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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * H261 parser |
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| 3 | * Copyright (c) 2002-2004 Michael Niedermayer |
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| 4 | * Copyright (c) 2004 Maarten Daniels |
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| 5 | * |
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| 6 | * This file is part of FFmpeg. |
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| 7 | * |
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| 8 | * FFmpeg is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of the GNU Lesser General Public |
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| 10 | * License as published by the Free Software Foundation; either |
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| 11 | * version 2.1 of the License, or (at your option) any later version. |
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| 12 | * |
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| 13 | * FFmpeg is distributed in the hope that it will be useful, |
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 16 | * Lesser General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU Lesser General Public |
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| 19 | * License along with FFmpeg; if not, write to the Free Software |
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| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 21 | */ |
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| 22 | |||
| 23 | /** |
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| 24 | * @file |
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| 25 | * h261codec. |
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| 26 | */ |
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| 27 | |||
| 28 | #include "parser.h" |
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| 29 | |||
| 30 | static int h261_find_frame_end(ParseContext *pc, AVCodecContext *avctx, |
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| 31 | const uint8_t *buf, int buf_size) |
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| 32 | { |
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| 33 | int vop_found, i, j; |
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| 34 | uint32_t state; |
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| 35 | |||
| 36 | vop_found = pc->frame_start_found; |
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| 37 | state = pc->state; |
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| 38 | |||
| 39 | for (i = 0; i < buf_size && !vop_found; i++) { |
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| 40 | state = (state << 8) | buf[i]; |
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| 41 | for (j = 0; j < 8; j++) { |
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| 42 | if (((state >> j) & 0xFFFFF0) == 0x000100) { |
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| 43 | vop_found = 1; |
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| 44 | break; |
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| 45 | } |
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| 46 | } |
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| 47 | } |
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| 48 | if (vop_found) { |
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| 49 | for (; i < buf_size; i++) { |
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| 50 | state = (state << 8) | buf[i]; |
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| 51 | for (j = 0; j < 8; j++) { |
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| 52 | if (((state >> j) & 0xFFFFF0) == 0x000100) { |
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| 53 | pc->frame_start_found = 0; |
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| 54 | pc->state = (state >> (3 * 8)) + 0xFF00; |
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| 55 | return i - 2; |
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| 56 | } |
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| 57 | } |
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| 58 | } |
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| 59 | } |
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| 60 | |||
| 61 | pc->frame_start_found = vop_found; |
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| 62 | pc->state = state; |
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| 63 | return END_NOT_FOUND; |
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| 64 | } |
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| 65 | |||
| 66 | static int h261_parse(AVCodecParserContext *s, |
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| 67 | AVCodecContext *avctx, |
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| 68 | const uint8_t **poutbuf, int *poutbuf_size, |
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| 69 | const uint8_t *buf, int buf_size) |
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| 70 | { |
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| 71 | ParseContext *pc = s->priv_data; |
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| 72 | int next; |
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| 73 | |||
| 74 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
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| 75 | next = buf_size; |
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| 76 | } else { |
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| 77 | next = h261_find_frame_end(pc, avctx, buf, buf_size); |
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| 78 | if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
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| 79 | *poutbuf = NULL; |
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| 80 | *poutbuf_size = 0; |
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| 81 | return buf_size; |
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| 82 | } |
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| 83 | } |
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| 84 | *poutbuf = buf; |
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| 85 | *poutbuf_size = buf_size; |
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| 86 | return next; |
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| 87 | } |
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| 88 | |||
| 89 | AVCodecParser ff_h261_parser = { |
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| 90 | .codec_ids = { AV_CODEC_ID_H261 }, |
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| 91 | .priv_data_size = sizeof(ParseContext), |
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| 92 | .parser_parse = h261_parse, |
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| 93 | .parser_close = ff_parse_close, |
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| 94 | }; |