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path: root/libavcodec/vp9_superframe_bsf.c (plain)
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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#include "avcodec.h"
24#include "bsf.h"
25#include "get_bits.h"
26
27#define MAX_CACHE 8
28typedef struct VP9BSFContext {
29 int n_cache;
30 struct CachedBuf {
31 uint8_t *data;
32 int size;
33 } cache[MAX_CACHE];
34} VP9BSFContext;
35
36static void stats(const struct CachedBuf *in, int n_in,
37 unsigned *_max, unsigned *_sum)
38{
39 int n;
40 unsigned max = 0, sum = 0;
41
42 for (n = 0; n < n_in; n++) {
43 unsigned sz = in[n].size;
44
45 if (sz > max)
46 max = sz;
47 sum += sz;
48 }
49
50 *_max = max;
51 *_sum = sum;
52}
53
54static int merge_superframe(const struct CachedBuf *in, int n_in, AVPacket *out)
55{
56 unsigned max, sum, mag, marker, n, sz;
57 uint8_t *ptr;
58 int res;
59
60 stats(in, n_in, &max, &sum);
61 mag = av_log2(max) >> 3;
62 marker = 0xC0 + (mag << 3) + (n_in - 1);
63 sz = sum + 2 + (mag + 1) * n_in;
64 res = av_new_packet(out, sz);
65 if (res < 0)
66 return res;
67 ptr = out->data;
68 for (n = 0; n < n_in; n++) {
69 memcpy(ptr, in[n].data, in[n].size);
70 ptr += in[n].size;
71 }
72
73#define wloop(mag, wr) \
74 for (n = 0; n < n_in; n++) { \
75 wr; \
76 ptr += mag + 1; \
77 }
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
101static int vp9_superframe_filter(AVBSFContext *ctx, AVPacket *out)
102{
103 GetBitContext gb;
104 VP9BSFContext *s = ctx->priv_data;
105 AVPacket *in;
106 int res, invisible, profile, marker, uses_superframe_syntax = 0, n;
107
108 res = ff_bsf_get_packet(ctx, &in);
109 if (res < 0)
110 return res;
111
112 marker = in->data[in->size - 1];
113 if ((marker & 0xe0) == 0xc0) {
114 int nbytes = 1 + ((marker >> 3) & 0x3);
115 int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
116
117 uses_superframe_syntax = in->size >= idx_sz && in->data[in->size - idx_sz] == marker;
118 }
119
120 if ((res = init_get_bits8(&gb, in->data, in->size)) < 0)
121 goto done;
122
123 get_bits(&gb, 2); // frame marker
124 profile = get_bits1(&gb);
125 profile |= get_bits1(&gb) << 1;
126 if (profile == 3) profile += get_bits1(&gb);
127
128 if (get_bits1(&gb)) {
129 invisible = 0;
130 } else {
131 get_bits1(&gb); // keyframe
132 invisible = !get_bits1(&gb);
133 }
134
135 if (uses_superframe_syntax && s->n_cache > 0) {
136 av_log(ctx, AV_LOG_ERROR,
137 "Mixing of superframe syntax and naked VP9 frames not supported");
138 res = AVERROR_INVALIDDATA;
139 goto done;
140 } else if ((!invisible || uses_superframe_syntax) && !s->n_cache) {
141 // passthrough
142 av_packet_move_ref(out, in);
143 goto done;
144 } else if (s->n_cache + 1 >= MAX_CACHE) {
145 av_log(ctx, AV_LOG_ERROR,
146 "Too many invisible frames");
147 res = AVERROR_INVALIDDATA;
148 goto done;
149 }
150
151 s->cache[s->n_cache].size = in->size;
152 if (invisible && !uses_superframe_syntax) {
153 s->cache[s->n_cache].data = av_malloc(in->size);
154 if (!s->cache[s->n_cache].data) {
155 res = AVERROR(ENOMEM);
156 goto done;
157 }
158 memcpy(s->cache[s->n_cache++].data, in->data, in->size);
159 res = AVERROR(EAGAIN);
160 goto done;
161 }
162 av_assert0(s->n_cache > 0);
163
164 s->cache[s->n_cache].data = in->data;
165
166 // build superframe
167 if ((res = merge_superframe(s->cache, s->n_cache + 1, out)) < 0)
168 goto done;
169
170 for (n = 0; n < s->n_cache; n++)
171 av_freep(&s->cache[n].data);
172 s->n_cache = 0;
173
174 res = av_packet_copy_props(out, in);
175 if (res < 0)
176 goto done;
177
178done:
179 if (res < 0)
180 av_packet_unref(out);
181 av_packet_free(&in);
182 return res;
183}
184
185static void vp9_superframe_close(AVBSFContext *ctx)
186{
187 VP9BSFContext *s = ctx->priv_data;
188 int n;
189
190 // free cached data
191 for (n = 0; n < s->n_cache; n++)
192 av_freep(&s->cache[n].data);
193}
194
195static const enum AVCodecID codec_ids[] = {
196 AV_CODEC_ID_VP9, AV_CODEC_ID_NONE,
197};
198
199const AVBitStreamFilter ff_vp9_superframe_bsf = {
200 .name = "vp9_superframe",
201 .priv_data_size = sizeof(VP9BSFContext),
202 .filter = vp9_superframe_filter,
203 .close = vp9_superframe_close,
204 .codec_ids = codec_ids,
205};
206
generated by cgit at 2024-05-17 03:39:36 (GMT)