FFmpeg
vf_colorlevels.c
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1 /*
2  * Copyright (c) 2013 Paul B Mahol
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 #include "libavutil/imgutils.h"
22 #include "libavutil/opt.h"
23 #include "libavutil/pixdesc.h"
24 #include "avfilter.h"
25 #include "drawutils.h"
26 #include "formats.h"
27 #include "internal.h"
28 #include "video.h"
29 
30 #define R 0
31 #define G 1
32 #define B 2
33 #define A 3
34 
35 typedef struct Range {
36  double in_min, in_max;
37  double out_min, out_max;
38 } Range;
39 
40 typedef struct ColorLevelsContext {
41  const AVClass *class;
42  Range range[4];
43  int nb_comp;
44  int bpp;
45  int step;
46  uint8_t rgba_map[4];
47  int linesize;
49 
50 #define OFFSET(x) offsetof(ColorLevelsContext, x)
51 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
52 static const AVOption colorlevels_options[] = {
53  { "rimin", "set input red black point", OFFSET(range[R].in_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, FLAGS },
54  { "gimin", "set input green black point", OFFSET(range[G].in_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, FLAGS },
55  { "bimin", "set input blue black point", OFFSET(range[B].in_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, FLAGS },
56  { "aimin", "set input alpha black point", OFFSET(range[A].in_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, FLAGS },
57  { "rimax", "set input red white point", OFFSET(range[R].in_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, -1, 1, FLAGS },
58  { "gimax", "set input green white point", OFFSET(range[G].in_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, -1, 1, FLAGS },
59  { "bimax", "set input blue white point", OFFSET(range[B].in_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, -1, 1, FLAGS },
60  { "aimax", "set input alpha white point", OFFSET(range[A].in_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, -1, 1, FLAGS },
61  { "romin", "set output red black point", OFFSET(range[R].out_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
62  { "gomin", "set output green black point", OFFSET(range[G].out_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
63  { "bomin", "set output blue black point", OFFSET(range[B].out_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
64  { "aomin", "set output alpha black point", OFFSET(range[A].out_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
65  { "romax", "set output red white point", OFFSET(range[R].out_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
66  { "gomax", "set output green white point", OFFSET(range[G].out_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
67  { "bomax", "set output blue white point", OFFSET(range[B].out_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
68  { "aomax", "set output alpha white point", OFFSET(range[A].out_max), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
69  { NULL }
70 };
71 
72 AVFILTER_DEFINE_CLASS(colorlevels);
73 
75 {
76  static const enum AVPixelFormat pix_fmts[] = {
85  };
86 
87  AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
88  if (!fmts_list)
89  return AVERROR(ENOMEM);
90  return ff_set_common_formats(ctx, fmts_list);
91 }
92 
94 {
95  AVFilterContext *ctx = inlink->dst;
96  ColorLevelsContext *s = ctx->priv;
98 
99  s->nb_comp = desc->nb_components;
100  s->bpp = desc->comp[0].depth >> 3;
101  s->step = (av_get_padded_bits_per_pixel(desc) >> 3) / s->bpp;
102  s->linesize = inlink->w * s->step;
103  ff_fill_rgba_map(s->rgba_map, inlink->format);
104 
105  return 0;
106 }
107 
108 struct thread_data {
109  const uint8_t *srcrow;
113 
114  double coeff;
116 
117  int h;
118 
119  int imin;
120  int omin;
121 };
122 
123 #define LOAD_COMMON\
124  ColorLevelsContext *s = ctx->priv;\
125  const struct thread_data *td = arg;\
126 \
127  int process_h = td->h;\
128  const int slice_start = (process_h * jobnr ) / nb_jobs;\
129  const int slice_end = (process_h * (jobnr+1)) / nb_jobs;\
130  int x, y;\
131  const uint8_t *srcrow = td->srcrow;\
132  uint8_t *dstrow = td->dstrow;\
133  const int step = s->step;\
134  const uint8_t offset = td->offset;\
135 \
136  int imin = td->imin;\
137  int omin = td->omin;\
138  double coeff = td->coeff;\
139 
140 static int colorlevel_slice_8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
141 {
143 
144  for (y = slice_start; y < slice_end; y++) {
145  const uint8_t *src = srcrow + y * td->src_linesize;
146  uint8_t *dst = dstrow + y * td->dst_linesize;
147 
148  for (x = 0; x < s->linesize; x += step)
149  dst[x + offset] = av_clip_uint8((src[x + offset] - imin) * coeff + omin);
150  }
151 
152  return 0;
153 }
154 
155 static int colorlevel_slice_16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
156 {
158 
159  for (y = slice_start; y < slice_end; y++) {
160  const uint16_t *src = (const uint16_t *)(srcrow + y * td->src_linesize);
161  uint16_t *dst = (uint16_t *)(dstrow + y * td->dst_linesize);
162 
163  for (x = 0; x < s->linesize; x += step)
164  dst[x + offset] = av_clip_uint16((src[x + offset] - imin) * coeff + omin);
165  }
166 
167  return 0;
168 }
169 
171 {
172  AVFilterContext *ctx = inlink->dst;
173  ColorLevelsContext *s = ctx->priv;
174  AVFilterLink *outlink = ctx->outputs[0];
175  const int step = s->step;
176  AVFrame *out;
177  int x, y, i;
178 
179  if (av_frame_is_writable(in)) {
180  out = in;
181  } else {
182  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
183  if (!out) {
184  av_frame_free(&in);
185  return AVERROR(ENOMEM);
186  }
187  av_frame_copy_props(out, in);
188  }
189 
190  switch (s->bpp) {
191  case 1:
192  for (i = 0; i < s->nb_comp; i++) {
193  Range *r = &s->range[i];
194  const uint8_t offset = s->rgba_map[i];
195  const uint8_t *srcrow = in->data[0];
196  uint8_t *dstrow = out->data[0];
197  int imin = lrint(r->in_min * UINT8_MAX);
198  int imax = lrint(r->in_max * UINT8_MAX);
199  int omin = lrint(r->out_min * UINT8_MAX);
200  int omax = lrint(r->out_max * UINT8_MAX);
201  double coeff;
202  struct thread_data td;
203 
204  if (imin < 0) {
205  imin = UINT8_MAX;
206  for (y = 0; y < inlink->h; y++) {
207  const uint8_t *src = srcrow;
208 
209  for (x = 0; x < s->linesize; x += step)
210  imin = FFMIN(imin, src[x + offset]);
211  srcrow += in->linesize[0];
212  }
213  }
214  if (imax < 0) {
215  srcrow = in->data[0];
216  imax = 0;
217  for (y = 0; y < inlink->h; y++) {
218  const uint8_t *src = srcrow;
219 
220  for (x = 0; x < s->linesize; x += step)
221  imax = FFMAX(imax, src[x + offset]);
222  srcrow += in->linesize[0];
223  }
224  }
225 
226  srcrow = in->data[0];
227  coeff = (omax - omin) / (double)(imax - imin);
228 
229  td.srcrow = srcrow;
230  td.dstrow = dstrow;
231  td.dst_linesize = out->linesize[0];
232  td.src_linesize = in->linesize[0];
233  td.coeff = coeff;
234  td.offset = offset;
235  td.h = inlink->h;
236  td.imin = imin;
237  td.omin = omin;
238 
239  ctx->internal->execute(ctx, colorlevel_slice_8, &td, NULL,
240  FFMIN(inlink->h, ff_filter_get_nb_threads(ctx)));
241  }
242  break;
243  case 2:
244  for (i = 0; i < s->nb_comp; i++) {
245  Range *r = &s->range[i];
246  const uint8_t offset = s->rgba_map[i];
247  const uint8_t *srcrow = in->data[0];
248  uint8_t *dstrow = out->data[0];
249  int imin = lrint(r->in_min * UINT16_MAX);
250  int imax = lrint(r->in_max * UINT16_MAX);
251  int omin = lrint(r->out_min * UINT16_MAX);
252  int omax = lrint(r->out_max * UINT16_MAX);
253  double coeff;
254  struct thread_data td;
255 
256  if (imin < 0) {
257  imin = UINT16_MAX;
258  for (y = 0; y < inlink->h; y++) {
259  const uint16_t *src = (const uint16_t *)srcrow;
260 
261  for (x = 0; x < s->linesize; x += step)
262  imin = FFMIN(imin, src[x + offset]);
263  srcrow += in->linesize[0];
264  }
265  }
266  if (imax < 0) {
267  srcrow = in->data[0];
268  imax = 0;
269  for (y = 0; y < inlink->h; y++) {
270  const uint16_t *src = (const uint16_t *)srcrow;
271 
272  for (x = 0; x < s->linesize; x += step)
273  imax = FFMAX(imax, src[x + offset]);
274  srcrow += in->linesize[0];
275  }
276  }
277 
278  srcrow = in->data[0];
279  coeff = (omax - omin) / (double)(imax - imin);
280 
281  td.srcrow = srcrow;
282  td.dstrow = dstrow;
283  td.dst_linesize = out->linesize[0];
284  td.src_linesize = in->linesize[0];
285  td.coeff = coeff;
286  td.offset = offset;
287  td.h = inlink->h;
288  td.imin = imin;
289  td.omin = omin;
290 
291  ctx->internal->execute(ctx, colorlevel_slice_16, &td, NULL,
292  FFMIN(inlink->h, ff_filter_get_nb_threads(ctx)));
293  }
294  }
295 
296  if (in != out)
297  av_frame_free(&in);
298  return ff_filter_frame(outlink, out);
299 }
300 
301 static const AVFilterPad colorlevels_inputs[] = {
302  {
303  .name = "default",
304  .type = AVMEDIA_TYPE_VIDEO,
305  .filter_frame = filter_frame,
306  .config_props = config_input,
307  },
308  { NULL }
309 };
310 
312  {
313  .name = "default",
314  .type = AVMEDIA_TYPE_VIDEO,
315  },
316  { NULL }
317 };
318 
320  .name = "colorlevels",
321  .description = NULL_IF_CONFIG_SMALL("Adjust the color levels."),
322  .priv_size = sizeof(ColorLevelsContext),
323  .priv_class = &colorlevels_class,
325  .inputs = colorlevels_inputs,
326  .outputs = colorlevels_outputs,
328 };
#define NULL
Definition: coverity.c:32
#define G
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2522
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
AVOption.
Definition: opt.h:246
misc image utilities
Main libavfilter public API header.
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:68
const char * desc
Definition: nvenc.c:68
#define AV_PIX_FMT_RGBA64
Definition: pixfmt.h:377
#define AV_PIX_FMT_BGRA64
Definition: pixfmt.h:382
packed BGR 8:8:8, 32bpp, XBGRXBGR... X=unused/undefined
Definition: pixfmt.h:239
AVFrame * ff_get_video_buffer(AVFilterLink *link, int w, int h)
Request a picture buffer with a specific set of permissions.
Definition: video.c:99
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
#define src
Definition: vp8dsp.c:254
const uint8_t * srcrow
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:125
const char * name
Pad name.
Definition: internal.h:60
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1093
AVComponentDescriptor comp[4]
Parameters that describe how pixels are packed.
Definition: pixdesc.h:117
uint8_t
packed RGB 8:8:8, 32bpp, RGBXRGBX... X=unused/undefined
Definition: pixfmt.h:238
AVOptions.
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
#define A
packed ABGR 8:8:8:8, 32bpp, ABGRABGR...
Definition: pixfmt.h:94
static int query_formats(AVFilterContext *ctx)
#define AV_PIX_FMT_BGR48
Definition: pixfmt.h:378
double out_min
A filter pad used for either input or output.
Definition: internal.h:54
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:569
#define td
Definition: regdef.h:70
#define FLAGS
static const AVFilterPad colorlevels_inputs[]
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:202
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
packed BGRA 8:8:8:8, 32bpp, BGRABGRA...
Definition: pixfmt.h:95
const char * r
Definition: vf_curves.c:114
void * priv
private data for use by the filter
Definition: avfilter.h:353
int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel for the pixel format described by pixdesc, including any padding ...
Definition: pixdesc.c:2487
#define AVFILTER_FLAG_SLICE_THREADS
The filter supports multithreading by splitting frames into multiple parts and processing them concur...
Definition: avfilter.h:116
const char * arg
Definition: jacosubdec.c:66
#define AV_PIX_FMT_RGB48
Definition: pixfmt.h:373
#define FFMAX(a, b)
Definition: common.h:94
packed ARGB 8:8:8:8, 32bpp, ARGBARGB...
Definition: pixfmt.h:92
packed RGBA 8:8:8:8, 32bpp, RGBARGBA...
Definition: pixfmt.h:93
uint8_t nb_components
The number of components each pixel has, (1-4)
Definition: pixdesc.h:83
static int config_input(AVFilterLink *inlink)
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:802
#define FFMIN(a, b)
Definition: common.h:96
static const AVOption colorlevels_options[]
AVFormatContext * ctx
Definition: movenc.c:48
#define s(width, name)
Definition: cbs_vp9.c:257
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
int ff_fill_rgba_map(uint8_t *rgba_map, enum AVPixelFormat pix_fmt)
Definition: drawutils.c:35
misc drawing utilities
int av_frame_is_writable(AVFrame *frame)
Check if the frame data is writable.
Definition: frame.c:594
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
static int colorlevel_slice_8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
double in_min
#define B
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 inputs
static const AVFilterPad colorlevels_outputs[]
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(const uint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(const uint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(const int16_t *) pi >> 8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(const int16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(const int16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(const int32_t *) pi >> 24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(const int32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(const int32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(const float *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(const float *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(const float *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(const double *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(const double *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(const double *) pi *(1U<< 31))))#define SET_CONV_FUNC_GROUP(ofmt, ifmt) static void set_generic_function(AudioConvert *ac){}void ff_audio_convert_free(AudioConvert **ac){if(!*ac) return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt, int channels, int sample_rate, int apply_map){AudioConvert *ac;int in_planar, out_planar;ac=av_mallocz(sizeof(*ac));if(!ac) return NULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt) > 2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);return NULL;}return ac;}in_planar=ff_sample_fmt_is_planar(in_fmt, channels);out_planar=ff_sample_fmt_is_planar(out_fmt, channels);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}else if(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;else ac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);if(ARCH_AARCH64) ff_audio_convert_init_aarch64(ac);if(ARCH_ARM) ff_audio_convert_init_arm(ac);if(ARCH_X86) ff_audio_convert_init_x86(ac);return ac;}int ff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){int use_generic=1;int len=in->nb_samples;int p;if(ac->dc){av_log(ac->avr, AV_LOG_TRACE,"%d samples - audio_convert: %s to %s (dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));return ff_convert_dither(ac-> in
Describe the class of an AVClass context structure.
Definition: log.h:67
#define LOAD_COMMON
Filter definition.
Definition: avfilter.h:144
uint8_t * dstrow
double out_max
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:240
const char * name
Filter name.
Definition: avfilter.h:148
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVFilterInternal * internal
An opaque struct for libavfilter internal use.
Definition: avfilter.h:378
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
#define OFFSET(x)
avfilter_execute_func * execute
Definition: internal.h:155
static int slice_end(AVCodecContext *avctx, AVFrame *pict)
Handle slice ends.
Definition: mpeg12dec.c:2036
double in_max
AVFilter ff_vf_colorlevels
A list of supported formats for one end of a filter link.
Definition: formats.h:64
static const double coeff[2][5]
Definition: vf_owdenoise.c:72
#define lrint
Definition: tablegen.h:53
An instance of a filter.
Definition: avfilter.h:338
#define R
FILE * out
Definition: movenc.c:54
AVFILTER_DEFINE_CLASS(colorlevels)
uint8_t offset
internal API functions
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
int depth
Number of bits in the component.
Definition: pixdesc.h:58
packed RGB 8:8:8, 32bpp, XRGBXRGB... X=unused/undefined
Definition: pixfmt.h:237
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
static int colorlevel_slice_16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:654
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about which is also called distortion Distortion can be quantified by almost any quality measurement one chooses the sum of squared differences is used but more complex methods that consider psychovisual effects can be used as well It makes no difference in this discussion First step