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![Guillaume Martres](/assets/img/avatar_default.png)
Initially written by Guillaume Martres <smarter@ubuntu.com> as a GSoC project. Further contributions by the OpenHEVC project and other developers, namely: Mickaël Raulet <mraulet@insa-rennes.fr> Seppo Tomperi <seppo.tomperi@vtt.fi> Gildas Cocherel <gildas.cocherel@laposte.net> Khaled Jerbi <khaled_jerbi@yahoo.fr> Wassim Hamidouche <wassim.hamidouche@insa-rennes.fr> Vittorio Giovara <vittorio.giovara@gmail.com> Jan Ekström <jeebjp@gmail.com> Anton Khirnov <anton@khirnov.net> Martin Storsjö <martin@martin.st> Luca Barbato <lu_zero@gentoo.org> Yusuke Nakamura <muken.the.vfrmaniac@gmail.com> Reimar Döffinger <Reimar.Doeffinger@gmx.de> Diego Biurrun <diego@biurrun.de> Signed-off-by: Anton Khirnov <anton@khirnov.net>
126 lines
3.9 KiB
C
126 lines
3.9 KiB
C
/*
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* HEVC Annex B format parser
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*
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* Copyright (C) 2012 - 2013 Guillaume Martres
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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 "libavutil/common.h"
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#include "parser.h"
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#include "hevc.h"
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#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
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/**
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* Find the end of the current frame in the bitstream.
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* @return the position of the first byte of the next frame, or END_NOT_FOUND
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*/
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static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
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int buf_size)
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{
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int i;
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ParseContext *pc = s->priv_data;
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for (i = 0; i < buf_size; i++) {
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int nut;
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pc->state64 = (pc->state64 << 8) | buf[i];
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if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
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continue;
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nut = (pc->state64 >> 2 * 8 + 1) & 0x3F;
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// Beginning of access unit
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if ((nut >= NAL_VPS && nut <= NAL_AUD) || nut == NAL_SEI_PREFIX ||
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(nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
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if (pc->frame_start_found) {
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pc->frame_start_found = 0;
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return i - 5;
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}
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} else if (nut <= NAL_RASL_R ||
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(nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT)) {
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int first_slice_segment_in_pic_flag = buf[i] >> 7;
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if (first_slice_segment_in_pic_flag) {
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if (!pc->frame_start_found) {
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pc->frame_start_found = 1;
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s->key_frame = nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT;
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} else { // First slice of next frame found
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pc->frame_start_found = 0;
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return i - 5;
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}
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}
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}
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}
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return END_NOT_FOUND;
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}
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static int hevc_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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int next;
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ParseContext *pc = s->priv_data;
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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 = hevc_find_frame_end(s, 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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// Split after the parameter sets at the beginning of the stream if they exist.
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static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
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{
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int i;
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uint32_t state = -1;
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int has_ps = 0;
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for (i = 0; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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if (((state >> 8) & 0xFFFFFF) == START_CODE) {
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int nut = (state >> 1) & 0x3F;
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if (nut >= NAL_VPS && nut <= NAL_PPS)
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has_ps = 1;
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else if (has_ps)
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return i - 3;
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else // no parameter set at the beginning of the stream
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return 0;
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}
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}
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return 0;
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}
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AVCodecParser ff_hevc_parser = {
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.codec_ids = { AV_CODEC_ID_HEVC },
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.priv_data_size = sizeof(ParseContext),
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.parser_parse = hevc_parse,
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.parser_close = ff_parse_close,
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.split = hevc_split,
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};
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