FFmpeg
asvenc.c
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1 /*
2  * Copyright (c) 2003 Michael Niedermayer
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * ASUS V1/V2 encoder.
24  */
25 
26 #include "libavutil/attributes.h"
27 #include "libavutil/mem.h"
28 
29 #include "aandcttab.h"
30 #include "asv.h"
31 #include "avcodec.h"
32 #include "dct.h"
33 #include "fdctdsp.h"
34 #include "internal.h"
35 #include "mathops.h"
36 #include "mpeg12data.h"
37 
38 static inline void asv2_put_bits(PutBitContext *pb, int n, int v)
39 {
40  put_bits(pb, n, ff_reverse[v << (8 - n)]);
41 }
42 
43 static inline void asv1_put_level(PutBitContext *pb, int level)
44 {
45  unsigned int index = level + 3;
46 
47  if (index <= 6) {
48  put_bits(pb, ff_asv_level_tab[index][1], ff_asv_level_tab[index][0]);
49  } else {
50  put_bits(pb, ff_asv_level_tab[3][1], ff_asv_level_tab[3][0]);
51  put_sbits(pb, 8, level);
52  }
53 }
54 
55 static inline void asv2_put_level(ASV1Context *a, PutBitContext *pb, int level)
56 {
57  unsigned int index = level + 31;
58 
59  if (index <= 62) {
60  put_bits(pb, ff_asv2_level_tab[index][1], ff_asv2_level_tab[index][0]);
61  } else {
62  put_bits(pb, ff_asv2_level_tab[31][1], ff_asv2_level_tab[31][0]);
63  if (level < -128 || level > 127) {
64  av_log(a->avctx, AV_LOG_WARNING, "Clipping level %d, increase qscale\n", level);
65  level = av_clip_int8(level);
66  }
67  asv2_put_bits(pb, 8, level & 0xFF);
68  }
69 }
70 
71 static inline void asv1_encode_block(ASV1Context *a, int16_t block[64])
72 {
73  int i;
74  int nc_count = 0;
75 
76  put_bits(&a->pb, 8, (block[0] + 32) >> 6);
77  block[0] = 0;
78 
79  for (i = 0; i < 10; i++) {
80  const int index = ff_asv_scantab[4 * i];
81  int ccp = 0;
82 
83  if ((block[index + 0] = (block[index + 0] *
84  a->q_intra_matrix[index + 0] + (1 << 15)) >> 16))
85  ccp |= 8;
86  if ((block[index + 8] = (block[index + 8] *
87  a->q_intra_matrix[index + 8] + (1 << 15)) >> 16))
88  ccp |= 4;
89  if ((block[index + 1] = (block[index + 1] *
90  a->q_intra_matrix[index + 1] + (1 << 15)) >> 16))
91  ccp |= 2;
92  if ((block[index + 9] = (block[index + 9] *
93  a->q_intra_matrix[index + 9] + (1 << 15)) >> 16))
94  ccp |= 1;
95 
96  if (ccp) {
97  for (; nc_count; nc_count--)
98  put_bits(&a->pb, ff_asv_ccp_tab[0][1], ff_asv_ccp_tab[0][0]);
99 
100  put_bits(&a->pb, ff_asv_ccp_tab[ccp][1], ff_asv_ccp_tab[ccp][0]);
101 
102  if (ccp & 8)
103  asv1_put_level(&a->pb, block[index + 0]);
104  if (ccp & 4)
105  asv1_put_level(&a->pb, block[index + 8]);
106  if (ccp & 2)
107  asv1_put_level(&a->pb, block[index + 1]);
108  if (ccp & 1)
109  asv1_put_level(&a->pb, block[index + 9]);
110  } else {
111  nc_count++;
112  }
113  }
114  put_bits(&a->pb, ff_asv_ccp_tab[16][1], ff_asv_ccp_tab[16][0]);
115 }
116 
117 static inline void asv2_encode_block(ASV1Context *a, int16_t block[64])
118 {
119  int i;
120  int count = 0;
121 
122  for (count = 63; count > 3; count--) {
123  const int index = ff_asv_scantab[count];
124  if ((block[index] * a->q_intra_matrix[index] + (1 << 15)) >> 16)
125  break;
126  }
127 
128  count >>= 2;
129 
130  asv2_put_bits(&a->pb, 4, count);
131  asv2_put_bits(&a->pb, 8, (block[0] + 32) >> 6);
132  block[0] = 0;
133 
134  for (i = 0; i <= count; i++) {
135  const int index = ff_asv_scantab[4 * i];
136  int ccp = 0;
137 
138  if ((block[index + 0] = (block[index + 0] *
139  a->q_intra_matrix[index + 0] + (1 << 15)) >> 16))
140  ccp |= 8;
141  if ((block[index + 8] = (block[index + 8] *
142  a->q_intra_matrix[index + 8] + (1 << 15)) >> 16))
143  ccp |= 4;
144  if ((block[index + 1] = (block[index + 1] *
145  a->q_intra_matrix[index + 1] + (1 << 15)) >> 16))
146  ccp |= 2;
147  if ((block[index + 9] = (block[index + 9] *
148  a->q_intra_matrix[index + 9] + (1 << 15)) >> 16))
149  ccp |= 1;
150 
151  av_assert2(i || ccp < 8);
152  if (i)
153  put_bits(&a->pb, ff_asv_ac_ccp_tab[ccp][1], ff_asv_ac_ccp_tab[ccp][0]);
154  else
155  put_bits(&a->pb, ff_asv_dc_ccp_tab[ccp][1], ff_asv_dc_ccp_tab[ccp][0]);
156 
157  if (ccp) {
158  if (ccp & 8)
159  asv2_put_level(a, &a->pb, block[index + 0]);
160  if (ccp & 4)
161  asv2_put_level(a, &a->pb, block[index + 8]);
162  if (ccp & 2)
163  asv2_put_level(a, &a->pb, block[index + 1]);
164  if (ccp & 1)
165  asv2_put_level(a, &a->pb, block[index + 9]);
166  }
167  }
168 }
169 
170 #define MAX_MB_SIZE (30 * 16 * 16 * 3 / 2 / 8)
171 
172 static inline int encode_mb(ASV1Context *a, int16_t block[6][64])
173 {
174  int i;
175 
176  av_assert0(a->pb.buf_end - a->pb.buf - (put_bits_count(&a->pb) >> 3) >= MAX_MB_SIZE);
177 
178  if (a->avctx->codec_id == AV_CODEC_ID_ASV1) {
179  for (i = 0; i < 6; i++)
180  asv1_encode_block(a, block[i]);
181  } else {
182  for (i = 0; i < 6; i++) {
183  asv2_encode_block(a, block[i]);
184  }
185  }
186  return 0;
187 }
188 
189 static inline void dct_get(ASV1Context *a, const AVFrame *frame,
190  int mb_x, int mb_y)
191 {
192  int16_t (*block)[64] = a->block;
193  int linesize = frame->linesize[0];
194  int i;
195 
196  uint8_t *ptr_y = frame->data[0] + (mb_y * 16 * linesize) + mb_x * 16;
197  uint8_t *ptr_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
198  uint8_t *ptr_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
199 
200  a->pdsp.get_pixels(block[0], ptr_y, linesize);
201  a->pdsp.get_pixels(block[1], ptr_y + 8, linesize);
202  a->pdsp.get_pixels(block[2], ptr_y + 8 * linesize, linesize);
203  a->pdsp.get_pixels(block[3], ptr_y + 8 * linesize + 8, linesize);
204  for (i = 0; i < 4; i++)
205  a->fdsp.fdct(block[i]);
206 
207  if (!(a->avctx->flags & AV_CODEC_FLAG_GRAY)) {
208  a->pdsp.get_pixels(block[4], ptr_cb, frame->linesize[1]);
209  a->pdsp.get_pixels(block[5], ptr_cr, frame->linesize[2]);
210  for (i = 4; i < 6; i++)
211  a->fdsp.fdct(block[i]);
212  }
213 }
214 
216  const AVFrame *pict, int *got_packet)
217 {
218  ASV1Context *const a = avctx->priv_data;
219  int size, ret;
220  int mb_x, mb_y;
221 
222  if (pict->width % 16 || pict->height % 16) {
223  AVFrame *clone = av_frame_alloc();
224  int i;
225 
226  if (!clone)
227  return AVERROR(ENOMEM);
228  clone->format = pict->format;
229  clone->width = FFALIGN(pict->width, 16);
230  clone->height = FFALIGN(pict->height, 16);
231  ret = av_frame_get_buffer(clone, 0);
232  if (ret < 0) {
233  av_frame_free(&clone);
234  return ret;
235  }
236 
237  ret = av_frame_copy(clone, pict);
238  if (ret < 0) {
239  av_frame_free(&clone);
240  return ret;
241  }
242 
243  for (i = 0; i<3; i++) {
244  int x, y;
245  int w = AV_CEIL_RSHIFT(pict->width, !!i);
246  int h = AV_CEIL_RSHIFT(pict->height, !!i);
247  int w2 = AV_CEIL_RSHIFT(clone->width, !!i);
248  int h2 = AV_CEIL_RSHIFT(clone->height, !!i);
249  for (y=0; y<h; y++)
250  for (x=w; x<w2; x++)
251  clone->data[i][x + y*clone->linesize[i]] =
252  clone->data[i][w - 1 + y*clone->linesize[i]];
253  for (y=h; y<h2; y++)
254  for (x=0; x<w2; x++)
255  clone->data[i][x + y*clone->linesize[i]] =
256  clone->data[i][x + (h-1)*clone->linesize[i]];
257  }
258  ret = encode_frame(avctx, pkt, clone, got_packet);
259 
260  av_frame_free(&clone);
261  return ret;
262  }
263 
264  if ((ret = ff_alloc_packet2(avctx, pkt, a->mb_height * a->mb_width * MAX_MB_SIZE +
265  AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0)
266  return ret;
267 
268  init_put_bits(&a->pb, pkt->data, pkt->size);
269 
270  for (mb_y = 0; mb_y < a->mb_height2; mb_y++) {
271  for (mb_x = 0; mb_x < a->mb_width2; mb_x++) {
272  dct_get(a, pict, mb_x, mb_y);
273  encode_mb(a, a->block);
274  }
275  }
276 
277  if (a->mb_width2 != a->mb_width) {
278  mb_x = a->mb_width2;
279  for (mb_y = 0; mb_y < a->mb_height2; mb_y++) {
280  dct_get(a, pict, mb_x, mb_y);
281  encode_mb(a, a->block);
282  }
283  }
284 
285  if (a->mb_height2 != a->mb_height) {
286  mb_y = a->mb_height2;
287  for (mb_x = 0; mb_x < a->mb_width; mb_x++) {
288  dct_get(a, pict, mb_x, mb_y);
289  encode_mb(a, a->block);
290  }
291  }
292  emms_c();
293 
295  while (put_bits_count(&a->pb) & 31)
296  put_bits(&a->pb, 8, 0);
297 
298  flush_put_bits(&a->pb);
299  size = put_bits_count(&a->pb) / 32;
300 
301  if (avctx->codec_id == AV_CODEC_ID_ASV1) {
302  a->bbdsp.bswap_buf((uint32_t *) pkt->data,
303  (uint32_t *) pkt->data, size);
304  } else {
305  int i;
306  for (i = 0; i < 4 * size; i++)
307  pkt->data[i] = ff_reverse[pkt->data[i]];
308  }
309 
310  pkt->size = size * 4;
311  pkt->flags |= AV_PKT_FLAG_KEY;
312  *got_packet = 1;
313 
314  return 0;
315 }
316 
318 {
319  ASV1Context *const a = avctx->priv_data;
320  int i;
321  const int scale = avctx->codec_id == AV_CODEC_ID_ASV1 ? 1 : 2;
322 
323  ff_asv_common_init(avctx);
324  ff_fdctdsp_init(&a->fdsp, avctx);
325  ff_pixblockdsp_init(&a->pdsp, avctx);
326 
327  if (avctx->global_quality <= 0)
328  avctx->global_quality = 4 * FF_QUALITY_SCALE;
329 
330  a->inv_qscale = (32 * scale * FF_QUALITY_SCALE +
331  avctx->global_quality / 2) / avctx->global_quality;
332 
333  avctx->extradata = av_mallocz(8);
334  if (!avctx->extradata)
335  return AVERROR(ENOMEM);
336  avctx->extradata_size = 8;
337  ((uint32_t *) avctx->extradata)[0] = av_le2ne32(a->inv_qscale);
338  ((uint32_t *) avctx->extradata)[1] = av_le2ne32(AV_RL32("ASUS"));
339 
340  for (i = 0; i < 64; i++) {
341  if (a->fdsp.fdct == ff_fdct_ifast) {
342  int q = 32LL * scale * ff_mpeg1_default_intra_matrix[i] * ff_aanscales[i];
343  a->q_intra_matrix[i] = (((int64_t)a->inv_qscale << 30) + q / 2) / q;
344  } else {
345  int q = 32 * scale * ff_mpeg1_default_intra_matrix[i];
346  a->q_intra_matrix[i] = ((a->inv_qscale << 16) + q / 2) / q;
347  }
348  }
349 
350  return 0;
351 }
352 
353 #if CONFIG_ASV1_ENCODER
355  .name = "asv1",
356  .long_name = NULL_IF_CONFIG_SMALL("ASUS V1"),
357  .type = AVMEDIA_TYPE_VIDEO,
358  .id = AV_CODEC_ID_ASV1,
359  .priv_data_size = sizeof(ASV1Context),
360  .init = encode_init,
361  .encode2 = encode_frame,
362  .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
363  AV_PIX_FMT_NONE },
364  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
365 };
366 #endif
367 
368 #if CONFIG_ASV2_ENCODER
370  .name = "asv2",
371  .long_name = NULL_IF_CONFIG_SMALL("ASUS V2"),
372  .type = AVMEDIA_TYPE_VIDEO,
373  .id = AV_CODEC_ID_ASV2,
374  .priv_data_size = sizeof(ASV1Context),
375  .init = encode_init,
376  .encode2 = encode_frame,
377  .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
378  AV_PIX_FMT_NONE },
379  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
380 };
381 #endif
static int encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
Definition: asvenc.c:215
This structure describes decoded (raw) audio or video data.
Definition: frame.h:308
const uint8_t ff_asv_ac_ccp_tab[16][2]
Definition: asv.c:60
void ff_fdct_ifast(int16_t *data)
Definition: jfdctfst.c:208
static void put_sbits(PutBitContext *pb, int n, int32_t value)
Definition: put_bits.h:258
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:218
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
Memory handling functions.
int16_t block[6][64]
Definition: asv.h:57
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
const uint8_t ff_reverse[256]
Definition: reverse.c:23
int size
Definition: packet.h:364
AVCodecContext * avctx
Definition: asv.h:43
#define FF_QUALITY_SCALE
Definition: avutil.h:230
void avpriv_align_put_bits(PutBitContext *s)
Pad the bitstream with zeros up to the next byte boundary.
Definition: bitstream.c:48
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:237
static AVPacket pkt
#define av_le2ne32(x)
Definition: bswap.h:96
av_cold void ff_fdctdsp_init(FDCTDSPContext *c, AVCodecContext *avctx)
Definition: fdctdsp.c:26
AVCodec.
Definition: codec.h:190
PixblockDSPContext pdsp
Definition: asv.h:48
Macro definitions for various function/variable attributes.
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size)
Check AVPacket size and/or allocate data.
Definition: encode.c:33
#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:40
const uint8_t ff_asv2_level_tab[63][2]
Definition: asv.c:67
The exact code depends on how similar the blocks are and how related they are to the block
uint8_t
#define av_cold
Definition: attributes.h:88
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:190
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
void(* bswap_buf)(uint32_t *dst, const uint32_t *src, int w)
Definition: bswapdsp.h:25
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:627
const uint8_t ff_asv_ccp_tab[17][2]
Definition: asv.c:43
const uint16_t ff_aanscales[64]
Definition: aandcttab.c:26
uint8_t * data
Definition: packet.h:363
const uint8_t ff_asv_dc_ccp_tab[8][2]
Definition: asv.c:55
ptrdiff_t size
Definition: opengl_enc.c:100
int mb_height2
Definition: asv.h:56
#define AV_CODEC_FLAG_GRAY
Only decode/encode grayscale.
Definition: avcodec.h:308
#define AV_INPUT_BUFFER_MIN_SIZE
minimum encoding buffer size Used to avoid some checks during header writing.
Definition: avcodec.h:222
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:401
int width
Definition: frame.h:366
BswapDSPContext bbdsp
Definition: asv.h:45
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:203
av_cold void ff_asv_common_init(AVCodecContext *avctx)
Definition: asv.c:83
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:606
uint8_t * buf
Definition: put_bits.h:52
static int encode_mb(ASV1Context *a, int16_t block[6][64])
Definition: asvenc.c:172
const char * name
Name of the codec implementation.
Definition: codec.h:197
GLsizei count
Definition: opengl_enc.c:108
av_cold void ff_pixblockdsp_init(PixblockDSPContext *c, AVCodecContext *avctx)
Definition: pixblockdsp.c:81
ASUS V1/V2 encoder/decoder common data.
int av_frame_copy(AVFrame *dst, const AVFrame *src)
Copy the frame data from src to dst.
Definition: frame.c:812
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:369
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:81
uint8_t w
Definition: llviddspenc.c:38
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
static av_cold int encode_init(AVCodecContext *avctx)
Definition: asvenc.c:317
AVCodec ff_asv1_encoder
void(* fdct)(int16_t *block)
Definition: fdctdsp.h:27
AVCodec ff_asv2_encoder
int mb_width
Definition: asv.h:53
static void asv1_encode_block(ASV1Context *a, int16_t block[64])
Definition: asvenc.c:71
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames...
Definition: frame.h:381
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:536
#define MAX_MB_SIZE
Definition: asvenc.c:170
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:339
main external API structure.
Definition: avcodec.h:526
PutBitContext pb
Definition: asv.h:49
int q_intra_matrix[64]
Definition: asv.h:59
MPEG-1/2 tables.
uint8_t * buf_end
Definition: put_bits.h:52
static void asv1_put_level(PutBitContext *pb, int level)
Definition: asvenc.c:43
int extradata_size
Definition: avcodec.h:628
FDCTDSPContext fdsp
Definition: asv.h:46
static void dct_get(ASV1Context *a, const AVFrame *frame, int mb_x, int mb_y)
Definition: asvenc.c:189
int index
Definition: gxfenc.c:89
const uint16_t ff_mpeg1_default_intra_matrix[256]
Definition: mpeg12data.c:30
int mb_width2
Definition: asv.h:55
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:300
int av_frame_get_buffer(AVFrame *frame, int align)
Allocate new buffer(s) for audio or video data.
Definition: frame.c:337
int global_quality
Global quality for codecs which cannot change it per frame.
Definition: avcodec.h:592
void(* get_pixels)(int16_t *av_restrict block, const uint8_t *pixels, ptrdiff_t stride)
Definition: pixblockdsp.h:29
AAN (Arai, Agui and Nakajima) (I)DCT tables.
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:322
uint8_t level
Definition: svq3.c:205
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
int inv_qscale
Definition: asv.h:52
common internal api header.
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:115
static void asv2_encode_block(ASV1Context *a, int16_t block[64])
Definition: asvenc.c:117
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:62
void * priv_data
Definition: avcodec.h:553
static void asv2_put_bits(PutBitContext *pb, int n, int v)
Definition: asvenc.c:38
int height
Definition: frame.h:366
static void asv2_put_level(ASV1Context *a, PutBitContext *pb, int level)
Definition: asvenc.c:55
const uint8_t ff_asv_scantab[64]
Definition: asv.c:32
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
const uint8_t ff_asv_level_tab[7][2]
Definition: asv.c:51
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
This structure stores compressed data.
Definition: packet.h:340
int mb_height
Definition: asv.h:54
for(j=16;j >0;--j)
int i
Definition: input.c:407
#define AV_CEIL_RSHIFT(a, b)
Definition: common.h:58