FFmpeg
pafvideo.c
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1 /*
2  * Packed Animation File video decoder
3  * Copyright (c) 2012 Paul B Mahol
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 "avcodec.h"
25 #include "bytestream.h"
26 #include "copy_block.h"
27 #include "internal.h"
28 
29 
30 static const uint8_t block_sequences[16][8] = {
31  { 0, 0, 0, 0, 0, 0, 0, 0 },
32  { 2, 0, 0, 0, 0, 0, 0, 0 },
33  { 5, 7, 0, 0, 0, 0, 0, 0 },
34  { 5, 0, 0, 0, 0, 0, 0, 0 },
35  { 6, 0, 0, 0, 0, 0, 0, 0 },
36  { 5, 7, 5, 7, 0, 0, 0, 0 },
37  { 5, 7, 5, 0, 0, 0, 0, 0 },
38  { 5, 7, 6, 0, 0, 0, 0, 0 },
39  { 5, 5, 0, 0, 0, 0, 0, 0 },
40  { 3, 0, 0, 0, 0, 0, 0, 0 },
41  { 6, 6, 0, 0, 0, 0, 0, 0 },
42  { 2, 4, 0, 0, 0, 0, 0, 0 },
43  { 2, 4, 5, 7, 0, 0, 0, 0 },
44  { 2, 4, 5, 0, 0, 0, 0, 0 },
45  { 2, 4, 6, 0, 0, 0, 0, 0 },
46  { 2, 4, 5, 7, 5, 7, 0, 0 },
47 };
48 
49 typedef struct PAFVideoDecContext {
52 
53  int width;
54  int height;
55 
57  uint8_t *frame[4];
58  int dirty[4];
61 
62  uint8_t *opcodes;
64 
66 {
67  PAFVideoDecContext *c = avctx->priv_data;
68  int i;
69 
70  av_frame_free(&c->pic);
71 
72  for (i = 0; i < 4; i++)
73  av_freep(&c->frame[i]);
74 
75  return 0;
76 }
77 
79 {
80  PAFVideoDecContext *c = avctx->priv_data;
81  int i;
82  int ret;
83 
84  c->width = avctx->width;
85  c->height = avctx->height;
86 
87  if (avctx->height & 3 || avctx->width & 3) {
88  av_log(avctx, AV_LOG_ERROR,
89  "width %d and height %d must be multiplie of 4.\n",
90  avctx->width, avctx->height);
91  return AVERROR_INVALIDDATA;
92  }
93 
94  avctx->pix_fmt = AV_PIX_FMT_PAL8;
95  ret = av_image_check_size2(avctx->width, FFALIGN(avctx->height, 256), avctx->max_pixels, avctx->pix_fmt, 0, avctx);
96  if (ret < 0)
97  return ret;
98 
99  c->pic = av_frame_alloc();
100  if (!c->pic)
101  return AVERROR(ENOMEM);
102 
103  c->frame_size = avctx->width * FFALIGN(avctx->height, 256);
104  c->video_size = avctx->width * avctx->height;
105  for (i = 0; i < 4; i++) {
106  c->frame[i] = av_mallocz(c->frame_size);
107  if (!c->frame[i])
108  return AVERROR(ENOMEM);
109  }
110 
111  return 0;
112 }
113 
114 static void read4x4block(PAFVideoDecContext *c, uint8_t *dst, int width)
115 {
116  int i;
117 
118  for (i = 0; i < 4; i++) {
119  bytestream2_get_buffer(&c->gb, dst, 4);
120  dst += width;
121  }
122 }
123 
124 static void copy_color_mask(uint8_t *dst, int width, uint8_t mask, uint8_t color)
125 {
126  int i;
127 
128  for (i = 0; i < 4; i++) {
129  if (mask & (1 << 7 - i))
130  dst[i] = color;
131  if (mask & (1 << 3 - i))
132  dst[width + i] = color;
133  }
134 }
135 
136 static void copy_src_mask(uint8_t *dst, int width, uint8_t mask, const uint8_t *src)
137 {
138  int i;
139 
140  for (i = 0; i < 4; i++) {
141  if (mask & (1 << 7 - i))
142  dst[i] = src[i];
143  if (mask & (1 << 3 - i))
144  dst[width + i] = src[width + i];
145  }
146 }
147 
149  const uint8_t **p,
150  const uint8_t **pend)
151 {
152  int val = bytestream2_get_be16(&c->gb);
153  int page = val >> 14;
154  int x = (val & 0x7F);
155  int y = ((val >> 7) & 0x7F);
156 
157  *p = c->frame[page] + x * 2 + y * 2 * c->width;
158  *pend = c->frame[page] + c->frame_size;
159 }
160 
161 static int decode_0(PAFVideoDecContext *c, uint8_t *pkt, uint8_t code)
162 {
163  uint32_t opcode_size, offset;
164  uint8_t *dst, *dend, mask = 0, color = 0;
165  const uint8_t *src, *send, *opcodes;
166  int i, j, op = 0;
167 
168  i = bytestream2_get_byte(&c->gb);
169  if (i) {
170  if (code & 0x10) {
171  int align;
172 
173  align = bytestream2_tell(&c->gb) & 3;
174  if (align)
175  bytestream2_skip(&c->gb, 4 - align);
176  }
177  do {
178  int page, val, x, y;
179  val = bytestream2_get_be16(&c->gb);
180  page = val >> 14;
181  x = (val & 0x7F) * 2;
182  y = ((val >> 7) & 0x7F) * 2;
183  dst = c->frame[page] + x + y * c->width;
184  dend = c->frame[page] + c->frame_size;
185  offset = (x & 0x7F) * 2;
186  j = bytestream2_get_le16(&c->gb) + offset;
187  if (bytestream2_get_bytes_left(&c->gb) < (j - offset) * 16)
188  return AVERROR_INVALIDDATA;
189  c->dirty[page] = 1;
190  do {
191  offset++;
192  if (dst + 3 * c->width + 4 > dend)
193  return AVERROR_INVALIDDATA;
194  read4x4block(c, dst, c->width);
195  if ((offset & 0x3F) == 0)
196  dst += c->width * 3;
197  dst += 4;
198  } while (offset < j);
199  } while (--i);
200  }
201 
202  dst = c->frame[c->current_frame];
203  dend = c->frame[c->current_frame] + c->frame_size;
204  do {
205  set_src_position(c, &src, &send);
206  if ((src + 3 * c->width + 4 > send) ||
207  (dst + 3 * c->width + 4 > dend) ||
208  bytestream2_get_bytes_left(&c->gb) < 4)
209  return AVERROR_INVALIDDATA;
210  copy_block4(dst, src, c->width, c->width, 4);
211  i++;
212  if ((i & 0x3F) == 0)
213  dst += c->width * 3;
214  dst += 4;
215  } while (i < c->video_size / 16);
216 
217  opcode_size = bytestream2_get_le16(&c->gb);
218  bytestream2_skip(&c->gb, 2);
219 
220  if (bytestream2_get_bytes_left(&c->gb) < opcode_size)
221  return AVERROR_INVALIDDATA;
222 
223  opcodes = pkt + bytestream2_tell(&c->gb);
224  bytestream2_skipu(&c->gb, opcode_size);
225 
226  dst = c->frame[c->current_frame];
227 
228  for (i = 0; i < c->height; i += 4, dst += c->width * 3)
229  for (j = 0; j < c->width; j += 4, dst += 4) {
230  int opcode, k = 0;
231  if (op > opcode_size)
232  return AVERROR_INVALIDDATA;
233  if (j & 4) {
234  opcode = opcodes[op] & 15;
235  op++;
236  } else {
237  opcode = opcodes[op] >> 4;
238  }
239 
240  while (block_sequences[opcode][k]) {
241  offset = c->width * 2;
242  code = block_sequences[opcode][k++];
243 
244  switch (code) {
245  case 2:
246  offset = 0;
247  case 3:
248  color = bytestream2_get_byte(&c->gb);
249  case 4:
250  mask = bytestream2_get_byte(&c->gb);
251  copy_color_mask(dst + offset, c->width, mask, color);
252  break;
253  case 5:
254  offset = 0;
255  case 6:
256  set_src_position(c, &src, &send);
257  case 7:
258  if (src + offset + c->width + 4 > send)
259  return AVERROR_INVALIDDATA;
260  mask = bytestream2_get_byte(&c->gb);
261  copy_src_mask(dst + offset, c->width, mask, src + offset);
262  break;
263  }
264  }
265  }
266 
267  return 0;
268 }
269 
270 static int paf_video_decode(AVCodecContext *avctx, void *data,
271  int *got_frame, AVPacket *pkt)
272 {
273  PAFVideoDecContext *c = avctx->priv_data;
274  uint8_t code, *dst, *end;
275  int i, frame, ret;
276 
277  if (pkt->size < 2)
278  return AVERROR_INVALIDDATA;
279 
280  bytestream2_init(&c->gb, pkt->data, pkt->size);
281 
282  code = bytestream2_get_byte(&c->gb);
283  if ((code & 0xF) > 4 || (code & 0xF) == 3) {
284  avpriv_request_sample(avctx, "unknown/invalid code");
285  return AVERROR_INVALIDDATA;
286  }
287 
288  if ((code & 0xF) == 0 &&
289  c->video_size / 32 - (int64_t)bytestream2_get_bytes_left(&c->gb) > c->video_size / 32 * (int64_t)avctx->discard_damaged_percentage / 100)
290  return AVERROR_INVALIDDATA;
291 
292  if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
293  return ret;
294 
295  if (code & 0x20) { // frame is keyframe
296  memset(c->pic->data[1], 0, AVPALETTE_SIZE);
297  c->current_frame = 0;
298  c->pic->key_frame = 1;
299  c->pic->pict_type = AV_PICTURE_TYPE_I;
300  } else {
301  c->pic->key_frame = 0;
302  c->pic->pict_type = AV_PICTURE_TYPE_P;
303  }
304 
305  if (code & 0x40) { // palette update
306  uint32_t *out = (uint32_t *)c->pic->data[1];
307  int index, count;
308 
309  index = bytestream2_get_byte(&c->gb);
310  count = bytestream2_get_byte(&c->gb) + 1;
311 
312  if (index + count > 256)
313  return AVERROR_INVALIDDATA;
314  if (bytestream2_get_bytes_left(&c->gb) < 3 * count)
315  return AVERROR_INVALIDDATA;
316 
317  out += index;
318  for (i = 0; i < count; i++) {
319  unsigned r, g, b;
320 
321  r = bytestream2_get_byteu(&c->gb);
322  r = r << 2 | r >> 4;
323  g = bytestream2_get_byteu(&c->gb);
324  g = g << 2 | g >> 4;
325  b = bytestream2_get_byteu(&c->gb);
326  b = b << 2 | b >> 4;
327  *out++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;
328  }
329  c->pic->palette_has_changed = 1;
330  }
331 
332  c->dirty[c->current_frame] = 1;
333  if (code & 0x20)
334  for (i = 0; i < 4; i++) {
335  if (c->dirty[i])
336  memset(c->frame[i], 0, c->frame_size);
337  c->dirty[i] = 0;
338  }
339 
340  switch (code & 0x0F) {
341  case 0:
342  /* Block-based motion compensation using 4x4 blocks with either
343  * horizontal or vertical vectors; might incorporate VQ as well. */
344  if ((ret = decode_0(c, pkt->data, code)) < 0)
345  return ret;
346  break;
347  case 1:
348  /* Uncompressed data. This mode specifies that (width * height) bytes
349  * should be copied directly from the encoded buffer into the output. */
350  dst = c->frame[c->current_frame];
351  // possibly chunk length data
352  bytestream2_skip(&c->gb, 2);
353  if (bytestream2_get_bytes_left(&c->gb) < c->video_size)
354  return AVERROR_INVALIDDATA;
355  bytestream2_get_bufferu(&c->gb, dst, c->video_size);
356  break;
357  case 2:
358  /* Copy reference frame: Consume the next byte in the stream as the
359  * reference frame (which should be 0, 1, 2, or 3, and should not be
360  * the same as the current frame number). */
361  frame = bytestream2_get_byte(&c->gb);
362  if (frame > 3)
363  return AVERROR_INVALIDDATA;
364  if (frame != c->current_frame)
365  memcpy(c->frame[c->current_frame], c->frame[frame], c->frame_size);
366  break;
367  case 4:
368  /* Run length encoding.*/
369  dst = c->frame[c->current_frame];
370  end = dst + c->video_size;
371 
372  bytestream2_skip(&c->gb, 2);
373 
374  while (dst < end) {
375  int8_t code;
376  int count;
377 
378  if (bytestream2_get_bytes_left(&c->gb) < 2)
379  return AVERROR_INVALIDDATA;
380 
381  code = bytestream2_get_byteu(&c->gb);
382  count = FFABS(code) + 1;
383 
384  if (dst + count > end)
385  return AVERROR_INVALIDDATA;
386  if (code < 0)
387  memset(dst, bytestream2_get_byteu(&c->gb), count);
388  else
389  bytestream2_get_buffer(&c->gb, dst, count);
390  dst += count;
391  }
392  break;
393  default:
394  av_assert0(0);
395  }
396 
397  av_image_copy_plane(c->pic->data[0], c->pic->linesize[0],
398  c->frame[c->current_frame], c->width,
399  c->width, c->height);
400 
401  c->current_frame = (c->current_frame + 1) & 3;
402  if ((ret = av_frame_ref(data, c->pic)) < 0)
403  return ret;
404 
405  *got_frame = 1;
406 
407  return pkt->size;
408 }
409 
411  .name = "paf_video",
412  .long_name = NULL_IF_CONFIG_SMALL("Amazing Studio Packed Animation File Video"),
413  .type = AVMEDIA_TYPE_VIDEO,
414  .id = AV_CODEC_ID_PAF_VIDEO,
415  .priv_data_size = sizeof(PAFVideoDecContext),
416  .init = paf_video_init,
417  .close = paf_video_close,
419  .capabilities = AV_CODEC_CAP_DR1,
421 };
AVCodec
AVCodec.
Definition: codec.h:202
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
decode_0
static int decode_0(PAFVideoDecContext *c, uint8_t *pkt, uint8_t code)
Definition: pafvideo.c:161
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
PAFVideoDecContext::opcodes
uint8_t * opcodes
Definition: pafvideo.c:62
r
const char * r
Definition: vf_curves.c:116
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
out
FILE * out
Definition: movenc.c:54
color
Definition: vf_paletteuse.c:599
GetByteContext
Definition: bytestream.h:33
bytestream2_skipu
static av_always_inline void bytestream2_skipu(GetByteContext *g, unsigned int size)
Definition: bytestream.h:174
PAFVideoDecContext::gb
GetByteContext gb
Definition: pafvideo.c:51
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
PAFVideoDecContext::frame_size
int frame_size
Definition: pafvideo.c:59
index
fg index
Definition: ffmpeg_filter.c:168
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
b
#define b
Definition: input.c:40
data
const char data[16]
Definition: mxf.c:143
PAFVideoDecContext::frame
uint8_t * frame[4]
Definition: pafvideo.c:57
PAFVideoDecContext::width
int width
Definition: pafvideo.c:53
av_image_copy_plane
void av_image_copy_plane(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize, int bytewidth, int height)
Copy image plane from src to dst.
Definition: imgutils.c:374
bytestream2_skip
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:168
U
#define U(x)
Definition: vp56_arith.h:37
val
static double val(void *priv, double ch)
Definition: aeval.c:76
copy_src_mask
static void copy_src_mask(uint8_t *dst, int width, uint8_t mask, const uint8_t *src)
Definition: pafvideo.c:136
av_image_check_size2
int av_image_check_size2(unsigned int w, unsigned int h, int64_t max_pixels, enum AVPixelFormat pix_fmt, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of a plane of an image with...
Definition: imgutils.c:289
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:99
PAFVideoDecContext::current_frame
int current_frame
Definition: pafvideo.c:56
PAFVideoDecContext
Definition: pafvideo.c:49
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
mask
static const uint16_t mask[17]
Definition: lzw.c:38
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
width
#define width
g
const char * g
Definition: vf_curves.c:117
op
static int op(uint8_t **dst, const uint8_t *dst_end, GetByteContext *gb, int pixel, int count, int *x, int width, int linesize)
Perform decode operation.
Definition: anm.c:75
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
paf_video_init
static av_cold int paf_video_init(AVCodecContext *avctx)
Definition: pafvideo.c:78
AVCodecContext::max_pixels
int64_t max_pixels
The number of pixels per image to maximally accept.
Definition: avcodec.h:1886
copy_color_mask
static void copy_color_mask(uint8_t *dst, int width, uint8_t mask, uint8_t color)
Definition: pafvideo.c:124
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:65
block_sequences
static const uint8_t block_sequences[16][8]
Definition: pafvideo.c:30
ff_paf_video_decoder
const AVCodec ff_paf_video_decoder
Definition: pafvideo.c:410
AVPALETTE_SIZE
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
src
#define src
Definition: vp8dsp.c:255
bytestream2_get_buffer
static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g, uint8_t *dst, unsigned int size)
Definition: bytestream.h:267
read4x4block
static void read4x4block(PAFVideoDecContext *c, uint8_t *dst, int width)
Definition: pafvideo.c:114
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
bytestream2_get_bytes_left
static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:158
bytestream2_tell
static av_always_inline int bytestream2_tell(GetByteContext *g)
Definition: bytestream.h:192
PAFVideoDecContext::video_size
int video_size
Definition: pafvideo.c:60
PAFVideoDecContext::pic
AVFrame * pic
Definition: pafvideo.c:50
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:327
color
static const uint32_t color[16+AV_CLASS_CATEGORY_NB]
Definition: log.c:92
PAFVideoDecContext::dirty
int dirty[4]
Definition: pafvideo.c:58
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
copy_block4
static void copy_block4(uint8_t *dst, const uint8_t *src, ptrdiff_t dstStride, ptrdiff_t srcStride, int h)
Definition: copy_block.h:37
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
copy_block.h
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:50
AV_CODEC_ID_PAF_VIDEO
@ AV_CODEC_ID_PAF_VIDEO
Definition: codec_id.h:229
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:263
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
paf_video_decode
static int paf_video_decode(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *pkt)
Definition: pafvideo.c:270
AVCodecContext::height
int height
Definition: avcodec.h:556
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:593
avcodec.h
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1759
ret
ret
Definition: filter_design.txt:187
set_src_position
static void set_src_position(PAFVideoDecContext *c, const uint8_t **p, const uint8_t **pend)
Definition: pafvideo.c:148
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AVCodecContext
main external API structure.
Definition: avcodec.h:383
AVCodecContext::discard_damaged_percentage
int discard_damaged_percentage
The percentage of damaged samples to discard a frame.
Definition: avcodec.h:1966
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
PAFVideoDecContext::height
int height
Definition: pafvideo.c:54
bytestream2_get_bufferu
static av_always_inline unsigned int bytestream2_get_bufferu(GetByteContext *g, uint8_t *dst, unsigned int size)
Definition: bytestream.h:277
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:37
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
bytestream.h
imgutils.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
paf_video_close
static av_cold int paf_video_close(AVCodecContext *avctx)
Definition: pafvideo.c:65
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61