| 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 "opus.h" |
| 30 | #include "parser.h" |
| 31 | #include "bytestream.h" |
| 32 | |
| 33 | typedef struct OpusParseContext { |
| 34 | OpusContext ctx; |
| 35 | OpusPacket pkt; |
| 36 | int extradata_parsed; |
| 37 | ParseContext pc; |
| 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 | }; |