FFmpeg
buffersink.h
Go to the documentation of this file.
1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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_BUFFERSINK_H
20 #define AVFILTER_BUFFERSINK_H
21 
22 /**
23  * @file
24  * @ingroup lavfi_buffersink
25  * memory buffer sink API for audio and video
26  */
27 
28 #include "avfilter.h"
29 
30 /**
31  * @defgroup lavfi_buffersink Buffer sink API
32  * @ingroup lavfi
33  * @{
34  *
35  * The buffersink and abuffersink filters are there to connect filter graphs
36  * to applications. They have a single input, connected to the graph, and no
37  * output. Frames must be extracted using av_buffersink_get_frame() or
38  * av_buffersink_get_samples().
39  *
40  * The format negotiated by the graph during configuration can be obtained
41  * using the accessor functions:
42  * - av_buffersink_get_time_base(),
43  * - av_buffersink_get_format(),
44  * - av_buffersink_get_frame_rate(),
45  * - av_buffersink_get_w(),
46  * - av_buffersink_get_h(),
47  * - av_buffersink_get_sample_aspect_ratio(),
48  * - av_buffersink_get_channels(),
49  * - av_buffersink_get_ch_layout(),
50  * - av_buffersink_get_sample_rate().
51  *
52  * The layout returned by av_buffersink_get_ch_layout() must de uninitialized
53  * by the caller.
54  *
55  * The format can be constrained by setting options, using av_opt_set() and
56  * related functions with the AV_OPT_SEARCH_CHILDREN flag.
57  * - pixel_formats (array of pixel formats),
58  * - colorspaces (array of int),
59  * - colorranges (array of int),
60  * - sample_formats (array of sample formats),
61  * - samplerates (array of int),
62  * - channel_layouts (array of channel layouts)
63  * If an option is not set, all corresponding formats are accepted.
64  */
65 
66 /**
67  * Get a frame with filtered data from sink and put it in frame.
68  *
69  * @param ctx pointer to a buffersink or abuffersink filter context.
70  * @param frame pointer to an allocated frame that will be filled with data.
71  * The data must be freed using av_frame_unref() / av_frame_free()
72  * @param flags a combination of AV_BUFFERSINK_FLAG_* flags
73  *
74  * @return >= 0 in for success, a negative AVERROR code for failure.
75  */
77 
78 /**
79  * Tell av_buffersink_get_buffer_ref() to read video/samples buffer
80  * reference, but not remove it from the buffer. This is useful if you
81  * need only to read a video/samples buffer, without to fetch it.
82  */
83 #define AV_BUFFERSINK_FLAG_PEEK 1
84 
85 /**
86  * Tell av_buffersink_get_buffer_ref() not to request a frame from its input.
87  * If a frame is already buffered, it is read (and removed from the buffer),
88  * but if no frame is present, return AVERROR(EAGAIN).
89  */
90 #define AV_BUFFERSINK_FLAG_NO_REQUEST 2
91 
92 /**
93  * Set the frame size for an audio buffer sink.
94  *
95  * All calls to av_buffersink_get_buffer_ref will return a buffer with
96  * exactly the specified number of samples, or AVERROR(EAGAIN) if there is
97  * not enough. The last buffer at EOF will be padded with 0.
98  */
100 
101 /**
102  * @defgroup lavfi_buffersink_accessors Buffer sink accessors
103  * Get the properties of the stream
104  * @{
105  */
106 
110 
117 
120  AVChannelLayout *ch_layout);
122 
124 
125 /** @} */
126 
127 /**
128  * Get a frame with filtered data from sink and put it in frame.
129  *
130  * @param ctx pointer to a context of a buffersink or abuffersink AVFilter.
131  * @param frame pointer to an allocated frame that will be filled with data.
132  * The data must be freed using av_frame_unref() / av_frame_free()
133  *
134  * @return
135  * - >= 0 if a frame was successfully returned.
136  * - AVERROR(EAGAIN) if no frames are available at this point; more
137  * input frames must be added to the filtergraph to get more output.
138  * - AVERROR_EOF if there will be no more output frames on this sink.
139  * - A different negative AVERROR code in other failure cases.
140  */
142 
143 /**
144  * Same as av_buffersink_get_frame(), but with the ability to specify the number
145  * of samples read. This function is less efficient than
146  * av_buffersink_get_frame(), because it copies the data around.
147  *
148  * @param ctx pointer to a context of the abuffersink AVFilter.
149  * @param frame pointer to an allocated frame that will be filled with data.
150  * The data must be freed using av_frame_unref() / av_frame_free()
151  * frame will contain exactly nb_samples audio samples, except at
152  * the end of stream, when it can contain less than nb_samples.
153  *
154  * @return The return codes have the same meaning as for
155  * av_buffersink_get_frame().
156  *
157  * @warning do not mix this function with av_buffersink_get_frame(). Use only one or
158  * the other with a single sink, not both.
159  */
161 
162 /**
163  * @}
164  */
165 
166 #endif /* AVFILTER_BUFFERSINK_H */
av_buffersink_get_ch_layout
int av_buffersink_get_ch_layout(const AVFilterContext *ctx, AVChannelLayout *ch_layout)
Definition: buffersink.c:279
av_buffersink_get_samples
int av_buffersink_get_samples(AVFilterContext *ctx, AVFrame *frame, int nb_samples)
Same as av_buffersink_get_frame(), but with the ability to specify the number of samples read.
Definition: buffersink.c:148
av_buffersink_get_sample_aspect_ratio
AVRational av_buffersink_get_sample_aspect_ratio(const AVFilterContext *ctx)
av_buffersink_get_frame_flags
int av_buffersink_get_frame_flags(AVFilterContext *ctx, AVFrame *frame, int flags)
Get a frame with filtered data from sink and put it in frame.
Definition: buffersink.c:142
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:389
av_buffersink_get_hw_frames_ctx
AVBufferRef * av_buffersink_get_hw_frames_ctx(const AVFilterContext *ctx)
Definition: buffersink.c:266
av_buffersink_set_frame_size
void av_buffersink_set_frame_size(AVFilterContext *ctx, unsigned frame_size)
Set the frame size for an audio buffer sink.
Definition: buffersink.c:230
av_buffersink_get_frame_rate
AVRational av_buffersink_get_frame_rate(const AVFilterContext *ctx)
Definition: buffersink.c:259
frame_size
int frame_size
Definition: mxfenc.c:2424
av_buffersink_get_frame
int av_buffersink_get_frame(AVFilterContext *ctx, AVFrame *frame)
Get a frame with filtered data from sink and put it in frame.
Definition: buffersink.c:89
av_buffersink_get_format
int av_buffersink_get_format(const AVFilterContext *ctx)
av_buffersink_get_time_base
AVRational av_buffersink_get_time_base(const AVFilterContext *ctx)
ctx
AVFormatContext * ctx
Definition: movenc.c:49
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVMediaType
AVMediaType
Definition: avutil.h:199
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:311
av_buffersink_get_type
enum AVMediaType av_buffersink_get_type(const AVFilterContext *ctx)
av_buffersink_get_w
int av_buffersink_get_w(const AVFilterContext *ctx)
AVColorSpace
AVColorSpace
YUV colorspace type.
Definition: pixfmt.h:609
av_buffersink_get_h
int av_buffersink_get_h(const AVFilterContext *ctx)
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
av_buffersink_get_sample_rate
int av_buffersink_get_sample_rate(const AVFilterContext *ctx)
avfilter.h
av_buffersink_get_channels
int av_buffersink_get_channels(const AVFilterContext *ctx)
Definition: buffersink.c:273
AVFilterContext
An instance of a filter.
Definition: avfilter.h:457
AVBufferRef
A reference to a data buffer.
Definition: buffer.h:82
av_buffersink_get_colorspace
enum AVColorSpace av_buffersink_get_colorspace(const AVFilterContext *ctx)
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:482
AVColorRange
AVColorRange
Visual content value range.
Definition: pixfmt.h:651
av_buffersink_get_color_range
enum AVColorRange av_buffersink_get_color_range(const AVFilterContext *ctx)