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11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
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16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 #ifndef AVFILTER_FORMATS_H
20 #define AVFILTER_FORMATS_H
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.
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.
41 * For example, consider the filter chain:
42 * filter (a) --> (b) filter (b) --> (c) filter
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:
50 * First, the first link's lists are merged, yielding:
51 * filter (a) --> (a) filter (a) --> (c) filter
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
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.
64 struct AVFilterFormats {
65 unsigned format_count; ///< number of formats
66 int *formats; ///< list of media formats
68 unsigned refcount; ///< number of references to this list
69 struct AVFilterFormats ***refs; ///< references to this list
72 typedef struct AVFilterChannelLayouts {
73 uint64_t *channel_layouts; ///< list of channel layouts
74 int nb_channel_layouts; ///< number of channel layouts
76 unsigned refcount; ///< number of references to this list
77 struct AVFilterChannelLayouts ***refs; ///< references to this list
78 } AVFilterChannelLayouts;
81 * Return a channel layouts/samplerates list which contains the intersection of
82 * the layouts/samplerates of a and b. Also, all the references of a, all the
83 * references of b, and a and b themselves will be deallocated.
85 * If a and b do not share any common elements, neither is modified, and NULL
88 AVFilterChannelLayouts *ff_merge_channel_layouts(AVFilterChannelLayouts *a,
89 AVFilterChannelLayouts *b);
90 AVFilterFormats *ff_merge_samplerates(AVFilterFormats *a,
94 * Construct an empty AVFilterChannelLayouts/AVFilterFormats struct --
95 * representing any channel layout/sample rate.
97 AVFilterChannelLayouts *ff_all_channel_layouts(void);
98 AVFilterFormats *ff_all_samplerates(void);
100 AVFilterChannelLayouts *avfilter_make_format64_list(const int64_t *fmts);
104 * A helper for query_formats() which sets all links to the same list of channel
105 * layouts/sample rates. If there are no links hooked to this filter, the list
108 void ff_set_common_channel_layouts(AVFilterContext *ctx,
109 AVFilterChannelLayouts *layouts);
110 void ff_set_common_samplerates(AVFilterContext *ctx,
111 AVFilterFormats *samplerates);
114 * A helper for query_formats() which sets all links to the same list of
115 * formats. If there are no links hooked to this filter, the list of formats is
118 void ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
120 int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout);
123 * Add *ref as a new reference to f.
125 void ff_channel_layouts_ref(AVFilterChannelLayouts *f,
126 AVFilterChannelLayouts **ref);
129 * Remove a reference to a channel layouts list.
131 void ff_channel_layouts_unref(AVFilterChannelLayouts **ref);
133 void ff_channel_layouts_changeref(AVFilterChannelLayouts **oldref,
134 AVFilterChannelLayouts **newref);
136 int ff_default_query_formats(AVFilterContext *ctx);
140 * Create a list of supported formats. This is intended for use in
141 * AVFilter->query_formats().
143 * @param fmts list of media formats, terminated by -1
144 * @return the format list, with no existing references
146 AVFilterFormats *ff_make_format_list(const int *fmts);
149 * Add fmt to the list of media formats contained in *avff.
150 * If *avff is NULL the function allocates the filter formats struct
151 * and puts its pointer in *avff.
153 * @return a non negative value in case of success, or a negative
154 * value corresponding to an AVERROR code in case of error
156 int ff_add_format(AVFilterFormats **avff, int64_t fmt);
159 * Return a list of all formats supported by FFmpeg for the given media type.
161 AVFilterFormats *ff_all_formats(enum AVMediaType type);
164 * Construct a formats list containing all planar sample formats.
166 AVFilterFormats *ff_planar_sample_fmts(void);
169 * Return a format list which contains the intersection of the formats of
170 * a and b. Also, all the references of a, all the references of b, and
171 * a and b themselves will be deallocated.
173 * If a and b do not share any common formats, neither is modified, and NULL
176 AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
179 * Add *ref as a new reference to formats.
180 * That is the pointers will point like in the ascii art below:
182 * |formats |<--------.
183 * | ____ | ____|___________________
185 * | |* * | | | | | | AVFilterLink
186 * | |* *--------->|*ref|
187 * | |____| | | |____|
188 * |________| |________________________
190 void ff_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
193 * If *ref is non-NULL, remove *ref as a reference to the format list
194 * it currently points to, deallocates that list if this was the last
195 * reference, and sets *ref to NULL.
198 * ________ ________ NULL
199 * |formats |<--------. |formats | ^
200 * | ____ | ____|________________ | ____ | ____|________________
201 * | |refs| | | __|_ | |refs| | | __|_
202 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
203 * | |* *--------->|*ref| | |* | | | |*ref|
204 * | |____| | | |____| | |____| | | |____|
205 * |________| |_____________________ |________| |_____________________
207 void ff_formats_unref(AVFilterFormats **ref);
213 * |formats |<---------. |formats |<---------.
214 * | ____ | ___|___ | ____ | ___|___
215 * | |refs| | | | | | |refs| | | | | NULL
216 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
217 * | |* * | | |_______| | |* * | | |_______| ___|___
218 * | |____| | | |____| | | | |
219 * |________| |________| |*oldref|
222 void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref);
224 #endif /* AVFILTER_FORMATS_H */