FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rtpdec_vp9.c
Go to the documentation of this file.
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 {
31  uint32_t timestamp;
32 };
33 
34 static av_cold int vp9_init(AVFormatContext *ctx, int st_index,
36 {
38  "RTP/VP9 support is still experimental\n");
39 
40  return 0;
41 }
42 
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 */
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 
329 {
330  ffio_free_dyn_buf(&vp9->buf);
331 }
332 
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,
341 };
Bytestream IO Context.
Definition: avio.h:155
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
const char * g
Definition: vf_curves.c:112
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
RTP/JPEG specific private data.
Definition: rdt.c:83
int index
stream index in AVFormatContext
Definition: avformat.h:890
static AVPacket pkt
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:87
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1290
Format I/O context.
Definition: avformat.h:1349
uint8_t
#define av_cold
Definition: attributes.h:82
static int flags
Definition: log.c:57
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:205
#define av_log(a,...)
uint32_t timestamp
current frame timestamp
Definition: rtpdec_ac3.c:31
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define RTP_FLAG_MARKER
RTP marker bit was set for this packet.
Definition: rtpdec.h:93
static void vp9_close_context(PayloadContext *vp9)
Definition: rtpdec_vp9.c:328
#define AVERROR(e)
Definition: error.h:43
const char * r
Definition: vf_curves.c:111
RTPDynamicProtocolHandler ff_vp9_dynamic_handler
Definition: rtpdec_vp9.c:333
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
AVFormatContext * ctx
Definition: movenc.c:48
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1347
Stream structure.
Definition: avformat.h:889
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
static av_cold int vp9_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
Definition: rtpdec_vp9.c:34
void * buf
Definition: avisynth_c.h:690
uint8_t * buf
the temporary storage buffer
Definition: rtpdec_asf.c:183
#define u(width,...)
const char * enc_name
Definition: rtpdec.h:116
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
#define RTP_VP9_DESC_REQUIRED_SIZE
Definition: rtpdec_vp9.c:27
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:910
static int parse_packet(AVFormatContext *s, AVPacket *pkt, int stream_index)
Parse a packet, add all split parts to parse_queue.
Definition: utils.c:1392
int len
This structure stores compressed data.
Definition: avcodec.h:1634
#define av_unused
Definition: attributes.h:125