1/*
2 * Copyright (C) 2008 Michael Niedermayer
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "libavutil/intreadwrite.h"
22#include "parser.h"
23
24typedef struct VP9ParseContext {
25    int n_frames; // 1-8
26    int size[8];
27} VP9ParseContext;
28
29static void parse_frame(AVCodecParserContext *ctx, const uint8_t *buf, int size)
30{
31    if (buf[0] & 0x4) {
32        ctx->pict_type = AV_PICTURE_TYPE_P;
33        ctx->key_frame = 0;
34    } else {
35        ctx->pict_type = AV_PICTURE_TYPE_I;
36        ctx->key_frame = 1;
37    }
38}
39
40static int parse(AVCodecParserContext *ctx,
41                 AVCodecContext *avctx,
42                 const uint8_t **out_data, int *out_size,
43                 const uint8_t *data, int size)
44{
45    VP9ParseContext *s = ctx->priv_data;
46    int marker;
47
48    if (size <= 0) {
49        *out_size = 0;
50        *out_data = data;
51
52        return 0;
53    }
54
55    if (s->n_frames > 0) {
56        *out_data = data;
57        *out_size = s->size[--s->n_frames];
58        parse_frame(ctx, *out_data, *out_size);
59
60        return s->n_frames > 0 ? *out_size : size /* i.e. include idx tail */;
61    }
62
63    marker = data[size - 1];
64    if ((marker & 0xe0) == 0xc0) {
65        int nbytes = 1 + ((marker >> 3) & 0x3);
66        int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
67
68        if (size >= idx_sz && data[size - idx_sz] == marker) {
69            const uint8_t *idx = data + size + 1 - idx_sz;
70            int first = 1;
71
72            switch (nbytes) {
73#define case_n(a, rd) \
74            case a: \
75                while (n_frames--) { \
76                    unsigned sz = rd; \
77                    idx += a; \
78                    if (sz > size) { \
79                        s->n_frames = 0; \
80                        av_log(avctx, AV_LOG_ERROR, \
81                               "Superframe packet size too big: %u > %d\n", \
82                               sz, size); \
83                        return size; \
84                    } \
85                    if (first) { \
86                        first = 0; \
87                        *out_data = data; \
88                        *out_size = sz; \
89                        s->n_frames = n_frames; \
90                    } else { \
91                        s->size[n_frames] = sz; \
92                    } \
93                    data += sz; \
94                    size -= sz; \
95                } \
96                parse_frame(ctx, *out_data, *out_size); \
97                return *out_size
98
99                case_n(1, *idx);
100                case_n(2, AV_RL16(idx));
101                case_n(3, AV_RL24(idx));
102                case_n(4, AV_RL32(idx));
103            }
104        }
105    }
106
107    *out_data = data;
108    *out_size = size;
109    parse_frame(ctx, data, size);
110
111    return size;
112}
113
114AVCodecParser ff_vp9_parser = {
115    .codec_ids      = { AV_CODEC_ID_VP9 },
116    .priv_data_size = sizeof(VP9ParseContext),
117    .parser_parse   = parse,
118};
119