mirror of https://git.ffmpeg.org/ffmpeg.git
130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/*
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* MPEG-4 encoder/decoder internal header.
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* Copyright (c) 2000,2001 Fabrice Bellard
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* Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
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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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#ifndef AVCODEC_MPEG4VIDEO_H
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#define AVCODEC_MPEG4VIDEO_H
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#include <stdint.h>
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#include "mpegvideo.h"
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void ff_mpeg4_clean_buffers(MpegEncContext *s);
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int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s);
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void ff_mpeg4_init_direct_mv(MpegEncContext *s);
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/**
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* @return the mb_type
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*/
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int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
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#if 0 //3IV1 is quite rare and it slows things down a tiny bit
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#define IS_3IV1 s->codec_tag == AV_RL32("3IV1")
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#else
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#define IS_3IV1 0
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#endif
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/**
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* Predict the dc.
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* encoding quantized level -> quantized diff
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* decoding quantized diff -> quantized level
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* @param n block index (0-3 are luma, 4-5 are chroma)
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* @param dir_ptr pointer to an integer where the prediction direction will be stored
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*/
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static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level,
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int *dir_ptr, int encoding)
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{
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int a, b, c, wrap, pred, scale, ret;
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int16_t *dc_val;
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/* find prediction */
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if (n < 4)
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scale = s->y_dc_scale;
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else
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scale = s->c_dc_scale;
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if (IS_3IV1)
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scale = 8;
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wrap = s->block_wrap[n];
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dc_val = s->dc_val[0] + s->block_index[n];
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/* B C
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* A X
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*/
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a = dc_val[-1];
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b = dc_val[-1 - wrap];
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c = dc_val[-wrap];
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/* outside slice handling (we can't do that by memset as we need the
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* dc for error resilience) */
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if (s->first_slice_line && n != 3) {
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if (n != 2)
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b = c = 1024;
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if (n != 1 && s->mb_x == s->resync_mb_x)
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b = a = 1024;
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}
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if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
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if (n == 0 || n == 4 || n == 5)
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b = 1024;
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}
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if (abs(a - b) < abs(b - c)) {
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pred = c;
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*dir_ptr = 1; /* top */
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} else {
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pred = a;
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*dir_ptr = 0; /* left */
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}
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/* we assume pred is positive */
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pred = FASTDIV((pred + (scale >> 1)), scale);
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if (encoding) {
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ret = level - pred;
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} else {
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level += pred;
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ret = level;
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}
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level *= scale;
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if (level & (~2047)) {
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if (!s->encoding && (s->avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_AGGRESSIVE))) {
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if (level < 0) {
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av_log(s->avctx, AV_LOG_ERROR,
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"dc<0 at %dx%d\n", s->mb_x, s->mb_y);
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return AVERROR_INVALIDDATA;
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}
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if (level > 2048 + scale) {
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av_log(s->avctx, AV_LOG_ERROR,
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"dc overflow at %dx%d\n", s->mb_x, s->mb_y);
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return AVERROR_INVALIDDATA;
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}
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}
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if (level < 0)
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level = 0;
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else if (!(s->workaround_bugs & FF_BUG_DC_CLIP))
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level = 2047;
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}
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dc_val[0] = level;
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return ret;
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}
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#endif /* AVCODEC_MPEG4VIDEO_H */
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