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 #include <string.h>
20
21 #include "libavutil/common.h"
22 #include "libavutil/mem.h"
23
24 #include "bsf.h"
25 #include "bsf_internal.h"
26 #include "cbs.h"
27 #include "cbs_bsf.h"
28 #include "cbs_h264.h"
29 #include "h264.h"
30
31
32 typedef struct H264RedundantPPSContext {
33 CBSBSFContext common;
34
35 int global_pic_init_qp;
36 int current_pic_init_qp;
37 int extradata_pic_init_qp;
38 } H264RedundantPPSContext;
39
40
h264_redundant_pps_fixup_pps(H264RedundantPPSContext * ctx,CodedBitstreamUnit * unit)41 static int h264_redundant_pps_fixup_pps(H264RedundantPPSContext *ctx,
42 CodedBitstreamUnit *unit)
43 {
44 H264RawPPS *pps;
45 int err;
46
47 // The changes we are about to perform affect the parsing process,
48 // so we must make sure that the PPS is writable, otherwise the
49 // parsing of future slices will be incorrect and even raise errors.
50 err = ff_cbs_make_unit_writable(ctx->common.input, unit);
51 if (err < 0)
52 return err;
53 pps = unit->content;
54
55 // Record the current value of pic_init_qp in order to fix up
56 // following slices, then overwrite with the global value.
57 ctx->current_pic_init_qp = pps->pic_init_qp_minus26 + 26;
58 pps->pic_init_qp_minus26 = ctx->global_pic_init_qp - 26;
59
60 // Some PPSs have this set, so it must be set in all of them.
61 // (Slices which do not use such a PPS on input will still have
62 // *_weight_l*flag as zero and therefore write equivalently.)
63 pps->weighted_pred_flag = 1;
64
65 return 0;
66 }
67
h264_redundant_pps_fixup_slice(H264RedundantPPSContext * ctx,H264RawSliceHeader * slice)68 static int h264_redundant_pps_fixup_slice(H264RedundantPPSContext *ctx,
69 H264RawSliceHeader *slice)
70 {
71 int qp;
72
73 qp = ctx->current_pic_init_qp + slice->slice_qp_delta;
74 slice->slice_qp_delta = qp - ctx->global_pic_init_qp;
75
76 return 0;
77 }
78
h264_redundant_pps_update_fragment(AVBSFContext * bsf,AVPacket * pkt,CodedBitstreamFragment * au)79 static int h264_redundant_pps_update_fragment(AVBSFContext *bsf,
80 AVPacket *pkt,
81 CodedBitstreamFragment *au)
82 {
83 H264RedundantPPSContext *ctx = bsf->priv_data;
84 int au_has_sps;
85 int err, i;
86
87 au_has_sps = 0;
88 for (i = 0; i < au->nb_units; i++) {
89 CodedBitstreamUnit *nal = &au->units[i];
90
91 if (nal->type == H264_NAL_SPS)
92 au_has_sps = 1;
93 if (nal->type == H264_NAL_PPS) {
94 err = h264_redundant_pps_fixup_pps(ctx, nal);
95 if (err < 0)
96 return err;
97 if (!au_has_sps) {
98 av_log(bsf, AV_LOG_VERBOSE, "Deleting redundant PPS "
99 "at %"PRId64".\n", pkt->pts);
100 ff_cbs_delete_unit(au, i);
101 i--;
102 continue;
103 }
104 }
105 if (nal->type == H264_NAL_SLICE ||
106 nal->type == H264_NAL_IDR_SLICE) {
107 H264RawSlice *slice = nal->content;
108 h264_redundant_pps_fixup_slice(ctx, &slice->header);
109 }
110 }
111
112 return 0;
113 }
114
h264_redundant_pps_flush(AVBSFContext * bsf)115 static void h264_redundant_pps_flush(AVBSFContext *bsf)
116 {
117 H264RedundantPPSContext *ctx = bsf->priv_data;
118 ctx->current_pic_init_qp = ctx->extradata_pic_init_qp;
119 }
120
121 static const CBSBSFType h264_redundant_pps_type = {
122 .codec_id = AV_CODEC_ID_H264,
123 .fragment_name = "access unit",
124 .unit_name = "NAL unit",
125 .update_fragment = &h264_redundant_pps_update_fragment,
126 };
127
h264_redundant_pps_init(AVBSFContext * bsf)128 static int h264_redundant_pps_init(AVBSFContext *bsf)
129 {
130 H264RedundantPPSContext *ctx = bsf->priv_data;
131
132 ctx->global_pic_init_qp = 26;
133
134 return ff_cbs_bsf_generic_init(bsf, &h264_redundant_pps_type);
135 }
136
137 static const enum AVCodecID h264_redundant_pps_codec_ids[] = {
138 AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
139 };
140
141 const AVBitStreamFilter ff_h264_redundant_pps_bsf = {
142 .name = "h264_redundant_pps",
143 .priv_data_size = sizeof(H264RedundantPPSContext),
144 .init = &h264_redundant_pps_init,
145 .flush = &h264_redundant_pps_flush,
146 .close = &ff_cbs_bsf_generic_close,
147 .filter = &ff_cbs_bsf_generic_filter,
148 .codec_ids = h264_redundant_pps_codec_ids,
149 };
150