mpegvideo_common.h

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * The simplest mpeg encoder (well, it was the simplest!)
 * Copyright (c) 2000,2001 Fabrice Bellard.
 * Copyright (c) 2002-2004 Michael Niedermayer <[e-mail]>
 *
 * 4MV & hq & B-frame encoding stuff by Michael Niedermayer <[e-mail]>
 *
 * 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
 */

/**
 * @file mpegvideo_common.h
 * The simplest mpeg encoder (well, it was the simplest!).
 */

#ifndef MPEGVIDEO_COMMON_H
#define MPEGVIDEO_COMMON_H

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "mjpegenc.h"
#include "msmpeg4.h"
#include "faandct.h"
#include <limits.h>

int dct_quantize_c(MpegEncContext *s, DCTELEM *block, int n, int qscale, int *overflow);
int dct_quantize_trellis_c(MpegEncContext *s, DCTELEM *block, int n, int qscale, int *overflow);
void  denoise_dct_c(MpegEncContext *s, DCTELEM *block);
void copy_picture(Picture *dst, Picture *src);

/**
 * allocates a Picture
 * The pixels are allocated/set by calling get_buffer() if shared=0
 */
int alloc_picture(MpegEncContext *s, Picture *pic, int shared);

/**
 * sets the given MpegEncContext to common defaults (same for encoding and decoding).
 * the changed fields will not depend upon the prior state of the MpegEncContext.
 */
void MPV_common_defaults(MpegEncContext *s);

static inline void gmc1_motion(MpegEncContext *s,
                               uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr,
                               uint8_t **ref_picture)
{
    uint8_t *ptr;
    int offset, src_x, src_y, linesize, uvlinesize;
    int motion_x, motion_y;
    int emu=0;

    motion_x= s->sprite_offset[0][0];
    motion_y= s->sprite_offset[0][1];
    src_x = s->mb_x * 16 + (motion_x >> (s->sprite_warping_accuracy+1));
    src_y = s->mb_y * 16 + (motion_y >> (s->sprite_warping_accuracy+1));
    motion_x<<=(3-s->sprite_warping_accuracy);
    motion_y<<=(3-s->sprite_warping_accuracy);
    src_x = av_clip(src_x, -16, s->width);
    if (src_x == s->width)
        motion_x =0;
    src_y = av_clip(src_y, -16, s->height);
    if (src_y == s->height)
        motion_y =0;

    linesize = s->linesize;
    uvlinesize = s->uvlinesize;

    ptr = ref_picture[0] + (src_y * linesize) + src_x;

    if(s->flags&CODEC_FLAG_EMU_EDGE){
        if(   (unsigned)src_x >= s->h_edge_pos - 17
           || (unsigned)src_y >= s->v_edge_pos - 17){
            ff_emulated_edge_mc(s->edge_emu_buffer, ptr, linesize, 17, 17, src_x, src_y, s->h_edge_pos, s->v_edge_pos);
            ptr= s->edge_emu_buffer;
        }
    }

    if((motion_x|motion_y)&7){
        s->dsp.gmc1(dest_y  , ptr  , linesize, 16, motion_x&15, motion_y&15, 128 - s->no_rounding);
        s->dsp.gmc1(dest_y+8, ptr+8, linesize, 16, motion_x&15, motion_y&15, 128 - s->no_rounding);
    }else{
        int dxy;

        dxy= ((motion_x>>3)&1) | ((motion_y>>2)&2);
        if (s->no_rounding){
            s->dsp.put_no_rnd_pixels_tab[0][dxy](dest_y, ptr, linesize, 16);
        }else{
            s->dsp.put_pixels_tab       [0][dxy](dest_y, ptr, linesize, 16);
        }
    }

    if(ENABLE_GRAY && s->flags&CODEC_FLAG_GRAY) return;

    motion_x= s->sprite_offset[1][0];
    motion_y= s->sprite_offset[1][1];
    src_x = s->mb_x * 8 + (motion_x >> (s->sprite_warping_accuracy+1));
    src_y = s->mb_y * 8 + (motion_y >> (s->sprite_warping_accuracy+1));
    motion_x<<=(3-s->sprite_warping_accuracy);
    motion_y<<=(3-s->sprite_warping_accuracy);
    src_x = av_clip(src_x, -8, s->width>>1);
    if (src_x == s->width>>1)
        motion_x =0;
    src_y = av_clip(src_y, -8, s->height>>1);
    if (src_y == s->height>>1)
        motion_y =0;

    offset = (src_y * uvlinesize) + src_x;
    ptr = ref_picture[1] + offset;
    if(s->flags&CODEC_FLAG_EMU_EDGE){
        if(   (unsigned)src_x >= (s->h_edge_pos>>1) - 9
           || (unsigned)src_y >= (s->v_edge_pos>>1) - 9){
            ff_emulated_edge_mc(s->edge_emu_buffer, ptr, uvlinesize, 9, 9, src_x, src_y, s->h_edge_pos>>1, s->v_edge_pos>>1);
            ptr= s->edge_emu_buffer;
            emu=1;
        }
    }
    s->dsp.gmc1(dest_cb, ptr, uvlinesize, 8, motion_x&15, motion_y&15, 128 - s->no_rounding);

    ptr = ref_picture[2] + offset;
    if(emu){
        ff_emulated_edge_mc(s->edge_emu_buffer, ptr, uvlinesize, 9, 9, src_x, src_y, s->h_edge_pos>>1, s->v_edge_pos>>1);
        ptr= s->edge_emu_buffer;
    }
    s->dsp.gmc1(dest_cr, ptr, uvlinesize, 8, motion_x&15, motion_y&15, 128 - s->no_rounding);

    return;
}

static inline void gmc_motion(MpegEncContext *s,
                               uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr,
                               uint8_t **ref_picture)
{
    uint8_t *ptr;
    int linesize, uvlinesize;
    const int a= s->sprite_warping_accuracy;
    int ox, oy;

    linesize = s->linesize;
    uvlinesize = s->uvlinesize;

    ptr = ref_picture[0];

    ox= s->sprite_offset[0][0] + s->sprite_delta[0][0]*s->mb_x*16 + s->sprite_delta[0][1]*s->mb_y*16;
    oy= s->sprite_offset[0][1] + s->sprite_delta[1][0]*s->mb_x*16 + s->sprite_delta[1][1]*s->mb_y*16;

    s->dsp.gmc(dest_y, ptr, linesize, 16,
           ox,
           oy,
           s->sprite_delta[0][0], s->sprite_delta[0][1],
           s->sprite_delta[1][0], s->sprite_delta[1][1],
           a+1, (1<<(2*a+1)) - s->no_rounding,
           s->h_edge_pos, s->v_edge_pos);
    s->dsp.gmc(dest_y+8, ptr, linesize, 16,
           ox + s->sprite_delta[0][0]*8,
           oy + s->sprite_delta[1][0]*8,
           s->sprite_delta[0][0], s->sprite_delta[0][1],
           s->sprite_delta[1][0], s->sprite_delta[1][1],
           a+1, (1<<(2*a+1)) - s->no_rounding,
           s->h_edge_pos, s->v_edge_pos);

    if(ENABLE_GRAY && s->flags&CODEC_FLAG_GRAY) return;

    ox= s->sprite_offset[1][0] + s->sprite_delta[0][0]*s->mb_x*8 + s->sprite_delta[0][1]*s->mb_y*8;
    oy= s->sprite_offset[1][1] + s->sprite_delta[1][0]*s->mb_x*8 + s->sprite_delta[1][1]*s->mb_y*8;

    ptr = ref_picture[1];
    s->dsp.gmc(dest_cb, ptr, uvlinesize, 8,
           ox,
           oy,
           s->sprite_delta[0][0], s->sprite_delta[0][1],
           s->sprite_delta[1][0], s->sprite_delta[1][1],
           a+1, (1<<(2*a+1)) - s->no_rounding,
           s->h_edge_pos>>1, s->v_edge_pos>>1);

    ptr = ref_picture[2];
    s->dsp.gmc(dest_cr, ptr, uvlinesize, 8,
           ox,
           oy,
           s->sprite_delta[0][0], s->sprite_delta[0][1],
           s->sprite_delta[1][0], s->sprite_delta[1][1],
           a+1, (1<<(2*a+1)) - s->no_rounding,
           s->h_edge_pos>>1, s->v_edge_pos>>1);
}

static inline int hpel_motion(MpegEncContext *s,
                                  uint8_t *dest, uint8_t *src,
                                  int field_based, int field_select,
                                  int src_x, int src_y,
                                  int width, int height, int stride,
                                  int h_edge_pos, int v_edge_pos,
                                  int w, int h, op_pixels_func *pix_op,
                                  int motion_x, int motion_y)
{
    int dxy;
    int emu=0;

    dxy = ((motion_y & 1) << 1) | (motion_x & 1);
    src_x += motion_x >> 1;
    src_y += motion_y >> 1;

    /* WARNING: do no forget half pels */
    src_x = av_clip(src_x, -16, width); //FIXME unneeded for emu?
    if (src_x == width)
        dxy &= ~1;
    src_y = av_clip(src_y, -16, height);
    if (src_y == height)
        dxy &= ~2;
    src += src_y * stride + src_x;

    if(s->unrestricted_mv && (s->flags&CODEC_FLAG_EMU_EDGE)){
        if(   (unsigned)src_x > h_edge_pos - (motion_x&1) - w
           || (unsigned)src_y > v_edge_pos - (motion_y&1) - h){
            ff_emulated_edge_mc(s->edge_emu_buffer, src, s->linesize, w+1, (h+1)<<field_based,
                             src_x, src_y<<field_based, h_edge_pos, s->v_edge_pos);
            src= s->edge_emu_buffer;
            emu=1;
        }
    }
    if(field_select)
        src += s->linesize;
    pix_op[dxy](dest, src, stride, h);
    return emu;
}

/* apply one mpeg motion vector to the three components */
static av_always_inline void mpeg_motion(MpegEncContext *s,
                               uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr,
                               int field_based, int bottom_field, int field_select,
                               uint8_t **ref_picture, op_pixels_func (*pix_op)[4],
                               int motion_x, int motion_y, int h)
{
    uint8_t *ptr_y, *ptr_cb, *ptr_cr;
    int dxy, uvdxy, mx, my, src_x, src_y, uvsrc_x, uvsrc_y, v_edge_pos, uvlinesize, linesize;

#if 0
if(s->quarter_sample)
{
    motion_x>>=1;
    motion_y>>=1;
}
#endif

    v_edge_pos = s->v_edge_pos >> field_based;
    linesize   = s->current_picture.linesize[0] << field_based;
    uvlinesize = s->current_picture.linesize[1] << field_based;

    dxy = ((motion_y & 1) << 1) | (motion_x & 1);
    src_x = s->mb_x* 16               + (motion_x >> 1);
    src_y =(s->mb_y<<(4-field_based)) + (motion_y >> 1);

    if (s->out_format == FMT_H263) {
        if((s->workaround_bugs & FF_BUG_HPEL_CHROMA) && field_based){
            mx = (motion_x>>1)|(motion_x&1);
            my = motion_y >>1;
            uvdxy = ((my & 1) << 1) | (mx & 1);
            uvsrc_x = s->mb_x* 8               + (mx >> 1);
            uvsrc_y = (s->mb_y<<(3-field_based)) + (my >> 1);
        }else{
            uvdxy = dxy | (motion_y & 2) | ((motion_x & 2) >> 1);
            uvsrc_x = src_x>>1;
            uvsrc_y = src_y>>1;
        }
    }else if(s->out_format == FMT_H261){//even chroma mv's are full pel in H261
        mx = motion_x / 4;