-/*
- * This macro interpolates the value of both fields at a point halfway
- * between lines and takes the squared difference. In field resolution
- * the point is a quarter pixel below a line in one field and a quarter
- * pixel above a line in other.
- *
- * (The result is actually multiplied by 25)
- */
-#define DIFF(a, as, b, bs) ((t) = ((*(a) - (b)[bs]) << 2) + (a)[(as) << 1] - (b)[-(bs)], (t) * (t))
-
-/*
- * Find which field combination has the smallest average squared difference
- * between the fields.
- */
-static enum PhaseMode analyze_plane(void *ctx, enum PhaseMode mode, AVFrame *old, AVFrame *new)
-{
- double bdiff, tdiff, pdiff;
-
- if (mode == AUTO) {
- mode = new->interlaced_frame ? new->top_field_first ?
- TOP_FIRST : BOTTOM_FIRST : PROGRESSIVE;
- } else if (mode == AUTO_ANALYZE) {
- mode = new->interlaced_frame ? new->top_field_first ?
- TOP_FIRST_ANALYZE : BOTTOM_FIRST_ANALYZE : FULL_ANALYZE;
- }
-
- if (mode <= BOTTOM_FIRST) {
- bdiff = pdiff = tdiff = 65536.0;
- } else {
- const int ns = new->linesize[0];
- const int os = old->linesize[0];
- const uint8_t *nptr = new->data[0];
- const uint8_t *optr = old->data[0];
- const int h = new->height;
- const int w = new->width;
- int bdif, tdif, pdif;
- double scale;
-
- int top = 0, t;
- const uint8_t *rend, *end = nptr + (h - 2) * ns;
-
- bdiff = pdiff = tdiff = 0.0;
-
- nptr += ns;
- optr += os;
- while (nptr < end) {
- pdif = tdif = bdif = 0;
-
- switch (mode) {
- case TOP_FIRST_ANALYZE:
- if (top) {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- tdif += DIFF(nptr, ns, optr, os);
- }
- } else {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- tdif += DIFF(optr, os, nptr, ns);
- }
- }
- break;
- case BOTTOM_FIRST_ANALYZE:
- if (top) {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- bdif += DIFF(optr, os, nptr, ns);
- }
- } else {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- bdif += DIFF(nptr, ns, optr, os);
- }
- }
- break;
- case ANALYZE:
- if (top) {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- tdif += DIFF(nptr, ns, optr, os);
- bdif += DIFF(optr, os, nptr, ns);
- }
- } else {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- bdif += DIFF(nptr, ns, optr, os);
- tdif += DIFF(optr, os, nptr, ns);
- }
- }
- break;
- case FULL_ANALYZE:
- if (top) {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- tdif += DIFF(nptr, ns, optr, os);
- bdif += DIFF(optr, os, nptr, ns);
- }
- } else {
- for (rend = nptr + w; nptr < rend; nptr++, optr++) {
- pdif += DIFF(nptr, ns, nptr, ns);
- bdif += DIFF(nptr, ns, optr, os);
- tdif += DIFF(optr, os, nptr, ns);
- }
- }
- break;
- default:
- av_assert0(0);
- }
-
- pdiff += (double)pdif;
- tdiff += (double)tdif;
- bdiff += (double)bdif;
- nptr += ns - w;
- optr += os - w;
- top ^= 1;
- }
-
- scale = 1.0 / (w * (h - 3)) / 25.0;
- pdiff *= scale;
- tdiff *= scale;
- bdiff *= scale;
-
- if (mode == TOP_FIRST_ANALYZE) {
- bdiff = 65536.0;
- } else if (mode == BOTTOM_FIRST_ANALYZE) {
- tdiff = 65536.0;
- } else if (mode == ANALYZE) {
- pdiff = 65536.0;
- }
-
- if (bdiff < pdiff && bdiff < tdiff) {
- mode = BOTTOM_FIRST;
- } else if (tdiff < pdiff && tdiff < bdiff) {
- mode = TOP_FIRST;
- } else {
- mode = PROGRESSIVE;
- }
- }
-
- av_log(ctx, AV_LOG_DEBUG, "mode=%c tdiff=%f bdiff=%f pdiff=%f\n",
- mode == BOTTOM_FIRST ? 'b' : mode == TOP_FIRST ? 't' : 'p',
- tdiff, bdiff, pdiff);
- return mode;
-}
-