blob: 893573eb822988b0860bd84d95d57f38f9fa0f8f
1 | /* |
2 | * Copyright (c) 2013-2014 Mozilla Corporation |
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 | /** |
22 | * @file |
23 | * Opus parser |
24 | * |
25 | * Determines the duration for each packet. |
26 | */ |
27 | |
28 | #include "avcodec.h" |
29 | #include "bytestream.h" |
30 | #include "opus.h" |
31 | #include "parser.h" |
32 | |
33 | typedef struct OpusParseContext { |
34 | ParseContext pc; |
35 | OpusContext ctx; |
36 | OpusPacket pkt; |
37 | int extradata_parsed; |
38 | int ts_framing; |
39 | } OpusParseContext; |
40 | |
41 | static const uint8_t *parse_opus_ts_header(const uint8_t *start, int *payload_len, int buf_len) |
42 | { |
43 | const uint8_t *buf = start + 1; |
44 | int start_trim_flag, end_trim_flag, control_extension_flag, control_extension_length; |
45 | uint8_t flags; |
46 | |
47 | GetByteContext gb; |
48 | bytestream2_init(&gb, buf, buf_len); |
49 | |
50 | flags = bytestream2_get_byte(&gb); |
51 | start_trim_flag = (flags >> 4) & 1; |
52 | end_trim_flag = (flags >> 3) & 1; |
53 | control_extension_flag = (flags >> 2) & 1; |
54 | |
55 | *payload_len = 0; |
56 | while (bytestream2_peek_byte(&gb) == 0xff) |
57 | *payload_len += bytestream2_get_byte(&gb); |
58 | |
59 | *payload_len += bytestream2_get_byte(&gb); |
60 | |
61 | if (start_trim_flag) |
62 | bytestream2_skip(&gb, 2); |
63 | if (end_trim_flag) |
64 | bytestream2_skip(&gb, 2); |
65 | if (control_extension_flag) { |
66 | control_extension_length = bytestream2_get_byte(&gb); |
67 | bytestream2_skip(&gb, control_extension_length); |
68 | } |
69 | |
70 | return buf + bytestream2_tell(&gb); |
71 | } |
72 | |
73 | /** |
74 | * Find the end of the current frame in the bitstream. |
75 | * @return the position of the first byte of the next frame, or -1 |
76 | */ |
77 | static int opus_find_frame_end(AVCodecParserContext *ctx, AVCodecContext *avctx, |
78 | const uint8_t *buf, int buf_size, int *header_len) |
79 | { |
80 | OpusParseContext *s = ctx->priv_data; |
81 | ParseContext *pc = &s->pc; |
82 | int ret, start_found, i = 0, payload_len = 0; |
83 | const uint8_t *payload; |
84 | uint32_t state; |
85 | uint16_t hdr; |
86 | *header_len = 0; |
87 | |
88 | if (!buf_size) |
89 | return 0; |
90 | |
91 | start_found = pc->frame_start_found; |
92 | state = pc->state; |
93 | payload = buf; |
94 | |
95 | /* Check if we're using Opus in MPEG-TS framing */ |
96 | if (!s->ts_framing && buf_size > 2) { |
97 | hdr = AV_RB16(buf); |
98 | if ((hdr & OPUS_TS_MASK) == OPUS_TS_HEADER) |
99 | s->ts_framing = 1; |
100 | } |
101 | |
102 | if (s->ts_framing && !start_found) { |
103 | for (i = 0; i < buf_size-2; i++) { |
104 | state = (state << 8) | payload[i]; |
105 | if ((state & OPUS_TS_MASK) == OPUS_TS_HEADER) { |
106 | payload = parse_opus_ts_header(payload, &payload_len, buf_size - i); |
107 | *header_len = payload - buf; |
108 | start_found = 1; |
109 | break; |
110 | } |
111 | } |
112 | } |
113 | |
114 | if (!s->ts_framing) |
115 | payload_len = buf_size; |
116 | |
117 | if (avctx->extradata && !s->extradata_parsed) { |
118 | ret = ff_opus_parse_extradata(avctx, &s->ctx); |
119 | if (ret < 0) { |
120 | av_log(avctx, AV_LOG_ERROR, "Error parsing Ogg extradata.\n"); |
121 | return AVERROR_INVALIDDATA; |
122 | } |
123 | av_freep(&s->ctx.channel_maps); |
124 | s->extradata_parsed = 1; |
125 | } |
126 | |
127 | if (payload_len <= buf_size && (!s->ts_framing || start_found)) { |
128 | ret = ff_opus_parse_packet(&s->pkt, payload, payload_len, s->ctx.nb_streams > 1); |
129 | if (ret < 0) { |
130 | av_log(avctx, AV_LOG_ERROR, "Error parsing Opus packet header.\n"); |
131 | pc->frame_start_found = 0; |
132 | return AVERROR_INVALIDDATA; |
133 | } |
134 | |
135 | ctx->duration = s->pkt.frame_count * s->pkt.frame_duration; |
136 | } |
137 | |
138 | if (s->ts_framing) { |
139 | if (start_found) { |
140 | if (payload_len + *header_len <= buf_size) { |
141 | pc->frame_start_found = 0; |
142 | pc->state = -1; |
143 | return payload_len + *header_len; |
144 | } |
145 | } |
146 | |
147 | pc->frame_start_found = start_found; |
148 | pc->state = state; |
149 | return END_NOT_FOUND; |
150 | } |
151 | |
152 | return buf_size; |
153 | } |
154 | |
155 | static int opus_parse(AVCodecParserContext *ctx, AVCodecContext *avctx, |
156 | const uint8_t **poutbuf, int *poutbuf_size, |
157 | const uint8_t *buf, int buf_size) |
158 | { |
159 | OpusParseContext *s = ctx->priv_data; |
160 | ParseContext *pc = &s->pc; |
161 | int next, header_len; |
162 | |
163 | next = opus_find_frame_end(ctx, avctx, buf, buf_size, &header_len); |
164 | |
165 | if (s->ts_framing && next != AVERROR_INVALIDDATA && |
166 | ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
167 | *poutbuf = NULL; |
168 | *poutbuf_size = 0; |
169 | return buf_size; |
170 | } |
171 | |
172 | if (next == AVERROR_INVALIDDATA){ |
173 | *poutbuf = NULL; |
174 | *poutbuf_size = 0; |
175 | return buf_size; |
176 | } |
177 | |
178 | *poutbuf = buf + header_len; |
179 | *poutbuf_size = buf_size - header_len; |
180 | return next; |
181 | } |
182 | |
183 | AVCodecParser ff_opus_parser = { |
184 | .codec_ids = { AV_CODEC_ID_OPUS }, |
185 | .priv_data_size = sizeof(OpusParseContext), |
186 | .parser_parse = opus_parse, |
187 | .parser_close = ff_parse_close |
188 | }; |
189 |