lavfi: add fieldorder filter

Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Changelog

@@ -90,6 +90,7 @@ version 0.7_beta1:
 - AAC encoding via libvo-aacenc
 - AMR-WB encoding via libvo-amrwbenc
 - xWMA demuxer
+- fieldorder video filter added
 
 
 version 0.6:

doc/filters.texi

@@ -386,6 +386,39 @@ fade=in:0:25, fade=out:975:25
 fade=in:5:20
 @end example
 
+@section fieldorder
+
+Transform the field order of the input video.
+
+It accepts one parameter which specifies the required field order that
+the input interlaced video will be transformed to. The parameter can
+assume one of the following values:
+
+@table @option
+@item 0 or bff
+output bottom field first
+@item 1 or tff
+output top field first
+@end table
+
+Default value is "tff".
+
+Transformation is achieved by shifting the picture content up or down
+by one line, and filling the remaining line with appropriate picture content.
+This method is consistent with most broadcast field order converters.
+
+If the input video is not flagged as being interlaced, or it is already
+flagged as being of the required output field order then this filter does
+not alter the incoming video.
+
+This filter is very useful when converting to or from PAL DV material,
+which is bottom field first.
+
+For example:
+@example
+./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
+@end example
+
 @section fifo
 
 Buffer input images and send them when they are requested.

libavfilter/Makefile

@@ -27,6 +27,7 @@ OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
 OBJS-$(CONFIG_CROPDETECT_FILTER)             += vf_cropdetect.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
 OBJS-$(CONFIG_FADE_FILTER)                   += vf_fade.o
+OBJS-$(CONFIG_FIELDORDER_FILTER)             += vf_fieldorder.o
 OBJS-$(CONFIG_FIFO_FILTER)                   += vf_fifo.o
 OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o
 OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o

libavfilter/allfilters.c

@@ -46,6 +46,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (CROPDETECT,  cropdetect,  vf);
     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);
     REGISTER_FILTER (FADE,        fade,        vf);
+    REGISTER_FILTER (FIELDORDER,  fieldorder,  vf);
     REGISTER_FILTER (FIFO,        fifo,        vf);
     REGISTER_FILTER (FORMAT,      format,      vf);
     REGISTER_FILTER (FREI0R,      frei0r,      vf);

libavfilter/avfilter.h

@@ -26,7 +26,7 @@
 #include "libavutil/samplefmt.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR  0
+#define LIBAVFILTER_VERSION_MINOR  1
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_fieldorder.c

@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2011 Mark Himsley
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * video field order filter, heavily influenced by vf_pad.c
+ */
+
+/* #define DEBUG */
+
+#include "libavutil/imgutils.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+
+typedef struct
+{
+    unsigned int dst_tff;      ///< output bff/tff
+    int          line_size[4]; ///< bytes of pixel data per line for each plane
+} FieldOrderContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    FieldOrderContext *fieldorder = ctx->priv;
+
+    const char *tff = "tff";
+    const char *bff = "bff";
+
+    if (!args) {
+        fieldorder->dst_tff = 1;
+    } else if (sscanf(args, "%u", &fieldorder->dst_tff) == 1) {
+        fieldorder->dst_tff = !!fieldorder->dst_tff;
+    } else if (!strcmp(tff, args)) {
+        fieldorder->dst_tff = 1;
+    } else if (!strcmp(bff, args)) {
+        fieldorder->dst_tff = 0;
+    } else {
+        av_log(ctx, AV_LOG_ERROR, "Invalid argument '%s'.\n", args);
+        return AVERROR(EINVAL);
+    }
+
+    av_log(ctx, AV_LOG_INFO, "output field order: %s\n",
+            fieldorder->dst_tff ? tff : bff);
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats  *formats;
+    enum PixelFormat pix_fmt;
+    int              ret;
+
+    /** accept any input pixel format that is not hardware accelerated, not
+     *  a bitstream format, and does not have vertically sub-sampled chroma */
+    if (ctx->inputs[0]) {
+        formats = NULL;
+        for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
+            if (!(  av_pix_fmt_descriptors[pix_fmt].flags & PIX_FMT_HWACCEL
+                 || av_pix_fmt_descriptors[pix_fmt].flags & PIX_FMT_BITSTREAM)
+                && av_pix_fmt_descriptors[pix_fmt].nb_components
+                && !av_pix_fmt_descriptors[pix_fmt].log2_chroma_h
+                && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
+                avfilter_formats_unref(&formats);
+                return ret;
+            }
+        avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);
+        avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);
+    }
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext   *ctx        = inlink->dst;
+    FieldOrderContext *fieldorder = ctx->priv;
+    int               plane;
+
+    /** full an array with the number of bytes that the video
+     *  data occupies per line for each plane of the input video */
+    for (plane = 0; plane < 4; plane++) {
+        fieldorder->line_size[plane] = av_image_get_linesize(
+                inlink->format,
+                inlink->w,
+                plane);
+    }
+
+    return 0;
+}
+
+static AVFilterBufferRef *get_video_buffer(AVFilterLink *inlink, int perms, int w, int h)
+{
+    AVFilterContext   *ctx        = inlink->dst;
+    AVFilterLink      *outlink    = ctx->outputs[0];
+
+    return avfilter_get_video_buffer(outlink, perms, w, h);
+}
+
+static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
+{
+    AVFilterContext   *ctx        = inlink->dst;
+    AVFilterLink      *outlink    = ctx->outputs[0];
+
+    AVFilterBufferRef *outpicref;
+
+    outpicref = avfilter_ref_buffer(inpicref, ~0);
+    outlink->out_buf = outpicref;
+
+    avfilter_start_frame(outlink, outpicref);
+}
+
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+    AVFilterContext   *ctx        = inlink->dst;
+    FieldOrderContext *fieldorder = ctx->priv;
+    AVFilterLink      *outlink    = ctx->outputs[0];
+
+    AVFilterBufferRef *inpicref   = inlink->cur_buf;
+
+    /** can only currently do slices if this filter is doing nothing
+     *  because this filter is moving picture content, the output
+     *  slice will contain different video lines than the input slice
+     *  and that complexity will be added later */
+    if (  !inpicref->video->interlaced
+        || inpicref->video->top_field_first == fieldorder->dst_tff) {
+        avfilter_draw_slice(outlink, y, h, slice_dir);
+    }
+}
+
+static void end_frame(AVFilterLink *inlink)
+{
+    AVFilterContext   *ctx        = inlink->dst;
+    FieldOrderContext *fieldorder = ctx->priv;
+    AVFilterLink      *outlink    = ctx->outputs[0];
+
+    AVFilterBufferRef *inpicref   = inlink->cur_buf;
+    AVFilterBufferRef *outpicref  = outlink->out_buf;
+
+    int               h, w, plane, line_step, line_size, line;
+    uint8_t           *cpy_src, *cpy_dst;
+
+    if (    inpicref->video->interlaced
+         && inpicref->video->top_field_first != fieldorder->dst_tff) {
+        av_dlog(ctx,
+                "picture will move %s one line\n",
+                fieldorder->dst_tff ? "up" : "down");
+        h = inpicref->video->h;
+        w = inpicref->video->w;
+        for (plane = 0; plane < 4 && inpicref->data[plane]; plane++) {
+            line_step = inpicref->linesize[plane];
+            line_size = fieldorder->line_size[plane];
+            cpy_src = inpicref->data[plane];
+            cpy_dst = outpicref->data[plane];
+            if (fieldorder->dst_tff) {
+                /** Move every line up one line, working from
+                 *  the top to the bottom of the frame.
+                 *  The original top line is lost.
+                 *  The new last line is created as a copy of the
+                 *  penultimate line from that field. */
+                for (line = 0; line < h; line++) {
+                    if (1 + line < outpicref->video->h) {
+                        memcpy(cpy_dst, cpy_src + line_step, line_size);
+                    } else {
+                        memcpy(cpy_dst, cpy_src - line_step - line_step, line_size);
+                    }
+                    cpy_src += line_step;
+                    cpy_dst += line_step;
+                }
+            } else {
+                /** Move every line down one line, working from
+                 *  the bottom to the top of the frame.
+                 *  The original bottom line is lost.
+                 *  The new first line is created as a copy of the
+                 *  second line from that field. */
+                cpy_src += (h - 1) * line_step;
+                cpy_dst += (h - 1) * line_step;
+                for (line = h - 1; line >= 0 ; line--) {
+                    if (line > 0) {
+                        memcpy(cpy_dst, cpy_src - line_step, line_size);
+                    } else {
+                        memcpy(cpy_dst, cpy_src + line_step + line_step, line_size);
+                    }
+                    cpy_src -= line_step;
+                    cpy_dst -= line_step;
+                }
+            }
+        }
+        outpicref->video->top_field_first = fieldorder->dst_tff;
+        avfilter_draw_slice(outlink, 0, h, 1);
+    } else {
+        av_dlog(ctx,
+                "not interlaced or field order already correct\n");
+    }
+
+    avfilter_end_frame(outlink);
+    avfilter_unref_buffer(inpicref);
+}
+
+AVFilter avfilter_vf_fieldorder = {
+    .name          = "fieldorder",
+    .description   = NULL_IF_CONFIG_SMALL("Set the field order."),
+    .init          = init,
+    .priv_size     = sizeof(FieldOrderContext),
+    .query_formats = query_formats,
+    .inputs        = (AVFilterPad[]) {{ .name             = "default",
+                                        .type             = AVMEDIA_TYPE_VIDEO,
+                                        .config_props     = config_input,
+                                        .start_frame      = start_frame,
+                                        .get_video_buffer = get_video_buffer,
+                                        .draw_slice       = draw_slice,
+                                        .end_frame        = end_frame,
+                                        .min_perms        = AV_PERM_READ,
+                                        .rej_perms        = AV_PERM_REUSE2|AV_PERM_PRESERVE,},
+                                      { .name = NULL}},
+    .outputs       = (AVFilterPad[]) {{ .name             = "default",
+                                        .type             = AVMEDIA_TYPE_VIDEO, },
+                                      { .name = NULL}},
+};