FFmpeg
vp9_superframe_split_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  *
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 /**
20  * @file
21  * This bitstream filter splits VP9 superframes into packets containing
22  * just one frame.
23  */
24 
25 #include <stddef.h>
26 
27 #include "bsf.h"
28 #include "bsf_internal.h"
29 #include "bytestream.h"
30 #include "get_bits.h"
31 
32 typedef struct VP9SFSplitContext {
34 
35  int nb_frames;
38  int sizes[8];
40 
42 {
44  AVPacket *in;
45  int i, j, ret, marker;
46  int is_superframe = !!s->buffer_pkt->data;
47 
48  if (!s->buffer_pkt->data) {
49  ret = ff_bsf_get_packet_ref(ctx, s->buffer_pkt);
50  if (ret < 0)
51  return ret;
52  in = s->buffer_pkt;
53 
54  if (!in->size)
55  goto passthrough;
56 
57  marker = in->data[in->size - 1];
58  if ((marker & 0xe0) == 0xc0) {
59  int length_size = 1 + ((marker >> 3) & 0x3);
60  int nb_frames = 1 + (marker & 0x7);
61  int idx_size = 2 + nb_frames * length_size;
62 
63  if (in->size >= idx_size && in->data[in->size - idx_size] == marker) {
64  GetByteContext bc;
65  int64_t total_size = 0;
66 
67  bytestream2_init(&bc, in->data + in->size + 1 - idx_size,
68  nb_frames * length_size);
69 
70  for (i = 0; i < nb_frames; i++) {
71  int frame_size = 0;
72  for (j = 0; j < length_size; j++)
73  frame_size |= bytestream2_get_byte(&bc) << (j * 8);
74 
75  total_size += frame_size;
76  if (frame_size <= 0 || total_size > in->size - idx_size) {
78  "Invalid frame size in a superframe: %d\n", frame_size);
79  ret = AVERROR(EINVAL);
80  goto fail;
81  }
82  s->sizes[i] = frame_size;
83  }
84  s->nb_frames = nb_frames;
85  s->next_frame = 0;
86  s->next_frame_offset = 0;
87  is_superframe = 1;
88  }
89  }
90  }
91 
92  if (is_superframe) {
93  GetBitContext gb;
94  int profile, invisible = 0;
95 
96  ret = av_packet_ref(out, s->buffer_pkt);
97  if (ret < 0)
98  goto fail;
99 
100  out->data += s->next_frame_offset;
101  out->size = s->sizes[s->next_frame];
102 
103  s->next_frame_offset += out->size;
104  s->next_frame++;
105 
106  if (s->next_frame >= s->nb_frames)
107  av_packet_unref(s->buffer_pkt);
108 
109  ret = init_get_bits8(&gb, out->data, out->size);
110  if (ret < 0)
111  goto fail;
112 
113  get_bits(&gb, 2); // frame_marker
114  profile = get_bits1(&gb);
115  profile |= get_bits1(&gb) << 1;
116  if (profile == 3)
117  get_bits1(&gb);
118  if (!get_bits1(&gb)) {
119  get_bits1(&gb);
120  invisible = !get_bits1(&gb);
121  }
122 
123  if (invisible)
124  out->pts = AV_NOPTS_VALUE;
125 
126  } else {
127 passthrough:
128  av_packet_move_ref(out, s->buffer_pkt);
129  }
130 
131  return 0;
132 fail:
133  if (ret < 0)
135  av_packet_unref(s->buffer_pkt);
136  return ret;
137 }
138 
140 {
142 
143  s->buffer_pkt = av_packet_alloc();
144  if (!s->buffer_pkt)
145  return AVERROR(ENOMEM);
146 
147  return 0;
148 }
149 
151 {
153  av_packet_unref(s->buffer_pkt);
154 }
155 
157 {
159  av_packet_free(&s->buffer_pkt);
160 }
161 
163  .p.name = "vp9_superframe_split",
164  .p.codec_ids = (const enum AVCodecID []){ AV_CODEC_ID_VP9, AV_CODEC_ID_NONE },
165  .priv_data_size = sizeof(VP9SFSplitContext),
170 };
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:422
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
bsf_internal.h
out
FILE * out
Definition: movenc.c:54
GetByteContext
Definition: bytestream.h:33
AVBitStreamFilter::name
const char * name
Definition: bsf.h:112
AVPacket::data
uint8_t * data
Definition: packet.h:374
VP9SFSplitContext
Definition: vp9_superframe_split_bsf.c:32
filter
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
Definition: filter_design.txt:228
av_packet_free
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
Definition: avpacket.c:73
AVBSFContext
The bitstream filter state.
Definition: bsf.h:68
init
static int init
Definition: av_tx.c:47
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:380
bsf.h
fail
#define fail()
Definition: checkasm.h:130
GetBitContext
Definition: get_bits.h:62
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:678
s
#define s(width, name)
Definition: cbs_vp9.c:256
vp9_superframe_split_init
static int vp9_superframe_split_init(AVBSFContext *ctx)
Definition: vp9_superframe_split_bsf.c:139
frame_size
int frame_size
Definition: mxfenc.c:2201
AV_CODEC_ID_VP9
@ AV_CODEC_ID_VP9
Definition: codec_id.h:218
ctx
AVFormatContext * ctx
Definition: movenc.c:48
get_bits.h
VP9SFSplitContext::buffer_pkt
AVPacket * buffer_pkt
Definition: vp9_superframe_split_bsf.c:33
VP9SFSplitContext::sizes
int sizes[8]
Definition: vp9_superframe_split_bsf.c:38
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:606
FFBitStreamFilter
Definition: bsf_internal.h:27
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:499
av_packet_ref
int av_packet_ref(AVPacket *dst, const AVPacket *src)
Setup a new reference to the data described by a given packet.
Definition: avpacket.c:430
av_packet_move_ref
void av_packet_move_ref(AVPacket *dst, AVPacket *src)
Move every field in src to dst and reset src.
Definition: avpacket.c:479
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:47
VP9SFSplitContext::next_frame
int next_frame
Definition: vp9_superframe_split_bsf.c:36
FFBitStreamFilter::p
AVBitStreamFilter p
The public AVBitStreamFilter.
Definition: bsf_internal.h:31
AVPacket::size
int size
Definition: packet.h:375
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
VP9SFSplitContext::nb_frames
int nb_frames
Definition: vp9_superframe_split_bsf.c:35
av_packet_alloc
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
Definition: avpacket.c:62
VP9SFSplitContext::next_frame_offset
size_t next_frame_offset
Definition: vp9_superframe_split_bsf.c:37
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:48
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
profile
int profile
Definition: mxfenc.c:2005
ret
ret
Definition: filter_design.txt:187
ff_vp9_superframe_split_bsf
const FFBitStreamFilter ff_vp9_superframe_split_bsf
Definition: vp9_superframe_split_bsf.c:162
vp9_superframe_split_flush
static void vp9_superframe_split_flush(AVBSFContext *ctx)
Definition: vp9_superframe_split_bsf.c:150
vp9_superframe_split_filter
static int vp9_superframe_split_filter(AVBSFContext *ctx, AVPacket *out)
Definition: vp9_superframe_split_bsf.c:41
AVPacket
This structure stores compressed data.
Definition: packet.h:351
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
ff_bsf_get_packet_ref
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:257
vp9_superframe_split_uninit
static void vp9_superframe_split_uninit(AVBSFContext *ctx)
Definition: vp9_superframe_split_bsf.c:156
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1241