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 <inttypes.h>
20
21 #include "libavutil/log.h"
22
23 #include "bsf.h"
24 #include "bsf_internal.h"
25 #include "cbs.h"
26 #include "cbs_bsf.h"
27 #include "cbs_h264.h"
28 #include "codec_id.h"
29 #include "h264.h"
30 #include "packet.h"
31
32 #define NEW_GLOBAL_PIC_INIT_QP 26
33
34 typedef struct H264RedundantPPSContext {
35 CBSBSFContext common;
36 } H264RedundantPPSContext;
37
38
h264_redundant_pps_fixup_pps(H264RedundantPPSContext * ctx,CodedBitstreamUnit * unit)39 static int h264_redundant_pps_fixup_pps(H264RedundantPPSContext *ctx,
40 CodedBitstreamUnit *unit)
41 {
42 H264RawPPS *pps;
43 int err;
44
45 // The changes we are about to perform affect the parsing process,
46 // so we must make sure that the PPS is writable, otherwise the
47 // parsing of future slices will be incorrect and even raise errors.
48 err = ff_cbs_make_unit_writable(ctx->common.input, unit);
49 if (err < 0)
50 return err;
51 pps = unit->content;
52
53 // Overwrite pic_init_qp with the global value.
54 pps->pic_init_qp_minus26 = NEW_GLOBAL_PIC_INIT_QP - 26;
55
56 // Some PPSs have this set, so it must be set in all of them.
57 // (Slices which do not use such a PPS on input will still have
58 // *_weight_l*flag as zero and therefore write equivalently.)
59 pps->weighted_pred_flag = 1;
60
61 return 0;
62 }
63
h264_redundant_pps_fixup_slice(H264RedundantPPSContext * ctx,H264RawSliceHeader * slice)64 static int h264_redundant_pps_fixup_slice(H264RedundantPPSContext *ctx,
65 H264RawSliceHeader *slice)
66 {
67 const CodedBitstreamH264Context *const in = ctx->common.input->priv_data;
68 const H264RawPPS *const pps = in->pps[slice->pic_parameter_set_id];
69
70 // We modified the PPS's qp value, now offset this by applying
71 // the negative offset to the slices.
72 slice->slice_qp_delta += pps->pic_init_qp_minus26
73 - (NEW_GLOBAL_PIC_INIT_QP - 26);
74
75 return 0;
76 }
77
h264_redundant_pps_update_fragment(AVBSFContext * bsf,AVPacket * pkt,CodedBitstreamFragment * au)78 static int h264_redundant_pps_update_fragment(AVBSFContext *bsf,
79 AVPacket *pkt,
80 CodedBitstreamFragment *au)
81 {
82 H264RedundantPPSContext *ctx = bsf->priv_data;
83 int au_has_sps;
84 int err, i;
85
86 au_has_sps = 0;
87 for (i = 0; i < au->nb_units; i++) {
88 CodedBitstreamUnit *nal = &au->units[i];
89
90 if (nal->type == H264_NAL_SPS)
91 au_has_sps = 1;
92 if (nal->type == H264_NAL_PPS) {
93 err = h264_redundant_pps_fixup_pps(ctx, nal);
94 if (err < 0)
95 return err;
96 if (!au_has_sps) {
97 av_log(bsf, AV_LOG_VERBOSE, "Deleting redundant PPS "
98 "at %"PRId64".\n", pkt->pts);
99 ff_cbs_delete_unit(au, i);
100 i--;
101 continue;
102 }
103 }
104 if (nal->type == H264_NAL_SLICE ||
105 nal->type == H264_NAL_IDR_SLICE) {
106 H264RawSlice *slice = nal->content;
107 h264_redundant_pps_fixup_slice(ctx, &slice->header);
108 }
109 }
110
111 return 0;
112 }
113
114 static const CBSBSFType h264_redundant_pps_type = {
115 .codec_id = AV_CODEC_ID_H264,
116 .fragment_name = "access unit",
117 .unit_name = "NAL unit",
118 .update_fragment = &h264_redundant_pps_update_fragment,
119 };
120
h264_redundant_pps_init(AVBSFContext * bsf)121 static int h264_redundant_pps_init(AVBSFContext *bsf)
122 {
123 return ff_cbs_bsf_generic_init(bsf, &h264_redundant_pps_type);
124 }
125
126 static const enum AVCodecID h264_redundant_pps_codec_ids[] = {
127 AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
128 };
129
130 const FFBitStreamFilter ff_h264_redundant_pps_bsf = {
131 .p.name = "h264_redundant_pps",
132 .p.codec_ids = h264_redundant_pps_codec_ids,
133 .priv_data_size = sizeof(H264RedundantPPSContext),
134 .init = &h264_redundant_pps_init,
135 .close = &ff_cbs_bsf_generic_close,
136 .filter = &ff_cbs_bsf_generic_filter,
137 };
138