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
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 {
33 AVPacket *buffer_pkt;
34
35 int nb_frames;
36 int next_frame;
37 size_t next_frame_offset;
38 int sizes[8];
39 } VP9SFSplitContext;
40
vp9_superframe_split_filter(AVBSFContext *ctx, AVPacket *out)41 static int vp9_superframe_split_filter(AVBSFContext *ctx, AVPacket *out)
42 {
43 VP9SFSplitContext *s = ctx->priv_data;
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) {
77 av_log(ctx, AV_LOG_ERROR,
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)
134 av_packet_unref(out);
135 av_packet_unref(s->buffer_pkt);
136 return ret;
137 }
138
vp9_superframe_split_init(AVBSFContext *ctx)139 static int vp9_superframe_split_init(AVBSFContext *ctx)
140 {
141 VP9SFSplitContext *s = ctx->priv_data;
142
143 s->buffer_pkt = av_packet_alloc();
144 if (!s->buffer_pkt)
145 return AVERROR(ENOMEM);
146
147 return 0;
148 }
149
vp9_superframe_split_flush(AVBSFContext *ctx)150 static void vp9_superframe_split_flush(AVBSFContext *ctx)
151 {
152 VP9SFSplitContext *s = ctx->priv_data;
153 av_packet_unref(s->buffer_pkt);
154 }
155
vp9_superframe_split_uninit(AVBSFContext *ctx)156 static void vp9_superframe_split_uninit(AVBSFContext *ctx)
157 {
158 VP9SFSplitContext *s = ctx->priv_data;
159 av_packet_free(&s->buffer_pkt);
160 }
161
162 const FFBitStreamFilter ff_vp9_superframe_split_bsf = {
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),
166 .init = vp9_superframe_split_init,
167 .flush = vp9_superframe_split_flush,
168 .close = vp9_superframe_split_uninit,
169 .filter = vp9_superframe_split_filter,
170 };
171