FFmpeg
vp9_superframe_bsf.c
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1 /*
2  * Vp9 invisible (alt-ref) frame to superframe merge bitstream filter
3  * Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/avassert.h"
23 
24 #include "bsf.h"
25 #include "bsf_internal.h"
26 #include "get_bits.h"
27 
28 #define MAX_CACHE 8
29 typedef struct VP9BSFContext {
30  int n_cache;
33 
34 static void stats(AVPacket * const *in, int n_in,
35  unsigned *_max, unsigned *_sum)
36 {
37  int n;
38  unsigned max = 0, sum = 0;
39 
40  for (n = 0; n < n_in; n++) {
41  unsigned sz = in[n]->size;
42 
43  if (sz > max)
44  max = sz;
45  sum += sz;
46  }
47 
48  *_max = max;
49  *_sum = sum;
50 }
51 
52 static int merge_superframe(AVPacket * const *in, int n_in, AVPacket *out)
53 {
54  unsigned max, sum, mag, marker, n, sz;
55  uint8_t *ptr;
56  int res;
57 
58  stats(in, n_in, &max, &sum);
59  mag = av_log2(max) >> 3;
60  marker = 0xC0 + (mag << 3) + (n_in - 1);
61  sz = sum + 2 + (mag + 1) * n_in;
62  res = av_new_packet(out, sz);
63  if (res < 0)
64  return res;
65  ptr = out->data;
66  for (n = 0; n < n_in; n++) {
67  memcpy(ptr, in[n]->data, in[n]->size);
68  ptr += in[n]->size;
69  }
70 
71 #define wloop(mag, wr) \
72  do { \
73  for (n = 0; n < n_in; n++) { \
74  wr; \
75  ptr += mag + 1; \
76  } \
77  } while (0)
78 
79  // write superframe with marker 110[mag:2][nframes:3]
80  *ptr++ = marker;
81  switch (mag) {
82  case 0:
83  wloop(mag, *ptr = in[n]->size);
84  break;
85  case 1:
86  wloop(mag, AV_WL16(ptr, in[n]->size));
87  break;
88  case 2:
89  wloop(mag, AV_WL24(ptr, in[n]->size));
90  break;
91  case 3:
92  wloop(mag, AV_WL32(ptr, in[n]->size));
93  break;
94  }
95  *ptr++ = marker;
96  av_assert0(ptr == &out->data[out->size]);
97 
98  return 0;
99 }
100 
102 {
103  GetBitContext gb;
105  int res, invisible, profile, marker, uses_superframe_syntax = 0, n;
106 
107  res = ff_bsf_get_packet_ref(ctx, pkt);
108  if (res < 0)
109  return res;
110 
111  if (!pkt->size) {
112  /* In case the cache is empty we can pass side-data-only packets
113  * through unchanged. Otherwise, such a packet makes no sense. */
114  if (!s->n_cache)
115  return 0;
116  res = AVERROR_INVALIDDATA;
117  goto done;
118  }
119 
120  marker = pkt->data[pkt->size - 1];
121  if ((marker & 0xe0) == 0xc0) {
122  int nbytes = 1 + ((marker >> 3) & 0x3);
123  int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
124 
125  uses_superframe_syntax = pkt->size >= idx_sz && pkt->data[pkt->size - idx_sz] == marker;
126  }
127 
128  if ((res = init_get_bits8(&gb, pkt->data, pkt->size)) < 0)
129  goto done;
130 
131  get_bits(&gb, 2); // frame marker
132  profile = get_bits1(&gb);
133  profile |= get_bits1(&gb) << 1;
134  if (profile == 3) profile += get_bits1(&gb);
135 
136  if (get_bits1(&gb)) {
137  invisible = 0;
138  } else {
139  get_bits1(&gb); // keyframe
140  invisible = !get_bits1(&gb);
141  }
142 
143  if (uses_superframe_syntax && s->n_cache > 0) {
145  "Mixing of superframe syntax and naked VP9 frames not supported\n");
146  res = AVERROR(ENOSYS);
147  goto done;
148  } else if ((!invisible || uses_superframe_syntax) && !s->n_cache) {
149  // passthrough
150  return 0;
151  } else if (s->n_cache + 1 >= MAX_CACHE) {
153  "Too many invisible frames\n");
154  res = AVERROR_INVALIDDATA;
155  goto done;
156  }
157 
158  av_packet_move_ref(s->cache[s->n_cache++], pkt);
159 
160  if (invisible) {
161  return AVERROR(EAGAIN);
162  }
163  av_assert0(s->n_cache > 0);
164 
165  // build superframe
166  if ((res = merge_superframe(s->cache, s->n_cache, pkt)) < 0)
167  goto done;
168 
169  res = av_packet_copy_props(pkt, s->cache[s->n_cache - 1]);
170  if (res < 0)
171  goto done;
172 
173  for (n = 0; n < s->n_cache; n++)
174  av_packet_unref(s->cache[n]);
175  s->n_cache = 0;
176 
177 done:
178  if (res < 0)
180  return res;
181 }
182 
184 {
186  int n;
187 
188  // alloc cache packets
189  for (n = 0; n < MAX_CACHE; n++) {
190  s->cache[n] = av_packet_alloc();
191  if (!s->cache[n])
192  return AVERROR(ENOMEM);
193  }
194 
195  return 0;
196 }
197 
199 {
201  int n;
202 
203  // unref cached data
204  for (n = 0; n < s->n_cache; n++)
205  av_packet_unref(s->cache[n]);
206  s->n_cache = 0;
207 }
208 
210 {
212  int n;
213 
214  // free cached data
215  for (n = 0; n < MAX_CACHE; n++)
216  av_packet_free(&s->cache[n]);
217 }
218 
219 static const enum AVCodecID codec_ids[] = {
221 };
222 
224  .p.name = "vp9_superframe",
225  .p.codec_ids = codec_ids,
226  .priv_data_size = sizeof(VP9BSFContext),
230  .close = vp9_superframe_close,
231 };
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
AV_WL32
#define AV_WL32(p, v)
Definition: intreadwrite.h:426
out
FILE * out
Definition: movenc.c:54
vp9_superframe_close
static void vp9_superframe_close(AVBSFContext *ctx)
Definition: vp9_superframe_bsf.c:209
stats
static void stats(AVPacket *const *in, int n_in, unsigned *_max, unsigned *_sum)
Definition: vp9_superframe_bsf.c:34
VP9BSFContext::cache
AVPacket * cache[MAX_CACHE]
Definition: vp9_superframe_bsf.c:31
VP9BSFContext
Definition: vp9_superframe_bsf.c:29
AVBitStreamFilter::name
const char * name
Definition: bsf.h:112
AVPacket::data
uint8_t * data
Definition: packet.h:374
data
const char data[16]
Definition: mxf.c:146
MAX_CACHE
#define MAX_CACHE
Definition: vp9_superframe_bsf.c:28
max
#define max(a, b)
Definition: cuda_runtime.h:33
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
VP9BSFContext::n_cache
int n_cache
Definition: vp9_superframe_bsf.c:30
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
ff_vp9_superframe_bsf
const FFBitStreamFilter ff_vp9_superframe_bsf
Definition: vp9_superframe_bsf.c:223
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
bsf.h
GetBitContext
Definition: get_bits.h:61
avassert.h
pkt
AVPacket * pkt
Definition: movenc.c:59
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:667
s
#define s(width, name)
Definition: cbs_vp9.c:256
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:97
AV_CODEC_ID_VP9
@ AV_CODEC_ID_VP9
Definition: codec_id.h:220
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
ctx
AVFormatContext * ctx
Definition: movenc.c:48
get_bits.h
codec_ids
static enum AVCodecID codec_ids[]
Definition: vp9_superframe_bsf.c:219
wloop
#define wloop(mag, wr)
vp9_superframe_init
static int vp9_superframe_init(AVBSFContext *ctx)
Definition: vp9_superframe_bsf.c:183
FFBitStreamFilter
Definition: bsf_internal.h:27
AV_WL24
#define AV_WL24(p, d)
Definition: intreadwrite.h:464
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
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:49
FFBitStreamFilter::p
AVBitStreamFilter p
The public AVBitStreamFilter.
Definition: bsf_internal.h:31
vp9_superframe_filter
static int vp9_superframe_filter(AVBSFContext *ctx, AVPacket *pkt)
Definition: vp9_superframe_bsf.c:101
AVPacket::size
int size
Definition: packet.h:375
merge_superframe
static int merge_superframe(AVPacket *const *in, int n_in, AVPacket *out)
Definition: vp9_superframe_bsf.c:52
size
int size
Definition: twinvq_data.h:10344
AV_WL16
#define AV_WL16(p, v)
Definition: intreadwrite.h:412
av_packet_alloc
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
Definition: avpacket.c:62
av_packet_copy_props
int av_packet_copy_props(AVPacket *dst, const AVPacket *src)
Copy only "properties" fields from src to dst.
Definition: avpacket.c:385
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:50
profile
int profile
Definition: mxfenc.c:2006
vp9_superframe_flush
static void vp9_superframe_flush(AVBSFContext *ctx)
Definition: vp9_superframe_bsf.c:198
flush
void(* flush)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:365
AVPacket
This structure stores compressed data.
Definition: packet.h:351
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
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1244
av_log2
int av_log2(unsigned v)
Definition: intmath.c:26