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
28 typedef struct VP9BSFContext {
29 int n_cache;
30 AVPacket *cache[MAX_CACHE];
31 } VP9BSFContext;
32
stats(AVPacket * const * in,int n_in,unsigned * _max,unsigned * _sum)33 static void stats(AVPacket * const *in, int n_in,
34 unsigned *_max, unsigned *_sum)
35 {
36 int n;
37 unsigned max = 0, sum = 0;
38
39 for (n = 0; n < n_in; n++) {
40 unsigned sz = in[n]->size;
41
42 if (sz > max)
43 max = sz;
44 sum += sz;
45 }
46
47 *_max = max;
48 *_sum = sum;
49 }
50
merge_superframe(AVPacket * const * in,int n_in,AVPacket * out)51 static int merge_superframe(AVPacket * const *in, int n_in, AVPacket *out)
52 {
53 unsigned max, sum, mag, marker, n, sz;
54 uint8_t *ptr;
55 int res;
56
57 stats(in, n_in, &max, &sum);
58 mag = av_log2(max) >> 3;
59 marker = 0xC0 + (mag << 3) + (n_in - 1);
60 sz = sum + 2 + (mag + 1) * n_in;
61 res = av_new_packet(out, sz);
62 if (res < 0)
63 return res;
64 ptr = out->data;
65 for (n = 0; n < n_in; n++) {
66 memcpy(ptr, in[n]->data, in[n]->size);
67 ptr += in[n]->size;
68 }
69
70 #define wloop(mag, wr) \
71 do { \
72 for (n = 0; n < n_in; n++) { \
73 wr; \
74 ptr += mag + 1; \
75 } \
76 } while (0)
77
78 // write superframe with marker 110[mag:2][nframes:3]
79 *ptr++ = marker;
80 switch (mag) {
81 case 0:
82 wloop(mag, *ptr = in[n]->size);
83 break;
84 case 1:
85 wloop(mag, AV_WL16(ptr, in[n]->size));
86 break;
87 case 2:
88 wloop(mag, AV_WL24(ptr, in[n]->size));
89 break;
90 case 3:
91 wloop(mag, AV_WL32(ptr, in[n]->size));
92 break;
93 }
94 *ptr++ = marker;
95 av_assert0(ptr == &out->data[out->size]);
96
97 return 0;
98 }
99
vp9_superframe_filter(AVBSFContext * ctx,AVPacket * out)100 static int vp9_superframe_filter(AVBSFContext *ctx, AVPacket *out)
101 {
102 GetBitContext gb;
103 VP9BSFContext *s = ctx->priv_data;
104 AVPacket *in;
105 int res, invisible, profile, marker, uses_superframe_syntax = 0, n;
106
107 res = ff_bsf_get_packet(ctx, &in);
108 if (res < 0)
109 return res;
110
111 marker = in->data[in->size - 1];
112 if ((marker & 0xe0) == 0xc0) {
113 int nbytes = 1 + ((marker >> 3) & 0x3);
114 int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
115
116 uses_superframe_syntax = in->size >= idx_sz && in->data[in->size - idx_sz] == marker;
117 }
118
119 if ((res = init_get_bits8(&gb, in->data, in->size)) < 0)
120 goto done;
121
122 get_bits(&gb, 2); // frame marker
123 profile = get_bits1(&gb);
124 profile |= get_bits1(&gb) << 1;
125 if (profile == 3) profile += get_bits1(&gb);
126
127 if (get_bits1(&gb)) {
128 invisible = 0;
129 } else {
130 get_bits1(&gb); // keyframe
131 invisible = !get_bits1(&gb);
132 }
133
134 if (uses_superframe_syntax && s->n_cache > 0) {
135 av_log(ctx, AV_LOG_ERROR,
136 "Mixing of superframe syntax and naked VP9 frames not supported");
137 res = AVERROR(ENOSYS);
138 goto done;
139 } else if ((!invisible || uses_superframe_syntax) && !s->n_cache) {
140 // passthrough
141 av_packet_move_ref(out, in);
142 goto done;
143 } else if (s->n_cache + 1 >= MAX_CACHE) {
144 av_log(ctx, AV_LOG_ERROR,
145 "Too many invisible frames");
146 res = AVERROR_INVALIDDATA;
147 goto done;
148 }
149
150 av_packet_move_ref(s->cache[s->n_cache++], in);
151
152 if (invisible) {
153 res = AVERROR(EAGAIN);
154 goto done;
155 }
156 av_assert0(s->n_cache > 0);
157
158 // build superframe
159 if ((res = merge_superframe(s->cache, s->n_cache, out)) < 0)
160 goto done;
161
162 res = av_packet_copy_props(out, s->cache[s->n_cache - 1]);
163 if (res < 0)
164 goto done;
165
166 for (n = 0; n < s->n_cache; n++)
167 av_packet_unref(s->cache[n]);
168 s->n_cache = 0;
169
170 done:
171 if (res < 0)
172 av_packet_unref(out);
173 av_packet_free(&in);
174 return res;
175 }
176
vp9_superframe_init(AVBSFContext * ctx)177 static int vp9_superframe_init(AVBSFContext *ctx)
178 {
179 VP9BSFContext *s = ctx->priv_data;
180 int n;
181
182 // alloc cache packets
183 for (n = 0; n < MAX_CACHE; n++) {
184 s->cache[n] = av_packet_alloc();
185 if (!s->cache[n])
186 return AVERROR(ENOMEM);
187 }
188
189 return 0;
190 }
191
vp9_superframe_flush(AVBSFContext * ctx)192 static void vp9_superframe_flush(AVBSFContext *ctx)
193 {
194 VP9BSFContext *s = ctx->priv_data;
195 int n;
196
197 // unref cached data
198 for (n = 0; n < s->n_cache; n++)
199 av_packet_unref(s->cache[n]);
200 s->n_cache = 0;
201 }
202
vp9_superframe_close(AVBSFContext * ctx)203 static void vp9_superframe_close(AVBSFContext *ctx)
204 {
205 VP9BSFContext *s = ctx->priv_data;
206 int n;
207
208 // free cached data
209 for (n = 0; n < MAX_CACHE; n++)
210 av_packet_free(&s->cache[n]);
211 }
212
213 static const enum AVCodecID codec_ids[] = {
214 AV_CODEC_ID_VP9, AV_CODEC_ID_NONE,
215 };
216
217 const AVBitStreamFilter ff_vp9_superframe_bsf = {
218 .name = "vp9_superframe",
219 .priv_data_size = sizeof(VP9BSFContext),
220 .filter = vp9_superframe_filter,
221 .init = vp9_superframe_init,
222 .flush = vp9_superframe_flush,
223 .close = vp9_superframe_close,
224 .codec_ids = codec_ids,
225 };
226