FFmpeg
h264_redundant_pps_bsf.c
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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
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8  *
9  * FFmpeg is distributed in the hope that it will be useful,
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11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
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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 {
34 
39 
40 
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.
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 
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 
80  AVPacket *pkt,
82 {
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;
109  }
110  }
111 
112  return 0;
113 }
114 
116 {
119 }
120 
123  .fragment_name = "access unit",
124  .unit_name = "NAL unit",
125  .update_fragment = &h264_redundant_pps_update_fragment,
126 };
127 
129 {
131 
132  ctx->global_pic_init_qp = 26;
133 
134  return ff_cbs_bsf_generic_init(bsf, &h264_redundant_pps_type);
135 }
136 
139 };
140 
142  .name = "h264_redundant_pps",
143  .priv_data_size = sizeof(H264RedundantPPSContext),
146  .close = &ff_cbs_bsf_generic_close,
149 };
static int h264_redundant_pps_update_fragment(AVBSFContext *bsf, AVPacket *pkt, CodedBitstreamFragment *au)
static int h264_redundant_pps_init(AVBSFContext *bsf)
int nb_units
Number of units in this fragment.
Definition: cbs.h:149
static void flush(AVCodecContext *avctx)
Memory handling functions.
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
enum AVCodecID codec_id
Definition: cbs_bsf.h:26
CodedBitstreamUnitType type
Codec-specific type of this unit.
Definition: cbs.h:70
The bitstream filter state.
Definition: bsf.h:49
static const CBSBSFType h264_redundant_pps_type
static AVPacket pkt
void * priv_data
Opaque filter-specific private data.
Definition: bsf.h:70
const AVBitStreamFilter ff_h264_redundant_pps_bsf
int ff_cbs_bsf_generic_init(AVBSFContext *bsf, const CBSBSFType *type)
Initialise generic CBS BSF setup.
Definition: cbs_bsf.c:112
uint8_t weighted_pred_flag
Definition: cbs_h264.h:205
static int h264_redundant_pps_fixup_slice(H264RedundantPPSContext *ctx, H264RawSliceHeader *slice)
int8_t slice_qp_delta
Definition: cbs_h264.h:365
const char * name
Definition: bsf.h:99
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:210
Coded bitstream unit structure.
Definition: cbs.h:66
void * content
Pointer to the decomposed form of this unit.
Definition: cbs.h:103
CodedBitstreamUnit * units
Pointer to an array of units of length nb_units_allocated.
Definition: cbs.h:164
#define av_log(a,...)
H.264 common definitions.
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce then the filter should push the output frames on the output link immediately As an exception to the previous rule if the input frame is enough to produce several output frames then the filter needs output only at least one per link The additional frames can be left buffered in the filter
static int h264_redundant_pps_fixup_pps(H264RedundantPPSContext *ctx, CodedBitstreamUnit *unit)
void ff_cbs_bsf_generic_close(AVBSFContext *bsf)
Close a generic CBS BSF instance.
Definition: cbs_bsf.c:152
AVFormatContext * ctx
Definition: movenc.c:48
int ff_cbs_bsf_generic_filter(AVBSFContext *bsf, AVPacket *pkt)
Filter operation for CBS BSF.
Definition: cbs_bsf.c:63
static void h264_redundant_pps_flush(AVBSFContext *bsf)
Coded bitstream fragment structure, combining one or more units.
Definition: cbs.h:118
static int FUNC() pps(CodedBitstreamContext *ctx, RWContext *rw, H264RawPPS *current)
void ff_cbs_delete_unit(CodedBitstreamFragment *frag, int position)
Delete a unit from a fragment and free all memory it uses.
Definition: cbs.c:812
common internal and external API header
static enum AVCodecID codec_ids[]
static enum AVCodecID h264_redundant_pps_codec_ids[]
H264RawSliceHeader header
Definition: cbs_h264.h:378
int8_t pic_init_qp_minus26
Definition: cbs_h264.h:208
CodedBitstreamContext * input
Definition: cbs_bsf.h:51
This structure stores compressed data.
Definition: packet.h:340
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:356
int ff_cbs_make_unit_writable(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Make the content of a unit writable so that internal fields can be modified.
Definition: cbs.c:1011
int i
Definition: input.c:407