[FFmpeg-devel] [PATCH] added expr evaluation to drawtext - fontsize

Michael Niedermayer michael at niedermayer.cc
Thu Sep 8 18:50:49 EEST 2016


On Tue, Sep 06, 2016 at 10:27:24AM -0700, Brett Harrison wrote:
> This patch addresses your concerns.
> 
> On Fri, Sep 2, 2016 at 5:05 PM, Michael Niedermayer <michael at niedermayer.cc>
> wrote:
> 
> > On Fri, Sep 02, 2016 at 03:31:21PM -0700, Brett Harrison wrote:
> > > Addressed the following concerns.
> > >
> > > ===
> > >
> > > >libavfilter/vf_drawtext.c: In function ‘update_fontsize’:
> > > >libavfilter/vf_drawtext.c:422:5: warning: ISO C90 forbids mixed
> > declarations and code [->Wdeclaration-after-statement]
> > >
> > > Fixed this.
> > >
> > > >also patch breaks:
> > > >./ffmpeg -i m.mpg  -vf >drawtext=fontfile=/usr/share/
> > fonts/truetype/msttcorefonts/arial.ttf:text=a -f null -
> > >
> > > >[AVFilterGraph @ 0x37a6960] Error initializing filter 'drawtext' with
> > args >'fontfile=/usr/share/fonts/truetype/msttcorefonts/arial.ttf:text=a'
> > >
> > > This is fixed.
> > >
> > > ===
> > >
> > > >>* +        av_log(ctx, AV_LOG_ERROR, "Font not open\n");
> > > *
> > > >I was wondering: Was does this message tell the user?
> > >
> > > I changed this error to read "Unable to initialize font".  This error
> > > should only be seen if set_fontsize() is called before the font is
> > > loaded.  I don't think a user would be able to cause this because if
> > > the font fails to load ffmpeg would error out before this.  It is a
> > > sanity check.
> > >
> > > ===
> > >
> > > For the concerns about multiple to many brackets on "if ((ret =
> > > update_fontsize(ctx)))",
> > >
> > > I removed the "ret =" part as I wasn't using the value anyway.
> > >
> > >
> > > On Fri, Sep 2, 2016 at 6:13 AM, Nicolas George <george at nsup.org> wrote:
> > >
> > > > Le septidi 17 fructidor, an CCXXIV, Moritz Barsnick a écrit :
> > > > > *Assuming* he means "assign update_fontsize()'s return value to ret,
> > > > > and check whether ret is != 0", which would correspond to the more
> > > > > verbose
> > > > >   if ((ret = update_fontsize(ctx)) != 0) {
> > > > >
> > > > > is it sufficient to say:
> > > > >   if (ret = update_fontsize(ctx)) {
> > > > >
> > > > > or is it required, or is it more readable or even desired by "style
> > > > > guide" to say:
> > > > >   if ((ret = update_fontsize(ctx))) {
> > > > > (to clarify it's a check of an assignment) - this is what Brett used,
> > > >
> > > > Ah. Parentheses over the whole expression are always optional, but in
> > this
> > > > particular case, there is a good reason:
> > > >
> > > > <stdin>:4:1: warning: suggest parentheses around assignment used as
> > truth
> > > > value [-Wparentheses]
> > > >
> > > > Forgetting to double the equal in a comparison is a common mistake,
> > > > compilers detect it. But then you need a way of stating when it is
> > > > intentional.
> > > >
> > > > Regards,
> > > >
> > > > --
> > > >   Nicolas George
> > > >
> > > > _______________________________________________
> > > > ffmpeg-devel mailing list
> > > > ffmpeg-devel at ffmpeg.org
> > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > > >
> > > >
> >
> > >  vf_drawtext.c |  125 ++++++++++++++++++++++++++++++
> > +++++++++++++++++++++-------
> > >  1 file changed, 112 insertions(+), 13 deletions(-)
> > > 311d60f04d959ddfd47ed8ea66d0f015725dd511  0001-added-expr-evaluation-to-
> > drawtext-fontsize.patch
> > > From 665b3f1c458222d64a9ba4f1c71d343766ee9e6b Mon Sep 17 00:00:00 2001
> > > From: Brett Harrison <brett.harrison at musicmastermind.com>
> > > Date: Fri, 26 Aug 2016 14:29:34 -0700
> > > Subject: [PATCH] added expr evaluation to drawtext - fontsize
> > >
> > > ---
> > >  libavfilter/vf_drawtext.c | 125 ++++++++++++++++++++++++++++++
> > +++++++++++-----
> > >  1 file changed, 112 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> > > index 214aef0..a483679 100644
> > > --- a/libavfilter/vf_drawtext.c
> > > +++ b/libavfilter/vf_drawtext.c
> > > @@ -156,7 +156,10 @@ typedef struct DrawTextContext {
> > >      int max_glyph_h;                ///< max glyph height
> > >      int shadowx, shadowy;
> > >      int borderw;                    ///< border width
> > > +    char *fontsize_expr;            ///< expression for fontsize
> > > +    AVExpr *fontsize_pexpr;         ///< parsed expressions for fontsize
> > >      unsigned int fontsize;          ///< font size to use
> > > +    unsigned int default_fontsize;  ///< default font size to use
> > >
> > >      short int draw_box;             ///< draw box around text - true or
> > false
> > >      int boxborderw;                 ///< box border width
> > > @@ -209,7 +212,7 @@ static const AVOption drawtext_options[]= {
> > >      {"shadowcolor", "set shadow color",     OFFSET(shadowcolor.rgba),
> >  AV_OPT_TYPE_COLOR,  {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS},
> > >      {"box",         "set box",              OFFSET(draw_box),
> >  AV_OPT_TYPE_BOOL,   {.i64=0},     0,        1       , FLAGS},
> > >      {"boxborderw",  "set box border width", OFFSET(boxborderw),
> >  AV_OPT_TYPE_INT,    {.i64=0},     INT_MIN,  INT_MAX , FLAGS},
> > > -    {"fontsize",    "set font size",        OFFSET(fontsize),
> >  AV_OPT_TYPE_INT,    {.i64=0},     0,        INT_MAX , FLAGS},
> > > +    {"fontsize",    "set font size",        OFFSET(fontsize_expr),
> > AV_OPT_TYPE_STRING, {.str=NULL},  CHAR_MIN, CHAR_MAX , FLAGS},
> > >      {"x",           "set x expression",     OFFSET(x_expr),
> >  AV_OPT_TYPE_STRING, {.str="0"},   CHAR_MIN, CHAR_MAX, FLAGS},
> > >      {"y",           "set y expression",     OFFSET(y_expr),
> >  AV_OPT_TYPE_STRING, {.str="0"},   CHAR_MIN, CHAR_MAX, FLAGS},
> > >      {"shadowx",     "set shadow x offset",  OFFSET(shadowx),
> > AV_OPT_TYPE_INT,    {.i64=0},     INT_MIN,  INT_MAX , FLAGS},
> > > @@ -280,6 +283,7 @@ typedef struct Glyph {
> > >      FT_Glyph glyph;
> > >      FT_Glyph border_glyph;
> > >      uint32_t code;
> > > +    unsigned int fontsize;
> > >      FT_Bitmap bitmap; ///< array holding bitmaps of font
> > >      FT_Bitmap border_bitmap; ///< array holding bitmaps of font border
> > >      FT_BBox bbox;
> > > @@ -292,7 +296,11 @@ static int glyph_cmp(const 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;
> > > +
> > > +    if (diff != 0)
> > > +         return diff > 0 ? 1 : -1;
> > > +    else
> > > +         return FFDIFFSIGN((int64_t)a->fontsize,
> > (int64_t)bb->fontsize);
> > >  }
> > >
> > >  /**
> > > @@ -316,6 +324,7 @@ static int load_glyph(AVFilterContext *ctx, Glyph
> > **glyph_ptr, uint32_t code)
> > >          goto error;
> > >      }
> > >      glyph->code  = code;
> > > +    glyph->fontsize = s->fontsize;
> > >
> > >      if (FT_Get_Glyph(s->face->glyph, &glyph->glyph)) {
> > >          ret = AVERROR(EINVAL);
> > > @@ -365,6 +374,72 @@ error:
> > >      return ret;
> > >  }
> > >
> > > +static av_cold int set_fontsize(AVFilterContext *ctx)
> > > +{
> > > +    int err;
> > > +    DrawTextContext *s = ctx->priv;
> > > +
> > > +    if (s->face == NULL) {
> > > +        av_log(ctx, AV_LOG_ERROR, "Unable to initialize font\n");
> > > +        return AVERROR(EINVAL);
> > > +    }
> > > +
> > > +    if ((err = FT_Set_Pixel_Sizes(s->face, 0, s->fontsize))) {
> > > +        av_log(ctx, AV_LOG_ERROR, "Could not set font size to %d
> > pixels: %s\n",
> > > +               s->fontsize, FT_ERRMSG(err));
> > > +        return AVERROR(EINVAL);
> > > +    }
> > > +
> > > +    return 0;
> > > +}
> > > +
> > > +static av_cold int parse_fontsize(AVFilterContext *ctx)
> > > +{
> > > +    DrawTextContext *s = ctx->priv;
> > > +
> > > +    if (s->fontsize_expr == NULL)
> > > +        return AVERROR(EINVAL);
> > > +
> > > +    av_expr_free(s->fontsize_pexpr);
> > > +    s->fontsize_pexpr = NULL;
> > > +
> >
> > > +    if (av_expr_parse(&s->fontsize_pexpr, s->fontsize_expr, var_names,
> > > +                             NULL, NULL, fun2_names, fun2, 0, ctx) < 0)
> > > +        return AVERROR(EINVAL);
> >
> > the error code should probably be forwarded
> >
> >
> > > +
> > > +    return 0;
> > > +}
> > > +
> > > +static av_cold int update_fontsize(AVFilterContext *ctx)
> > > +{
> > > +    DrawTextContext *s = ctx->priv;
> > > +    unsigned int fontsize = s->default_fontsize;
> > > +    int err;
> > > +    double size;
> > > +
> > > +    // if no fontsize specified use the default
> > > +    if (s->fontsize_expr != NULL) {
> >
> > > +        if ((err = parse_fontsize(ctx) < 0))
> > > +           return err;
> >
> > This looks wrong, the () is placed incorrectly
> >
> >
> > [...]
> > > @@ -1352,7 +1450,8 @@ static int filter_frame(AVFilterLink *inlink,
> > AVFrame *frame)
> > >      s->var_values[VAR_PICT_TYPE] = frame->pict_type;
> > >      s->metadata = av_frame_get_metadata(frame);
> > >
> > > -    draw_text(ctx, frame, frame->width, frame->height);
> >
> > > +    if ((ret = draw_text(ctx, frame, frame->width, frame->height) < 0))
> > > +        return ret;
> >
> > same
> >
> > also error codes in ffmpeg are negative, this if its intended to be
> > as is woul introduce a positive error code
> >
> > [...]
> >
> > --
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > Old school: Use the lowest level language in which you can solve the
> > problem
> >             conveniently.
> > New school: Use the highest level language in which the latest
> > supercomputer
> >             can solve the problem without the user falling asleep waiting.
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> >

>  vf_drawtext.c |  126 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 113 insertions(+), 13 deletions(-)
> d9624210e5ec9554f037959b3ca6e240b76c27db  0001-added-expr-evaluation-to-drawtext-fontsize.patch
> From 42687746fac27416c6b1d3de29142b2448bdd66e Mon Sep 17 00:00:00 2001
> From: Brett Harrison <brett.harrison at musicmastermind.com>
> Date: Fri, 26 Aug 2016 14:29:34 -0700
> Subject: [PATCH] added expr evaluation to drawtext - fontsize
> 
> ---
>  libavfilter/vf_drawtext.c | 126 +++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 113 insertions(+), 13 deletions(-)
> 
> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> index 214aef0..b345cfc 100644
> --- a/libavfilter/vf_drawtext.c
> +++ b/libavfilter/vf_drawtext.c
> @@ -156,7 +156,10 @@ typedef struct DrawTextContext {
>      int max_glyph_h;                ///< max glyph height
>      int shadowx, shadowy;
>      int borderw;                    ///< border width
> +    char *fontsize_expr;            ///< expression for fontsize
> +    AVExpr *fontsize_pexpr;         ///< parsed expressions for fontsize
>      unsigned int fontsize;          ///< font size to use
> +    unsigned int default_fontsize;  ///< default font size to use
>  
>      short int draw_box;             ///< draw box around text - true or false
>      int boxborderw;                 ///< box border width
> @@ -209,7 +212,7 @@ static const AVOption drawtext_options[]= {
>      {"shadowcolor", "set shadow color",     OFFSET(shadowcolor.rgba),   AV_OPT_TYPE_COLOR,  {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS},
>      {"box",         "set box",              OFFSET(draw_box),           AV_OPT_TYPE_BOOL,   {.i64=0},     0,        1       , FLAGS},
>      {"boxborderw",  "set box border width", OFFSET(boxborderw),         AV_OPT_TYPE_INT,    {.i64=0},     INT_MIN,  INT_MAX , FLAGS},
> -    {"fontsize",    "set font size",        OFFSET(fontsize),           AV_OPT_TYPE_INT,    {.i64=0},     0,        INT_MAX , FLAGS},
> +    {"fontsize",    "set font size",        OFFSET(fontsize_expr),      AV_OPT_TYPE_STRING, {.str=NULL},  CHAR_MIN, CHAR_MAX , FLAGS},
>      {"x",           "set x expression",     OFFSET(x_expr),             AV_OPT_TYPE_STRING, {.str="0"},   CHAR_MIN, CHAR_MAX, FLAGS},
>      {"y",           "set y expression",     OFFSET(y_expr),             AV_OPT_TYPE_STRING, {.str="0"},   CHAR_MIN, CHAR_MAX, FLAGS},
>      {"shadowx",     "set shadow x offset",  OFFSET(shadowx),            AV_OPT_TYPE_INT,    {.i64=0},     INT_MIN,  INT_MAX , FLAGS},
> @@ -280,6 +283,7 @@ typedef struct Glyph {
>      FT_Glyph glyph;
>      FT_Glyph border_glyph;
>      uint32_t code;
> +    unsigned int fontsize;
>      FT_Bitmap bitmap; ///< array holding bitmaps of font
>      FT_Bitmap border_bitmap; ///< array holding bitmaps of font border
>      FT_BBox bbox;
> @@ -292,7 +296,11 @@ static int glyph_cmp(const 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;
> +
> +    if (diff != 0)
> +         return diff > 0 ? 1 : -1;
> +    else
> +         return FFDIFFSIGN((int64_t)a->fontsize, (int64_t)bb->fontsize);
>  }
>  
>  /**
> @@ -316,6 +324,7 @@ static int load_glyph(AVFilterContext *ctx, Glyph **glyph_ptr, uint32_t code)
>          goto error;
>      }
>      glyph->code  = code;
> +    glyph->fontsize = s->fontsize;
>  
>      if (FT_Get_Glyph(s->face->glyph, &glyph->glyph)) {
>          ret = AVERROR(EINVAL);
> @@ -365,6 +374,73 @@ error:
>      return ret;
>  }
>  
> +static av_cold int set_fontsize(AVFilterContext *ctx)
> +{
> +    int err;
> +    DrawTextContext *s = ctx->priv;
> +

> +    if (s->face == NULL) {
> +        av_log(ctx, AV_LOG_ERROR, "Unable to initialize font\n");
> +        return AVERROR(EINVAL);

How can this be NULL ?


[...]

> @@ -1216,12 +1310,16 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame,
>      x = 0;
>      y = 0;
>  
> +    if (update_fontsize(ctx) != 0)
> +        return AVERROR(EINVAL);

error checks should be < 0 and the error code should be forwarded


[...]

> @@ -1352,7 +1451,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>      s->var_values[VAR_PICT_TYPE] = frame->pict_type;
>      s->metadata = av_frame_get_metadata(frame);
>  
> -    draw_text(ctx, frame, frame->width, frame->height);
> +    if ((ret = draw_text(ctx, frame, frame->width, frame->height)) < 0)
> +        return ret;

this change looks unrelated and should be in a seperate patch.
Also i think this leaks frame if you return here


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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