FFmpeg
rtpdec_vp9.c
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1 /*
2  * RTP parser for VP9 payload format (draft version 02) - experimental
3  * Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/intreadwrite.h"
23 
24 #include "avio_internal.h"
25 #include "rtpdec_formats.h"
26 
27 #define RTP_VP9_DESC_REQUIRED_SIZE 1
28 
29 struct PayloadContext {
30  AVIOContext *buf;
31  uint32_t timestamp;
32 };
33 
34 static av_cold int vp9_init(AVFormatContext *ctx, int st_index,
35  PayloadContext *data)
36 {
37  av_log(ctx, AV_LOG_WARNING,
38  "RTP/VP9 support is still experimental\n");
39 
40  return 0;
41 }
42 
43 static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx,
44  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
45  const uint8_t *buf, int len, uint16_t seq,
46  int flags)
47 {
48  int has_pic_id, has_layer_idc, has_ref_idc, has_ss_data;
49  av_unused int pic_id = 0, non_key_frame = 0, inter_picture_layer_frame;
50  av_unused int layer_temporal = -1, layer_spatial = -1, layer_quality = -1;
51  int ref_fields = 0, has_ref_field_ext_pic_id = 0;
52  int first_fragment, last_fragment;
53  int rtp_m;
54  int res = 0;
55 
56  /* drop data of previous packets in case of non-continuous (lossy) packet stream */
57  if (rtp_vp9_ctx->buf && rtp_vp9_ctx->timestamp != *timestamp)
58  ffio_free_dyn_buf(&rtp_vp9_ctx->buf);
59 
60  /* sanity check for size of input packet: 1 byte payload at least */
61  if (len < RTP_VP9_DESC_REQUIRED_SIZE + 1) {
62  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet, got %d bytes\n", len);
63  return AVERROR_INVALIDDATA;
64  }
65 
66  /*
67  * decode the required VP9 payload descriptor according to section 4.2 of the spec.:
68  *
69  * 0 1 2 3 4 5 6 7
70  * +-+-+-+-+-+-+-+-+
71  * |I|P|L|F|B|E|V|-| (REQUIRED)
72  * +-+-+-+-+-+-+-+-+
73  *
74  * I: PictureID present
75  * P: Inter-picture predicted layer frame
76  * L: Layer indices present
77  * F: Flexible mode
78  * B: Start of VP9 frame
79  * E: End of picture
80  * V: Scalability Structure (SS) present
81  */
82  has_pic_id = !!(buf[0] & 0x80);
83  inter_picture_layer_frame = !!(buf[0] & 0x40);
84  has_layer_idc = !!(buf[0] & 0x20);
85  has_ref_idc = !!(buf[0] & 0x10);
86  first_fragment = !!(buf[0] & 0x08);
87  last_fragment = !!(buf[0] & 0x04);
88  has_ss_data = !!(buf[0] & 0x02);
89 
90  rtp_m = !!(flags & RTP_FLAG_MARKER);
91 
92  /* sanity check for markers: B should always be equal to the RTP M marker */
93  if (last_fragment != rtp_m) {
94  av_log(ctx, AV_LOG_ERROR, "Invalid combination of B and M marker (%d != %d)\n", last_fragment, rtp_m);
95  return AVERROR_INVALIDDATA;
96  }
97 
98  /* pass the extensions field */
99  buf += RTP_VP9_DESC_REQUIRED_SIZE;
100  len -= RTP_VP9_DESC_REQUIRED_SIZE;
101 
102  /*
103  * decode the 1-byte/2-byte picture ID:
104  *
105  * 0 1 2 3 4 5 6 7
106  * +-+-+-+-+-+-+-+-+
107  * I: |M|PICTURE ID | (RECOMMENDED)
108  * +-+-+-+-+-+-+-+-+
109  * M: | EXTENDED PID | (RECOMMENDED)
110  * +-+-+-+-+-+-+-+-+
111  *
112  * M: The most significant bit of the first octet is an extension flag.
113  * PictureID: 8 or 16 bits including the M bit.
114  */
115  if (has_pic_id) {
116  /* check for 1-byte or 2-byte picture index */
117  if (buf[0] & 0x80) {
118  if (len < 2) {
119  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
120  return AVERROR_INVALIDDATA;
121  }
122  pic_id = AV_RB16(buf) & 0x7fff;
123  buf += 2;
124  len -= 2;
125  } else {
126  pic_id = buf[0] & 0x7f;
127  buf++;
128  len--;
129  }
130  }
131 
132  /*
133  * decode layer indices
134  *
135  * 0 1 2 3 4 5 6 7
136  * +-+-+-+-+-+-+-+-+
137  * L: | T | S | Q | R | (CONDITIONALLY RECOMMENDED)
138  * +-+-+-+-+-+-+-+-+
139  *
140  * T, S and Q are 2-bit indices for temporal, spatial, and quality layers.
141  * If "F" is set in the initial octet, R is 2 bits representing the number
142  * of reference fields this frame refers to.
143  */
144  if (has_layer_idc) {
145  if (len < 1) {
146  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
147  return AVERROR_INVALIDDATA;
148  }
149  layer_temporal = buf[0] & 0xC0;
150  layer_spatial = buf[0] & 0x30;
151  layer_quality = buf[0] & 0x0C;
152  if (has_ref_idc) {
153  ref_fields = buf[0] & 0x03;
154  if (ref_fields)
155  non_key_frame = 1;
156  }
157  buf++;
158  len--;
159  }
160 
161  /*
162  * decode the reference fields
163  *
164  * 0 1 2 3 4 5 6 7
165  * +-+-+-+-+-+-+-+-+ -\
166  * F: | PID |X| RS| RQ| (OPTIONAL) .
167  * +-+-+-+-+-+-+-+-+ . - R times
168  * X: | EXTENDED PID | (OPTIONAL) .
169  * +-+-+-+-+-+-+-+-+ -/
170  *
171  * PID: The relative Picture ID referred to by this frame.
172  * RS and RQ: The spatial and quality layer IDs.
173  * X: 1 if this layer index has an extended relative Picture ID.
174  */
175  if (has_ref_idc) {
176  while (ref_fields) {
177  if (len < 1) {
178  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
179  return AVERROR_INVALIDDATA;
180  }
181 
182  has_ref_field_ext_pic_id = buf[0] & 0x10;
183 
184  /* pass ref. field */
185  if (has_ref_field_ext_pic_id) {
186  if (len < 2) {
187  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
188  return AVERROR_INVALIDDATA;
189  }
190 
191  /* ignore ref. data */
192 
193  buf += 2;
194  len -= 2;
195  } else {
196 
197  /* ignore ref. data */
198 
199  buf++;
200  len--;
201  }
202  ref_fields--;
203  }
204  }
205 
206  /*
207  * decode the scalability structure (SS)
208  *
209  * 0 1 2 3 4 5 6 7
210  * +-+-+-+-+-+-+-+-+
211  * V: | PATTERN LENGTH|
212  * +-+-+-+-+-+-+-+-+ -\
213  * | T | S | Q | R | (OPTIONAL) .
214  * +-+-+-+-+-+-+-+-+ -\ .
215  * | PID |X| RS| RQ| (OPTIONAL) . . - PAT. LEN. times
216  * +-+-+-+-+-+-+-+-+ . - R times .
217  * X: | EXTENDED PID | (OPTIONAL) . .
218  * +-+-+-+-+-+-+-+-+ -/ -/
219  *
220  * PID: The relative Picture ID referred to by this frame.
221  * RS and RQ: The spatial and quality layer IDs.
222  * X: 1 if this layer index has an extended relative Picture ID.
223  */
224  if (has_ss_data) {
225  int n_s, y, g, i;
226  if (len < 1) {
227  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
228  return AVERROR_INVALIDDATA;
229  }
230  n_s = buf[0] >> 5;
231  y = !!(buf[0] & 0x10);
232  g = !!(buf[0] & 0x08);
233  buf++;
234  len--;
235  if (n_s > 0) {
236  avpriv_report_missing_feature(ctx, "VP9 scalability structure with multiple layers");
237  return AVERROR_PATCHWELCOME;
238  }
239  if (y) {
240  if (len < 4 * (n_s + 1)) {
241  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
242  return AVERROR_INVALIDDATA;
243  }
244  for (i = 0; i < n_s + 1; i++) {
245  av_unused int w, h;
246  w = AV_RB16(buf);
247  h = AV_RB16(buf + 2);
248  buf += 4;
249  len -= 4;
250  }
251  }
252  if (g) {
253  int n_g;
254  if (len < 1) {
255  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
256  return AVERROR_INVALIDDATA;
257  }
258  n_g = buf[0];
259  buf++;
260  len--;
261  for (i = 0; i < n_g; i++) {
262  av_unused int t, u, r, j;
263  if (len < 1) {
264  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
265  return AVERROR_INVALIDDATA;
266  }
267  t = buf[0] >> 5;
268  u = !!(buf[0] & 0x10);
269  r = (buf[0] >> 2) & 0x03;
270  buf++;
271  len--;
272  if (len < r) {
273  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
274  return AVERROR_INVALIDDATA;
275  }
276  for (j = 0; j < r; j++) {
277  av_unused int p_diff = buf[0];
278  buf++;
279  len--;
280  }
281  }
282  }
283  }
284 
285  /*
286  * decode the VP9 payload header
287  *
288  * spec. is tbd
289  */
290  //XXX: implement when specified
291 
292  /* sanity check: 1 byte payload as minimum */
293  if (len < 1) {
294  av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
295  return AVERROR_INVALIDDATA;
296  }
297 
298  /* start frame buffering with new dynamic buffer */
299  if (!rtp_vp9_ctx->buf) {
300  /* sanity check: a new frame should have started */
301  if (first_fragment) {
302  res = avio_open_dyn_buf(&rtp_vp9_ctx->buf);
303  if (res < 0)
304  return res;
305  /* update the timestamp in the frame packet with the one from the RTP packet */
306  rtp_vp9_ctx->timestamp = *timestamp;
307  } else {
308  /* frame not started yet, need more packets */
309  return AVERROR(EAGAIN);
310  }
311  }
312 
313  /* write the fragment to the dyn. buffer */
314  avio_write(rtp_vp9_ctx->buf, buf, len);
315 
316  /* do we need more fragments? */
317  if (!last_fragment)
318  return AVERROR(EAGAIN);
319 
320  /* close frame buffering and create resulting A/V packet */
321  res = ff_rtp_finalize_packet(pkt, &rtp_vp9_ctx->buf, st->index);
322  if (res < 0)
323  return res;
324 
325  return 0;
326 }
327 
328 static void vp9_close_context(PayloadContext *vp9)
329 {
330  ffio_free_dyn_buf(&vp9->buf);
331 }
332 
333 const RTPDynamicProtocolHandler ff_vp9_dynamic_handler = {
334  .enc_name = "VP9",
335  .codec_type = AVMEDIA_TYPE_VIDEO,
336  .codec_id = AV_CODEC_ID_VP9,
337  .priv_data_size = sizeof(PayloadContext),
338  .init = vp9_init,
339  .close = vp9_close_context,
340  .parse_packet = vp9_handle_packet
341 };
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
vp9_handle_packet
static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
Definition: rtpdec_vp9.c:43
vp9_init
static av_cold int vp9_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
Definition: rtpdec_vp9.c:34
r
const char * r
Definition: vf_curves.c:126
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
u
#define u(width, name, range_min, range_max)
Definition: cbs_h2645.c:250
rtpdec_formats.h
vp9_close_context
static void vp9_close_context(PayloadContext *vp9)
Definition: rtpdec_vp9.c:328
av_unused
#define av_unused
Definition: attributes.h:131
w
uint8_t w
Definition: llviddspenc.c:38
RTP_FLAG_MARKER
#define RTP_FLAG_MARKER
RTP marker bit was set for this packet.
Definition: rtpdec.h:94
data
const char data[16]
Definition: mxf.c:148
ff_rtp_finalize_packet
int ff_rtp_finalize_packet(AVPacket *pkt, AVIOContext **dyn_buf, int stream_idx)
Close the dynamic buffer and make a packet from it.
Definition: rtpdec.c:1002
PayloadContext::timestamp
uint32_t timestamp
current frame timestamp
Definition: rtpdec_ac3.c:31
RTPDynamicProtocolHandler::enc_name
const char * enc_name
Definition: rtpdec.h:117
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
avio_open_dyn_buf
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1361
intreadwrite.h
g
const char * g
Definition: vf_curves.c:127
AV_CODEC_ID_VP9
@ AV_CODEC_ID_VP9
Definition: codec_id.h:220
ctx
AVFormatContext * ctx
Definition: movenc.c:48
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
AVIOContext
Bytestream IO Context.
Definition: avio.h:160
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:365
avpriv_report_missing_feature
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:200
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
avio_internal.h
len
int len
Definition: vorbis_enc_data.h:426
ffio_free_dyn_buf
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1434
AVStream
Stream structure.
Definition: avformat.h:743
RTP_VP9_DESC_REQUIRED_SIZE
#define RTP_VP9_DESC_REQUIRED_SIZE
Definition: rtpdec_vp9.c:27
PayloadContext::buf
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:183
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:749
ff_vp9_dynamic_handler
const RTPDynamicProtocolHandler ff_vp9_dynamic_handler
Definition: rtpdec_vp9.c:333
parse_packet
static int parse_packet(AVFormatContext *s, AVPacket *pkt, int stream_index, int flush)
Parse a packet, add all split parts to parse_queue.
Definition: demux.c:1154
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVPacket
This structure stores compressed data.
Definition: packet.h:499
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:482
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
h
h
Definition: vp9dsp_template.c:2038
PayloadContext
RTP/JPEG specific private data.
Definition: rdt.c:84
RTPDynamicProtocolHandler
Definition: rtpdec.h:116
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98
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