static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref) { AVFilterContext *ctx = link->dst; CropContext *crop = ctx->priv; AVFilterBufferRef *ref2; int i; picref->video->w = crop->w; picref->video->h = crop->h; ref2 = avfilter_ref_buffer(picref, ~0); crop->var_values[VAR_T] = picref->pts == AV_NOPTS_VALUE ? NAN : picref->pts * av_q2d(link->time_base); crop->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos; crop->var_values[VAR_X] = av_expr_eval(crop->x_pexpr, crop->var_values, NULL); crop->var_values[VAR_Y] = av_expr_eval(crop->y_pexpr, crop->var_values, NULL); crop->var_values[VAR_X] = av_expr_eval(crop->x_pexpr, crop->var_values, NULL); normalize_double(&crop->x, crop->var_values[VAR_X]); normalize_double(&crop->y, crop->var_values[VAR_Y]); if (crop->x < 0) crop->x = 0; if (crop->y < 0) crop->y = 0; if ((unsigned)crop->x + (unsigned)crop->w > link->w) crop->x = link->w - crop->w; if ((unsigned)crop->y + (unsigned)crop->h > link->h) crop->y = link->h - crop->h; crop->x &= ~((1 << crop->hsub) - 1); crop->y &= ~((1 << crop->vsub) - 1); av_log(ctx, AV_LOG_DEBUG, "n:%d t:%f x:%d y:%d x+w:%d y+h:%d\n", (int)crop->var_values[VAR_N], crop->var_values[VAR_T], crop->x, crop->y, crop->x+crop->w, crop->y+crop->h); ref2->data[0] += crop->y * ref2->linesize[0]; ref2->data[0] += crop->x * crop->max_step[0]; if (!(av_pix_fmt_descriptors[link->format].flags & PIX_FMT_PAL)) { for (i = 1; i < 3; i ++) { if (ref2->data[i]) { ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i]; ref2->data[i] += (crop->x * crop->max_step[i]) >> crop->hsub; } } } /* alpha plane */ if (ref2->data[3]) { ref2->data[3] += crop->y * ref2->linesize[3]; ref2->data[3] += crop->x * crop->max_step[3]; } avfilter_start_frame(link->dst->outputs[0], ref2); }