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 31 typedef 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). 53 typedef 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 */ 72 int 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 */ 80 void 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 */ 93 int ff_cbs_bsf_generic_filter(AVBSFContext *bsf, AVPacket *pkt); 94 95 96 // Options for element manipulation. 97 enum { 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