mirror of https://git.ffmpeg.org/ffmpeg.git
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/*
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* AVS2/IEEE 1857.4 video parser.
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* Copyright (c) 2018 Huiwen Ren <hwrenx@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "parser.h"
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#define SLICE_MAX_START_CODE 0x000001af
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#define ISPIC(x) ((x) == 0xB3 || (x) == 0xB6)
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#define ISUNIT(x) ((x) == 0xB0 || (x) == 0xB1 || (x) == 0xB2 || ISPIC(x))
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static int avs2_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
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{
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int pic_found = pc->frame_start_found;
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uint32_t state = pc->state;
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int cur = 0;
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if (!pic_found) {
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for (; cur < buf_size; ++cur) {
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state = (state<<8) | buf[cur];
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if (ISUNIT(buf[cur])){
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++cur;
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pic_found = 1;
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break;
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}
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}
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}
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if (pic_found) {
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if (!buf_size)
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return END_NOT_FOUND;
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for (; cur < buf_size; ++cur) {
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state = (state << 8) | buf[cur];
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if ((state & 0xFFFFFF00) == 0x100 && state > SLICE_MAX_START_CODE) {
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pc->frame_start_found = 0;
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pc->state = -1;
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return cur - 3;
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}
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}
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}
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pc->frame_start_found = pic_found;
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pc->state = state;
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return END_NOT_FOUND;
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}
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static int avs2_parse(AVCodecParserContext *s, AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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ParseContext *pc = s->priv_data;
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int next;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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next = avs2_find_frame_end(pc, buf, buf_size);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_avs2_parser = {
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.codec_ids = { AV_CODEC_ID_AVS2 },
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.priv_data_size = sizeof(ParseContext),
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.parser_parse = avs2_parse,
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.parser_close = ff_parse_close,
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.split = ff_mpeg4video_split,
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};
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