FFmpeg
yuv4mpegdec.c
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1 /*
2  * YUV4MPEG demuxer
3  * Copyright (c) 2001, 2002, 2003 Fabrice Bellard
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/imgutils.h"
23 
24 #include "avformat.h"
25 #include "internal.h"
26 #include "yuv4mpeg.h"
27 
28 /* Header size increased to allow room for optional flags */
29 #define MAX_YUV4_HEADER 96
30 #define MAX_FRAME_HEADER 80
31 
33 {
34  char header[MAX_YUV4_HEADER + 10]; // Include headroom for
35  // the longest option
36  char *tokstart, *tokend, *header_end;
37  int i;
38  AVIOContext *pb = s->pb;
39  int width = -1, height = -1, raten = 0,
40  rated = 0, aspectn = 0, aspectd = 0;
42  enum AVChromaLocation chroma_sample_location = AVCHROMA_LOC_UNSPECIFIED;
43  enum AVFieldOrder field_order = AV_FIELD_UNKNOWN;
45  AVStream *st;
46 
47  for (i = 0; i < MAX_YUV4_HEADER; i++) {
48  header[i] = avio_r8(pb);
49  if (header[i] == '\n') {
50  header[i + 1] = 0x20; // Add a space after last option.
51  // Makes parsing "444" vs "444alpha" easier.
52  header[i + 2] = 0;
53  break;
54  }
55  }
56  if (i == MAX_YUV4_HEADER) {
57  av_log(s, AV_LOG_ERROR, "Header too large.\n");
58  return AVERROR(EINVAL);
59  }
60  if (strncmp(header, Y4M_MAGIC, strlen(Y4M_MAGIC))) {
61  av_log(s, AV_LOG_ERROR, "Invalid magic number for yuv4mpeg.\n");
62  return AVERROR(EINVAL);
63  }
64 
65  header_end = &header[i + 1]; // Include space
66  for (tokstart = &header[strlen(Y4M_MAGIC) + 1];
67  tokstart < header_end; tokstart++) {
68  if (*tokstart == 0x20)
69  continue;
70  switch (*tokstart++) {
71  case 'W': // Width. Required.
72  width = strtol(tokstart, &tokend, 10);
73  tokstart = tokend;
74  break;
75  case 'H': // Height. Required.
76  height = strtol(tokstart, &tokend, 10);
77  tokstart = tokend;
78  break;
79  case 'C': // Color space
80  if (strncmp("420jpeg", tokstart, 7) == 0) {
81  pix_fmt = AV_PIX_FMT_YUV420P;
82  chroma_sample_location = AVCHROMA_LOC_CENTER;
83  } else if (strncmp("420mpeg2", tokstart, 8) == 0) {
84  pix_fmt = AV_PIX_FMT_YUV420P;
85  chroma_sample_location = AVCHROMA_LOC_LEFT;
86  } else if (strncmp("420paldv", tokstart, 8) == 0) {
87  pix_fmt = AV_PIX_FMT_YUV420P;
88  chroma_sample_location = AVCHROMA_LOC_TOPLEFT;
89  } else if (strncmp("420p16", tokstart, 6) == 0) {
90  pix_fmt = AV_PIX_FMT_YUV420P16;
91  } else if (strncmp("422p16", tokstart, 6) == 0) {
92  pix_fmt = AV_PIX_FMT_YUV422P16;
93  } else if (strncmp("444p16", tokstart, 6) == 0) {
94  pix_fmt = AV_PIX_FMT_YUV444P16;
95  } else if (strncmp("420p14", tokstart, 6) == 0) {
96  pix_fmt = AV_PIX_FMT_YUV420P14;
97  } else if (strncmp("422p14", tokstart, 6) == 0) {
98  pix_fmt = AV_PIX_FMT_YUV422P14;
99  } else if (strncmp("444p14", tokstart, 6) == 0) {
100  pix_fmt = AV_PIX_FMT_YUV444P14;
101  } else if (strncmp("420p12", tokstart, 6) == 0) {
102  pix_fmt = AV_PIX_FMT_YUV420P12;
103  } else if (strncmp("422p12", tokstart, 6) == 0) {
104  pix_fmt = AV_PIX_FMT_YUV422P12;
105  } else if (strncmp("444p12", tokstart, 6) == 0) {
106  pix_fmt = AV_PIX_FMT_YUV444P12;
107  } else if (strncmp("420p10", tokstart, 6) == 0) {
108  pix_fmt = AV_PIX_FMT_YUV420P10;
109  } else if (strncmp("422p10", tokstart, 6) == 0) {
110  pix_fmt = AV_PIX_FMT_YUV422P10;
111  } else if (strncmp("444p10", tokstart, 6) == 0) {
112  pix_fmt = AV_PIX_FMT_YUV444P10;
113  } else if (strncmp("420p9", tokstart, 5) == 0) {
114  pix_fmt = AV_PIX_FMT_YUV420P9;
115  } else if (strncmp("422p9", tokstart, 5) == 0) {
116  pix_fmt = AV_PIX_FMT_YUV422P9;
117  } else if (strncmp("444p9", tokstart, 5) == 0) {
118  pix_fmt = AV_PIX_FMT_YUV444P9;
119  } else if (strncmp("420", tokstart, 3) == 0) {
120  pix_fmt = AV_PIX_FMT_YUV420P;
121  chroma_sample_location = AVCHROMA_LOC_CENTER;
122  } else if (strncmp("411", tokstart, 3) == 0) {
123  pix_fmt = AV_PIX_FMT_YUV411P;
124  } else if (strncmp("422", tokstart, 3) == 0) {
125  pix_fmt = AV_PIX_FMT_YUV422P;
126  } else if (strncmp("444alpha", tokstart, 8) == 0 ) {
127  pix_fmt = AV_PIX_FMT_YUVA444P;
128  } else if (strncmp("444", tokstart, 3) == 0) {
129  pix_fmt = AV_PIX_FMT_YUV444P;
130  } else if (strncmp("mono16", tokstart, 6) == 0) {
131  pix_fmt = AV_PIX_FMT_GRAY16;
132  } else if (strncmp("mono12", tokstart, 6) == 0) {
133  pix_fmt = AV_PIX_FMT_GRAY12;
134  } else if (strncmp("mono10", tokstart, 6) == 0) {
135  pix_fmt = AV_PIX_FMT_GRAY10;
136  } else if (strncmp("mono9", tokstart, 5) == 0) {
137  pix_fmt = AV_PIX_FMT_GRAY9;
138  } else if (strncmp("mono", tokstart, 4) == 0) {
139  pix_fmt = AV_PIX_FMT_GRAY8;
140  } else {
141  av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains an unknown "
142  "pixel format.\n");
143  return AVERROR_INVALIDDATA;
144  }
145  while (tokstart < header_end && *tokstart != 0x20)
146  tokstart++;
147  break;
148  case 'I': // Interlace type
149  switch (*tokstart++){
150  case '?':
151  field_order = AV_FIELD_UNKNOWN;
152  break;
153  case 'p':
154  field_order = AV_FIELD_PROGRESSIVE;
155  break;
156  case 't':
157  field_order = AV_FIELD_TT;
158  break;
159  case 'b':
160  field_order = AV_FIELD_BB;
161  break;
162  case 'm':
163  av_log(s, AV_LOG_ERROR, "YUV4MPEG stream contains mixed "
164  "interlaced and non-interlaced frames.\n");
165  default:
166  av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
167  return AVERROR(EINVAL);
168  }
169  break;
170  case 'F': // Frame rate
171  sscanf(tokstart, "%d:%d", &raten, &rated); // 0:0 if unknown
172  while (tokstart < header_end && *tokstart != 0x20)
173  tokstart++;
174  break;
175  case 'A': // Pixel aspect
176  sscanf(tokstart, "%d:%d", &aspectn, &aspectd); // 0:0 if unknown
177  while (tokstart < header_end && *tokstart != 0x20)
178  tokstart++;
179  break;
180  case 'X': // Vendor extensions
181  if (strncmp("YSCSS=", tokstart, 6) == 0) {
182  // Older nonstandard pixel format representation
183  tokstart += 6;
184  if (strncmp("420JPEG", tokstart, 7) == 0)
185  alt_pix_fmt = AV_PIX_FMT_YUV420P;
186  else if (strncmp("420MPEG2", tokstart, 8) == 0)
187  alt_pix_fmt = AV_PIX_FMT_YUV420P;
188  else if (strncmp("420PALDV", tokstart, 8) == 0)
189  alt_pix_fmt = AV_PIX_FMT_YUV420P;
190  else if (strncmp("420P9", tokstart, 5) == 0)
191  alt_pix_fmt = AV_PIX_FMT_YUV420P9;
192  else if (strncmp("422P9", tokstart, 5) == 0)
193  alt_pix_fmt = AV_PIX_FMT_YUV422P9;
194  else if (strncmp("444P9", tokstart, 5) == 0)
195  alt_pix_fmt = AV_PIX_FMT_YUV444P9;
196  else if (strncmp("420P10", tokstart, 6) == 0)
197  alt_pix_fmt = AV_PIX_FMT_YUV420P10;
198  else if (strncmp("422P10", tokstart, 6) == 0)
199  alt_pix_fmt = AV_PIX_FMT_YUV422P10;
200  else if (strncmp("444P10", tokstart, 6) == 0)
201  alt_pix_fmt = AV_PIX_FMT_YUV444P10;
202  else if (strncmp("420P12", tokstart, 6) == 0)
203  alt_pix_fmt = AV_PIX_FMT_YUV420P12;
204  else if (strncmp("422P12", tokstart, 6) == 0)
205  alt_pix_fmt = AV_PIX_FMT_YUV422P12;
206  else if (strncmp("444P12", tokstart, 6) == 0)
207  alt_pix_fmt = AV_PIX_FMT_YUV444P12;
208  else if (strncmp("420P14", tokstart, 6) == 0)
209  alt_pix_fmt = AV_PIX_FMT_YUV420P14;
210  else if (strncmp("422P14", tokstart, 6) == 0)
211  alt_pix_fmt = AV_PIX_FMT_YUV422P14;
212  else if (strncmp("444P14", tokstart, 6) == 0)
213  alt_pix_fmt = AV_PIX_FMT_YUV444P14;
214  else if (strncmp("420P16", tokstart, 6) == 0)
215  alt_pix_fmt = AV_PIX_FMT_YUV420P16;
216  else if (strncmp("422P16", tokstart, 6) == 0)
217  alt_pix_fmt = AV_PIX_FMT_YUV422P16;
218  else if (strncmp("444P16", tokstart, 6) == 0)
219  alt_pix_fmt = AV_PIX_FMT_YUV444P16;
220  else if (strncmp("411", tokstart, 3) == 0)
221  alt_pix_fmt = AV_PIX_FMT_YUV411P;
222  else if (strncmp("422", tokstart, 3) == 0)
223  alt_pix_fmt = AV_PIX_FMT_YUV422P;
224  else if (strncmp("444", tokstart, 3) == 0)
225  alt_pix_fmt = AV_PIX_FMT_YUV444P;
226  } else if (strncmp("COLORRANGE=", tokstart, 11) == 0) {
227  tokstart += 11;
228  if (strncmp("FULL",tokstart, 4) == 0)
229  color_range = AVCOL_RANGE_JPEG;
230  else if (strncmp("LIMITED", tokstart, 7) == 0)
231  color_range = AVCOL_RANGE_MPEG;
232  }
233  while (tokstart < header_end && *tokstart != 0x20)
234  tokstart++;
235  break;
236  }
237  }
238 
239  if (width == -1 || height == -1) {
240  av_log(s, AV_LOG_ERROR, "YUV4MPEG has invalid header.\n");
241  return AVERROR_INVALIDDATA;
242  }
243 
244  if (pix_fmt == AV_PIX_FMT_NONE) {
245  if (alt_pix_fmt == AV_PIX_FMT_NONE)
246  pix_fmt = AV_PIX_FMT_YUV420P;
247  else
248  pix_fmt = alt_pix_fmt;
249  }
250 
251  if (raten <= 0 || rated <= 0) {
252  // Frame rate unknown
253  raten = 25;
254  rated = 1;
255  }
256 
257  if (aspectn == 0 && aspectd == 0) {
258  // Pixel aspect unknown
259  aspectd = 1;
260  }
261 
262  st = avformat_new_stream(s, NULL);
263  if (!st)
264  return AVERROR(ENOMEM);
265  st->codecpar->width = width;
266  st->codecpar->height = height;
267  av_reduce(&raten, &rated, raten, rated, (1UL << 31) - 1);
268  avpriv_set_pts_info(st, 64, rated, raten);
269  st->avg_frame_rate = av_inv_q(st->time_base);
270  st->codecpar->format = pix_fmt;
273  st->sample_aspect_ratio = (AVRational){ aspectn, aspectd };
274  st->codecpar->chroma_location = chroma_sample_location;
276  st->codecpar->field_order = field_order;
278  if ((int) s->packet_size < 0)
279  return s->packet_size;
280  s->internal->data_offset = avio_tell(pb);
281 
282  st->duration = (avio_size(pb) - avio_tell(pb)) / s->packet_size;
283 
284  return 0;
285 }
286 
288 {
289  int i;
290  char header[MAX_FRAME_HEADER+1];
291  int ret;
292  int64_t off = avio_tell(s->pb);
293 
294  for (i = 0; i < MAX_FRAME_HEADER; i++) {
295  header[i] = avio_r8(s->pb);
296  if (header[i] == '\n') {
297  header[i + 1] = 0;
298  break;
299  }
300  }
301  if (s->pb->error)
302  return s->pb->error;
303  else if (s->pb->eof_reached)
304  return AVERROR_EOF;
305  else if (i == MAX_FRAME_HEADER)
306  return AVERROR_INVALIDDATA;
307 
308  if (strncmp(header, Y4M_FRAME_MAGIC, strlen(Y4M_FRAME_MAGIC)))
309  return AVERROR_INVALIDDATA;
310 
311  ret = av_get_packet(s->pb, pkt, s->packet_size - Y4M_FRAME_MAGIC_LEN);
312  if (ret < 0)
313  return ret;
314  else if (ret != s->packet_size - Y4M_FRAME_MAGIC_LEN) {
315  return s->pb->eof_reached ? AVERROR_EOF : AVERROR(EIO);
316  }
317  pkt->stream_index = 0;
318  pkt->pts = (off - s->internal->data_offset) / s->packet_size;
319  pkt->duration = 1;
320  return 0;
321 }
322 
323 static int yuv4_read_seek(AVFormatContext *s, int stream_index,
324  int64_t pts, int flags)
325 {
326  int64_t pos;
327 
328  if (flags & AVSEEK_FLAG_BACKWARD)
329  pts = FFMAX(0, pts - 1);
330  if (pts < 0)
331  return -1;
332  pos = pts * s->packet_size;
333 
334  if (avio_seek(s->pb, pos + s->internal->data_offset, SEEK_SET) < 0)
335  return -1;
336  return 0;
337 }
338 
339 static int yuv4_probe(const AVProbeData *pd)
340 {
341  /* check file header */
342  if (strncmp(pd->buf, Y4M_MAGIC, sizeof(Y4M_MAGIC) - 1) == 0)
343  return AVPROBE_SCORE_MAX;
344  else
345  return 0;
346 }
347 
349  .name = "yuv4mpegpipe",
350  .long_name = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
351  .read_probe = yuv4_probe,
352  .read_header = yuv4_read_header,
353  .read_packet = yuv4_read_packet,
354  .read_seek = yuv4_read_seek,
355  .extensions = "y4m",
356 };
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2513
enum AVChromaLocation chroma_location
Definition: codec_par.h:150
unsigned int packet_size
Definition: avformat.h:1475
#define NULL
Definition: coverity.c:32
enum AVFieldOrder field_order
Video only.
Definition: codec_par.h:141
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static enum AVPixelFormat pix_fmt
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:346
MPEG-2/4 4:2:0, H.264 default for 4:2:0.
Definition: pixfmt.h:559
#define AV_PIX_FMT_YUV444P14
Definition: pixfmt.h:409
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:71
misc image utilities
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4938
int64_t data_offset
offset of the first packet
Definition: internal.h:80
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown)
Definition: avformat.h:938
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1804
#define AV_PIX_FMT_GRAY9
Definition: pixfmt.h:379
color_range
#define AV_PIX_FMT_YUV420P12
Definition: pixfmt.h:403
static AVPacket pkt
#define AV_PIX_FMT_GRAY10
Definition: pixfmt.h:380
Format I/O context.
Definition: avformat.h:1351
#define AV_PIX_FMT_GRAY12
Definition: pixfmt.h:381
int width
Video only.
Definition: codec_par.h:126
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:381
#define Y4M_FRAME_MAGIC
Definition: yuv4mpeg.h:25
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4519
#define height
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_PIX_FMT_YUV444P16
Definition: pixfmt.h:412
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:304
AVColorRange
MPEG vs JPEG YUV range.
Definition: pixfmt.h:535
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
Reduce a fraction.
Definition: rational.c:35
static const uint8_t header[24]
Definition: sdr2.c:67
#define AV_PIX_FMT_YUV422P12
Definition: pixfmt.h:404
#define av_log(a,...)
#define Y4M_MAGIC
Definition: yuv4mpeg.h:24
int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align)
Return the size in bytes of the amount of data required to store an image with the given parameters...
Definition: imgutils.c:466
static int yuv4_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: yuv4mpegdec.c:287
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
unsigned int pos
Definition: spdifenc.c:410
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
#define AV_PIX_FMT_YUV444P10
Definition: pixfmt.h:402
AVRational avg_frame_rate
Average framerate.
Definition: avformat.h:949
#define FFMAX(a, b)
Definition: common.h:94
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
#define AV_PIX_FMT_YUV422P9
Definition: pixfmt.h:397
#define AV_PIX_FMT_GRAY16
Definition: pixfmt.h:383
#define width
ITU-R 601, SMPTE 274M 296M S314M(DV 4:1:1), mpeg2 4:2:2.
Definition: pixfmt.h:561
#define s(width, name)
Definition: cbs_vp9.c:257
static int yuv4_read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags)
Definition: yuv4mpegdec.c:323
enum AVColorRange color_range
Video only.
Definition: codec_par.h:146
#define AV_PIX_FMT_YUV444P9
Definition: pixfmt.h:398
the normal 2^n-1 "JPEG" YUV ranges
Definition: pixfmt.h:538
Stream structure.
Definition: avformat.h:876
#define AV_PIX_FMT_YUV420P16
Definition: pixfmt.h:410
#define AV_PIX_FMT_YUV420P14
Definition: pixfmt.h:407
static int yuv4_read_header(AVFormatContext *s)
Definition: yuv4mpegdec.c:32
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
planar YUV 4:4:4 32bpp, (1 Cr & Cb sample per 1x1 Y & A samples)
Definition: pixfmt.h:177
#define AV_PIX_FMT_YUV420P10
Definition: pixfmt.h:399
Rational number (pair of numerator and denominator).
Definition: rational.h:58
#define AV_PIX_FMT_YUV420P9
Definition: pixfmt.h:396
int error
contains the error code or 0 if no error happened
Definition: avio.h:245
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
#define AV_PIX_FMT_YUV422P14
Definition: pixfmt.h:408
static int64_t pts
#define flags(name, subs,...)
Definition: cbs_av1.c:560
#define AV_PIX_FMT_YUV422P10
Definition: pixfmt.h:400
#define AV_PIX_FMT_YUV444P12
Definition: pixfmt.h:406
AVFieldOrder
Definition: codec_par.h:36
the normal 219*2^(n-8) "MPEG" YUV ranges
Definition: pixfmt.h:537
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:925
static av_always_inline AVRational av_inv_q(AVRational q)
Invert a rational.
Definition: rational.h:159
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
Y , 8bpp.
Definition: pixfmt.h:74
static int yuv4_probe(const AVProbeData *pd)
Definition: yuv4mpegdec.c:339
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:73
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:239
AVInputFormat ff_yuv4mpegpipe_demuxer
Definition: yuv4mpegdec.c:348
#define Y4M_FRAME_MAGIC_LEN
Definition: yuv4mpeg.h:26
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
AVChromaLocation
Location of chroma samples.
Definition: pixfmt.h:557
MPEG-1 4:2:0, JPEG 4:2:0, H.263 4:2:0.
Definition: pixfmt.h:560
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1023
int stream_index
Definition: packet.h:365
#define MAX_YUV4_HEADER
Definition: yuv4mpegdec.c:29
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:905
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
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
This structure stores compressed data.
Definition: packet.h:340
#define AV_PIX_FMT_YUV422P16
Definition: pixfmt.h:411
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:356
int i
Definition: input.c:407
#define MAX_FRAME_HEADER
Definition: yuv4mpegdec.c:30