PeerStreamer

/**

 * @file vp6.c

 * VP6 compatible video decoder

 *

 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>

 *

 * The VP6F decoder accepts an optional 1 byte extradata. It is composed of:

 *  - upper 4bits: difference between encoded width and visible width

 *  - lower 4bits: difference between encoded height and visible height

 *

 * 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

 */

#include <stdlib.h>

#include "avcodec.h"

#include "dsputil.h"

#include "bitstream.h"

#include "huffman.h"

#include "vp56.h"

#include "vp56data.h"

#include "vp6data.h"

static void vp6_parse_coeff(vp56_context_t *s);

static void vp6_parse_coeff_huffman(vp56_context_t *s);

static int vp6_parse_header(vp56_context_t *s, const uint8_t *buf, int buf_size,

                            int *golden_frame)

{

    vp56_range_coder_t *c = &s->c;

    int parse_filter_info = 0;

    int coeff_offset = 0;

    int vrt_shift = 0;

    int sub_version;

    int rows, cols;

    int res = 1;

    int separated_coeff = buf[0] & 1;

    s->framep[VP56_FRAME_CURRENT]->key_frame = !(buf[0] & 0x80);

    vp56_init_dequant(s, (buf[0] >> 1) & 0x3F);

    if (s->framep[VP56_FRAME_CURRENT]->key_frame) {

        sub_version = buf[1] >> 3;

        if (sub_version > 8)

            return 0;

        s->filter_header = buf[1] & 0x06;

        if (buf[1] & 1) {

            av_log(s->avctx, AV_LOG_ERROR, "interlacing not supported\n");

            return 0;

        }

        if (separated_coeff || !s->filter_header) {

            coeff_offset = AV_RB16(buf+2) - 2;

            buf += 2;

            buf_size -= 2;

        }

        rows = buf[2];  /* number of stored macroblock rows */

        cols = buf[3];  /* number of stored macroblock cols */

        /* buf[4] is number of displayed macroblock rows */

        /* buf[5] is number of displayed macroblock cols */

        if (16*cols != s->avctx->coded_width ||

            16*rows != s->avctx->coded_height) {

            avcodec_set_dimensions(s->avctx, 16*cols, 16*rows);

            if (s->avctx->extradata_size == 1) {

                s->avctx->width  -= s->avctx->extradata[0] >> 4;

                s->avctx->height -= s->avctx->extradata[0] & 0x0F;

            }

            res = 2;

        }

        vp56_init_range_decoder(c, buf+6, buf_size-6);

        vp56_rac_gets(c, 2);

        parse_filter_info = s->filter_header;

        if (sub_version < 8)

            vrt_shift = 5;

        s->sub_version = sub_version;

    } else {

        if (!s->sub_version)

            return 0;

        if (separated_coeff || !s->filter_header) {

            coeff_offset = AV_RB16(buf+1) - 2;

            buf += 2;

            buf_size -= 2;

        }

        vp56_init_range_decoder(c, buf+1, buf_size-1);

        *golden_frame = vp56_rac_get(c);

        if (s->filter_header) {

            s->deblock_filtering = vp56_rac_get(c);

            if (s->deblock_filtering)

                vp56_rac_get(c);

            if (s->sub_version > 7)

                parse_filter_info = vp56_rac_get(c);

        }

    }

    if (parse_filter_info) {

        if (vp56_rac_get(c)) {

            s->filter_mode = 2;

            s->sample_variance_threshold = vp56_rac_gets(c, 5) << vrt_shift;

            s->max_vector_length = 2 << vp56_rac_gets(c, 3);

        } else if (vp56_rac_get(c)) {

            s->filter_mode = 1;

        } else {

            s->filter_mode = 0;

        }

        if (s->sub_version > 7)

            s->filter_selection = vp56_rac_gets(c, 4);

        else

            s->filter_selection = 16;

    }

    s->use_huffman = vp56_rac_get(c);

    s->parse_coeff = vp6_parse_coeff;

    if (coeff_offset) {

        buf      += coeff_offset;

        buf_size -= coeff_offset;

        if (s->use_huffman) {

            s->parse_coeff = vp6_parse_coeff_huffman;

            init_get_bits(&s->gb, buf, buf_size<<3);

        } else {

            vp56_init_range_decoder(&s->cc, buf, buf_size);

            s->ccp = &s->cc;

        }

    } else {

        s->ccp = &s->c;

    }

    return res;

}

static void vp6_coeff_order_table_init(vp56_context_t *s)

{

    int i, pos, idx = 1;

    s->modelp->coeff_index_to_pos[0] = 0;

    for (i=0; i<16; i++)

        for (pos=1; pos<64; pos++)

            if (s->modelp->coeff_reorder[pos] == i)

                s->modelp->coeff_index_to_pos[idx++] = pos;

}

static void vp6_default_models_init(vp56_context_t *s)

{

    vp56_model_t *model = s->modelp;

    model->vector_dct[0] = 0xA2;

    model->vector_dct[1] = 0xA4;

    model->vector_sig[0] = 0x80;

    model->vector_sig[1] = 0x80;

    memcpy(model->mb_types_stats, vp56_def_mb_types_stats, sizeof(model->mb_types_stats));

    memcpy(model->vector_fdv, vp6_def_fdv_vector_model, sizeof(model->vector_fdv));

    memcpy(model->vector_pdv, vp6_def_pdv_vector_model, sizeof(model->vector_pdv));

    memcpy(model->coeff_runv, vp6_def_runv_coeff_model, sizeof(model->coeff_runv));

    memcpy(model->coeff_reorder, vp6_def_coeff_reorder, sizeof(model->coeff_reorder));

    vp6_coeff_order_table_init(s);

}

static void vp6_parse_vector_models(vp56_context_t *s)

{

    vp56_range_coder_t *c = &s->c;

    vp56_model_t *model = s->modelp;

    int comp, node;

    for (comp=0; comp<2; comp++) {

        if (vp56_rac_get_prob(c, vp6_sig_dct_pct[comp][0]))

            model->vector_dct[comp] = vp56_rac_gets_nn(c, 7);

        if (vp56_rac_get_prob(c, vp6_sig_dct_pct[comp][1]))

            model->vector_sig[comp] = vp56_rac_gets_nn(c, 7);

    }

    for (comp=0; comp<2; comp++)

        for (node=0; node<7; node++)

            if (vp56_rac_get_prob(c, vp6_pdv_pct[comp][node]))

                model->vector_pdv[comp][node] = vp56_rac_gets_nn(c, 7);

    for (comp=0; comp<2; comp++)

        for (node=0; node<8; node++)

            if (vp56_rac_get_prob(c, vp6_fdv_pct[comp][node]))

                model->vector_fdv[comp][node] = vp56_rac_gets_nn(c, 7);

}

static int vp6_huff_cmp(const void *va, const void *vb)

{

    const Node *a = va, *b = vb;

    return a->count >= b->count;

}

static void vp6_build_huff_tree(vp56_context_t *s, uint8_t coeff_model[],

                                const uint8_t *map, unsigned size, VLC *vlc)

{

    Node nodes[2*size], *tmp = &nodes[size];

    int a, b, i;

    /* first compute probabilities from model */

    tmp[0].count = 256;

    for (i=0; i<size-1; i++) {

        a = tmp[i].count *        coeff_model[i]  >> 8;

        b = tmp[i].count * (255 - coeff_model[i]) >> 8;

        nodes[map[2*i  ]].count = a + !a;

        nodes[map[2*i+1]].count = b + !b;

    }

    /* then build the huffman tree accodring to probabilities */

    ff_huff_build_tree(s->avctx, vlc, size, nodes, vp6_huff_cmp, 1);

}

static void vp6_parse_coeff_models(vp56_context_t *s)

{

    vp56_range_coder_t *c = &s->c;

    vp56_model_t *model = s->modelp;

    int def_prob[11];

    int node, cg, ctx, pos;

    int ct;    /* code type */

    int pt;    /* plane type (0 for Y, 1 for U or V) */

    memset(def_prob, 0x80, sizeof(def_prob));

    for (pt=0; pt<2; pt++)

        for (node=0; node<11; node++)

            if (vp56_rac_get_prob(c, vp6_dccv_pct[pt][node])) {

                def_prob[node] = vp56_rac_gets_nn(c, 7);

                model->coeff_dccv[pt][node] = def_prob[node];

            } else if (s->framep[VP56_FRAME_CURRENT]->key_frame) {

                model->coeff_dccv[pt][node] = def_prob[node];

            }

    if (vp56_rac_get(c)) {

        for (pos=1; pos<64; pos++)

            if (vp56_rac_get_prob(c, vp6_coeff_reorder_pct[pos]))

                model->coeff_reorder[pos] = vp56_rac_gets(c, 4);

        vp6_coeff_order_table_init(s);

    }

    for (cg=0; cg<2; cg++)

        for (node=0; node<14; node++)

            if (vp56_rac_get_prob(c, vp6_runv_pct[cg][node]))

                model->coeff_runv[cg][node] = vp56_rac_gets_nn(c, 7);

    for (ct=0; ct<3; ct++)

        for (pt=0; pt<2; pt++)

            for (cg=0; cg<6; cg++)

                for (node=0; node<11; node++)

                    if (vp56_rac_get_prob(c, vp6_ract_pct[ct][pt][cg][node])) {

                        def_prob[node] = vp56_rac_gets_nn(c, 7);

                        model->coeff_ract[pt][ct][cg][node] = def_prob[node];

                    } else if (s->framep[VP56_FRAME_CURRENT]->key_frame) {

                        model->coeff_ract[pt][ct][cg][node] = def_prob[node];

                    }

    if (s->use_huffman) {

        for (pt=0; pt<2; pt++) {

            vp6_build_huff_tree(s, model->coeff_dccv[pt],

                                vp6_huff_coeff_map, 12, &s->dccv_vlc[pt]);

            vp6_build_huff_tree(s, model->coeff_runv[pt],

                                vp6_huff_run_map, 9, &s->runv_vlc[pt]);

            for (ct=0; ct<3; ct++)

                for (cg = 0; cg < 6; cg++)

                    vp6_build_huff_tree(s, model->coeff_ract[pt][ct][cg],

                                        vp6_huff_coeff_map, 12,

                                        &s->ract_vlc[pt][ct][cg]);

        }

        memset(s->nb_null, 0, sizeof(s->nb_null));

    } else {

    /* coeff_dcct is a linear combination of coeff_dccv */

    for (pt=0; pt<2; pt++)

        for (ctx=0; ctx<3; ctx++)

            for (node=0; node<5; node++)

                model->coeff_dcct[pt][ctx][node] = av_clip(((model->coeff_dccv[pt][node] * vp6_dccv_lc[ctx][node][0] + 128) >> 8) + vp6_dccv_lc[ctx][node][1], 1, 255);

    }

}

static void vp6_parse_vector_adjustment(vp56_context_t *s, vp56_mv_t *vect)

{

    vp56_range_coder_t *c = &s->c;

    vp56_model_t *model = s->modelp;

    int comp;

    *vect = (vp56_mv_t) {0,0};

    if (s->vector_candidate_pos < 2)

        *vect = s->vector_candidate[0];

    for (comp=0; comp<2; comp++) {

        int i, delta = 0;

        if (vp56_rac_get_prob(c, model->vector_dct[comp])) {

            static const uint8_t prob_order[] = {0, 1, 2, 7, 6, 5, 4};

            for (i=0; i<sizeof(prob_order); i++) {

                int j = prob_order[i];

                delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][j])<<j;

            }

            if (delta & 0xF0)

                delta |= vp56_rac_get_prob(c, model->vector_fdv[comp][3])<<3;

            else

                delta |= 8;

        } else {

            delta = vp56_rac_get_tree(c, vp56_pva_tree,

                                      model->vector_pdv[comp]);

        }

        if (delta && vp56_rac_get_prob(c, model->vector_sig[comp]))

            delta = -delta;

        if (!comp)

            vect->x += delta;

        else

            vect->y += delta;

    }

}

/**

 * Read number of consecutive blocks with null DC or AC.

 * This value is < 74.

 */

static unsigned vp6_get_nb_null(vp56_context_t *s)

{

    unsigned val = get_bits(&s->gb, 2);

    if (val == 2)

        val += get_bits(&s->gb, 2);

    else if (val == 3) {

        val = get_bits1(&s->gb) << 2;

        val = 6+val + get_bits(&s->gb, 2+val);

    }

    return val;

}

static void vp6_parse_coeff_huffman(vp56_context_t *s)

{

    vp56_model_t *model = s->modelp;

    uint8_t *permute = s->scantable.permutated;

    VLC *vlc_coeff;

    int coeff, sign, coeff_idx;

    int b, cg, idx;

    int pt = 0;    /* plane type (0 for Y, 1 for U or V) */

    for (b=0; b<6; b++) {

        int ct = 0;    /* code type */

        if (b > 3) pt = 1;

        vlc_coeff = &s->dccv_vlc[pt];

        for (coeff_idx=0; coeff_idx<64; ) {

            int run = 1;

            if (coeff_idx<2 && s->nb_null[coeff_idx][pt]) {

                s->nb_null[coeff_idx][pt]--;

                if (coeff_idx)

                    break;

            } else {

                coeff = get_vlc2(&s->gb, vlc_coeff->table, 9, 3);

                if (coeff == 0) {

                    if (coeff_idx) {

                        int pt = (coeff_idx >= 6);

                        run += get_vlc2(&s->gb, s->runv_vlc[pt].table, 9, 3);

                        if (run >= 9)

                            run += get_bits(&s->gb, 6);

                    } else

                        s->nb_null[0][pt] = vp6_get_nb_null(s);

                    ct = 0;

                } else if (coeff == 11) {  /* end of block */

                    if (coeff_idx == 1)    /* first AC coeff ? */

                        s->nb_null[1][pt] = vp6_get_nb_null(s);

                    break;

                } else {

                    int coeff2 = vp56_coeff_bias[coeff];

                    if (coeff > 4)

                        coeff2 += get_bits(&s->gb, coeff <= 9 ? coeff - 4 : 11);

                    ct = 1 + (coeff2 > 1);

                    sign = get_bits1(&s->gb);

                    coeff2 = (coeff2 ^ -sign) + sign;

                    if (coeff_idx)

                        coeff2 *= s->dequant_ac;

                    idx = model->coeff_index_to_pos[coeff_idx];

                    s->block_coeff[b][permute[idx]] = coeff2;

                }

            }

            coeff_idx+=run;

            cg = FFMIN(vp6_coeff_groups[coeff_idx], 3);

            vlc_coeff = &s->ract_vlc[pt][ct][cg];

        }

    }

}

static void vp6_parse_coeff(vp56_context_t *s)

{

    vp56_range_coder_t *c = s->ccp;

    vp56_model_t *model = s->modelp;

    uint8_t *permute = s->scantable.permutated;

    uint8_t *model1, *model2, *model3;

    int coeff, sign, coeff_idx;

    int b, i, cg, idx, ctx;

    int pt = 0;    /* plane type (0 for Y, 1 for U or V) */

    for (b=0; b<6; b++) {

        int ct = 1;    /* code type */

        int run = 1;

        if (b > 3) pt = 1;

        ctx = s->left_block[vp56_b6to4[b]].not_null_dc

              + s->above_blocks[s->above_block_idx[b]].not_null_dc;

        model1 = model->coeff_dccv[pt];

        model2 = model->coeff_dcct[pt][ctx];

        for (coeff_idx=0; coeff_idx<64; ) {

            if ((coeff_idx>1 && ct==0) || vp56_rac_get_prob(c, model2[0])) {

                /* parse a coeff */

                if (vp56_rac_get_prob(c, model2[2])) {

                    if (vp56_rac_get_prob(c, model2[3])) {

                        idx = vp56_rac_get_tree(c, vp56_pc_tree, model1);

                        coeff = vp56_coeff_bias[idx+5];

                        for (i=vp56_coeff_bit_length[idx]; i>=0; i--)

                            coeff += vp56_rac_get_prob(c, vp56_coeff_parse_table[idx][i]) << i;

                    } else {

                        if (vp56_rac_get_prob(c, model2[4]))

                            coeff = 3 + vp56_rac_get_prob(c, model1[5]);

                        else

                            coeff = 2;

                    }

                    ct = 2;

                } else {

                    ct = 1;

                    coeff = 1;

                }

                sign = vp56_rac_get(c);

                coeff = (coeff ^ -sign) + sign;

                if (coeff_idx)

                    coeff *= s->dequant_ac;

                idx = model->coeff_index_to_pos[coeff_idx];

                s->block_coeff[b][permute[idx]] = coeff;

                run = 1;

            } else {

                /* parse a run */

                ct = 0;

                if (coeff_idx > 0) {

                    if (!vp56_rac_get_prob(c, model2[1]))

                        break;

                    model3 = model->coeff_runv[coeff_idx >= 6];

                    run = vp56_rac_get_tree(c, vp6_pcr_tree, model3);

                    if (!run)

                        for (run=9, i=0; i<6; i++)

                            run += vp56_rac_get_prob(c, model3[i+8]) << i;

                }

            }

            cg = vp6_coeff_groups[coeff_idx+=run];

            model1 = model2 = model->coeff_ract[pt][ct][cg];

        }

        s->left_block[vp56_b6to4[b]].not_null_dc =

        s->above_blocks[s->above_block_idx[b]].not_null_dc = !!s->block_coeff[b][0];

    }

}

static int vp6_adjust(int v, int t)

{

    int V = v, s = v >> 31;

    V ^= s;

    V -= s;

    if (V-t-1 >= (unsigned)(t-1))

        return v;

    V = 2*t - V;

    V += s;

    V ^= s;

    return V;

}

static int vp6_block_variance(uint8_t *src, int stride)

{

    int sum = 0, square_sum = 0;

    int y, x;

    for (y=0; y<8; y+=2) {

        for (x=0; x<8; x+=2) {

            sum += src[x];

            square_sum += src[x]*src[x];

        }

        src += 2*stride;

    }

    return (16*square_sum - sum*sum) >> 8;

}

static void vp6_filter_hv4(uint8_t *dst, uint8_t *src, int stride,

                           int delta, const int16_t *weights)

{

    int x, y;

    for (y=0; y<8; y++) {

        for (x=0; x<8; x++) {

            dst[x] = av_clip_uint8((  src[x-delta  ] * weights[0]

                                 + src[x        ] * weights[1]

                                 + src[x+delta  ] * weights[2]

                                 + src[x+2*delta] * weights[3] + 64) >> 7);

        }

        src += stride;

        dst += stride;

    }

}

static void vp6_filter_diag2(vp56_context_t *s, uint8_t *dst, uint8_t *src,

                             int stride, int h_weight, int v_weight)

{

    uint8_t *tmp = s->edge_emu_buffer+16;

    s->dsp.put_h264_chroma_pixels_tab[0](tmp, src, stride, 9, h_weight, 0);

    s->dsp.put_h264_chroma_pixels_tab[0](dst, tmp, stride, 8, 0, v_weight);

}

static void vp6_filter_diag4(uint8_t *dst, uint8_t *src, int stride,

                             const int16_t *h_weights,const int16_t *v_weights)

{

    int x, y;

    int tmp[8*11];

    int *t = tmp;

    src -= stride;

    for (y=0; y<11; y++) {

        for (x=0; x<8; x++) {

            t[x] = av_clip_uint8((  src[x-1] * h_weights[0]

                               + src[x  ] * h_weights[1]

                               + src[x+1] * h_weights[2]

                               + src[x+2] * h_weights[3] + 64) >> 7);

        }

        src += stride;

        t += 8;

    }

    t = tmp + 8;

    for (y=0; y<8; y++) {

        for (x=0; x<8; x++) {

            dst[x] = av_clip_uint8((  t[x-8 ] * v_weights[0]

                                 + t[x   ] * v_weights[1]

                                 + t[x+8 ] * v_weights[2]

                                 + t[x+16] * v_weights[3] + 64) >> 7);

        }

        dst += stride;

        t += 8;

    }

}

static void vp6_filter(vp56_context_t *s, uint8_t *dst, uint8_t *src,

                       int offset1, int offset2, int stride,

                       vp56_mv_t mv, int mask, int select, int luma)

{

    int filter4 = 0;

    int x8 = mv.x & mask;

    int y8 = mv.y & mask;

    if (luma) {

        x8 *= 2;

        y8 *= 2;

        filter4 = s->filter_mode;

        if (filter4 == 2) {

            if (s->max_vector_length &&

                (FFABS(mv.x) > s->max_vector_length ||

                 FFABS(mv.y) > s->max_vector_length)) {

                filter4 = 0;

            } else if (s->sample_variance_threshold

                       && (vp6_block_variance(src+offset1, stride)

                           < s->sample_variance_threshold)) {

                filter4 = 0;

            }

        }

    }

    if ((y8 && (offset2-offset1)*s->flip<0) || (!y8 && offset1 > offset2)) {

        offset1 = offset2;

    }

    if (filter4) {

        if (!y8) {                      /* left or right combine */

            vp6_filter_hv4(dst, src+offset1, stride, 1,

                           vp6_block_copy_filter[select][x8]);

        } else if (!x8) {               /* above or below combine */

            vp6_filter_hv4(dst, src+offset1, stride, stride,

                           vp6_block_copy_filter[select][y8]);

        } else {

            vp6_filter_diag4(dst, src+offset1 + ((mv.x^mv.y)>>31), stride,

                             vp6_block_copy_filter[select][x8],

                             vp6_block_copy_filter[select][y8]);

        }

    } else {

        if (!x8 || !y8) {

            s->dsp.put_h264_chroma_pixels_tab[0](dst, src+offset1, stride, 8, x8, y8);

        } else {

            vp6_filter_diag2(s, dst, src+offset1 + ((mv.x^mv.y)>>31), stride, x8, y8);

        }

    }

}

static int vp6_decode_init(AVCodecContext *avctx)

{

    vp56_context_t *s = avctx->priv_data;

    vp56_init(avctx, avctx->codec->id == CODEC_ID_VP6,

                     avctx->codec->id == CODEC_ID_VP6A);

    s->vp56_coord_div = vp6_coord_div;

    s->parse_vector_adjustment = vp6_parse_vector_adjustment;

    s->adjust = vp6_adjust;

    s->filter = vp6_filter;

    s->default_models_init = vp6_default_models_init;

    s->parse_vector_models = vp6_parse_vector_models;

    s->parse_coeff_models = vp6_parse_coeff_models;

    s->parse_header = vp6_parse_header;

    return 0;

}

AVCodec vp6_decoder = {

    "vp6",

    CODEC_TYPE_VIDEO,

    CODEC_ID_VP6,

    sizeof(vp56_context_t),

    vp6_decode_init,

    NULL,

    vp56_free,

    vp56_decode_frame,

    CODEC_CAP_DR1,

};

/* flash version, not flipped upside-down */

AVCodec vp6f_decoder = {

    "vp6f",

    CODEC_TYPE_VIDEO,

    CODEC_ID_VP6F,

    sizeof(vp56_context_t),

    vp6_decode_init,

    NULL,

    vp56_free,

    vp56_decode_frame,

    CODEC_CAP_DR1,

};

/* flash version, not flipped upside-down, with alpha channel */

AVCodec vp6a_decoder = {

    "vp6a",

    CODEC_TYPE_VIDEO,

    CODEC_ID_VP6A,

    sizeof(vp56_context_t),

    vp6_decode_init,

    NULL,

    vp56_free,

    vp56_decode_frame,

    CODEC_CAP_DR1,

};