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formats.h
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18 
19 #ifndef AVFILTER_FORMATS_H
20 #define AVFILTER_FORMATS_H
21 
22 #include "avfilter.h"
23 
24 /**
25  * A list of supported formats for one end of a filter link. This is used
26  * during the format negotiation process to try to pick the best format to
27  * use to minimize the number of necessary conversions. Each filter gives a
28  * list of the formats supported by each input and output pad. The list
29  * given for each pad need not be distinct - they may be references to the
30  * same list of formats, as is often the case when a filter supports multiple
31  * formats, but will always output the same format as it is given in input.
32  *
33  * In this way, a list of possible input formats and a list of possible
34  * output formats are associated with each link. When a set of formats is
35  * negotiated over a link, the input and output lists are merged to form a
36  * new list containing only the common elements of each list. In the case
37  * that there were no common elements, a format conversion is necessary.
38  * Otherwise, the lists are merged, and all other links which reference
39  * either of the format lists involved in the merge are also affected.
40  *
41  * For example, consider the filter chain:
42  * filter (a) --> (b) filter (b) --> (c) filter
43  *
44  * where the letters in parenthesis indicate a list of formats supported on
45  * the input or output of the link. Suppose the lists are as follows:
46  * (a) = {A, B}
47  * (b) = {A, B, C}
48  * (c) = {B, C}
49  *
50  * First, the first link's lists are merged, yielding:
51  * filter (a) --> (a) filter (a) --> (c) filter
52  *
53  * Notice that format list (b) now refers to the same list as filter list (a).
54  * Next, the lists for the second link are merged, yielding:
55  * filter (a) --> (a) filter (a) --> (a) filter
56  *
57  * where (a) = {B}.
58  *
59  * Unfortunately, when the format lists at the two ends of a link are merged,
60  * we must ensure that all links which reference either pre-merge format list
61  * get updated as well. Therefore, we have the format list structure store a
62  * pointer to each of the pointers to itself.
63  */
65  unsigned nb_formats; ///< number of formats
66  int *formats; ///< list of media formats
67 
68  unsigned refcount; ///< number of references to this list
69  struct AVFilterFormats ***refs; ///< references to this list
70 };
71 
72 /**
73  * A list of supported channel layouts.
74  *
75  * The list works the same as AVFilterFormats, except for the following
76  * differences:
77  * - A list with all_layouts = 1 means all channel layouts with a known
78  * disposition; nb_channel_layouts must then be 0.
79  * - A list with all_counts = 1 means all channel counts, with a known or
80  * unknown disposition; nb_channel_layouts must then be 0 and all_layouts 1.
81  * - The list must not contain a layout with a known disposition and a
82  * channel count with unknown disposition with the same number of channels
83  * (e.g. AV_CH_LAYOUT_STEREO and FF_COUNT2LAYOUT(2).
84  */
85 typedef struct AVFilterChannelLayouts {
86  uint64_t *channel_layouts; ///< list of channel layouts
87  int nb_channel_layouts; ///< number of channel layouts
88  char all_layouts; ///< accept any known channel layout
89  char all_counts; ///< accept any channel layout or count
90 
91  unsigned refcount; ///< number of references to this list
92  struct AVFilterChannelLayouts ***refs; ///< references to this list
94 
95 /**
96  * Encode a channel count as a channel layout.
97  * FF_COUNT2LAYOUT(c) means any channel layout with c channels, with a known
98  * or unknown disposition.
99  * The result is only valid inside AVFilterChannelLayouts and immediately
100  * related functions.
101  */
102 #define FF_COUNT2LAYOUT(c) (0x8000000000000000ULL | (c))
103 
104 /**
105  * Decode a channel count encoded as a channel layout.
106  * Return 0 if the channel layout was a real one.
107  */
108 #define FF_LAYOUT2COUNT(l) (((l) & 0x8000000000000000ULL) ? \
109  (int)((l) & 0x7FFFFFFF) : 0)
110 
111 /**
112  * Return a channel layouts/samplerates list which contains the intersection of
113  * the layouts/samplerates of a and b. Also, all the references of a, all the
114  * references of b, and a and b themselves will be deallocated.
115  *
116  * If a and b do not share any common elements, neither is modified, and NULL
117  * is returned.
118  */
122  AVFilterFormats *b);
123 
124 /**
125  * Construct an empty AVFilterChannelLayouts/AVFilterFormats struct --
126  * representing any channel layout (with known disposition)/sample rate.
127  */
130 
133 
134 /**
135  * Construct an AVFilterChannelLayouts coding for any channel layout, with
136  * known or unknown disposition.
137  */
140 
143 
145 AVFilterChannelLayouts *ff_make_formatu64_list(const uint64_t *fmts);
146 
147 
148 /**
149  * A helper for query_formats() which sets all links to the same list of channel
150  * layouts/sample rates. If there are no links hooked to this filter, the list
151  * is freed.
152  */
158  AVFilterFormats *samplerates);
159 
160 /**
161  * A helper for query_formats() which sets all links to the same list of
162  * formats. If there are no links hooked to this filter, the list of formats is
163  * freed.
164  */
167 
169 int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout);
170 
171 /**
172  * Add *ref as a new reference to f.
173  */
177 
178 /**
179  * Remove a reference to a channel layouts list.
180  */
182 
184  AVFilterChannelLayouts **newref);
185 
188 
189 /**
190  * Set the formats list to all existing formats.
191  * This function behaves like ff_default_query_formats(), except it also
192  * accepts channel layouts with unknown disposition. It should only be used
193  * with audio filters.
194  */
197 
198 
199 /**
200  * Create a list of supported formats. This is intended for use in
201  * AVFilter->query_formats().
202  *
203  * @param fmts list of media formats, terminated by -1
204  * @return the format list, with no existing references
205  */
207 AVFilterFormats *ff_make_format_list(const int *fmts);
208 
209 /**
210  * Add fmt to the list of media formats contained in *avff.
211  * If *avff is NULL the function allocates the filter formats struct
212  * and puts its pointer in *avff.
213  *
214  * @return a non negative value in case of success, or a negative
215  * value corresponding to an AVERROR code in case of error
216  */
218 int ff_add_format(AVFilterFormats **avff, int64_t fmt);
219 
220 /**
221  * Return a list of all formats supported by FFmpeg for the given media type.
222  */
225 
226 /**
227  * Construct a formats list containing all planar sample formats.
228  */
231 
232 /**
233  * Return a format list which contains the intersection of the formats of
234  * a and b. Also, all the references of a, all the references of b, and
235  * a and b themselves will be deallocated.
236  *
237  * If a and b do not share any common formats, neither is modified, and NULL
238  * is returned.
239  */
241  enum AVMediaType type);
242 
243 /**
244  * Add *ref as a new reference to formats.
245  * That is the pointers will point like in the ascii art below:
246  * ________
247  * |formats |<--------.
248  * | ____ | ____|___________________
249  * | |refs| | | __|_
250  * | |* * | | | | | | AVFilterLink
251  * | |* *--------->|*ref|
252  * | |____| | | |____|
253  * |________| |________________________
254  */
257 
258 /**
259  * If *ref is non-NULL, remove *ref as a reference to the format list
260  * it currently points to, deallocates that list if this was the last
261  * reference, and sets *ref to NULL.
262  *
263  * Before After
264  * ________ ________ NULL
265  * |formats |<--------. |formats | ^
266  * | ____ | ____|________________ | ____ | ____|________________
267  * | |refs| | | __|_ | |refs| | | __|_
268  * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
269  * | |* *--------->|*ref| | |* | | | |*ref|
270  * | |____| | | |____| | |____| | | |____|
271  * |________| |_____________________ |________| |_____________________
272  */
274 
275 /**
276  * Before After
277  * ________ ________
278  * |formats |<---------. |formats |<---------.
279  * | ____ | ___|___ | ____ | ___|___
280  * | |refs| | | | | | |refs| | | | | NULL
281  * | |* *--------->|*oldref| | |* *--------->|*newref| ^
282  * | |* * | | |_______| | |* * | | |_______| ___|___
283  * | |____| | | |____| | | | |
284  * |________| |________| |*oldref|
285  * |_______|
286  */
287 void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref);
288 
289 #endif /* AVFILTER_FORMATS_H */
av_warn_unused_result int ff_add_format(AVFilterFormats **avff, int64_t fmt)
Add fmt to the list of media formats contained in *avff.
Definition: formats.c:337
AVFilterChannelLayouts * ff_merge_channel_layouts(AVFilterChannelLayouts *a, AVFilterChannelLayouts *b)
Return a channel layouts/samplerates list which contains the intersection of the layouts/samplerates ...
Definition: formats.c:166
AVFormatContext * ctx
Definition: movenc-test.c:48
const char * fmt
Definition: avisynth_c.h:632
Main libavfilter public API header.
av_warn_unused_result AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition...
Definition: formats.c:410
av_warn_unused_result AVFilterChannelLayouts * ff_all_channel_layouts(void)
Construct an empty AVFilterChannelLayouts/AVFilterFormats struct – representing any channel layout (w...
Definition: formats.c:401
const char * b
Definition: vf_curves.c:109
av_warn_unused_result AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:395
void ff_formats_unref(AVFilterFormats **ref)
If *ref is non-NULL, remove *ref as a reference to the format list it currently points to...
Definition: formats.c:476
static enum AVSampleFormat formats[]
struct AVFilterChannelLayouts *** refs
references to this list
Definition: formats.h:92
AVFilterFormats * ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b, enum AVMediaType type)
Return a format list which contains the intersection of the formats of a and b.
Definition: formats.c:92
av_warn_unused_result int ff_default_query_formats(AVFilterContext *ctx)
Definition: formats.c:597
struct AVFilterFormats *** refs
references to this list
Definition: formats.h:69
void ff_channel_layouts_changeref(AVFilterChannelLayouts **oldref, AVFilterChannelLayouts **newref)
Definition: formats.c:499
static int ref[MAX_W *MAX_W]
unsigned refcount
number of references to this list
Definition: formats.h:68
av_warn_unused_result int ff_query_formats_all(AVFilterContext *ctx)
Set the formats list to all existing formats.
Definition: formats.c:602
av_warn_unused_result int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
Definition: formats.c:343
uint64_t * channel_layouts
list of channel layouts
Definition: formats.h:86
av_warn_unused_result AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
char all_counts
accept any channel layout or count
Definition: formats.h:89
av_warn_unused_result int ff_set_common_channel_layouts(AVFilterContext *ctx, AVFilterChannelLayouts *layouts)
A helper for query_formats() which sets all links to the same list of channel layouts/sample rates...
Definition: formats.c:549
av_warn_unused_result AVFilterFormats * ff_planar_sample_fmts(void)
Construct a formats list containing all planar sample formats.
Definition: formats.c:382
av_warn_unused_result AVFilterChannelLayouts * ff_make_formatu64_list(const uint64_t *fmts)
Definition: formats.c:292
av_warn_unused_result int ff_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref)
Add *ref as a new reference to formats.
Definition: formats.c:440
AVFilterFormats * ff_merge_samplerates(AVFilterFormats *a, AVFilterFormats *b)
Definition: formats.c:139
unsigned nb_formats
number of formats
Definition: formats.h:65
A list of supported channel layouts.
Definition: formats.h:85
av_warn_unused_result AVFilterChannelLayouts * avfilter_make_format64_list(const int64_t *fmts)
Definition: formats.c:303
av_warn_unused_result 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:568
char all_layouts
accept any known channel layout
Definition: formats.h:88
GLint GLenum type
Definition: opengl_enc.c:105
av_warn_unused_result int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:435
AVMediaType
Definition: avutil.h:191
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
av_warn_unused_result AVFilterFormats * ff_all_formats(enum AVMediaType type)
Return a list of all formats supported by FFmpeg for the given media type.
Definition: formats.c:350
#define av_warn_unused_result
Definition: attributes.h:56
int nb_channel_layouts
number of channel layouts
Definition: formats.h:87
unsigned refcount
number of references to this list
Definition: formats.h:91
A list of supported formats for one end of a filter link.
Definition: formats.h:64
void ff_channel_layouts_unref(AVFilterChannelLayouts **ref)
Remove a reference to a channel layouts list.
Definition: formats.c:481
An instance of a filter.
Definition: avfilter.h:305
av_warn_unused_result int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:556
void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref)
Before After |formats |<------—.
Definition: formats.c:505
int * formats
list of media formats
Definition: formats.h:66