lavfi: add error handling to start_frame().
[libav.git] / libavfilter / internal.h
1 /*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #ifndef AVFILTER_INTERNAL_H
20 #define AVFILTER_INTERNAL_H
21
22 /**
23 * @file
24 * internal API functions
25 */
26
27 #include "avfilter.h"
28
29 #if !FF_API_AVFILTERPAD_PUBLIC
30 /**
31 * A filter pad used for either input or output.
32 */
33 struct AVFilterPad {
34 /**
35 * Pad name. The name is unique among inputs and among outputs, but an
36 * input may have the same name as an output. This may be NULL if this
37 * pad has no need to ever be referenced by name.
38 */
39 const char *name;
40
41 /**
42 * AVFilterPad type.
43 */
44 enum AVMediaType type;
45
46 /**
47 * Minimum required permissions on incoming buffers. Any buffer with
48 * insufficient permissions will be automatically copied by the filter
49 * system to a new buffer which provides the needed access permissions.
50 *
51 * Input pads only.
52 */
53 int min_perms;
54
55 /**
56 * Permissions which are not accepted on incoming buffers. Any buffer
57 * which has any of these permissions set will be automatically copied
58 * by the filter system to a new buffer which does not have those
59 * permissions. This can be used to easily disallow buffers with
60 * AV_PERM_REUSE.
61 *
62 * Input pads only.
63 */
64 int rej_perms;
65
66 /**
67 * Callback called before passing the first slice of a new frame. If
68 * NULL, the filter layer will default to storing a reference to the
69 * picture inside the link structure.
70 *
71 * Input video pads only.
72 *
73 * @return >= 0 on success, a negative AVERROR on error. picref will be
74 * unreferenced by the caller in case of error.
75 */
76 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
77
78 /**
79 * Callback function to get a video buffer. If NULL, the filter system will
80 * use avfilter_default_get_video_buffer().
81 *
82 * Input video pads only.
83 */
84 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
85
86 /**
87 * Callback function to get an audio buffer. If NULL, the filter system will
88 * use avfilter_default_get_audio_buffer().
89 *
90 * Input audio pads only.
91 */
92 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
93 int nb_samples);
94
95 /**
96 * Callback called after the slices of a frame are completely sent. If
97 * NULL, the filter layer will default to releasing the reference stored
98 * in the link structure during start_frame().
99 *
100 * Input video pads only.
101 */
102 void (*end_frame)(AVFilterLink *link);
103
104 /**
105 * Slice drawing callback. This is where a filter receives video data
106 * and should do its processing.
107 *
108 * Input video pads only.
109 */
110 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
111
112 /**
113 * Samples filtering callback. This is where a filter receives audio data
114 * and should do its processing.
115 *
116 * Input audio pads only.
117 *
118 * @return >= 0 on success, a negative AVERROR on error. This function
119 * must ensure that samplesref is properly unreferenced on error if it
120 * hasn't been passed on to another filter.
121 */
122 int (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
123
124 /**
125 * Frame poll callback. This returns the number of immediately available
126 * samples. It should return a positive value if the next request_frame()
127 * is guaranteed to return one frame (with no delay).
128 *
129 * Defaults to just calling the source poll_frame() method.
130 *
131 * Output pads only.
132 */
133 int (*poll_frame)(AVFilterLink *link);
134
135 /**
136 * Frame request callback. A call to this should result in at least one
137 * frame being output over the given link. This should return zero on
138 * success, and another value on error.
139 *
140 * Output pads only.
141 */
142 int (*request_frame)(AVFilterLink *link);
143
144 /**
145 * Link configuration callback.
146 *
147 * For output pads, this should set the link properties such as
148 * width/height. This should NOT set the format property - that is
149 * negotiated between filters by the filter system using the
150 * query_formats() callback before this function is called.
151 *
152 * For input pads, this should check the properties of the link, and update
153 * the filter's internal state as necessary.
154 *
155 * For both input and output filters, this should return zero on success,
156 * and another value on error.
157 */
158 int (*config_props)(AVFilterLink *link);
159
160 /**
161 * The filter expects a fifo to be inserted on its input link,
162 * typically because it has a delay.
163 *
164 * input pads only.
165 */
166 int needs_fifo;
167 };
168 #endif
169
170 /** default handler for freeing audio/video buffer when there are no references left */
171 void ff_avfilter_default_free_buffer(AVFilterBuffer *buf);
172
173 /** Tell is a format is contained in the provided list terminated by -1. */
174 int ff_fmt_is_in(int fmt, const int *fmts);
175
176 #define FF_DPRINTF_START(ctx, func) av_dlog(NULL, "%-16s: ", #func)
177
178 void ff_dlog_link(void *ctx, AVFilterLink *link, int end);
179
180 /**
181 * Insert a new pad.
182 *
183 * @param idx Insertion point. Pad is inserted at the end if this point
184 * is beyond the end of the list of pads.
185 * @param count Pointer to the number of pads in the list
186 * @param padidx_off Offset within an AVFilterLink structure to the element
187 * to increment when inserting a new pad causes link
188 * numbering to change
189 * @param pads Pointer to the pointer to the beginning of the list of pads
190 * @param links Pointer to the pointer to the beginning of the list of links
191 * @param newpad The new pad to add. A copy is made when adding.
192 */
193 void ff_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
194 AVFilterPad **pads, AVFilterLink ***links,
195 AVFilterPad *newpad);
196
197 /** Insert a new input pad for the filter. */
198 static inline void ff_insert_inpad(AVFilterContext *f, unsigned index,
199 AVFilterPad *p)
200 {
201 ff_insert_pad(index, &f->nb_inputs, offsetof(AVFilterLink, dstpad),
202 &f->input_pads, &f->inputs, p);
203 #if FF_API_FOO_COUNT
204 f->input_count = f->nb_inputs;
205 #endif
206 }
207
208 /** Insert a new output pad for the filter. */
209 static inline void ff_insert_outpad(AVFilterContext *f, unsigned index,
210 AVFilterPad *p)
211 {
212 ff_insert_pad(index, &f->nb_outputs, offsetof(AVFilterLink, srcpad),
213 &f->output_pads, &f->outputs, p);
214 #if FF_API_FOO_COUNT
215 f->output_count = f->nb_outputs;
216 #endif
217 }
218
219 /**
220 * Poll a frame from the filter chain.
221 *
222 * @param link the input link
223 * @return the number of immediately available frames, a negative
224 * number in case of error
225 */
226 int ff_poll_frame(AVFilterLink *link);
227
228 /**
229 * Request an input frame from the filter at the other end of the link.
230 *
231 * @param link the input link
232 * @return zero on success
233 */
234 int ff_request_frame(AVFilterLink *link);
235
236 #endif /* AVFILTER_INTERNAL_H */