xref: /third_party/ffmpeg/libavcodec/cbs_bsf.h (revision cabdff1a) 
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 AVCODEC_CBS_BSF_H
20#define AVCODEC_CBS_BSF_H
21
22#include "libavutil/log.h"
23#include "libavutil/opt.h"
24
25#include "bsf.h"
26#include "codec_id.h"
27#include "cbs.h"
28#include "packet.h"
29
30
31typedef struct CBSBSFType {
32    enum AVCodecID codec_id;
33
34    // Name of a frame fragment in this codec (e.g. "access unit",
35    // "temporal unit").
36    const char *fragment_name;
37
38    // Name of a unit for this BSF, for use in error messages (e.g.
39    // "NAL unit", "OBU").
40    const char *unit_name;
41
42    // Update the content of a fragment with whatever metadata changes
43    // are desired.  The associated AVPacket is provided so that any side
44    // data associated with the fragment can be inspected or edited.  If
45    // pkt is NULL, then an extradata header fragment is being updated.
46    int (*update_fragment)(AVBSFContext *bsf, AVPacket *pkt,
47                           CodedBitstreamFragment *frag);
48} CBSBSFType;
49
50// Common structure for all generic CBS BSF users.  An instance of this
51// structure must be the first member of the BSF private context (to be
52// pointed to by AVBSFContext.priv_data).
53typedef struct CBSBSFContext {
54    const AVClass         *class;
55    const CBSBSFType      *type;
56
57    CodedBitstreamContext *input;
58    CodedBitstreamContext *output;
59    CodedBitstreamFragment fragment;
60} CBSBSFContext;
61
62/**
63 * Initialise generic CBS BSF setup.
64 *
65 * Creates the input and output CBS instances, and applies the filter to
66 * the extradata on the input codecpar if any is present.
67 *
68 * Since it calls the update_fragment() function immediately to deal with
69 * extradata, this should be called after any codec-specific setup is done
70 * (probably at the end of the FFBitStreamFilter.init function).
71 */
72int ff_cbs_bsf_generic_init(AVBSFContext *bsf, const CBSBSFType *type);
73
74/**
75 * Close a generic CBS BSF instance.
76 *
77 * If no other deinitialisation is required then this function can be used
78 * directly as FFBitStreamFilter.close.
79 */
80void ff_cbs_bsf_generic_close(AVBSFContext *bsf);
81
82/**
83 * Filter operation for CBS BSF.
84 *
85 * Reads the input packet into a CBS fragment, calls update_fragment() on
86 * it, then writes the result to an output packet.  If the input packet
87 * has AV_PKT_DATA_NEW_EXTRADATA side-data associated with it then it does
88 * the same thing to that new extradata to form the output side-data first.
89 *
90 * If the BSF does not do anything else then this function can be used
91 * directly as FFBitStreamFilter.filter.
92 */
93int ff_cbs_bsf_generic_filter(AVBSFContext *bsf, AVPacket *pkt);
94
95
96// Options for element manipulation.
97enum {
98    // Pass this element through unchanged.
99    BSF_ELEMENT_PASS,
100    // Insert this element, replacing any existing instances of it.
101    // Associated values may be provided explicitly (as addtional options)
102    // or implicitly (either as side data or deduced from other parts of
103    // the stream).
104    BSF_ELEMENT_INSERT,
105    // Remove this element if it appears in the stream.
106    BSF_ELEMENT_REMOVE,
107    // Extract this element to side data, so that further manipulation
108    // can happen elsewhere.
109    BSF_ELEMENT_EXTRACT,
110};
111
112#define BSF_ELEMENT_OPTIONS_PIR(name, help, field, opt_flags) \
113    { name, help, OFFSET(field), AV_OPT_TYPE_INT, \
114        { .i64 = BSF_ELEMENT_PASS }, \
115        BSF_ELEMENT_PASS, BSF_ELEMENT_REMOVE, opt_flags, name }, \
116    { "pass",   NULL, 0, AV_OPT_TYPE_CONST, \
117        { .i64 = BSF_ELEMENT_PASS   }, .flags = opt_flags, .unit = name }, \
118    { "insert", NULL, 0, AV_OPT_TYPE_CONST, \
119        { .i64 = BSF_ELEMENT_INSERT }, .flags = opt_flags, .unit = name }, \
120    { "remove", NULL, 0, AV_OPT_TYPE_CONST, \
121        { .i64 = BSF_ELEMENT_REMOVE }, .flags = opt_flags, .unit = name }
122
123#define BSF_ELEMENT_OPTIONS_PIRE(name, help, field, opt_flags) \
124    { name, help, OFFSET(field), AV_OPT_TYPE_INT, \
125        { .i64 = BSF_ELEMENT_PASS }, \
126        BSF_ELEMENT_PASS, BSF_ELEMENT_EXTRACT, opt_flags, name }, \
127    { "pass",   NULL, 0, AV_OPT_TYPE_CONST, \
128        { .i64 = BSF_ELEMENT_PASS    }, .flags = opt_flags, .unit = name }, \
129    { "insert", NULL, 0, AV_OPT_TYPE_CONST, \
130        { .i64 = BSF_ELEMENT_INSERT  }, .flags = opt_flags, .unit = name }, \
131    { "remove", NULL, 0, AV_OPT_TYPE_CONST, \
132        { .i64 = BSF_ELEMENT_REMOVE  }, .flags = opt_flags, .unit = name }, \
133    { "extract", NULL, 0, AV_OPT_TYPE_CONST, \
134        { .i64 = BSF_ELEMENT_EXTRACT }, .flags = opt_flags, .unit = name } \
135
136
137#endif /* AVCODEC_CBS_BSF_H */
138