FFmpeg
libavcodec
cbs_bsf.h
Go to the documentation of this file.
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/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_CBS_BSF_H
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#define AVCODEC_CBS_BSF_H
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#include "
libavutil/log.h
"
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#include "
libavutil/opt.h
"
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#include "
bsf.h
"
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#include "
codec_id.h
"
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#include "
cbs.h
"
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#include "
packet.h
"
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typedef
struct
CBSBSFType
{
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enum
AVCodecID
codec_id
;
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// Name of a frame fragment in this codec (e.g. "access unit",
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// "temporal unit").
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const
char
*
fragment_name
;
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// Name of a unit for this BSF, for use in error messages (e.g.
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// "NAL unit", "OBU").
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const
char
*
unit_name
;
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// Update the content of a fragment with whatever metadata changes
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// are desired. The associated AVPacket is provided so that any side
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// data associated with the fragment can be inspected or edited. If
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// pkt is NULL, then an extradata header fragment is being updated.
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int
(*
update_fragment
)(
AVBSFContext
*bsf,
AVPacket
*
pkt
,
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CodedBitstreamFragment
*frag);
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}
CBSBSFType
;
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// Common structure for all generic CBS BSF users. An instance of this
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// structure must be the first member of the BSF private context (to be
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// pointed to by AVBSFContext.priv_data).
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typedef
struct
CBSBSFContext
{
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const
AVClass
*
class
;
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const
CBSBSFType
*
type
;
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CodedBitstreamContext
*
input
;
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CodedBitstreamContext
*
output
;
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CodedBitstreamFragment
fragment
;
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}
CBSBSFContext
;
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/**
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* Initialise generic CBS BSF setup.
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*
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* Creates the input and output CBS instances, and applies the filter to
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* the extradata on the input codecpar if any is present.
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*
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* Since it calls the update_fragment() function immediately to deal with
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* extradata, this should be called after any codec-specific setup is done
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* (probably at the end of the FFBitStreamFilter.init function).
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*/
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int
ff_cbs_bsf_generic_init
(
AVBSFContext
*bsf,
const
CBSBSFType
*
type
);
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/**
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* Close a generic CBS BSF instance.
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*
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* If no other deinitialisation is required then this function can be used
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* directly as FFBitStreamFilter.close.
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*/
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void
ff_cbs_bsf_generic_close
(
AVBSFContext
*bsf);
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/**
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* Filter operation for CBS BSF.
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*
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* Reads the input packet into a CBS fragment, calls update_fragment() on
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* it, then writes the result to an output packet. If the input packet
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* has AV_PKT_DATA_NEW_EXTRADATA side-data associated with it then it does
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* the same thing to that new extradata to form the output side-data first.
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*
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* If the BSF does not do anything else then this function can be used
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* directly as FFBitStreamFilter.filter.
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*/
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int
ff_cbs_bsf_generic_filter
(
AVBSFContext
*bsf,
AVPacket
*
pkt
);
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// Options for element manipulation.
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enum
{
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// Pass this element through unchanged.
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BSF_ELEMENT_PASS
,
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// Insert this element, replacing any existing instances of it.
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// Associated values may be provided explicitly (as additional options)
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// or implicitly (either as side data or deduced from other parts of
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// the stream).
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BSF_ELEMENT_INSERT
,
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// Remove this element if it appears in the stream.
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BSF_ELEMENT_REMOVE
,
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// Extract this element to side data, so that further manipulation
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// can happen elsewhere.
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BSF_ELEMENT_EXTRACT
,
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};
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#define BSF_ELEMENT_OPTIONS_PIR(name, help, field, opt_flags) \
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{ name, help, OFFSET(field), AV_OPT_TYPE_INT, \
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{ .i64 = BSF_ELEMENT_PASS }, \
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BSF_ELEMENT_PASS, BSF_ELEMENT_REMOVE, opt_flags, .unit = name }, \
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{ "pass", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_PASS }, .flags = opt_flags, .unit = name }, \
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{ "insert", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_INSERT }, .flags = opt_flags, .unit = name }, \
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{ "remove", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_REMOVE }, .flags = opt_flags, .unit = name }
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#define BSF_ELEMENT_OPTIONS_PIRE(name, help, field, opt_flags) \
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{ name, help, OFFSET(field), AV_OPT_TYPE_INT, \
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{ .i64 = BSF_ELEMENT_PASS }, \
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BSF_ELEMENT_PASS, BSF_ELEMENT_EXTRACT, opt_flags, .unit = name }, \
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{ "pass", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_PASS }, .flags = opt_flags, .unit = name }, \
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{ "insert", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_INSERT }, .flags = opt_flags, .unit = name }, \
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{ "remove", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_REMOVE }, .flags = opt_flags, .unit = name }, \
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{ "extract", NULL, 0, AV_OPT_TYPE_CONST, \
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{ .i64 = BSF_ELEMENT_EXTRACT }, .flags = opt_flags, .unit = name } \
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#endif
/* AVCODEC_CBS_BSF_H */
opt.h
CBSBSFType::codec_id
enum AVCodecID codec_id
Definition:
cbs_bsf.h:32
CodedBitstreamContext
Context structure for coded bitstream operations.
Definition:
cbs.h:219
CBSBSFContext
Definition:
cbs_bsf.h:53
cbs.h
ff_cbs_bsf_generic_filter
int ff_cbs_bsf_generic_filter(AVBSFContext *bsf, AVPacket *pkt)
Filter operation for CBS BSF.
Definition:
cbs_bsf.c:61
CBSBSFContext::input
CodedBitstreamContext * input
Definition:
cbs_bsf.h:57
AVBSFContext
The bitstream filter state.
Definition:
bsf.h:68
CBSBSFType::fragment_name
const char * fragment_name
Definition:
cbs_bsf.h:36
BSF_ELEMENT_REMOVE
@ BSF_ELEMENT_REMOVE
Definition:
cbs_bsf.h:106
bsf.h
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition:
writing_filters.txt:86
CBSBSFType::update_fragment
int(* update_fragment)(AVBSFContext *bsf, AVPacket *pkt, CodedBitstreamFragment *frag)
Definition:
cbs_bsf.h:46
pkt
AVPacket * pkt
Definition:
movenc.c:59
codec_id.h
CodedBitstreamFragment
Coded bitstream fragment structure, combining one or more units.
Definition:
cbs.h:122
CBSBSFType::unit_name
const char * unit_name
Definition:
cbs_bsf.h:40
AVClass
Describe the class of an AVClass context structure.
Definition:
log.h:66
BSF_ELEMENT_PASS
@ BSF_ELEMENT_PASS
Definition:
cbs_bsf.h:99
CBSBSFContext::fragment
CodedBitstreamFragment fragment
Definition:
cbs_bsf.h:59
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition:
codec_id.h:49
CBSBSFType
Definition:
cbs_bsf.h:31
ff_cbs_bsf_generic_init
int ff_cbs_bsf_generic_init(AVBSFContext *bsf, const CBSBSFType *type)
Initialise generic CBS BSF setup.
Definition:
cbs_bsf.c:110
log.h
packet.h
CBSBSFContext::type
const CBSBSFType * type
Definition:
cbs_bsf.h:55
ff_cbs_bsf_generic_close
void ff_cbs_bsf_generic_close(AVBSFContext *bsf)
Close a generic CBS BSF instance.
Definition:
cbs_bsf.c:155
AVPacket
This structure stores compressed data.
Definition:
packet.h:499
BSF_ELEMENT_EXTRACT
@ BSF_ELEMENT_EXTRACT
Definition:
cbs_bsf.h:109
int
int
Definition:
ffmpeg_filter.c:409
CBSBSFContext::output
CodedBitstreamContext * output
Definition:
cbs_bsf.h:58
BSF_ELEMENT_INSERT
@ BSF_ELEMENT_INSERT
Definition:
cbs_bsf.h:104
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