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/*
* MPEG-4 encoder/decoder internal header.
* Copyright (c) 2000,2001 Fabrice Bellard
* Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_MPEG4VIDEO_H
#define AVCODEC_MPEG4VIDEO_H
#include <stdint.h>
#include "mpegvideo.h"
void ff_mpeg4_clean_buffers(MpegEncContext *s);
int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s);
void ff_mpeg4_init_direct_mv(MpegEncContext *s);
/**
* @return the mb_type
*/
int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
#if 0 //3IV1 is quite rare and it slows things down a tiny bit
#define IS_3IV1 s->codec_tag == AV_RL32("3IV1")
#else
#define IS_3IV1 0
#endif
/**
* Predict the dc.
* encoding quantized level -> quantized diff
* decoding quantized diff -> quantized level
* @param n block index (0-3 are luma, 4-5 are chroma)
* @param dir_ptr pointer to an integer where the prediction direction will be stored
*/
static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level,
int *dir_ptr, int encoding)
{
int a, b, c, wrap, pred, scale, ret;
int16_t *dc_val;
/* find prediction */
if (n < 4)
scale = s->y_dc_scale;
else
scale = s->c_dc_scale;
if (IS_3IV1)
scale = 8;
wrap = s->block_wrap[n];
dc_val = s->dc_val[0] + s->block_index[n];
/* B C
* A X
*/
a = dc_val[-1];
b = dc_val[-1 - wrap];
c = dc_val[-wrap];
/* outside slice handling (we can't do that by memset as we need the
* dc for error resilience) */
if (s->first_slice_line && n != 3) {
if (n != 2)
b = c = 1024;
if (n != 1 && s->mb_x == s->resync_mb_x)
b = a = 1024;
}
if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
if (n == 0 || n == 4 || n == 5)
b = 1024;
}
if (abs(a - b) < abs(b - c)) {
pred = c;
*dir_ptr = 1; /* top */
} else {
pred = a;
*dir_ptr = 0; /* left */
}
/* we assume pred is positive */
pred = FASTDIV((pred + (scale >> 1)), scale);
if (encoding) {
ret = level - pred;
} else {
level += pred;
ret = level;
}
level *= scale;
if (level & (~2047)) {
if (!s->encoding && (s->avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_AGGRESSIVE))) {
if (level < 0) {
av_log(s->avctx, AV_LOG_ERROR,
"dc<0 at %dx%d\n", s->mb_x, s->mb_y);
return AVERROR_INVALIDDATA;
}
if (level > 2048 + scale) {
av_log(s->avctx, AV_LOG_ERROR,
"dc overflow at %dx%d\n", s->mb_x, s->mb_y);
return AVERROR_INVALIDDATA;
}
}
if (level < 0)
level = 0;
else if (!(s->workaround_bugs & FF_BUG_DC_CLIP))
level = 2047;
}
dc_val[0] = level;
return ret;
}
#endif /* AVCODEC_MPEG4VIDEO_H */
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