lavfi: Port drawtext filter by Hemanth from the libavfilter soc repo

With the following additions:
* support to anti-aliased glyph rendering
* support to UTF-8 text and Unicode chars rendering
* support for RGB packed formats
* fix minor errors and typos in the filter description
* extend/clarify examples in the filter description

Signed-off-by: Anton Khirnov <anton@khirnov.net>

6 files changed, 805 insertions, 2 deletions

diff --git a/configure b/configure
index a33b6e6f0b..29440d80a9 100755
--- a/configure
+++ b/configure
@@ -169,6 +169,7 @@ External library support:
                            and libraw1394 [no]
   --enable-libdirac        enable Dirac support via libdirac [no]
   --enable-libfaac         enable FAAC support via libfaac [no]
+  --enable-libfreetype     enable libfreetype [no]
   --enable-libgsm          enable GSM support via libgsm [no]
   --enable-libmp3lame      enable MP3 encoding via libmp3lame [no]
   --enable-libnut          enable NUT (de)muxing via libnut,
@@ -928,6 +929,7 @@ CONFIG_LIST="
     libdc1394
     libdirac
     libfaac
+    libfreetype
     libgsm
     libmp3lame
     libnut
@@ -1077,6 +1079,7 @@ HAVE_LIST="
     llrintf
     local_aligned_16
     local_aligned_8
+    localtime_r
     log2
     log2f
     loongson
@@ -1462,6 +1465,7 @@ udp_protocol_deps="network"
 # filters
 blackframe_filter_deps="gpl"
 cropdetect_filter_deps="gpl"
+drawtext_filter_deps="libfreetype"
 frei0r_filter_deps="frei0r dlopen strtok_r"
 frei0r_src_filter_deps="frei0r dlopen strtok_r"
 hqdn3d_filter_deps="gpl"
@@ -2782,6 +2786,7 @@ check_func  getrusage
 check_struct "sys/time.h sys/resource.h" "struct rusage" ru_maxrss
 check_func  inet_aton $network_extralibs
 check_func  isatty
+check_func  localtime_r
 check_func  ${malloc_prefix}memalign            && enable memalign
 check_func  mkstemp
 check_func  mmap
@@ -2868,6 +2873,7 @@ enabled libdirac   && require_pkg_config dirac                          \
     "libdirac_decoder/dirac_parser.h libdirac_encoder/dirac_encoder.h"  \
     "dirac_decoder_init dirac_encoder_init"
 enabled libfaac    && require2 libfaac "stdint.h faac.h" faacEncGetVersion -lfaac
+enabled libfreetype && require_pkg_config freetype2 "ft2build.h freetype/freetype.h" FT_Init_FreeType
 enabled libgsm     && require  libgsm gsm/gsm.h gsm_create -lgsm
 enabled libmp3lame && require  "libmp3lame >= 3.98.3" lame/lame.h lame_set_VBR_quality -lmp3lame
 enabled libnut     && require  libnut libnut.h nut_demuxer_init -lnut
diff --git a/doc/filters.texi b/doc/filters.texi
index 35b61d170d..4f5e2380a3 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -353,6 +353,129 @@ drawbox
 drawbox=10:20:200:60:red@@0.5"
 @end example
 
+@section drawtext
+
+Draw text string or text from specified file on top of video using the
+libfreetype library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libfreetype}.
+
+The filter also recognizes strftime() sequences in the provided text
+and expands them accordingly. Check the documentation of strftime().
+
+The filter accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
+
+The description of the accepted parameters follows.
+
+@table @option
+
+@item fontfile
+The font file to be used for drawing text. Path must be included.
+This parameter is mandatory.
+
+@item text
+The text string to be drawn. The text must be a sequence of UTF-8
+encoded characters.
+This parameter is mandatory if no file is specified with the parameter
+@var{textfile}.
+
+@item textfile
+A text file containing text to be drawn. The text must be a sequence
+of UTF-8 encoded characters.
+
+This parameter is mandatory if no text string is specified with the
+parameter @var{text}.
+
+If both text and textfile are specified, an error is thrown.
+
+@item x, y
+The offsets where text will be drawn within the video frame.
+Relative to the top/left border of the output image.
+
+The default value of @var{x} and @var{y} is 0.
+
+@item fontsize
+The font size to be used for drawing text.
+The default value of @var{fontsize} is 16.
+
+@item fontcolor
+The color to be used for drawing fonts.
+Either a string (e.g. "red") or in 0xRRGGBB[AA] format
+(e.g. "0xff000033"), possibly followed by an alpha specifier.
+The default value of @var{fontcolor} is "black".
+
+@item boxcolor
+The color to be used for drawing box around text.
+Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
+(e.g. "0xff00ff"), possibly followed by an alpha specifier.
+The default value of @var{boxcolor} is "white".
+
+@item box
+Used to draw a box around text using background color.
+Value should be either 1 (enable) or 0 (disable).
+The default value of @var{box} is 0.
+
+@item ft_load_flags
+Flags to be used for loading the fonts.
+
+The flags map the corresponding flags supported by libfreetype, and are
+a combination of the following values:
+@table @var
+@item default
+@item no_scale
+@item no_hinting
+@item render
+@item no_bitmap
+@item vertical_layout
+@item force_autohint
+@item crop_bitmap
+@item pedantic
+@item ignore_global_advance_width
+@item no_recurse
+@item ignore_transform
+@item monochrome
+@item linear_design
+@item no_autohint
+@item end table
+@end table
+
+Default value is "render".
+
+For more information consult the documentation for the FT_LOAD_*
+libfreetype flags.
+
+@item tabsize
+The size in number of spaces to use for rendering the tab.
+Default value is 4.
+@end table
+
+For example the command:
+@example
+drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
+@end example
+
+will draw "Test Text" with font FreeSerif, using the default values
+for the optional parameters.
+
+The command:
+@example
+drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
+          x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
+@end example
+
+will draw 'Test Text' with font FreeSerif of size 24 at position x=100
+and y=50 (counting from the top-left corner of the screen), text is
+yellow with a red box around it. Both the text and the box have an
+opacity of 20%.
+
+Note that the double quotes are not necessary if spaces are not used
+within the parameter list.
+
+For more information about libfreetype, check:
+@url{http://www.freetype.org/}.
+
 @section fade
 
 Apply fade-in/out effect to input video.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 0683af3564..2ed1f937a3 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -26,6 +26,7 @@ OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o
 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
 OBJS-$(CONFIG_CROPDETECT_FILTER)             += vf_cropdetect.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
+OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o
 OBJS-$(CONFIG_FADE_FILTER)                   += vf_fade.o
 OBJS-$(CONFIG_FIELDORDER_FILTER)             += vf_fieldorder.o
 OBJS-$(CONFIG_FIFO_FILTER)                   += vf_fifo.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 9801d9281e..e29b4f97bd 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -45,6 +45,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (CROP,        crop,        vf);
     REGISTER_FILTER (CROPDETECT,  cropdetect,  vf);
     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);
+    REGISTER_FILTER (DRAWTEXT,    drawtext,    vf);
     REGISTER_FILTER (FADE,        fade,        vf);
     REGISTER_FILTER (FIELDORDER,  fieldorder,  vf);
     REGISTER_FILTER (FIFO,        fifo,        vf);
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 8947baadbe..c126cae093 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -26,8 +26,8 @@
 #include "libavutil/samplefmt.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR  3
-#define LIBAVFILTER_VERSION_MICRO  1
+#define LIBAVFILTER_VERSION_MINOR  4
+#define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
new file mode 100644
index 0000000000..21ec176103
--- /dev/null
+++ b/libavfilter/vf_drawtext.c
@@ -0,0 +1,672 @@
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ * Copyright (c) 2010 S.N. Hemanth Meenakshisundaram
+ * Copyright (c) 2003 Gustavo Sverzut Barbieri <gsbarbieri@yahoo.com.br>
+ *
+ * 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
+ * drawtext filter, based on the original FFmpeg vhook/drawtext.c
+ * filter by Gustavo Sverzut Barbieri
+ */
+
+#include <sys/time.h>
+#include <time.h>
+
+#include "libavutil/colorspace.h"
+#include "libavutil/file.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/tree.h"
+#include "avfilter.h"
+#include "drawutils.h"
+
+#undef time
+
+#include <ft2build.h>
+#include <freetype/config/ftheader.h>
+#include FT_FREETYPE_H
+#include FT_GLYPH_H
+
+typedef struct {
+    const AVClass *class;
+    uint8_t *fontfile;              ///< font to be used
+    uint8_t *text;                  ///< text to be drawn
+    uint8_t *text_priv;             ///< used to detect whether text changed
+    int ft_load_flags;              ///< flags used for loading fonts, see FT_LOAD_*
+    FT_Vector *positions;           ///< positions for each element in the text
+    char *textfile;                 ///< file with text to be drawn
+    unsigned int x;                 ///< x position to start drawing text
+    unsigned int y;                 ///< y position to start drawing text
+    unsigned int fontsize;          ///< font size to use
+    char *fontcolor_string;         ///< font color as string
+    char *boxcolor_string;          ///< box color as string
+    uint8_t fontcolor[4];           ///< foreground color
+    uint8_t boxcolor[4];            ///< background color
+    uint8_t fontcolor_rgba[4];      ///< foreground color in RGBA
+    uint8_t boxcolor_rgba[4];       ///< background color in RGBA
+
+    short int draw_box;             ///< draw box around text - true or false
+    int use_kerning;                ///< font kerning is used - true/false
+    int tabsize;                    ///< tab size
+
+    FT_Library library;             ///< freetype font library handle
+    FT_Face face;                   ///< freetype font face handle
+    struct AVTreeNode *glyphs;      ///< rendered glyphs, stored using the UTF-32 char code
+    int hsub, vsub;                 ///< chroma subsampling values
+    int is_packed_rgb;
+    int pixel_step[4];              ///< distance in bytes between the component of each pixel
+    uint8_t rgba_map[4];            ///< map RGBA offsets to the positions in the packed RGBA format
+    uint8_t *box_line[4];           ///< line used for filling the box background
+} DrawTextContext;
+
+#define OFFSET(x) offsetof(DrawTextContext, x)
+
+static const AVOption drawtext_options[]= {
+{"fontfile", "set font file",        OFFSET(fontfile),         FF_OPT_TYPE_STRING, 0,  CHAR_MIN, CHAR_MAX },
+{"text",     "set text",             OFFSET(text),             FF_OPT_TYPE_STRING, 0,  CHAR_MIN, CHAR_MAX },
+{"textfile", "set text file",        OFFSET(textfile),         FF_OPT_TYPE_STRING, 0,  CHAR_MIN, CHAR_MAX },
+{"fontcolor","set foreground color", OFFSET(fontcolor_string), FF_OPT_TYPE_STRING, 0,  CHAR_MIN, CHAR_MAX },
+{"boxcolor", "set box color",        OFFSET(boxcolor_string),  FF_OPT_TYPE_STRING, 0,  CHAR_MIN, CHAR_MAX },
+{"box",      "set box",              OFFSET(draw_box),         FF_OPT_TYPE_INT,    0,         0,        1 },
+{"fontsize", "set font size",        OFFSET(fontsize),         FF_OPT_TYPE_INT,   16,         1,       72 },
+{"x",        "set x",                OFFSET(x),                FF_OPT_TYPE_INT,    0,         0,  INT_MAX },
+{"y",        "set y",                OFFSET(y),                FF_OPT_TYPE_INT,    0,         0,  INT_MAX },
+{"tabsize",  "set tab size",         OFFSET(tabsize),          FF_OPT_TYPE_INT,    4,         0,  INT_MAX },
+
+/* FT_LOAD_* flags */
+{"ft_load_flags", "set font loading flags for libfreetype",   OFFSET(ft_load_flags),  FF_OPT_TYPE_FLAGS,  FT_LOAD_DEFAULT|FT_LOAD_RENDER, 0, INT_MAX, 0, "ft_load_flags" },
+{"default",                     "set default",                     0, FF_OPT_TYPE_CONST, FT_LOAD_DEFAULT,                     INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"no_scale",                    "set no_scale",                    0, FF_OPT_TYPE_CONST, FT_LOAD_NO_SCALE,                    INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"no_hinting",                  "set no_hinting",                  0, FF_OPT_TYPE_CONST, FT_LOAD_NO_HINTING,                  INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"render",                      "set render",                      0, FF_OPT_TYPE_CONST, FT_LOAD_RENDER,                      INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"no_bitmap",                   "set no_bitmap",                   0, FF_OPT_TYPE_CONST, FT_LOAD_NO_BITMAP,                   INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"vertical_layout",             "set vertical_layout",             0, FF_OPT_TYPE_CONST, FT_LOAD_VERTICAL_LAYOUT,             INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"force_autohint",              "set force_autohint",              0, FF_OPT_TYPE_CONST, FT_LOAD_FORCE_AUTOHINT,              INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"crop_bitmap",                 "set crop_bitmap",                 0, FF_OPT_TYPE_CONST, FT_LOAD_CROP_BITMAP,                 INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"pedantic",                    "set pedantic",                    0, FF_OPT_TYPE_CONST, FT_LOAD_PEDANTIC,                    INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"ignore_global_advance_width", "set ignore_global_advance_width", 0, FF_OPT_TYPE_CONST, FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH, INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"no_recurse",                  "set no_recurse",                  0, FF_OPT_TYPE_CONST, FT_LOAD_NO_RECURSE,                  INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"ignore_transform",            "set ignore_transform",            0, FF_OPT_TYPE_CONST, FT_LOAD_IGNORE_TRANSFORM,            INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"monochrome",                  "set monochrome",                  0, FF_OPT_TYPE_CONST, FT_LOAD_MONOCHROME,                  INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"linear_design",               "set linear_design",               0, FF_OPT_TYPE_CONST, FT_LOAD_LINEAR_DESIGN,               INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{"no_autohint",                 "set no_autohint",                 0, FF_OPT_TYPE_CONST, FT_LOAD_NO_AUTOHINT,                 INT_MIN, INT_MAX, 0, "ft_load_flags" },
+{NULL},
+};
+
+static const char *drawtext_get_name(void *ctx)
+{
+    return "drawtext";
+}
+
+static const AVClass drawtext_class = {
+    "DrawTextContext",
+    drawtext_get_name,
+    drawtext_options
+};
+
+#undef __FTERRORS_H__
+#define FT_ERROR_START_LIST {
+#define FT_ERRORDEF(e, v, s) { (e), (s) },
+#define FT_ERROR_END_LIST { 0, NULL } };
+
+struct ft_error
+{
+    int err;
+    const char *err_msg;
+} static ft_errors[] =
+#include FT_ERRORS_H
+
+#define FT_ERRMSG(e) ft_errors[e].err_msg
+
+typedef struct {
+    FT_Glyph *glyph;
+    uint32_t code;
+    FT_Bitmap bitmap; ///< array holding bitmaps of font
+    FT_BBox bbox;
+    int advance;
+    int bitmap_left;
+    int bitmap_top;
+} Glyph;
+
+static int glyph_cmp(void *key, const void *b)
+{
+    const Glyph *a = key, *bb = b;
+    int64_t diff = (int64_t)a->code - (int64_t)bb->code;
+    return diff > 0 ? 1 : diff < 0 ? -1 : 0;
+}
+
+/**
+ * Load glyphs corresponding to the UTF-32 codepoint code.
+ */
+static int load_glyph(AVFilterContext *ctx, Glyph **glyph_ptr, uint32_t code)
+{
+    DrawTextContext *dtext = ctx->priv;
+    Glyph *glyph;
+    struct AVTreeNode *node = NULL;
+    int ret;
+
+    /* load glyph into dtext->face->glyph */
+    if (FT_Load_Char(dtext->face, code, dtext->ft_load_flags))
+        return AVERROR(EINVAL);
+
+    /* save glyph */
+    if (!(glyph = av_mallocz(sizeof(*glyph))) ||
+        !(glyph->glyph = av_mallocz(sizeof(*glyph->glyph)))) {
+        ret = AVERROR(ENOMEM);
+        goto error;
+    }
+    glyph->code  = code;
+
+    if (FT_Get_Glyph(dtext->face->glyph, glyph->glyph)) {
+        ret = AVERROR(EINVAL);
+        goto error;
+    }
+
+    glyph->bitmap      = dtext->face->glyph->bitmap;
+    glyph->bitmap_left = dtext->face->glyph->bitmap_left;
+    glyph->bitmap_top  = dtext->face->glyph->bitmap_top;
+    glyph->advance     = dtext->face->glyph->advance.x >> 6;
+
+    /* measure text height to calculate text_height (or the maximum text height) */
+    FT_Glyph_Get_CBox(*glyph->glyph, ft_glyph_bbox_pixels, &glyph->bbox);
+
+    /* cache the newly created glyph */
+    if (!(node = av_mallocz(av_tree_node_size))) {
+        ret = AVERROR(ENOMEM);
+        goto error;
+    }
+    av_tree_insert(&dtext->glyphs, glyph, glyph_cmp, &node);
+
+    if (glyph_ptr)
+        *glyph_ptr = glyph;
+    return 0;
+
+error:
+    if (glyph)
+        av_freep(&glyph->glyph);
+    av_freep(&glyph);
+    av_freep(&node);
+    return ret;
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    int err;
+    DrawTextContext *dtext = ctx->priv;
+    Glyph *glyph;
+
+    dtext->class = &drawtext_class;
+    av_opt_set_defaults2(dtext, 0, 0);
+    dtext->fontcolor_string = av_strdup("black");
+    dtext->boxcolor_string = av_strdup("white");
+
+    if ((err = (av_set_options_string(dtext, args, "=", ":"))) < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
+        return err;
+    }
+
+    if (!dtext->fontfile) {
+        av_log(ctx, AV_LOG_ERROR, "No font filename provided\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (dtext->textfile) {
+        uint8_t *textbuf;
+        size_t textbuf_size;
+
+        if (dtext->text) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Both text and text file provided. Please provide only one\n");
+            return AVERROR(EINVAL);
+        }
+        if ((err = av_file_map(dtext->textfile, &textbuf, &textbuf_size, 0, ctx)) < 0) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "The text file '%s' could not be read or is empty\n",
+                   dtext->textfile);
+            return err;
+        }
+
+        if (!(dtext->text = av_malloc(textbuf_size+1)))
+            return AVERROR(ENOMEM);
+        memcpy(dtext->text, textbuf, textbuf_size);
+        dtext->text[textbuf_size] = 0;
+        av_file_unmap(textbuf, textbuf_size);
+    }
+
+    if (!dtext->text) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Either text or a valid file must be provided\n");
+        return AVERROR(EINVAL);
+    }
+
+    if ((err = av_parse_color(dtext->fontcolor_rgba, dtext->fontcolor_string, -1, ctx))) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Invalid font color '%s'\n", dtext->fontcolor_string);
+        return err;
+    }
+
+    if ((err = av_parse_color(dtext->boxcolor_rgba, dtext->boxcolor_string, -1, ctx))) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Invalid box color '%s'\n", dtext->boxcolor_string);
+        return err;
+    }
+
+    if ((err = FT_Init_FreeType(&(dtext->library)))) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Could not load FreeType: %s\n", FT_ERRMSG(err));
+        return AVERROR(EINVAL);
+    }
+
+    /* load the face, and set up the encoding, which is by default UTF-8 */
+    if ((err = FT_New_Face(dtext->library, dtext->fontfile, 0, &dtext->face))) {
+        av_log(ctx, AV_LOG_ERROR, "Could not load fontface from file '%s': %s\n",
+               dtext->fontfile, FT_ERRMSG(err));
+        return AVERROR(EINVAL);
+    }
+    if ((err = FT_Set_Pixel_Sizes(dtext->face, 0, dtext->fontsize))) {
+        av_log(ctx, AV_LOG_ERROR, "Could not set font size to %d pixels: %s\n",
+               dtext->fontsize, FT_ERRMSG(err));
+        return AVERROR(EINVAL);
+    }
+
+    dtext->use_kerning = FT_HAS_KERNING(dtext->face);
+
+    /* load the fallback glyph with code 0 */
+    load_glyph(ctx, NULL, 0);
+
+    /* set the tabsize in pixels */
+    if ((err = load_glyph(ctx, &glyph, ' ') < 0)) {
+        av_log(ctx, AV_LOG_ERROR, "Could not set tabsize.\n");
+        return err;
+    }
+    dtext->tabsize *= glyph->advance;
+
+#if !HAVE_LOCALTIME_R
+    av_log(ctx, AV_LOG_WARNING, "strftime() expansion unavailable!\n");
+#endif
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_ARGB,    PIX_FMT_RGBA,
+        PIX_FMT_ABGR,    PIX_FMT_BGRA,
+        PIX_FMT_RGB24,   PIX_FMT_BGR24,
+        PIX_FMT_YUV420P, PIX_FMT_YUV444P,
+        PIX_FMT_YUV422P, PIX_FMT_YUV411P,
+        PIX_FMT_YUV410P, PIX_FMT_YUV440P,
+        PIX_FMT_NONE
+    };
+
+    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int glyph_enu_free(void *opaque, void *elem)
+{
+    av_free(elem);
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    DrawTextContext *dtext = ctx->priv;
+    int i;
+
+    av_freep(&dtext->fontfile);
+    av_freep(&dtext->text);
+    av_freep(&dtext->fontcolor_string);
+    av_freep(&dtext->boxcolor_string);
+    av_freep(&dtext->positions);
+    av_tree_enumerate(dtext->glyphs, NULL, NULL, glyph_enu_free);
+    av_tree_destroy(dtext->glyphs);
+    dtext->glyphs = 0;
+    FT_Done_Face(dtext->face);
+    FT_Done_FreeType(dtext->library);
+
+    for (i = 0; i < 4; i++) {
+        av_freep(&dtext->box_line[i]);
+        dtext->pixel_step[i] = 0;
+    }
+
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    DrawTextContext *dtext = inlink->dst->priv;
+    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
+    int ret;
+
+    dtext->hsub = pix_desc->log2_chroma_w;
+    dtext->vsub = pix_desc->log2_chroma_h;
+
+    if ((ret =
+         ff_fill_line_with_color(dtext->box_line, dtext->pixel_step,
+                                 inlink->w, dtext->boxcolor,
+                                 inlink->format, dtext->boxcolor_rgba,
+                                 &dtext->is_packed_rgb, dtext->rgba_map)) < 0)
+        return ret;
+
+    if (!dtext->is_packed_rgb) {
+        uint8_t *rgba = dtext->fontcolor_rgba;
+        dtext->fontcolor[0] = RGB_TO_Y_CCIR(rgba[0], rgba[1], rgba[2]);
+        dtext->fontcolor[1] = RGB_TO_U_CCIR(rgba[0], rgba[1], rgba[2], 0);
+        dtext->fontcolor[2] = RGB_TO_V_CCIR(rgba[0], rgba[1], rgba[2], 0);
+        dtext->fontcolor[3] = rgba[3];
+    }
+
+    return 0;
+}
+
+#define GET_BITMAP_VAL(r, c)                                            \
+    bitmap->pixel_mode == FT_PIXEL_MODE_MONO ?                          \
+        (bitmap->buffer[(r) * bitmap->pitch + ((c)>>3)] & (0x80 >> ((c)&7))) * 255 : \
+         bitmap->buffer[(r) * bitmap->pitch +  (c)]
+
+#define SET_PIXEL_YUV(picref, yuva_color, val, x, y, hsub, vsub) {           \
+    luma_pos    = ((x)          ) + ((y)          ) * picref->linesize[0]; \
+    chroma_pos1 = ((x) >> (hsub)) + ((y) >> (vsub)) * picref->linesize[1]; \
+    chroma_pos2 = ((x) >> (hsub)) + ((y) >> (vsub)) * picref->linesize[2]; \
+    alpha = (yuva_color[3] * (val)) / 255;                               \
+    picref->data[0][luma_pos] = (alpha * yuva_color[0] + (255 - alpha) * picref->data[0][luma_pos]) >> 8; \
+    alpha = (yuva_color[3] * (val)) / 224;                               \
+    picref->data[1][chroma_pos1] = 16 + (alpha * (yuva_color[1]-16) + (224 - alpha) * (picref->data[1][chroma_pos1]-16)) / 224; \
+    picref->data[2][chroma_pos2] = 16 + (alpha * (yuva_color[2]-16) + (224 - alpha) * (picref->data[2][chroma_pos2]-16)) / 224; \
+}
+
+static inline int draw_glyph_yuv(AVFilterBufferRef *picref, FT_Bitmap *bitmap, unsigned int x,
+                                 unsigned int y, unsigned int width, unsigned int height,
+                                 const uint8_t yuva_color[4], int hsub, int vsub)
+{
+    int r, c, alpha;
+    unsigned int luma_pos, chroma_pos1, chroma_pos2;
+    uint8_t src_val, dst_pixel[4];
+
+    for (r = 0; r < bitmap->rows && r+y < height; r++) {
+        for (c = 0; c < bitmap->width && c+x < width; c++) {
+            /* get pixel in the picref (destination) */
+            dst_pixel[0] = picref->data[0][  c+x           +  (y+r)          * picref->linesize[0]];
+            dst_pixel[1] = picref->data[1][((c+x) >> hsub) + ((y+r) >> vsub) * picref->linesize[1]];
+            dst_pixel[2] = picref->data[2][((c+x) >> hsub) + ((y+r) >> vsub) * picref->linesize[2]];
+
+            /* get intensity value in the glyph bitmap (source) */
+            src_val = GET_BITMAP_VAL(r, c);
+            if (!src_val)
+                continue;
+
+            SET_PIXEL_YUV(picref, yuva_color, src_val, c+x, y+r, hsub, vsub);
+        }
+    }
+
+    return 0;
+}
+
+#define SET_PIXEL_RGB(picref, rgba_color, val, x, y, pixel_step, r_off, g_off, b_off, a_off) { \
+    p   = picref->data[0] + (x) * pixel_step + ((y) * picref->linesize[0]); \
+    alpha = (rgba_color[3] * (val)) / 255;                              \
+    *(p+r_off) = (alpha * rgba_color[0] + (255 - alpha) * *(p+r_off)) >> 8; \
+    *(p+g_off) = (alpha * rgba_color[1] + (255 - alpha) * *(p+g_off)) >> 8; \
+    *(p+b_off) = (alpha * rgba_color[2] + (255 - alpha) * *(p+b_off)) >> 8; \
+}
+
+static inline int draw_glyph_rgb(AVFilterBufferRef *picref, FT_Bitmap *bitmap,
+                                 unsigned int x, unsigned int y,
+                                 unsigned int width, unsigned int height, int pixel_step,
+                                 const uint8_t rgba_color[4], const uint8_t rgba_map[4])
+{
+    int r, c, alpha;
+    uint8_t *p;
+    uint8_t src_val, dst_pixel[4];
+
+    for (r = 0; r < bitmap->rows && r+y < height; r++) {
+        for (c = 0; c < bitmap->width && c+x < width; c++) {
+            /* get pixel in the picref (destination) */
+            dst_pixel[0] = picref->data[0][(c+x + rgba_map[0]) * pixel_step +
+                                           (y+r) * picref->linesize[0]];
+            dst_pixel[1] = picref->data[0][(c+x + rgba_map[1]) * pixel_step +
+                                           (y+r) * picref->linesize[0]];
+            dst_pixel[2] = picref->data[0][(c+x + rgba_map[2]) * pixel_step +
+                                           (y+r) * picref->linesize[0]];
+
+            /* get intensity value in the glyph bitmap (source) */
+            src_val = GET_BITMAP_VAL(r, c);
+            if (!src_val)
+                continue;
+
+            SET_PIXEL_RGB(picref, rgba_color, src_val, c+x, y+r, pixel_step,
+                          rgba_map[0], rgba_map[1], rgba_map[2], rgba_map[3]);
+        }
+    }
+
+    return 0;
+}
+
+static inline void drawbox(AVFilterBufferRef *picref, unsigned int x, unsigned int y,
+                           unsigned int width, unsigned int height,
+                           uint8_t *line[4], int pixel_step[4], uint8_t color[4],
+                           int hsub, int vsub, int is_rgba_packed, uint8_t rgba_map[4])
+{
+    int i, j, alpha;
+
+    if (color[3] != 0xFF) {
+        if (is_rgba_packed) {
+            uint8_t *p;
+            for (j = 0; j < height; j++)
+                for (i = 0; i < width; i++)
+                    SET_PIXEL_RGB(picref, color, 255, i+x, y+j, pixel_step[0],
+                                  rgba_map[0], rgba_map[1], rgba_map[2], rgba_map[3]);
+        } else {
+            unsigned int luma_pos, chroma_pos1, chroma_pos2;
+            for (j = 0; j < height; j++)
+                for (i = 0; i < width; i++)
+                    SET_PIXEL_YUV(picref, color, 255, i+x, y+j, hsub, vsub);
+        }
+    } else {
+        ff_draw_rectangle(picref->data, picref->linesize,
+                          line, pixel_step, hsub, vsub,
+                          x, y, width, height);
+    }
+}
+
+static inline int is_newline(uint32_t c)
+{
+    return (c == '\n' || c == '\r' || c == '\f' || c == '\v');
+}
+
+static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
+                     int width, int height)
+{
+    DrawTextContext *dtext = ctx->priv;
+    uint32_t code = 0, prev_code = 0;
+    int x = 0, y = 0, i = 0;
+    int text_height, baseline;
+    uint8_t *p;
+    int str_w = 0;
+    int y_min = 32000, y_max = -32000;
+    FT_Vector delta;
+    Glyph *glyph = NULL, *prev_glyph = NULL;
+    Glyph dummy = { 0 };
+
+    if (dtext->text != dtext->text_priv) {
+#if HAVE_LOCALTIME_R
+        time_t now = time(0);
+        struct tm ltime;
+        uint8_t *buf = NULL;
+        int     buflen = 2*strlen(dtext->text) + 1, len;
+
+        localtime_r(&now, &ltime);
+
+        while ((buf = av_realloc(buf, buflen))) {
+            *buf = 1;
+            if ((len = strftime(buf, buflen, dtext->text, &ltime)) != 0 || *buf == 0)
+                break;
+            buflen *= 2;
+        }
+        if (!buf)
+            return AVERROR(ENOMEM);
+        av_freep(&dtext->text);
+        dtext->text = dtext->text_priv = buf;
+#else
+        dtext->text_priv = dtext->text;
+#endif
+        if (!(dtext->positions = av_realloc(dtext->positions,
+                                            strlen(dtext->text)*sizeof(*dtext->positions))))
+            return AVERROR(ENOMEM);
+    }
+
+    x = dtext->x;
+    y = dtext->y;
+
+    /* load and cache glyphs */
+    for (i = 0, p = dtext->text; *p; i++) {
+        GET_UTF8(code, *p++, continue;);
+
+        /* get glyph */
+        dummy.code = code;
+        glyph = av_tree_find(dtext->glyphs, &dummy, glyph_cmp, NULL);
+        if (!glyph)
+            load_glyph(ctx, &glyph, code);
+
+        y_min = FFMIN(glyph->bbox.yMin, y_min);
+        y_max = FFMAX(glyph->bbox.yMax, y_max);
+    }
+    text_height = y_max - y_min;
+    baseline    = y_max;
+
+    /* compute and save position for each glyph */
+    glyph = NULL;
+    for (i = 0, p = dtext->text; *p; i++) {
+        GET_UTF8(code, *p++, continue;);
+
+        /* skip the \n in the sequence \r\n */
+        if (prev_code == '\r' && code == '\n')
+            continue;
+
+        prev_code = code;
+        if (is_newline(code)) {
+            str_w = FFMAX(str_w, x - dtext->x);
+            y += text_height;
+            x = dtext->x;
+            continue;
+        }
+
+        /* get glyph */
+        prev_glyph = glyph;
+        dummy.code = code;
+        glyph = av_tree_find(dtext->glyphs, &dummy, glyph_cmp, NULL);
+
+        /* kerning */
+        if (dtext->use_kerning && prev_glyph && glyph->code) {
+            FT_Get_Kerning(dtext->face, prev_glyph->code, glyph->code,
+                           ft_kerning_default, &delta);
+            x += delta.x >> 6;
+        }
+
+        if (x + glyph->bbox.xMax >= width) {
+            str_w = FFMAX(str_w, x - dtext->x);
+            y += text_height;
+            x = dtext->x;
+        }
+
+        /* save position */
+        dtext->positions[i].x = x + glyph->bitmap_left;
+        dtext->positions[i].y = y - glyph->bitmap_top + baseline;
+        if (code == '\t') x  = (x / dtext->tabsize + 1)*dtext->tabsize;
+        else              x += glyph->advance;
+    }
+
+    str_w = FFMIN(width - dtext->x - 1, FFMAX(str_w, x - dtext->x));
+    y     = FFMIN(y + text_height, height - 1);
+
+    /* draw box */
+    if (dtext->draw_box)
+        drawbox(picref, dtext->x, dtext->y, str_w, y-dtext->y,
+                dtext->box_line, dtext->pixel_step, dtext->boxcolor,
+                dtext->hsub, dtext->vsub, dtext->is_packed_rgb, dtext->rgba_map);
+
+    /* draw glyphs */
+    for (i = 0, p = dtext->text; *p; i++) {
+        Glyph dummy = { 0 };
+        GET_UTF8(code, *p++, continue;);
+
+        /* skip new line chars, just go to new line */
+        if (is_newline(code) || code == ' ' || code == '\t')
+            continue;
+
+        dummy.code = code;
+        glyph = av_tree_find(dtext->glyphs, &dummy, glyph_cmp, NULL);
+
+        if (glyph->bitmap.pixel_mode != FT_PIXEL_MODE_MONO &&
+            glyph->bitmap.pixel_mode != FT_PIXEL_MODE_GRAY)
+            return AVERROR(EINVAL);
+
+        if (dtext->is_packed_rgb) {
+            draw_glyph_rgb(picref, &glyph->bitmap,
+                           dtext->positions[i].x, dtext->positions[i].y, width, height,
+                           dtext->pixel_step[0], dtext->fontcolor_rgba, dtext->rgba_map);
+        } else {
+            draw_glyph_yuv(picref, &glyph->bitmap,
+                           dtext->positions[i].x, dtext->positions[i].y, width, height,
+                           dtext->fontcolor, dtext->hsub, dtext->vsub);
+        }
+    }
+
+    return 0;
+}
+
+static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { }
+
+static void end_frame(AVFilterLink *inlink)
+{
+    AVFilterLink *outlink = inlink->dst->outputs[0];
+    AVFilterBufferRef *picref = inlink->cur_buf;
+
+    draw_text(inlink->dst, picref, picref->video->w, picref->video->h);
+
+    avfilter_draw_slice(outlink, 0, picref->video->h, 1);
+    avfilter_end_frame(outlink);
+}
+
+AVFilter avfilter_vf_drawtext = {
+    .name          = "drawtext",
+    .description   = NULL_IF_CONFIG_SMALL("Draw text on top of video frames using libfreetype library."),
+    .priv_size     = sizeof(DrawTextContext),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+
+    .inputs    = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO,
+                                    .get_video_buffer = avfilter_null_get_video_buffer,
+                                    .start_frame      = avfilter_null_start_frame,
+                                    .draw_slice       = null_draw_slice,
+                                    .end_frame        = end_frame,
+                                    .config_props     = config_input,
+                                    .min_perms        = AV_PERM_WRITE |
+                                                        AV_PERM_READ,
+                                    .rej_perms        = AV_PERM_PRESERVE },
+                                  { .name = NULL}},
+    .outputs   = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO, },
+                                  { .name = NULL}},
+};