path: root/libavfilter/libmpcodecs/pullup.c

/*
 * This file is part of MPlayer.
 *
 * MPlayer is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MPlayer 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with MPlayer; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "pullup.h"
#include "cpudetect.h"



#if ARCH_X86
#if HAVE_MMX
static int diff_y_mmx(unsigned char *a, unsigned char *b, int s)
{
    int ret;
    __asm__ volatile (
        "movl $4, %%ecx \n\t"
        "pxor %%mm4, %%mm4 \n\t"
        "pxor %%mm7, %%mm7 \n\t"

        "1: \n\t"

        "movq (%%"REG_S"), %%mm0 \n\t"
        "movq (%%"REG_S"), %%mm2 \n\t"
        "add  %%"REG_a", %%"REG_S" \n\t"
        "movq (%%"REG_D"), %%mm1 \n\t"
        "add  %%"REG_a", %%"REG_D" \n\t"
        "psubusb %%mm1, %%mm2 \n\t"
        "psubusb %%mm0, %%mm1 \n\t"
        "movq %%mm2, %%mm0 \n\t"
        "movq %%mm1, %%mm3 \n\t"
        "punpcklbw %%mm7, %%mm0 \n\t"
        "punpcklbw %%mm7, %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm2 \n\t"
        "punpckhbw %%mm7, %%mm3 \n\t"
        "paddw %%mm0, %%mm4 \n\t"
        "paddw %%mm1, %%mm4 \n\t"
        "paddw %%mm2, %%mm4 \n\t"
        "paddw %%mm3, %%mm4 \n\t"

        "decl %%ecx \n\t"
        "jnz 1b \n\t"

        "movq %%mm4, %%mm3 \n\t"
        "punpcklwd %%mm7, %%mm4 \n\t"
        "punpckhwd %%mm7, %%mm3 \n\t"
        "paddd %%mm4, %%mm3 \n\t"
        "movd %%mm3, %%eax \n\t"
        "psrlq $32, %%mm3 \n\t"
        "movd %%mm3, %%edx \n\t"
        "addl %%edx, %%eax \n\t"
        "emms \n\t"
        : "=a" (ret)
        : "S" (a), "D" (b), "a" (s)
        : "%ecx", "%edx"
        );
    return ret;
}

static int licomb_y_mmx(unsigned char *a, unsigned char *b, int s)
{
    int ret;
    __asm__ volatile (
        "movl $4, %%ecx \n\t"
        "pxor %%mm6, %%mm6 \n\t"
        "pxor %%mm7, %%mm7 \n\t"
        "sub  %%"REG_a", %%"REG_D" \n\t"

        "2: \n\t"

        "movq (%%"REG_D"), %%mm0 \n\t"
        "movq (%%"REG_D"), %%mm1 \n\t"
        "punpcklbw %%mm7, %%mm0 \n\t"
        "movq (%%"REG_D",%%"REG_a"), %%mm2 \n\t"
        "punpcklbw %%mm7, %%mm1 \n\t"
        "punpcklbw %%mm7, %%mm2 \n\t"
        "paddw %%mm0, %%mm0 \n\t"
        "paddw %%mm2, %%mm1 \n\t"
        "movq %%mm0, %%mm2 \n\t"
        "psubusw %%mm1, %%mm0 \n\t"
        "psubusw %%mm2, %%mm1 \n\t"
        "paddw %%mm0, %%mm6 \n\t"
        "paddw %%mm1, %%mm6 \n\t"

        "movq (%%"REG_S"), %%mm0 \n\t"
        "movq (%%"REG_D"), %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm0 \n\t"
        "movq (%%"REG_D",%%"REG_a"), %%mm2 \n\t"
        "punpckhbw %%mm7, %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm2 \n\t"
        "paddw %%mm0, %%mm0 \n\t"
        "paddw %%mm2, %%mm1 \n\t"
        "movq %%mm0, %%mm2 \n\t"
        "psubusw %%mm1, %%mm0 \n\t"
        "psubusw %%mm2, %%mm1 \n\t"
        "paddw %%mm0, %%mm6 \n\t"
        "paddw %%mm1, %%mm6 \n\t"

        "movq (%%"REG_D",%%"REG_a"), %%mm0 \n\t"
        "movq (%%"REG_S"), %%mm1 \n\t"
        "punpcklbw %%mm7, %%mm0 \n\t"
        "movq (%%"REG_S",%%"REG_a"), %%mm2 \n\t"
        "punpcklbw %%mm7, %%mm1 \n\t"
        "punpcklbw %%mm7, %%mm2 \n\t"
        "paddw %%mm0, %%mm0 \n\t"
        "paddw %%mm2, %%mm1 \n\t"
        "movq %%mm0, %%mm2 \n\t"
        "psubusw %%mm1, %%mm0 \n\t"
        "psubusw %%mm2, %%mm1 \n\t"
        "paddw %%mm0, %%mm6 \n\t"
        "paddw %%mm1, %%mm6 \n\t"

        "movq (%%"REG_D",%%"REG_a"), %%mm0 \n\t"
        "movq (%%"REG_S"), %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm0 \n\t"
        "movq (%%"REG_S",%%"REG_a"), %%mm2 \n\t"
        "punpckhbw %%mm7, %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm2 \n\t"
        "paddw %%mm0, %%mm0 \n\t"
        "paddw %%mm2, %%mm1 \n\t"
        "movq %%mm0, %%mm2 \n\t"
        "psubusw %%mm1, %%mm0 \n\t"
        "psubusw %%mm2, %%mm1 \n\t"
        "paddw %%mm0, %%mm6 \n\t"
        "paddw %%mm1, %%mm6 \n\t"

        "add  %%"REG_a", %%"REG_S" \n\t"
        "add  %%"REG_a", %%"REG_D" \n\t"
        "decl %%ecx \n\t"
        "jnz 2b \n\t"

        "movq %%mm6, %%mm5 \n\t"
        "punpcklwd %%mm7, %%mm6 \n\t"
        "punpckhwd %%mm7, %%mm5 \n\t"
        "paddd %%mm6, %%mm5 \n\t"
        "movd %%mm5, %%eax \n\t"
        "psrlq $32, %%mm5 \n\t"
        "movd %%mm5, %%edx \n\t"
        "addl %%edx, %%eax \n\t"

        "emms \n\t"
        : "=a" (ret)
        : "S" (a), "D" (b), "a" (s)
        : "%ecx", "%edx"
        );
    return ret;
}

static int var_y_mmx(unsigned char *a, unsigned char *b, int s)
{
    int ret;
    __asm__ volatile (
        "movl $3, %%ecx \n\t"
        "pxor %%mm4, %%mm4 \n\t"
        "pxor %%mm7, %%mm7 \n\t"

        "1: \n\t"

        "movq (%%"REG_S"), %%mm0 \n\t"
        "movq (%%"REG_S"), %%mm2 \n\t"
        "movq (%%"REG_S",%%"REG_a"), %%mm1 \n\t"
        "add  %%"REG_a", %%"REG_S" \n\t"
        "psubusb %%mm1, %%mm2 \n\t"
        "psubusb %%mm0, %%mm1 \n\t"
        "movq %%mm2, %%mm0 \n\t"
        "movq %%mm1, %%mm3 \n\t"
        "punpcklbw %%mm7, %%mm0 \n\t"
        "punpcklbw %%mm7, %%mm1 \n\t"
        "punpckhbw %%mm7, %%mm2 \n\t"
        "punpckhbw %%mm7, %%mm3 \n\t"
        "paddw %%mm0, %%mm4 \n\t"
        "paddw %%mm1, %%mm4 \n\t"
        "paddw %%mm2, %%mm4 \n\t"
        "paddw %%mm3, %%mm4 \n\t"

        "decl %%ecx \n\t"
        "jnz 1b \n\t"

        "movq %%mm4, %%mm3 \n\t"
        "punpcklwd %%mm7, %%mm4 \n\t"
        "punpckhwd %%mm7, %%mm3 \n\t"
        "paddd %%mm4, %%mm3 \n\t"
        "movd %%mm3, %%eax \n\t"
        "psrlq $32, %%mm3 \n\t"
        "movd %%mm3, %%edx \n\t"
        "addl %%edx, %%eax \n\t"
        "emms \n\t"
        : "=a" (ret)
        : "S" (a), "a" (s)
        : "%ecx", "%edx"
        );
    return 4*ret;
}
#endif
#endif

#define ABS(a) (((a)^((a)>>31))-((a)>>31))

static int diff_y(unsigned char *a, unsigned char *b, int s)
{
    int i, j, diff=0;
    for (i=4; i; i--) {
        for (j=0; j<8; j++) diff += ABS(a[j]-b[j]);
        a+=s; b+=s;
    }
    return diff;
}

static int licomb_y(unsigned char *a, unsigned char *b, int s)
{
    int i, j, diff=0;
    for (i=4; i; i--) {
        for (j=0; j<8; j++)
            diff += ABS((a[j]<<1) - b[j-s] - b[j])
                + ABS((b[j]<<1) - a[j] - a[j+s]);
        a+=s; b+=s;
    }
    return diff;
}

#if 0
static int qpcomb_y(unsigned char *a, unsigned char *b, int s)
{
    int i, j, diff=0;
    for (i=4; i; i--) {
        for (j=0; j<8; j++)
            diff += ABS(a[j] - 3*b[j-s] + 3*a[j+s] - b[j]);
        a+=s; b+=s;
    }
    return diff;
}

static int licomb_y_test(unsigned char *a, unsigned char *b, int s)
{
    int c = licomb_y(a,b,s);
    int m = licomb_y_mmx(a,b,s);
    if (c != m) printf("%d != %d\n", c, m);
    return m;
}
#endif

static int var_y(unsigned char *a, unsigned char *b, int s)
{
    int i, j, var=0;
    for (i=3; i; i--) {
        for (j=0; j<8; j++) {
            var += ABS(a[j]-a[j+s]);
        }
        a+=s; b+=s;
    }
    return 4*var; /* match comb scaling */
}









static void alloc_buffer(struct pullup_context *c, struct pullup_buffer *b)
{
    int i;
    if (b->planes) return;
    b->planes = calloc(c->nplanes, sizeof(unsigned char *));
    for (i = 0; i < c->nplanes; i++) {
        b->planes[i] = malloc(c->h[i]*c->stride[i]);
        /* Deal with idiotic 128=0 for chroma: */
        memset(b->planes[i], c->background[i], c->h[i]*c->stride[i]);
    }
}

struct pullup_buffer *pullup_lock_buffer(struct pullup_buffer *b, int parity)
{
    if (!b) return 0;
    if ((parity+1) & 1) b->lock[0]++;
    if ((parity+1) & 2) b->lock[1]++;
    return b;
}

void pullup_release_buffer(struct pullup_buffer *b, int parity)
{
    if (!b) return;
    if ((parity+1) & 1) b->lock[0]--;
    if ((parity+1) & 2) b->lock[1]--;
}

struct pullup_buffer *pullup_get_buffer(struct pullup_context *c, int parity)
{
    int i;

    /* Try first to get the sister buffer for the previous field */
    if (parity < 2 && c->last && parity != c->last->parity
        && !c->last->buffer->lock[parity]) {
        alloc_buffer(c, c->last->buffer);
        return pullup_lock_buffer(c->last->buffer, parity);
    }

    /* Prefer a buffer with both fields open */
    for (i = 0; i < c->nbuffers; i++) {
        if (c->buffers[i].lock[0]) continue;
        if (c->buffers[i].lock[1]) continue;
        alloc_buffer(c, &c->buffers[i]);
        return pullup_lock_buffer(&c->buffers[i], parity);
    }

    if (parity == 2) return 0;

    /* Search for any half-free buffer */
    for (i = 0; i < c->nbuffers; i++) {
        if (((parity+1) & 1) && c->buffers[i].lock[0]) continue;
        if (((parity+1) & 2) && c->buffers[i].lock[1]) continue;
        alloc_buffer(c, &c->buffers[i]);
        return pullup_lock_buffer(&c->buffers[i], parity);
    }

    return 0;
}






static void compute_metric(struct pullup_context *c,
    struct pullup_field *fa, int pa,
    struct pullup_field *fb, int pb,
    int (*func)(unsigned char *, unsigned char *, int), int *dest)
{
    unsigned char *a, *b;
    int x, y;
    int mp = c->metric_plane;
    int xstep = c->bpp[mp];
    int ystep = c->stride[mp]<<3;
    int s = c->stride[mp]<<1; /* field stride */
    int w = c->metric_w*xstep;

    if (!fa->buffer || !fb->buffer) return;

    /* Shortcut for duplicate fields (e.g. from RFF flag) */
    if (fa->buffer == fb->buffer && pa == pb) {
        memset(dest, 0, c->metric_len * sizeof(int));
        return;
    }

    a = fa->buffer->planes[mp] + pa * c->stride[mp] + c->metric_offset;
    b = fb->buffer->planes[mp] + pb * c->stride[mp] + c->metric_offset;

    for (y = c->metric_h; y; y--) {
        for (x = 0; x < w; x += xstep) {
            *dest++ = func(a + x, b + x, s);
        }
        a += ystep; b += ystep;
    }
}





static void alloc_metrics(struct pullup_context *c, struct pullup_field *f)
{
    f->diffs = calloc(c->metric_len, sizeof(int));
    f->comb = calloc(c->metric_len, sizeof(int));
    f->var = calloc(c->metric_len, sizeof(int));
    /* add more metrics here as needed */
}

static struct pullup_field *make_field_queue(struct pullup_context *c, int len)
{
    struct pullup_field *head, *f;
    f = head = calloc(1, sizeof(struct pullup_field));
    alloc_metrics(c, f);
    for (; len > 0; len--) {
        f->next = calloc(1, sizeof(struct pullup_field));
        f->next->prev = f;
        f = f->next;
        alloc_metrics(c, f);
    }
    f->next = head;
    head->prev = f;
    return head;
}

static void check_field_queue(struct pullup_context *c)
{
    if (c->head->next == c->first) {
        struct pullup_field *f = calloc(1, sizeof(struct pullup_field));
        alloc_metrics(c, f);
        f->prev = c->head;
        f->next = c->first;
        c->head->next = f;
        c->first->prev = f;
    }
}

void pullup_submit_field(struct pullup_context *c, struct pullup_buffer *b, int parity)
{
    struct pullup_field *f;

    /* Grow the circular list if needed */
    check_field_queue(c);

    /* Cannot have two fields of same parity in a row; drop the new one */
    if (c->last && c->last->parity == parity) return;

    f = c->head;
    f->parity = parity;
    f->buffer = pullup_lock_buffer(b, parity);
    f->flags = 0;
    f->breaks = 0;
    f->affinity = 0;

    compute_metric(c, f, parity, f->prev->prev, parity, c->diff, f->diffs);
    compute_metric(c, parity?f->prev:f, 0, parity?f:f->prev, 1, c->comb, f->comb);
    compute_metric(c, f, parity, f, -1, c->var, f->var);

    /* Advance the circular list */
    if (!c->first) c->first = c->head;
    c->last = c->head;
    c->head = c->head->next;
}

void pullup_flush_fields(struct pullup_context *c)
{
    struct pullup_field *f;

    for (f = c->first; f && f != c->head; f = f->next) {
        pullup_release_buffer(f->buffer, f->parity);
        f->buffer = 0;
    }
    c->first = c->last = 0;
}








#define F_HAVE_BREAKS 1
#define F_HAVE_AFFINITY 2


#define BREAK_LEFT 1
#define BREAK_RIGHT 2




static int queue_length(struct pullup_field *begin, struct pullup_field *end)
{
    int count = 1;
    struct pullup_field *f;

    if (!begin || !end) return 0;
    for (f = begin; f != end; f = f->next) count++;
    return count;
}

static int find_first_break(struct pullup_field *f, int max)
{
    int i;
    for (i = 0; i < max; i++) {
        if (f->breaks & BREAK_RIGHT || f->next->breaks & BREAK_LEFT)
            return i+1;
        f = f->next;
    }
    return 0;
}

static void compute_breaks(struct pullup_context *c, struct pullup_field *f0)
{
    int i;
    struct pullup_field *f1 = f0->next;
    struct pullup_field *f2 = f1->next;
    struct pullup_field *f3 = f2->next;
    int l, max_l=0, max_r=0;
    //struct pullup_field *ff;
    //for (i=0, ff=c->first; ff != f0; i++, ff=ff->next);

    if (f0->flags & F_HAVE_BREAKS) return;
    //printf("\n%d: ", i);
    f0->flags |= F_HAVE_BREAKS;

    /* Special case when fields are 100% identical */
    if (f0->buffer == f2->buffer && f1->buffer != f3->buffer) {
        f2->breaks |= BREAK_RIGHT;
        return;
    }
    if (f0->buffer != f2->buffer && f1->buffer == f3->buffer) {
        f1->breaks |= BREAK_LEFT;
        return;
    }

    for (i = 0; i < c->metric_len; i++) {
        l = f2->diffs[i] - f3->diffs[i];
        if (l > max_l) max_l = l;
        if (-l > max_r) max_r = -l;
    }
    /* Don't get tripped up when differences are mostly quant error */
    //printf("%d %d\n", max_l, max_r);
    if (max_l + max_r < 128) return;
    if (max_l > 4*max_r) f1->breaks |= BREAK_LEFT;
    if (max_r > 4*max_l) f2->breaks |= BREAK_RIGHT;
}

static void compute_affinity(struct pullup_context *c, struct pullup_field *f)
{
    int i;
    int max_l=0, max_r=0, l;
    if (f->flags & F_HAVE_AFFINITY) return;
    f->flags |= F_HAVE_AFFINITY;
    if (f->buffer == f->next->next->buffer) {
        f->affinity = 1;
        f->next->affinity = 0;
        f->next->next->affinity = -1;
        f->next->flags |= F_HAVE_AFFINITY;
        f->next->next->flags |= F_HAVE_AFFINITY;
        return;
    }
    if (1) {
        for (i = 0; i < c->metric_len; i++) {
            int lv = f->prev->var[i];
            int rv = f->next->var[i];
            int v = f->var[i];
            int lc = f->comb[i] - (v+lv) + ABS(v-lv);
            int rc = f->next->comb[i] - (v+rv) + ABS(v-rv);
            lc = lc>0 ? lc : 0;
            rc = rc>0 ? rc : 0;
            l = lc - rc;
            if (l > max_l) max_l = l;
            if (-l > max_r) max_r = -l;
        }
        if (max_l + max_r < 64) return;
        if (max_r > 6*max_l) f->affinity = -1;
        else if (max_l > 6*max_r) f->affinity = 1;
    } else {
        for (i = 0; i < c->metric_len; i++) {
            l = f->comb[i] - f->next->comb[i];
            if (l > max_l) max_l = l;
            if (-l > max_r) max_r = -l;
        }
        if (max_l + max_r < 64) return;
        if (max_r > 2*max_l) f->affinity = -1;
        else if (max_l > 2*max_r) f->affinity = 1;
    }
}

static void foo(struct pullup_context *c)
{
    struct pullup_field *f = c->first;
    int i, n = queue_length(f, c->last);
    for (i = 0; i < n-1; i++) {
        if (i < n-3) compute_breaks(c, f);
        compute_affinity(c, f);
        f = f->next;
    }
}

static int decide_frame_length(struct pullup_context *c)
{
    struct pullup_field *f0 = c->first;
    struct pullup_field *f1 = f0->next;
    struct pullup_field *f2 = f1->next;
    int l;

    if (queue_length(c->first, c->last) < 4) return 0;
    foo(c);

    if (f0->affinity == -1) return 1;

    l = find_first_break(f0, 3);
    if (l == 1 && c->strict_breaks < 0) l = 0;

    switch (l) {
    case 1:
        if (c->strict_breaks < 1 && f0->affinity == 1 && f1->affinity == -1)
            return 2;
        else return 1;
    case 2:
        /* FIXME: strictly speaking, f0->prev is no longer valid... :) */
        if (c->strict_pairs
            && (f0->prev->breaks & BREAK_RIGHT) && (f2->breaks & BREAK_LEFT)
            && (f0->affinity != 1 || f1->affinity != -1) )
            return 1;
        if (f1->affinity == 1) return 1;
        else return 2;
    case 3:
        if (f2->affinity == 1) return 2;
        else return 3;
    default:
        /* 9 possibilities covered before switch */
        if (f1->affinity == 1) return 1; /* covers 6 */
        else if (f1->affinity == -1) return 2; /* covers 6 */
        else if (f2->affinity == -1) { /* covers 2 */
            if (f0->affinity == 1) return 3;
            else return 1;
        }
        else return 2; /* the remaining 6 */
    }
}


static void print_aff_and_breaks(struct pullup_context *c, struct pullup_field *f)
{
    int i;
    struct pullup_field *f0 = f;
    const char aff_l[] = "+..", aff_r[] = "..+";
    printf("\naffinity: ");
    for (i = 0; i < 4; i++) {
        printf("%c%d%c", aff_l[1+f->affinity], i, aff_r[1+f->affinity]);
        f = f->next;
    }
    f = f0;
    printf("\nbreaks:   ");
    for (i=0; i<4; i++) {
        printf("%c%d%c", f->breaks & BREAK_LEFT ? '|' : '.', i, f->breaks & BREAK_RIGHT ? '|' : '.');
        f = f->next;
    }
    printf("\n");
}





struct pullup_frame *pullup_get_frame(struct pullup_context *c)
{
    int i;
    struct pullup_frame *fr = c->frame;
    int n = decide_frame_length(c);
    int aff = c->first->next->affinity;

    if (!n) return 0;
    if (fr->lock) return 0;

    if (c->verbose) {
        print_aff_and_breaks(c, c->first);
        printf("duration: %d    \n", n);
    }

    fr->lock++;
    fr->length = n;
    fr->parity = c->first->parity;
    fr->buffer = 0;
    for (i = 0; i < n; i++) {
        /* We cheat and steal the buffer without release+relock */
        fr->ifields[i] = c->first->buffer;
        c->first->buffer = 0;
        c->first = c->first->next;
    }

    if (n == 1) {
        fr->ofields[fr->parity] = fr->ifields[0];
        fr->ofields[fr->parity^1] = 0;
    } else if (n == 2) {
        fr->ofields[fr->parity] = fr->ifields[0];
        fr->ofields[fr->parity^1] = fr->ifields[1];
    } else if (n == 3) {
        if (aff == 0)
            aff = (fr->ifields[0] == fr->ifields[1]) ? -1 : 1;
        /* else if (c->verbose) printf("forced aff: %d    \n", aff); */
        fr->ofields[fr->parity] = fr->ifields[1+aff];
        fr->ofields[fr->parity^1] = fr->ifields[1];
    }
    pullup_lock_buffer(fr->ofields[0], 0);
    pullup_lock_buffer(fr->ofields[1], 1);

    if (fr->ofields[0] == fr->ofields[1]) {
        fr->buffer = fr->ofields[0];
        pullup_lock_buffer(fr->buffer, 2);
        return fr;
    }
    return fr;
}

static void copy_field(struct pullup_context *c, struct pullup_buffer *dest,
    struct pullup_buffer *src, int parity)
{
    int i, j;
    unsigned char *d, *s;
    for (i = 0; i < c->nplanes; i++) {
        s = src->planes[i] + parity*c->stride[i];
        d = dest->planes[i] + parity*c->stride[i];
        for (j = c->h[i]>>1; j; j--) {
            memcpy(d, s, c->stride[i]);
            s += c->stride[i]<<1;
            d += c->stride[i]<<1;
        }
    }
}

void pullup_pack_frame(struct pullup_context *c, struct pullup_frame *fr)
{
    int i;
    if (fr->buffer) return;
    if (fr->length < 2) return; /* FIXME: deal with this */
    for (i = 0; i < 2; i++)
    {
        if (fr->ofields[i]->lock[i^1]) continue;
        fr->buffer = fr->ofields[i];
        pullup_lock_buffer(fr->buffer, 2);
        copy_field(c, fr->buffer, fr->ofields[i^1], i^1);
        return;
    }
    fr->buffer = pullup_get_buffer(c, 2);
    copy_field(c, fr->buffer, fr->ofields[0], 0);
    copy_field(c, fr->buffer, fr->ofields[1], 1);
}

void pullup_release_frame(struct pullup_frame *fr)
{
    int i;
    for (i = 0; i < fr->length; i++)
        pullup_release_buffer(fr->ifields[i], fr->parity ^ (i&1));
    pullup_release_buffer(fr->ofields[0], 0);
    pullup_release_buffer(fr->ofields[1], 1);
    if (fr->buffer) pullup_release_buffer(fr->buffer, 2);
    fr->lock--;
}






struct pullup_context *pullup_alloc_context(void)
{
    struct pullup_context *c;

    c = calloc(1, sizeof(struct pullup_context));

    return c;
}

void pullup_preinit_context(struct pullup_context *c)
{
    c->bpp = calloc(c->nplanes, sizeof(int));
    c->w = calloc(c->nplanes, sizeof(int));
    c->h = calloc(c->nplanes, sizeof(int));
    c->stride = calloc(c->nplanes, sizeof(int));
    c->background = calloc(c->nplanes, sizeof(int));
}

void pullup_init_context(struct pullup_context *c)
{
    int mp = c->metric_plane;
    if (c->nbuffers < 10) c->nbuffers = 10;
    c->buffers = calloc(c->nbuffers, sizeof (struct pullup_buffer));

    c->metric_w = (c->w[mp] - ((c->junk_left + c->junk_right) << 3)) >> 3;
    c->metric_h = (c->h[mp] - ((c->junk_top + c->junk_bottom) << 1)) >> 3;
    c->metric_offset = c->junk_left*c->bpp[mp] + (c->junk_top<<1)*c->stride[mp];
    c->metric_len = c->metric_w * c->metric_h;

    c->head = make_field_queue(c, 8);

    c->frame = calloc(1, sizeof (struct pullup_frame));
    c->frame->ifields = calloc(3, sizeof (struct pullup_buffer *));

    switch(c->format) {
    case PULLUP_FMT_Y:
        c->diff = diff_y;
        c->comb = licomb_y;
        c->var = var_y;
#if ARCH_X86
#if HAVE_MMX
        if (c->cpu & PULLUP_CPU_MMX) {
            c->diff = diff_y_mmx;
            c->comb = licomb_y_mmx;
            c->var = var_y_mmx;
        }
#endif
#endif
        /* c->comb = qpcomb_y; */
        break;
#if 0
    case PULLUP_FMT_YUY2:
        c->diff = diff_yuy2;
        break;
    case PULLUP_FMT_RGB32:
        c->diff = diff_rgb32;
        break;
#endif
    }
}

void pullup_free_context(struct pullup_context *c)
{
    struct pullup_field *f;
    free(c->buffers);
    f = c->head;
    do {
        if (!f) break;
        free(f->diffs);
        free(f->comb);
        f = f->next;
        free(f->prev);
    } while (f != c->head);
    free(c->frame);
    free(c);
}