FFmpeg
ljpegenc.c
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1 /*
2  * lossless JPEG encoder
3  * Copyright (c) 2000, 2001 Fabrice Bellard
4  * Copyright (c) 2003 Alex Beregszaszi
5  * Copyright (c) 2003-2004 Michael Niedermayer
6  *
7  * Support for external huffman table, various fixes (AVID workaround),
8  * aspecting, new decode_frame mechanism and apple mjpeg-b support
9  * by Alex Beregszaszi
10  *
11  * This file is part of FFmpeg.
12  *
13  * FFmpeg is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU Lesser General Public
15  * License as published by the Free Software Foundation; either
16  * version 2.1 of the License, or (at your option) any later version.
17  *
18  * FFmpeg is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21  * Lesser General Public License for more details.
22  *
23  * You should have received a copy of the GNU Lesser General Public
24  * License along with FFmpeg; if not, write to the Free Software
25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26  */
27 
28 /**
29  * @file
30  * lossless JPEG encoder.
31  */
32 
33 #include "libavutil/frame.h"
34 #include "libavutil/mem.h"
35 #include "libavutil/pixdesc.h"
36 
37 #include "avcodec.h"
38 #include "idctdsp.h"
39 #include "internal.h"
40 #include "jpegtables.h"
41 #include "mjpegenc_common.h"
42 #include "mjpeg.h"
43 
44 typedef struct LJpegEncContext {
45  AVClass *class;
48  uint16_t matrix[64];
49 
50  int vsample[4];
51  int hsample[4];
52 
53  uint16_t huff_code_dc_luminance[12];
57 
58  uint16_t (*scratch)[4];
59  int pred;
61 
63  const AVFrame *frame)
64 {
65  LJpegEncContext *s = avctx->priv_data;
66  const int width = frame->width;
67  const int height = frame->height;
68  const int linesize = frame->linesize[0];
69  uint16_t (*buffer)[4] = s->scratch;
70  int left[4], top[4], topleft[4];
71  int x, y, i;
72 
73 #if FF_API_PRIVATE_OPT
75  if (avctx->prediction_method)
76  s->pred = avctx->prediction_method + 1;
78 #endif
79 
80  for (i = 0; i < 4; i++)
81  buffer[0][i] = 1 << (9 - 1);
82 
83  for (y = 0; y < height; y++) {
84  const int modified_predictor = y ? s->pred : 1;
85  uint8_t *ptr = frame->data[0] + (linesize * y);
86 
87  if (pb->buf_end - pb->buf - (put_bits_count(pb) >> 3) < width * 4 * 4) {
88  av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
89  return -1;
90  }
91 
92  for (i = 0; i < 4; i++)
93  top[i]= left[i]= topleft[i]= buffer[0][i];
94 
95  for (x = 0; x < width; x++) {
96  if(avctx->pix_fmt == AV_PIX_FMT_BGR24){
97  buffer[x][1] = ptr[3 * x + 0] - ptr[3 * x + 1] + 0x100;
98  buffer[x][2] = ptr[3 * x + 2] - ptr[3 * x + 1] + 0x100;
99  buffer[x][0] = (ptr[3 * x + 0] + 2 * ptr[3 * x + 1] + ptr[3 * x + 2]) >> 2;
100  }else{
101  buffer[x][1] = ptr[4 * x + 0] - ptr[4 * x + 1] + 0x100;
102  buffer[x][2] = ptr[4 * x + 2] - ptr[4 * x + 1] + 0x100;
103  buffer[x][0] = (ptr[4 * x + 0] + 2 * ptr[4 * x + 1] + ptr[4 * x + 2]) >> 2;
104  if (avctx->pix_fmt == AV_PIX_FMT_BGRA)
105  buffer[x][3] = ptr[4 * x + 3];
106  }
107 
108  for (i = 0; i < 3 + (avctx->pix_fmt == AV_PIX_FMT_BGRA); i++) {
109  int pred, diff;
110 
111  PREDICT(pred, topleft[i], top[i], left[i], modified_predictor);
112 
113  topleft[i] = top[i];
114  top[i] = buffer[x+1][i];
115 
116  left[i] = buffer[x][i];
117 
118  diff = ((left[i] - pred + 0x100) & 0x1FF) - 0x100;
119 
120  if (i == 0 || i == 3)
121  ff_mjpeg_encode_dc(pb, diff, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
122  else
123  ff_mjpeg_encode_dc(pb, diff, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
124  }
125  }
126  }
127 
128  return 0;
129 }
130 
132  const AVFrame *frame, int predictor,
133  int mb_x, int mb_y)
134 {
135  int i;
136 
137  if (mb_x == 0 || mb_y == 0) {
138  for (i = 0; i < 3; i++) {
139  uint8_t *ptr;
140  int x, y, h, v, linesize;
141  h = s->hsample[i];
142  v = s->vsample[i];
143  linesize = frame->linesize[i];
144 
145  for (y = 0; y < v; y++) {
146  for (x = 0; x < h; x++) {
147  int pred;
148 
149  ptr = frame->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
150  if (y == 0 && mb_y == 0) {
151  if (x == 0 && mb_x == 0)
152  pred = 128;
153  else
154  pred = ptr[-1];
155  } else {
156  if (x == 0 && mb_x == 0) {
157  pred = ptr[-linesize];
158  } else {
159  PREDICT(pred, ptr[-linesize - 1], ptr[-linesize],
160  ptr[-1], predictor);
161  }
162  }
163 
164  if (i == 0)
165  ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
166  else
167  ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
168  }
169  }
170  }
171  } else {
172  for (i = 0; i < 3; i++) {
173  uint8_t *ptr;
174  int x, y, h, v, linesize;
175  h = s->hsample[i];
176  v = s->vsample[i];
177  linesize = frame->linesize[i];
178 
179  for (y = 0; y < v; y++) {
180  for (x = 0; x < h; x++) {
181  int pred;
182 
183  ptr = frame->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
184  PREDICT(pred, ptr[-linesize - 1], ptr[-linesize], ptr[-1], predictor);
185 
186  if (i == 0)
187  ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
188  else
189  ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
190  }
191  }
192  }
193  }
194 }
195 
197  const AVFrame *frame)
198 {
199  LJpegEncContext *s = avctx->priv_data;
200  const int mb_width = (avctx->width + s->hsample[0] - 1) / s->hsample[0];
201  const int mb_height = (avctx->height + s->vsample[0] - 1) / s->vsample[0];
202  int mb_x, mb_y;
203 
204 #if FF_API_PRIVATE_OPT
206  if (avctx->prediction_method)
207  s->pred = avctx->prediction_method + 1;
209 #endif
210 
211  for (mb_y = 0; mb_y < mb_height; mb_y++) {
212  if (pb->buf_end - pb->buf - (put_bits_count(pb) >> 3) <
213  mb_width * 4 * 3 * s->hsample[0] * s->vsample[0]) {
214  av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
215  return -1;
216  }
217 
218  for (mb_x = 0; mb_x < mb_width; mb_x++)
219  ljpeg_encode_yuv_mb(s, pb, frame, s->pred, mb_x, mb_y);
220  }
221 
222  return 0;
223 }
224 
226  const AVFrame *pict, int *got_packet)
227 {
228  LJpegEncContext *s = avctx->priv_data;
229  PutBitContext pb;
230  const int width = avctx->width;
231  const int height = avctx->height;
232  const int mb_width = (width + s->hsample[0] - 1) / s->hsample[0];
233  const int mb_height = (height + s->vsample[0] - 1) / s->vsample[0];
234  int max_pkt_size = AV_INPUT_BUFFER_MIN_SIZE;
235  int ret, header_bits;
236 
237  if( avctx->pix_fmt == AV_PIX_FMT_BGR0
238  || avctx->pix_fmt == AV_PIX_FMT_BGR24)
239  max_pkt_size += width * height * 3 * 4;
240  else if(avctx->pix_fmt == AV_PIX_FMT_BGRA)
241  max_pkt_size += width * height * 4 * 4;
242  else {
243  max_pkt_size += mb_width * mb_height * 3 * 4
244  * s->hsample[0] * s->vsample[0];
245  }
246 
247  if ((ret = ff_alloc_packet2(avctx, pkt, max_pkt_size, 0)) < 0)
248  return ret;
249 
250  init_put_bits(&pb, pkt->data, pkt->size);
251 
252  ff_mjpeg_encode_picture_header(avctx, &pb, &s->scantable,
253  s->pred, s->matrix, s->matrix);
254 
255  header_bits = put_bits_count(&pb);
256 
257  if( avctx->pix_fmt == AV_PIX_FMT_BGR0
258  || avctx->pix_fmt == AV_PIX_FMT_BGRA
259  || avctx->pix_fmt == AV_PIX_FMT_BGR24)
260  ret = ljpeg_encode_bgr(avctx, &pb, pict);
261  else
262  ret = ljpeg_encode_yuv(avctx, &pb, pict);
263  if (ret < 0)
264  return ret;
265 
266  emms_c();
267 
268  ff_mjpeg_escape_FF(&pb, header_bits >> 3);
269  ff_mjpeg_encode_picture_trailer(&pb, header_bits);
270 
271  flush_put_bits(&pb);
272  pkt->size = put_bits_ptr(&pb) - pb.buf;
274  *got_packet = 1;
275 
276  return 0;
277 }
278 
280 {
281  LJpegEncContext *s = avctx->priv_data;
282 
283  av_freep(&s->scratch);
284 
285  return 0;
286 }
287 
289 {
290  LJpegEncContext *s = avctx->priv_data;
291 
292  if ((avctx->pix_fmt == AV_PIX_FMT_YUV420P ||
293  avctx->pix_fmt == AV_PIX_FMT_YUV422P ||
294  avctx->pix_fmt == AV_PIX_FMT_YUV444P ||
295  avctx->color_range == AVCOL_RANGE_MPEG) &&
297  av_log(avctx, AV_LOG_ERROR,
298  "Limited range YUV is non-standard, set strict_std_compliance to "
299  "at least unofficial to use it.\n");
300  return AVERROR(EINVAL);
301  }
302 
303 #if FF_API_CODED_FRAME
306  avctx->coded_frame->key_frame = 1;
308 #endif
309 
310  s->scratch = av_malloc_array(avctx->width + 1, sizeof(*s->scratch));
311  if (!s->scratch)
312  goto fail;
313 
314  ff_idctdsp_init(&s->idsp, avctx);
315  ff_init_scantable(s->idsp.idct_permutation, &s->scantable,
317 
318  ff_mjpeg_init_hvsample(avctx, s->hsample, s->vsample);
319 
320  ff_mjpeg_build_huffman_codes(s->huff_size_dc_luminance,
321  s->huff_code_dc_luminance,
324  ff_mjpeg_build_huffman_codes(s->huff_size_dc_chrominance,
325  s->huff_code_dc_chrominance,
328 
329  return 0;
330 fail:
331  ljpeg_encode_close(avctx);
332  return AVERROR(ENOMEM);
333 }
334 
335 #define OFFSET(x) offsetof(LJpegEncContext, x)
336 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
337 static const AVOption options[] = {
338 { "pred", "Prediction method", OFFSET(pred), AV_OPT_TYPE_INT, { .i64 = 1 }, 1, 3, VE, "pred" },
339  { "left", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, INT_MIN, INT_MAX, VE, "pred" },
340  { "plane", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN, INT_MAX, VE, "pred" },
341  { "median", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 3 }, INT_MIN, INT_MAX, VE, "pred" },
342 
343  { NULL},
344 };
345 
346 static const AVClass ljpeg_class = {
347  .class_name = "ljpeg",
348  .item_name = av_default_item_name,
349  .option = options,
350  .version = LIBAVUTIL_VERSION_INT,
351 };
352 
354  .name = "ljpeg",
355  .long_name = NULL_IF_CONFIG_SMALL("Lossless JPEG"),
356  .type = AVMEDIA_TYPE_VIDEO,
357  .id = AV_CODEC_ID_LJPEG,
358  .priv_data_size = sizeof(LJpegEncContext),
359  .priv_class = &ljpeg_class,
361  .encode2 = ljpeg_encode_frame,
362  .close = ljpeg_encode_close,
363  .capabilities = AV_CODEC_CAP_FRAME_THREADS,
364  .pix_fmts = (const enum AVPixelFormat[]){
369 };
ff_mjpeg_encode_dc
void ff_mjpeg_encode_dc(PutBitContext *pb, int val, uint8_t *huff_size, uint16_t *huff_code)
Definition: mjpegenc_common.c:594
AVCodec
AVCodec.
Definition: codec.h:190
FF_ENABLE_DEPRECATION_WARNINGS
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:85
ff_init_scantable
av_cold void ff_init_scantable(uint8_t *permutation, ScanTable *st, const uint8_t *src_scantable)
Definition: idctdsp.c:29
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
jpegtables.h
mjpeg.h
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
ff_mjpeg_build_huffman_codes
void ff_mjpeg_build_huffman_codes(uint8_t *huff_size, uint16_t *huff_code, const uint8_t *bits_table, const uint8_t *val_table)
Definition: jpegtables.c:127
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
mjpegenc_common.h
LJpegEncContext::huff_code_dc_chrominance
uint16_t huff_code_dc_chrominance[12]
Definition: ljpegenc.c:54
ljpeg_encode_init
static av_cold int ljpeg_encode_init(AVCodecContext *avctx)
Definition: ljpegenc.c:288
init_put_bits
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:48
ff_mjpeg_encode_picture_header
void ff_mjpeg_encode_picture_header(AVCodecContext *avctx, PutBitContext *pb, ScanTable *intra_scantable, int pred, uint16_t luma_intra_matrix[64], uint16_t chroma_intra_matrix[64])
Definition: mjpegenc_common.c:248
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:300
pixdesc.h
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:355
AVOption
AVOption.
Definition: opt.h:246
LJpegEncContext
Definition: ljpegenc.c:44
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
AV_PIX_FMT_BGRA
@ AV_PIX_FMT_BGRA
packed BGRA 8:8:8:8, 32bpp, BGRABGRA...
Definition: pixfmt.h:95
ljpeg_encode_yuv
static int ljpeg_encode_yuv(AVCodecContext *avctx, PutBitContext *pb, const AVFrame *frame)
Definition: ljpegenc.c:196
avpriv_mjpeg_bits_dc_luminance
const uint8_t avpriv_mjpeg_bits_dc_luminance[17]
Definition: jpegtables.c:65
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:388
FF_COMPLIANCE_UNOFFICIAL
#define FF_COMPLIANCE_UNOFFICIAL
Allow unofficial extensions.
Definition: avcodec.h:1593
AVCodecContext::prediction_method
attribute_deprecated int prediction_method
Definition: avcodec.h:885
fail
#define fail()
Definition: checkasm.h:123
LJpegEncContext::huff_code_dc_luminance
uint16_t huff_code_dc_luminance[12]
Definition: ljpegenc.c:53
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:378
ljpeg_encode_yuv_mb
static void ljpeg_encode_yuv_mb(LJpegEncContext *s, PutBitContext *pb, const AVFrame *frame, int predictor, int mb_x, int mb_y)
Definition: ljpegenc.c:131
LJpegEncContext::huff_size_dc_luminance
uint8_t huff_size_dc_luminance[12]
Definition: ljpegenc.c:55
avpriv_mjpeg_bits_dc_chrominance
const uint8_t avpriv_mjpeg_bits_dc_chrominance[17]
Definition: jpegtables.c:70
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
av_cold
#define av_cold
Definition: attributes.h:90
AV_PIX_FMT_YUVJ422P
@ AV_PIX_FMT_YUVJ422P
planar YUV 4:2:2, 16bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV422P and setting col...
Definition: pixfmt.h:79
width
#define width
s
#define s(width, name)
Definition: cbs_vp9.c:257
avpriv_mjpeg_val_dc
const uint8_t avpriv_mjpeg_val_dc[12]
Definition: jpegtables.c:67
ljpeg_encode_bgr
static int ljpeg_encode_bgr(AVCodecContext *avctx, PutBitContext *pb, const AVFrame *frame)
Definition: ljpegenc.c:62
pix_fmts
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
AV_INPUT_BUFFER_MIN_SIZE
#define AV_INPUT_BUFFER_MIN_SIZE
Definition: avcodec.h:222
AV_PIX_FMT_YUV420P
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
PutBitContext
Definition: put_bits.h:35
AV_PIX_FMT_YUVJ444P
@ AV_PIX_FMT_YUVJ444P
planar YUV 4:4:4, 24bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV444P and setting col...
Definition: pixfmt.h:80
AV_CODEC_CAP_FRAME_THREADS
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: codec.h:106
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
PutBitContext::buf
uint8_t * buf
Definition: put_bits.h:38
NULL
#define NULL
Definition: coverity.c:32
AVCodecContext::color_range
enum AVColorRange color_range
MPEG vs JPEG YUV range.
Definition: avcodec.h:1161
AV_PIX_FMT_YUVJ420P
@ AV_PIX_FMT_YUVJ420P
planar YUV 4:2:0, 12bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV420P and setting col...
Definition: pixfmt.h:78
ljpeg_encode_frame
static int ljpeg_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
Definition: ljpegenc.c:225
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
ljpeg_encode_close
static av_cold int ljpeg_encode_close(AVCodecContext *avctx)
Definition: ljpegenc.c:279
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
ljpeg_class
static const AVClass ljpeg_class
Definition: ljpegenc.c:346
AV_PIX_FMT_BGR0
@ AV_PIX_FMT_BGR0
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:240
LJpegEncContext::vsample
int vsample[4]
Definition: ljpegenc.c:50
AVFrame::pict_type
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:383
AVPacket::size
int size
Definition: packet.h:356
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:188
options
static const AVOption options[]
Definition: ljpegenc.c:337
OFFSET
#define OFFSET(x)
Definition: ljpegenc.c:335
LJpegEncContext::hsample
int hsample[4]
Definition: ljpegenc.c:51
LJpegEncContext::idsp
IDCTDSPContext idsp
Definition: ljpegenc.c:46
ff_ljpeg_encoder
AVCodec ff_ljpeg_encoder
Definition: ljpegenc.c:353
frame.h
height
#define height
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:361
VE
#define VE
Definition: ljpegenc.c:336
PutBitContext::buf_end
uint8_t * buf_end
Definition: put_bits.h:38
LJpegEncContext::huff_size_dc_chrominance
uint8_t huff_size_dc_chrominance[12]
Definition: ljpegenc.c:56
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
put_bits_count
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:67
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
uint8_t
uint8_t
Definition: audio_convert.c:194
ff_idctdsp_init
av_cold void ff_idctdsp_init(IDCTDSPContext *c, AVCodecContext *avctx)
Definition: idctdsp.c:238
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:197
AVCodecContext::height
int height
Definition: avcodec.h:699
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:736
AVCOL_RANGE_MPEG
@ AVCOL_RANGE_MPEG
the normal 219*2^(n-8) "MPEG" YUV ranges
Definition: pixfmt.h:534
LJpegEncContext::scratch
uint16_t(* scratch)[4]
Definition: ljpegenc.c:58
idctdsp.h
avcodec.h
ff_zigzag_direct
const uint8_t ff_zigzag_direct[64]
Definition: mathtables.c:98
LJpegEncContext::pred
int pred
Definition: ljpegenc.c:59
ret
ret
Definition: filter_design.txt:187
pred
static const float pred[4]
Definition: siprdata.h:259
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
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::strict_std_compliance
int strict_std_compliance
strictly follow the standard (MPEG-4, ...).
Definition: avcodec.h:1589
IDCTDSPContext
Definition: idctdsp.h:53
left
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:386
AVCodecContext::coded_frame
attribute_deprecated AVFrame * coded_frame
the picture in the bitstream
Definition: avcodec.h:1776
AVCodecContext
main external API structure.
Definition: avcodec.h:526
put_bits_ptr
static uint8_t * put_bits_ptr(PutBitContext *s)
Return the pointer to the byte where the bitstream writer will put the next bit.
Definition: put_bits.h:324
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:223
ff_mjpeg_escape_FF
void ff_mjpeg_escape_FF(PutBitContext *pb, int start)
Definition: mjpegenc_common.c:410
AV_PIX_FMT_YUV444P
@ AV_PIX_FMT_YUV444P
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:71
FF_DISABLE_DEPRECATION_WARNINGS
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:84
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_PIX_FMT_YUV422P
@ AV_PIX_FMT_YUV422P
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
mem.h
ff_mjpeg_init_hvsample
void ff_mjpeg_init_hvsample(AVCodecContext *avctx, int hsample[4], int vsample[4])
Definition: mjpegenc_common.c:221
flush_put_bits
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:101
ScanTable
Scantable.
Definition: idctdsp.h:31
diff
static av_always_inline int diff(const uint32_t a, const uint32_t b)
Definition: vf_palettegen.c:136
LJpegEncContext::scantable
ScanTable scantable
Definition: ljpegenc.c:47
AVPacket
This structure stores compressed data.
Definition: packet.h:332
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:553
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:699
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ff_mjpeg_encode_picture_trailer
void ff_mjpeg_encode_picture_trailer(PutBitContext *pb, int header_bits)
Definition: mjpegenc_common.c:587
h
h
Definition: vp9dsp_template.c:2038
PREDICT
#define PREDICT(ret, topleft, top, left, predictor)
Definition: mjpeg.h:118
ff_alloc_packet2
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:32
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:232
AV_CODEC_ID_LJPEG
@ AV_CODEC_ID_LJPEG
Definition: codec_id.h:58
LJpegEncContext::matrix
uint16_t matrix[64]
Definition: ljpegenc.c:48