepay->acc, &map, GST_MAP_READWRITE);
329 while (payload_len >= 80) {
330 guint offset;
331
332 /* Calculate where in the frame the payload should go */
333 location = calculate_difblock_location (payload);
334
335 if (location < 6) {
336 /* part of a header, set the flag to mark that we have the header. */
337 dvdepay->header_mask |= (1 << location);
338 GST_LOG_OBJECT (dvdepay, "got header at location %d, now %02x", location,
339 dvdepay->header_mask);
340 } else {
341 GST_LOG_OBJECT (dvdepay, "got block at location %d", location);
342 }
343
344 if (location != -1) {
345 /* get the byte offset of the dif block */
346 offset = location * 80;
347
348 /* And copy it in, provided the location is sane. */
349 if (offset <= dvdepay->frame_size - 80) {
350 memcpy (map.data + offset, payload, 80);
351 gst_rtp_copy_meta (GST_ELEMENT_CAST (dvdepay), dvdepay->acc,
352 rtp->buffer, 0);
353 }
354 }
355
356 payload += 80;
357 payload_len -= 80;
358 }
359 gst_buffer_unmap (dvdepay->acc, &map);
360
361 if (marker) {
362 GST_DEBUG_OBJECT (dvdepay, "marker bit complete frame %u", rtp_ts);
363 /* only copy the frame when we have a complete header */
364 if (dvdepay->header_mask == 0x3f) {
365 /* The marker marks the end of a frame that we need to push. The next frame
366 * will change the timestamp but we won't copy the accumulator again because
367 * we set the prev_ts to -1. */
368 out = gst_buffer_copy (dvdepay->acc);
369 gst_buffer_foreach_meta (dvdepay->acc, foreach_metadata_drop, NULL);
370 } else {
371 GST_WARNING_OBJECT (dvdepay, "waiting for frame headers %02x",
372 dvdepay->header_mask);
373 }
374 dvdepay->prev_ts = -1;
375 } else {
376 /* save last timestamp */
377 dvdepay->prev_ts = rtp_ts;
378 }
379 return out;
380 }
381
382 static void
gst_rtp_dv_depay_reset(GstRTPDVDepay * depay)383 gst_rtp_dv_depay_reset (GstRTPDVDepay * depay)
384 {
385 if (depay->acc)
386 gst_buffer_unref (depay->acc);
387 depay->acc = NULL;
388
389 depay->prev_ts = -1;
390 depay->header_mask = 0;
391 }
392
393 static GstStateChangeReturn
gst_rtp_dv_depay_change_state(GstElement * element,GstStateChange transition)394 gst_rtp_dv_depay_change_state (GstElement * element, GstStateChange transition)
395 {
396 GstStateChangeReturn ret;
397 GstRTPDVDepay *depay = GST_RTP_DV_DEPAY (element);
398
399 switch (transition) {
400 case GST_STATE_CHANGE_READY_TO_PAUSED:
401 gst_rtp_dv_depay_reset (depay);
402 break;
403 default:
404 break;
405 }
406
407 ret = GST_CALL_PARENT_WITH_DEFAULT (GST_ELEMENT_CLASS, change_state,
408 (element, transition), GST_STATE_CHANGE_FAILURE);
409
410 switch (transition) {
411 case GST_STATE_CHANGE_PAUSED_TO_READY:
412 gst_rtp_dv_depay_reset (depay);
413 break;
414 default:
415 break;
416 }
417 return ret;
418 }
419
420 gboolean
gst_rtp_dv_depay_plugin_init(GstPlugin * plugin)421 gst_rtp_dv_depay_plugin_init (GstPlugin * plugin)
422 {
423 return gst_element_register (plugin, "rtpdvdepay",
424 GST_RANK_SECONDARY, GST_TYPE_RTP_DV_DEPAY);
425 }
426