libavfilter: Add interlace detect filter.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/filters.texi

@@ -1695,6 +1695,11 @@ a float number which specifies chroma temporal strength, defaults to
 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
 @end table
 
+@section idet
+
+Interlaceing detect filter. This filter tries to detect if the input is
+interlaced or progressive. Top or bottom field first.
+
 @section lut, lutrgb, lutyuv
 
 Compute a look-up table for binding each pixel component input value

libavfilter/Makefile

@@ -67,6 +67,7 @@ OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o
 OBJS-$(CONFIG_GRADFUN_FILTER)                += vf_gradfun.o
 OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
 OBJS-$(CONFIG_HQDN3D_FILTER)                 += vf_hqdn3d.o
+OBJS-$(CONFIG_IDET_FILTER)                   += vf_idet.o
 OBJS-$(CONFIG_LUT_FILTER)                    += vf_lut.o
 OBJS-$(CONFIG_LUTRGB_FILTER)                 += vf_lut.o
 OBJS-$(CONFIG_LUTYUV_FILTER)                 += vf_lut.o

libavfilter/allfilters.c

@@ -75,6 +75,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (GRADFUN,     gradfun,     vf);
     REGISTER_FILTER (HFLIP,       hflip,       vf);
     REGISTER_FILTER (HQDN3D,      hqdn3d,      vf);
+    REGISTER_FILTER (IDET,        idet,        vf);
     REGISTER_FILTER (LUT,         lut,         vf);
     REGISTER_FILTER (LUTRGB,      lutrgb,      vf);
     REGISTER_FILTER (LUTYUV,      lutyuv,      vf);

libavfilter/vf_idet.c

@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2012 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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 "libavutil/cpu.h"
+#include "libavutil/common.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+
+#undef NDEBUG
+#include <assert.h>
+
+typedef struct {
+    float interlace_threshold;
+    float progressive_threshold;
+
+    AVFilterBufferRef *cur;
+    AVFilterBufferRef *next;
+    AVFilterBufferRef *prev;
+    AVFilterBufferRef *out;
+    int (*filter_line)(uint8_t *prev, uint8_t *cur, uint8_t *next, int w);
+
+    const AVPixFmtDescriptor *csp;
+} IDETContext;
+
+
+static int filter_line_c(const uint8_t *a, const uint8_t *b, const uint8_t *c, int w)
+{
+    int x;
+    int ret=0;
+
+    for(x=0; x<w; x++){
+        ret += FFABS((*a++ + *c++) - 2 * *b++);
+    }
+
+    return ret;
+}
+
+static int filter_line_c_16bit(const uint16_t *a, const uint16_t *b, const uint16_t *c, int w)
+{
+    int x;
+    int ret=0;
+
+    for(x=0; x<w; x++){
+        ret += FFABS((*a++ + *c++) - 2 * *b++);
+    }
+
+    return ret;
+}
+
+static void filter(AVFilterContext *ctx)
+{
+    IDETContext *idet = ctx->priv;
+    int y, i;
+    int64_t alpha[2]={0};
+    int64_t delta=0;
+    static int p=0, t=0, b=0, u=0;
+
+    for (i = 0; i < idet->csp->nb_components; i++) {
+        int w = idet->cur->video->w;
+        int h = idet->cur->video->h;
+        int refs = idet->cur->linesize[i];
+        int df = (idet->csp->comp[i].depth_minus1 + 8) / 8;
+
+        if (i && i<3) {
+            w >>= idet->csp->log2_chroma_w;
+            h >>= idet->csp->log2_chroma_h;
+        }
+
+        for (y = 2; y < h - 2; y++) {
+            uint8_t *prev = &idet->prev->data[i][y*refs];
+            uint8_t *cur  = &idet->cur ->data[i][y*refs];
+            uint8_t *next = &idet->next->data[i][y*refs];
+            alpha[ y   &1] += idet->filter_line(cur-refs, prev, cur+refs, w);
+            alpha[(y^1)&1] += idet->filter_line(cur-refs, next, cur+refs, w);
+            delta          += idet->filter_line(cur-refs,  cur, cur+refs, w);
+        }
+    }
+#if HAVE_MMX
+    __asm__ volatile("emms \n\t" : : : "memory");
+#endif
+
+    if      (alpha[0] / (float)alpha[1] > idet->interlace_threshold){
+        av_log(0, AV_LOG_INFO, "Interlaced, top field first\n");
+        t++;
+    }else if(alpha[1] / (float)alpha[0] > idet->interlace_threshold){
+        av_log(0, AV_LOG_INFO, "Interlaced, bottom field first\n");
+        b++;
+    }else if(alpha[1] / (float)delta    > idet->progressive_threshold){
+        av_log(0, AV_LOG_INFO, "Progressive\n");
+        p++;
+    }else{
+        av_log(0, AV_LOG_INFO, "Undetermined\n");
+        u++;
+    }
+//     av_log(0,0, "t%d b%d p%d u%d\n", t,b,p,u);
+}
+
+static void return_frame(AVFilterContext *ctx)
+{
+}
+
+static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
+{
+    AVFilterContext *ctx = link->dst;
+    IDETContext *idet = ctx->priv;
+
+    if (idet->prev)
+        avfilter_unref_buffer(idet->prev);
+    idet->prev = idet->cur;
+    idet->cur  = idet->next;
+    idet->next = picref;
+
+    if (!idet->cur)
+        return;
+
+    if (!idet->prev)
+        idet->prev = avfilter_ref_buffer(idet->cur, AV_PERM_READ);
+
+    avfilter_start_frame(ctx->outputs[0], avfilter_ref_buffer(idet->cur, AV_PERM_READ));
+}
+
+static void end_frame(AVFilterLink *link)
+{
+    AVFilterContext *ctx = link->dst;
+    IDETContext *idet = ctx->priv;
+
+    if (!idet->cur)
+        return;
+
+    if (!idet->csp)
+        idet->csp = &av_pix_fmt_descriptors[link->format];
+    if (idet->csp->comp[0].depth_minus1 / 8 == 1)
+        idet->filter_line = (void*)filter_line_c_16bit;
+
+    filter(ctx);
+
+    avfilter_draw_slice(ctx->outputs[0], 0, link->h, 1);
+    avfilter_end_frame(ctx->outputs[0]);
+}
+
+static int request_frame(AVFilterLink *link)
+{
+    AVFilterContext *ctx = link->src;
+    IDETContext *idet = ctx->priv;
+
+    do {
+        int ret;
+
+        if ((ret = avfilter_request_frame(link->src->inputs[0])))
+            return ret;
+    } while (!idet->cur);
+
+    return 0;
+}
+
+static int poll_frame(AVFilterLink *link)
+{
+    IDETContext *idet = link->src->priv;
+    int ret, val;
+
+    val = avfilter_poll_frame(link->src->inputs[0]);
+
+    if (val >= 1 && !idet->next) { //FIXME change API to not requre this red tape
+        if ((ret = avfilter_request_frame(link->src->inputs[0])) < 0)
+            return ret;
+        val = avfilter_poll_frame(link->src->inputs[0]);
+    }
+    assert(idet->next || !val);
+
+    return val;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    IDETContext *idet = ctx->priv;
+
+    if (idet->prev) avfilter_unref_buffer(idet->prev);
+    if (idet->cur ) avfilter_unref_buffer(idet->cur );
+    if (idet->next) avfilter_unref_buffer(idet->next);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_YUV420P,
+        PIX_FMT_YUV422P,
+        PIX_FMT_YUV444P,
+        PIX_FMT_YUV410P,
+        PIX_FMT_YUV411P,
+        PIX_FMT_GRAY8,
+        PIX_FMT_YUVJ420P,
+        PIX_FMT_YUVJ422P,
+        PIX_FMT_YUVJ444P,
+        AV_NE( PIX_FMT_GRAY16BE, PIX_FMT_GRAY16LE ),
+        PIX_FMT_YUV440P,
+        PIX_FMT_YUVJ440P,
+        AV_NE( PIX_FMT_YUV420P10BE, PIX_FMT_YUV420P10LE ),
+        AV_NE( PIX_FMT_YUV422P10BE, PIX_FMT_YUV422P10LE ),
+        AV_NE( PIX_FMT_YUV444P10BE, PIX_FMT_YUV444P10LE ),
+        AV_NE( PIX_FMT_YUV420P16BE, PIX_FMT_YUV420P16LE ),
+        AV_NE( PIX_FMT_YUV422P16BE, PIX_FMT_YUV422P16LE ),
+        AV_NE( PIX_FMT_YUV444P16BE, PIX_FMT_YUV444P16LE ),
+        PIX_FMT_YUVA420P,
+        PIX_FMT_NONE
+    };
+
+    avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    IDETContext *idet = ctx->priv;
+    int cpu_flags = av_get_cpu_flags();
+
+    idet->csp = NULL;
+
+    idet->interlace_threshold   = 1.01;
+    idet->progressive_threshold = 2.5;
+
+    if (args) sscanf(args, "%f:%f", &idet->interlace_threshold, &idet->progressive_threshold);
+
+    idet->filter_line = filter_line_c;
+
+    return 0;
+}
+
+static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { }
+
+AVFilter avfilter_vf_idet = {
+    .name          = "idet",
+    .description   = NULL_IF_CONFIG_SMALL("Interlace detect Filter."),
+
+    .priv_size     = sizeof(IDETContext),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+
+    .inputs    = (const AVFilterPad[]) {{ .name       = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO,
+                                    .start_frame      = start_frame,
+                                    .draw_slice       = null_draw_slice,
+                                    .end_frame        = end_frame,
+                                    .rej_perms        = AV_PERM_REUSE2, },
+                                  { .name = NULL}},
+
+    .outputs   = (const AVFilterPad[]) {{ .name       = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO,
+                                    .poll_frame       = poll_frame,
+                                    .request_frame    = request_frame, },
+                                  { .name = NULL}},
+};