mpeg12.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

static void common_init(MpegEncContext *s)
{
    s->y_dc_scale_table=
    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
}

void ff_mpeg1_clean_buffers(MpegEncContext *s){
    s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
    s->last_dc[1] = s->last_dc[0];
    s->last_dc[2] = s->last_dc[0];
    memset(s->last_mv, 0, sizeof(s->last_mv));
}

#ifdef CONFIG_ENCODERS

void ff_mpeg1_encode_slice_header(MpegEncContext *s){
    put_header(s, SLICE_MIN_START_CODE + s->mb_y);
    put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
    put_bits(&s->pb, 1, 0); /* slice extra information */
}

void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
{
    mpeg1_encode_sequence_header(s);

    /* mpeg1 picture header */
    put_header(s, PICTURE_START_CODE);
    /* temporal reference */

    // RAL: s->picture_number instead of s->fake_picture_number
    put_bits(&s->pb, 10, (s->picture_number - 
                          s->gop_picture_number) & 0x3ff); 
    s->fake_picture_number++;
    
    put_bits(&s->pb, 3, s->pict_type);
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
    
    // RAL: Forward f_code also needed for B frames
    if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
        if(s->codec_id == CODEC_ID_MPEG1VIDEO)
            put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
        else
            put_bits(&s->pb, 3, 7); /* forward_f_code */
    }
    
    // RAL: Backward f_code necessary for B frames
    if (s->pict_type == B_TYPE) {
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
        if(s->codec_id == CODEC_ID_MPEG1VIDEO)
            put_bits(&s->pb, 3, s->b_code); /* backward_f_code */
        else
            put_bits(&s->pb, 3, 7); /* backward_f_code */
    }

    put_bits(&s->pb, 1, 0); /* extra bit picture */
    
    if(s->codec_id == CODEC_ID_MPEG2VIDEO){
        put_header(s, EXT_START_CODE);
        put_bits(&s->pb, 4, 8); //pic ext
        if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
            put_bits(&s->pb, 4, s->f_code);
            put_bits(&s->pb, 4, s->f_code);
        }else{
            put_bits(&s->pb, 8, 255);
        }
        if (s->pict_type == B_TYPE) {
            put_bits(&s->pb, 4, s->b_code);
            put_bits(&s->pb, 4, s->b_code);
        }else{
            put_bits(&s->pb, 8, 255);
        }
        put_bits(&s->pb, 2, s->intra_dc_precision);
        put_bits(&s->pb, 2, s->picture_structure= PICT_FRAME);
        put_bits(&s->pb, 1, s->top_field_first);
        put_bits(&s->pb, 1, s->frame_pred_frame_dct= 1);
        put_bits(&s->pb, 1, s->concealment_motion_vectors);
        put_bits(&s->pb, 1, s->q_scale_type);
        put_bits(&s->pb, 1, s->intra_vlc_format);
        put_bits(&s->pb, 1, s->alternate_scan);
        put_bits(&s->pb, 1, s->repeat_first_field);
        put_bits(&s->pb, 1, s->chroma_420_type=1);
        put_bits(&s->pb, 1, s->progressive_frame=1);
        put_bits(&s->pb, 1, 0); //composite_display_flag
    }
    
    s->mb_y=0;
    ff_mpeg1_encode_slice_header(s);
}

void mpeg1_encode_mb(MpegEncContext *s,
                     DCTELEM block[6][64],
                     int motion_x, int motion_y)
{
    int i, cbp;
    const int mb_x = s->mb_x;
    const int mb_y = s->mb_y;
    const int first_mb= mb_x == s->resync_mb_x && mb_y == s->resync_mb_y;

    /* compute cbp */
    cbp = 0;
    for(i=0;i<6;i++) {
        if (s->block_last_index[i] >= 0)
            cbp |= 1 << (5 - i);
    }

    if (cbp == 0 && !first_mb && (mb_x != s->mb_width - 1 || (mb_y != s->mb_height - 1 && s->codec_id == CODEC_ID_MPEG1VIDEO)) && 
        ((s->pict_type == P_TYPE && (motion_x | motion_y) == 0) ||
        (s->pict_type == B_TYPE && s->mv_dir == s->last_mv_dir && (((s->mv_dir & MV_DIR_FORWARD) ? ((s->mv[0][0][0] - s->last_mv[0][0][0])|(s->mv[0][0][1] - s->last_mv[0][0][1])) : 0) |
        ((s->mv_dir & MV_DIR_BACKWARD) ? ((s->mv[1][0][0] - s->last_mv[1][0][0])|(s->mv[1][0][1] - s->last_mv[1][0][1])) : 0)) == 0))) {
        s->mb_skip_run++;
        s->qscale -= s->dquant;
        s->skip_count++;
        s->misc_bits++;
        s->last_bits++;
    } else {
        if(first_mb){
            assert(s->mb_skip_run == 0);
            encode_mb_skip_run(s, s->mb_x);
        }else{
            encode_mb_skip_run(s, s->mb_skip_run);
        }
        
        if (s->pict_type == I_TYPE) {
            if(s->dquant && cbp){
                put_bits(&s->pb, 2, 1); /* macroblock_type : macroblock_quant = 1 */
                put_bits(&s->pb, 5, s->qscale);
            }else{
                put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
                s->qscale -= s->dquant;
            }
            s->misc_bits+= get_bits_diff(s);
            s->i_count++;
        } else if (s->mb_intra) {
            if(s->dquant && cbp){
                put_bits(&s->pb, 6, 0x01);
                put_bits(&s->pb, 5, s->qscale);
            }else{
                put_bits(&s->pb, 5, 0x03);
                s->qscale -= s->dquant;
            }
            s->misc_bits+= get_bits_diff(s);
            s->i_count++;
            s->last_mv[0][0][0] = 
            s->last_mv[0][0][1] = 0;
        } else if (s->pict_type == P_TYPE) { 
                if (cbp != 0) {
                    if (motion_x == 0 && motion_y == 0) {
                        if(s->dquant){
                            put_bits(&s->pb, 5, 1); /* macroblock_pattern & quant */
                            put_bits(&s->pb, 5, s->qscale);
                        }else{
                            put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
                        }
                        s->misc_bits+= get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                    } else {
                        if(s->dquant){
                            put_bits(&s->pb, 5, 2); /* motion + cbp */
                            put_bits(&s->pb, 5, s->qscale);
                        }else{
                            put_bits(&s->pb, 1, 1); /* motion + cbp */
                        }
                        s->misc_bits+= get_bits_diff(s);
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
                        s->mv_bits+= get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                    }
                } else {
                    put_bits(&s->pb, 3, 1); /* motion only */
                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
                    s->qscale -= s->dquant;
                    s->mv_bits+= get_bits_diff(s);
                }
                s->f_count++;
        } else
            {    // RAL: All the following bloc added for B frames:
                if (cbp != 0)
                    {    // With coded bloc pattern
                    if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
                        {    // Bi-directional motion
                        if (s->dquant)
                            {    // With QScale
                            put_bits(&s->pb, 5, 2);
                            put_bits(&s->pb, 5, s->qscale);
                            }
                        else    // Without QScale
                            put_bits(&s->pb, 2, 3);
                        s->misc_bits += get_bits_diff(s);
                        mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
                        mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
                        mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
                        mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
                        s->b_count++;
                        s->f_count++;
                        s->mv_bits += get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                        }
                    else if (s->mv_dir == MV_DIR_BACKWARD)
                        {    // Backward motion
                        if (s->dquant)
                            {    // With QScale
                            put_bits(&s->pb, 6, 2);
                            put_bits(&s->pb, 5, s->qscale);
                            }
                        else    // Without QScale
                            put_bits(&s->pb, 3, 3);
                        s->misc_bits += get_bits_diff(s);
                        mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code); 
                        mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code); 
                        s->b_count++;
                        s->mv_bits += get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                        }
                    else if (s->mv_dir == MV_DIR_FORWARD)
                        {    // Forward motion
                        if (s->dquant)
                            {    // With QScale
                            put_bits(&s->pb, 6, 3);
                            put_bits(&s->pb, 5, s->qscale);
                            }
                        else    // Without QScale
                            put_bits(&s->pb, 4, 3);
                        s->misc_bits += get_bits_diff(s);
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code); 
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code); 
                        s->f_count++;
                        s->mv_bits += get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                        }
                    }
                else
                    {    // No coded bloc pattern
                    if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
                        {    // Bi-directional motion 
                        put_bits(&s->pb, 2, 2); /* backward & forward motion */
                        mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
                        mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
                        mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
                        mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
                        s->b_count++;
                        s->f_count++;
                        }
                    else if (s->mv_dir == MV_DIR_BACKWARD)
                        {    // Backward motion
                        put_bits(&s->pb, 3, 2); /* backward motion only */
                        mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code); 
                        mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code); 
                        s->b_count++;
                        }
                    else if (s->mv_dir == MV_DIR_FORWARD)
                        {    // Forward motion
                        put_bits(&s->pb, 4, 2); /* forward motion only */
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code); 
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code); 
                        s->f_count++;
                        }
                    s->qscale -= s->dquant;
                    s->mv_bits += get_bits_diff(s);
                    }
            // End of bloc from RAL
            }
        for(i=0;i<6;i++) {
            if (cbp & (1 << (5 - i))) {
                mpeg1_encode_block(s, block[i], i);
            }
        }
        s->mb_skip_run = 0;
        if(s->mb_intra)
            s->i_tex_bits+= get_bits_diff(s);
        else
            s->p_tex_bits+= get_bits_diff(s);
    }

    // RAL: By this:
    if (s->mv_dir & MV_DIR_FORWARD)
        {
        s->last_mv[0][0][0]= s->mv[0][0][0];
        s->last_mv[0][0][1]= s->mv[0][0][1];
        }
    if (s->mv_dir & MV_DIR_BACKWARD)
        {
        s->last_mv[1][0][0]= s->mv[1][0][0];
        s->last_mv[1][0][1]= s->mv[1][0][1];
        }
}

// RAL: Parameter added: f_or_b_code
static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code)
{
    int code, bit_size, l, m, bits, range, sign;

    if (val == 0) {
        /* zero vector */
        code = 0;
        put_bits(&s->pb,
                 mbMotionVectorTable[0][1], 
                 mbMotionVectorTable[0][0]); 
    } else {
        bit_size = f_or_b_code - 1;
        range = 1 << bit_size;
        /* modulo encoding */
        l = 16 * range;
        m = 2 * l;
        if (val < -l) {
            val += m;
        } else if (val >= l) {
            val -= m;
        }

        if (val >= 0) {
            val--;
            code = (val >> bit_size) + 1;
            bits = val & (range - 1);
            sign = 0;
        } else {
            val = -val;
            val--;
            code = (val >> bit_size) + 1;
            bits = val & (range - 1);
            sign = 1;
        }

        assert(code > 0 && code <= 16);

        put_bits(&s->pb,
                 mbMotionVectorTable[code][1], 
                 mbMotionVectorTable[code][0]); 

        put_bits(&s->pb, 1, sign);
        if (bit_size > 0) {
            put_bits(&s->pb, bit_size, bits);
        }
    }
}

void ff_mpeg1_encode_init(MpegEncContext *s)
{
    static int done=0;

    common_init(s);

    if(!done){
        int f_code;
        int mv;
	int i;

        done=1;
        init_rl(&rl_mpeg1);

	for(i=0; i<64; i++)
	{
		mpeg1_max_level[0][i]= rl_mpeg1.max_level[0][i];
		mpeg1_index_run[0][i]= rl_mpeg1.index_run[0][i];
	}
        
        init_uni_ac_vlc(&rl_mpeg1, uni_mpeg1_ac_vlc_bits, uni_mpeg1_ac_vlc_len);

	/* build unified dc encoding tables */
	for(i=-255; i<256; i++)
	{
		int adiff, index;
		int bits, code;
		int diff=i;

		adiff = ABS(diff);
		if(diff<0) diff--;
		index = vlc_dc_table[adiff];

		bits= vlc_dc_lum_bits[index] + index;