mpegvideo_enc.c

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_enc.c
 * The simplest mpeg encoder (well, it was the simplest!).
 */

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "mpegvideo_common.h"
#include "mjpegenc.h"
#include "msmpeg4.h"
#include "h263.h"
#include "faandct.h"
#include <limits.h>

//#undef NDEBUG
//#include <assert.h>

static int encode_picture(MpegEncContext *s, int picture_number);
static int dct_quantize_refine(MpegEncContext *s, DCTELEM *block, int16_t *weight, DCTELEM *orig, int n, int qscale);
static int sse_mb(MpegEncContext *s);

/* enable all paranoid tests for rounding, overflows, etc... */
//#define PARANOID

//#define DEBUG

static const uint16_t aanscales[64] = {
    /* precomputed values scaled up by 14 bits */
    16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
    22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
    21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
    19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
    16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
    12873, 17855, 16819, 15137, 12873, 10114,  6967,  3552,
    8867 , 12299, 11585, 10426,  8867,  6967,  4799,  2446,
    4520 ,  6270,  5906,  5315,  4520,  3552,  2446,  1247
};

static uint8_t default_mv_penalty[MAX_FCODE+1][MAX_MV*2+1];
static uint8_t default_fcode_tab[MAX_MV*2+1];

enum PixelFormat ff_yuv420p_list[2]= {PIX_FMT_YUV420P, -1};

static void convert_matrix(DSPContext *dsp, int (*qmat)[64], uint16_t (*qmat16)[2][64],
                           const uint16_t *quant_matrix, int bias, int qmin, int qmax, int intra)
{
    int qscale;
    int shift=0;

    for(qscale=qmin; qscale<=qmax; qscale++){
        int i;
        if (dsp->fdct == ff_jpeg_fdct_islow
#ifdef FAAN_POSTSCALE
            || dsp->fdct == ff_faandct
#endif
            ) {
            for(i=0;i<64;i++) {
                const int j= dsp->idct_permutation[i];
                /* 16 <= qscale * quant_matrix[i] <= 7905 */
                /* 19952         <= aanscales[i] * qscale * quant_matrix[i]           <= 249205026 */
                /* (1<<36)/19952 >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= (1<<36)/249205026 */
                /* 3444240       >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= 275 */

                qmat[qscale][i] = (int)((UINT64_C(1) << QMAT_SHIFT) /
                                (qscale * quant_matrix[j]));
            }
        } else if (dsp->fdct == fdct_ifast
#ifndef FAAN_POSTSCALE
                   || dsp->fdct == ff_faandct
#endif
                   ) {
            for(i=0;i<64;i++) {
                const int j= dsp->idct_permutation[i];
                /* 16 <= qscale * quant_matrix[i] <= 7905 */
                /* 19952         <= aanscales[i] * qscale * quant_matrix[i]           <= 249205026 */
                /* (1<<36)/19952 >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= (1<<36)/249205026 */
                /* 3444240       >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= 275 */

                qmat[qscale][i] = (int)((UINT64_C(1) << (QMAT_SHIFT + 14)) /
                                (aanscales[i] * qscale * quant_matrix[j]));
            }
        } else {
            for(i=0;i<64;i++) {
                const int j= dsp->idct_permutation[i];
                /* We can safely suppose that 16 <= quant_matrix[i] <= 255
                   So 16           <= qscale * quant_matrix[i]             <= 7905
                   so (1<<19) / 16 >= (1<<19) / (qscale * quant_matrix[i]) >= (1<<19) / 7905
                   so 32768        >= (1<<19) / (qscale * quant_matrix[i]) >= 67
                */
                qmat[qscale][i] = (int)((UINT64_C(1) << QMAT_SHIFT) / (qscale * quant_matrix[j]));
//                qmat  [qscale][i] = (1 << QMAT_SHIFT_MMX) / (qscale * quant_matrix[i]);
                qmat16[qscale][0][i] = (1 << QMAT_SHIFT_MMX) / (qscale * quant_matrix[j]);

                if(qmat16[qscale][0][i]==0 || qmat16[qscale][0][i]==128*256) qmat16[qscale][0][i]=128*256-1;
                qmat16[qscale][1][i]= ROUNDED_DIV(bias<<(16-QUANT_BIAS_SHIFT), qmat16[qscale][0][i]);
            }
        }

        for(i=intra; i<64; i++){
            int64_t max= 8191;
            if (dsp->fdct == fdct_ifast
#ifndef FAAN_POSTSCALE
                   || dsp->fdct == ff_faandct
#endif
                   ) {
                max= (8191LL*aanscales[i]) >> 14;
            }
            while(((max * qmat[qscale][i]) >> shift) > INT_MAX){
                shift++;
            }
        }
    }
    if(shift){
        av_log(NULL, AV_LOG_INFO, "Warning, QMAT_SHIFT is larger than %d, overflows possible\n", QMAT_SHIFT - shift);
    }
}

static inline void update_qscale(MpegEncContext *s){
    s->qscale= (s->lambda*139 + FF_LAMBDA_SCALE*64) >> (FF_LAMBDA_SHIFT + 7);
    s->qscale= av_clip(s->qscale, s->avctx->qmin, s->avctx->qmax);

    s->lambda2= (s->lambda*s->lambda + FF_LAMBDA_SCALE/2) >> FF_LAMBDA_SHIFT;
}

void ff_write_quant_matrix(PutBitContext *pb, uint16_t *matrix){
    int i;

    if(matrix){
        put_bits(pb, 1, 1);
        for(i=0;i<64;i++) {
            put_bits(pb, 8, matrix[ ff_zigzag_direct[i] ]);
        }
    }else
        put_bits(pb, 1, 0);
}

static void copy_picture_attributes(MpegEncContext *s, AVFrame *dst, AVFrame *src){
    int i;

    dst->pict_type              = src->pict_type;
    dst->quality                = src->quality;
    dst->coded_picture_number   = src->coded_picture_number;
    dst->display_picture_number = src->display_picture_number;
//    dst->reference              = src->reference;
    dst->pts                    = src->pts;
    dst->interlaced_frame       = src->interlaced_frame;
    dst->top_field_first        = src->top_field_first;

    if(s->avctx->me_threshold){
        if(!src->motion_val[0])
            av_log(s->avctx, AV_LOG_ERROR, "AVFrame.motion_val not set!\n");
        if(!src->mb_type)
            av_log(s->avctx, AV_LOG_ERROR, "AVFrame.mb_type not set!\n");
        if(!src->ref_index[0])
            av_log(s->avctx, AV_LOG_ERROR, "AVFrame.ref_index not set!\n");
        if(src->motion_subsample_log2 != dst->motion_subsample_log2)
            av_log(s->avctx, AV_LOG_ERROR, "AVFrame.motion_subsample_log2 doesn't match! (%d!=%d)\n",
            src->motion_subsample_log2, dst->motion_subsample_log2);

        memcpy(dst->mb_type, src->mb_type, s->mb_stride * s->mb_height * sizeof(dst->mb_type[0]));

        for(i=0; i<2; i++){
            int stride= ((16*s->mb_width )>>src->motion_subsample_log2) + 1;
            int height= ((16*s->mb_height)>>src->motion_subsample_log2);

            if(src->motion_val[i] && src->motion_val[i] != dst->motion_val[i]){
                memcpy(dst->motion_val[i], src->motion_val[i], 2*stride*height*sizeof(int16_t));
            }
            if(src->ref_index[i] && src->ref_index[i] != dst->ref_index[i]){
                memcpy(dst->ref_index[i], src->ref_index[i], s->b8_stride*2*s->mb_height*sizeof(int8_t));
            }
        }
    }
}

static void update_duplicate_context_after_me(MpegEncContext *dst, MpegEncContext *src){
#define COPY(a) dst->a= src->a
    COPY(pict_type);
    COPY(current_picture);
    COPY(f_code);
    COPY(b_code);
    COPY(qscale);
    COPY(lambda);
    COPY(lambda2);
    COPY(picture_in_gop_number);
    COPY(gop_picture_number);
    COPY(frame_pred_frame_dct); //FIXME don't set in encode_header
    COPY(progressive_frame); //FIXME don't set in encode_header
    COPY(partitioned_frame); //FIXME don't set in encode_header
#undef COPY
}

/**
 * sets the given MpegEncContext to defaults for encoding.
 * the changed fields will not depend upon the prior state of the MpegEncContext.
 */
static void MPV_encode_defaults(MpegEncContext *s){
    int i;
    MPV_common_defaults(s);

    for(i=-16; i<16; i++){
        default_fcode_tab[i + MAX_MV]= 1;
    }
    s->me.mv_penalty= default_mv_penalty;
    s->fcode_tab= default_fcode_tab;
}

/* init video encoder */
int MPV_encode_init(AVCodecContext *avctx)
{
    MpegEncContext *s = avctx->priv_data;
    int i;
    int chroma_h_shift, chroma_v_shift;

    MPV_encode_defaults(s);

    switch (avctx->codec_id) {
    case CODEC_ID_MPEG2VIDEO:
        if(avctx->pix_fmt != PIX_FMT_YUV420P && avctx->pix_fmt != PIX_FMT_YUV422P){
            av_log(avctx, AV_LOG_ERROR, "only YUV420 and YUV422 are supported\n");
            return -1;
        }
        break;
    case CODEC_ID_LJPEG:
    case CODEC_ID_MJPEG:
        if(avctx->pix_fmt != PIX_FMT_YUVJ420P && avctx->pix_fmt != PIX_FMT_YUVJ422P &&
           ((avctx->pix_fmt != PIX_FMT_YUV420P && avctx->pix_fmt != PIX_FMT_YUV422P) || avctx->strict_std_compliance>FF_COMPLIANCE_INOFFICIAL)){
            av_log(avctx, AV_LOG_ERROR, "colorspace not supported in jpeg\n");
            return -1;
        }
        break;
    default:
        if(avctx->pix_fmt != PIX_FMT_YUV420P){
            av_log(avctx, AV_LOG_ERROR, "only YUV420 is supported\n");
            return -1;
        }
    }

    switch (avctx->pix_fmt) {
    case PIX_FMT_YUVJ422P:
    case PIX_FMT_YUV422P:
        s->chroma_format = CHROMA_422;
        break;
    case PIX_FMT_YUVJ420P:
    case PIX_FMT_YUV420P:
    default:
        s->chroma_format = CHROMA_420;
        break;
    }

    s->bit_rate = avctx->bit_rate;
    s->width = avctx->width;
    s->height = avctx->height;
    if(avctx->gop_size > 600 && avctx->strict_std_compliance>FF_COMPLIANCE_EXPERIMENTAL){
        av_log(avctx, AV_LOG_ERROR, "Warning keyframe interval too large! reducing it ...\n");
        avctx->gop_size=600;
    }
    s->gop_size = avctx->gop_size;
    s->avctx = avctx;
    s->flags= avctx->flags;
    s->flags2= avctx->flags2;
    s->max_b_frames= avctx->max_b_frames;
    s->codec_id= avctx->codec->id;
    s->luma_elim_threshold  = avctx->luma_elim_threshold;
    s->chroma_elim_threshold= avctx->chroma_elim_threshold;
    s->strict_std_compliance= avctx->strict_std_compliance;
    s->data_partitioning= avctx->flags & CODEC_FLAG_PART;
    s->quarter_sample= (avctx->flags & CODEC_FLAG_QPEL)!=0;
    s->mpeg_quant= avctx->mpeg_quant;
    s->rtp_mode= !!avctx->rtp_payload_size;
    s->intra_dc_precision= avctx->intra_dc_precision;
    s->user_specified_pts = AV_NOPTS_VALUE;

    if (s->gop_size <= 1) {
        s->intra_only = 1;
        s->gop_size = 12;
    } else {
        s->intra_only = 0;
    }

    s->me_method = avctx->me_method;

    /* Fixed QSCALE */
    s->fixed_qscale = !!(avctx->flags & CODEC_FLAG_QSCALE);

    s->adaptive_quant= (   s->avctx->lumi_masking
                        || s->avctx->dark_masking
                        || s->avctx->temporal_cplx_masking
                        || s->avctx->spatial_cplx_masking
                        || s->avctx->p_masking
                        || s->avctx->border_masking
                        || (s->flags&CODEC_FLAG_QP_RD))
                       && !s->fixed_qscale;

    s->obmc= !!(s->flags & CODEC_FLAG_OBMC);
    s->loop_filter= !!(s->flags & CODEC_FLAG_LOOP_FILTER);
    s->alternate_scan= !!(s->flags & CODEC_FLAG_ALT_SCAN);
    s->intra_vlc_format= !!(s->flags2 & CODEC_FLAG2_INTRA_VLC);
    s->q_scale_type= !!(s->flags2 & CODEC_FLAG2_NON_LINEAR_QUANT);

    if(avctx->rc_max_rate && !avctx->rc_buffer_size){
        av_log(avctx, AV_LOG_ERROR, "a vbv buffer size is needed, for encoding with a maximum bitrate\n");
        return -1;
    }

    if(avctx->rc_min_rate && avctx->rc_max_rate != avctx->rc_min_rate){
        av_log(avctx, AV_LOG_INFO, "Warning min_rate > 0 but min_rate != max_rate isn't recommended!\n");
    }

    if(avctx->rc_min_rate && avctx->rc_min_rate > avctx->bit_rate){
        av_log(avctx, AV_LOG_ERROR, "bitrate below min bitrate\n");
        return -1;
    }

    if(avctx->rc_max_rate && avctx->rc_max_rate < avctx->bit_rate){
        av_log(avctx, AV_LOG_INFO, "bitrate above max bitrate\n");