[FFmpeg-devel,v2] vf_drawtext: Add pkt_pos, pkt_duration, pkt_size as variables

Submitted by greg Luce on June 11, 2019, 10:02 p.m.

Details

Message ID CAFrfS6YY5Pjph3i+5tZH4RL5W+3jWuXrWCZzYMa2k=X3MoxA0w@mail.gmail.com
State New
Headers show

Commit Message

greg Luce June 11, 2019, 10:02 p.m.
This is on the bug tracker at https://trac.ffmpeg.org/ticket/7947
Created with the help of the excellent Calvin Walton <calvin.walton@kepstin.ca>
and rewritten with the advice of the excellent Gyan <ffmpeg@gyani.pro>

---
 doc/filters.texi          | 24 +++++++++++++++++++++++-
 libavfilter/vf_drawtext.c |  9 +++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)


     draw_text(ctx, frame, frame->width, frame->height);

Comments

Michael Niedermayer June 12, 2019, 7:42 a.m.
On Tue, Jun 11, 2019 at 06:02:10PM -0400, greg Luce wrote:
> This is on the bug tracker at https://trac.ffmpeg.org/ticket/7947
> Created with the help of the excellent Calvin Walton <calvin.walton@kepstin.ca>
> and rewritten with the advice of the excellent Gyan <ffmpeg@gyani.pro>
> 
> ---
>  doc/filters.texi          | 24 +++++++++++++++++++++++-
>  libavfilter/vf_drawtext.c |  9 +++++++++
>  2 files changed, 32 insertions(+), 1 deletion(-)

git doesnt like this patch, probably messed up newlines

Applying: vf_drawtext: Add pkt_pos, pkt_duration, pkt_size as variables
error: corrupt patch at line 23
error: could not build fake ancestor


[...]
greg Luce June 12, 2019, 4:11 p.m.
Ooops apologies, .patch file attached and with hopefully better line breaks

On Wed, 12 Jun 2019 at 03:43, Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> On Tue, Jun 11, 2019 at 06:02:10PM -0400, greg Luce wrote:
> > This is on the bug tracker at https://trac.ffmpeg.org/ticket/7947
> > Created with the help of the excellent Calvin Walton <calvin.walton@kepstin.ca>
> > and rewritten with the advice of the excellent Gyan <ffmpeg@gyani.pro>
> >
> > ---
> >  doc/filters.texi          | 24 +++++++++++++++++++++++-
> >  libavfilter/vf_drawtext.c |  9 +++++++++
> >  2 files changed, 32 insertions(+), 1 deletion(-)
>
> git doesnt like this patch, probably messed up newlines
>
> Applying: vf_drawtext: Add pkt_pos, pkt_duration, pkt_size as variables
> error: corrupt patch at line 23
> error: could not build fake ancestor
>
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Dictatorship: All citizens are under surveillance, all their steps and
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Moritz Barsnick June 12, 2019, 9:32 p.m.
On Wed, Jun 12, 2019 at 12:11:16 -0400, greg Luce wrote:
> Ooops apologies, .patch file attached and with hopefully better line breaks

Yes, but something went wrong with its contents:

> Subject: [PATCH] Signed-off-by: greg Luce <electron.rotoscope@gmail.com>

This doesn't look correct. It's supposed to contain
Subject: vf_drawtext: Add pkt_pos, pkt_duration, pkt_size as variables
and the Signed-off-by line is to be somewhere in the remaining commit
message. How did you create the patch?

>  These parameters allow the @var{x} and @var{y} expressions to refer
> -each other, so you can for example specify @code{y=x/dar}.
> +to each other, so you can for example specify @code{y=x/dar}.
> +
> +@item pict_type
> +A 1 character description of the current packet's input picture type.
> +

Strictly speaking, you're fixing and amending existing documentation,
not related to your modifications. I personally don't mind, but others
will request you to do this is a separate patch.

> +@item pkt_pos
> +The current packet's position in the input datastream
> +(in bytes from the head of the source file).
> +
> +A value of -1 indicates this info is not available.

A non-related question: Do you understand when this is -1? (I myself
am looking for some filter or log info which can give me the pkt_pos
related to a certain time offset from the beginning of a file, as when
seeked using "-ss".)

> +The current packet's input duration.

"input duration" sounds confusing. You can likely drop the "input".

> +The current packet's input size (in bytes).

Ditto.

I can't comment on the rest, but like the feature.

You may need to bump libavfilter's MICRO version, as you are adding
features.

Moritz
greg Luce June 13, 2019, 2:07 a.m.
> This doesn't look correct. It's supposed to contain
> Subject: vf_drawtext: Add pkt_pos, pkt_duration, pkt_size as variables
> and the Signed-off-by line is to be somewhere in the remaining commit
> message. How did you create the patch?

I just cloned the main, made the change, and then did
"git format-patch -1 HEAD"
I'm afraid I don't know git very well. I'll just strip the head out of
the patch files so I can't get them wrong!

> Strictly speaking, you're fixing and amending existing documentation,
> not related to your modifications. I personally don't mind, but others
> will request you to do this is a separate patch.

Split into two separate patch files (attached) in case that helps

> A non-related question: Do you understand when this is -1? (I myself
> am looking for some filter or log info which can give me the pkt_pos
> related to a certain time offset from the beginning of a file, as when
> seeked using "-ss".)

I'm afraid I have no help for you there. I'm going on Gyan's advice from
https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2019-June/245249.html

> > +The current packet's input duration.
>
> "input duration" sounds confusing. You can likely drop the "input".
>
> > +The current packet's input size (in bytes).
>
> Ditto.

I'd included "input" since the frame rate and size might be changed
later, but you're right people can probably figure that out. I'll take
them out

> You may need to bump libavfilter's MICRO version, as you are adding
> features.

I can't speak to that and I wouldn't know how to do it, but good point!

Patch hide | download patch | download mbox

diff --git a/doc/filters.texi b/doc/filters.texi
index ec1c7c7591..e2ca2a8c08 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8961,8 +8961,23 @@  the width of the rendered text
 @item y
 the x and y offset coordinates where the text is drawn.

-These parameters allow the @var{x} and @var{y} expressions to refer
+These parameters allow the @var{x} and @var{y} expressions to refer to
 each other, so you can for example specify @code{y=x/dar}.
+
+@item pict_type
+A 1 character description of the current packet's input picture type.
+
+@item pkt_pos
+The current packet's position in the input datastream (in bytes from
the head of the source file).
+
+A value of -1 indicates this info is not available.
+
+@item pkt_duration
+The current packet's input duration.
+
+@item pkt_size
+The current packet's input size (in bytes).
+
 @end table

 @anchor{drawtext_expansion}
@@ -9032,6 +9047,13 @@  The first argument is mandatory and specifies
the metadata key.
 The second argument is optional and specifies a default value, used when the
 metadata key is not found or empty.

+Available metadata can be identified by inspecting entries starting with
+TAG included within each frame section printed by running @code{ffprobe
+-show_frames}.
+
+String metadata generated in filters leading to the drawtext filter are
+also available.
+
 @item n, frame_num
 The frame number, starting from 0.

diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 01cd7fa122..8f4badbdb5 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -88,6 +88,9 @@  static const char *const var_names[] = {
     "x",
     "y",
     "pict_type",
+    "pkt_pos",
+    "pkt_duration",
+    "pkt_size",
     NULL
 };

@@ -125,6 +128,9 @@  enum var_name {
     VAR_X,
     VAR_Y,
     VAR_PICT_TYPE,
+    VAR_PKT_POS,
+    VAR_PKT_DURATION,
+    VAR_PKT_SIZE,
     VAR_VARS_NB
 };

@@ -1516,6 +1522,9 @@  static int filter_frame(AVFilterLink *inlink,
AVFrame *frame)
         NAN : frame->pts * av_q2d(inlink->time_base);

     s->var_values[VAR_PICT_TYPE] = frame->pict_type;
+    s->var_values[VAR_PKT_POS] = frame->pkt_pos;
+    s->var_values[VAR_PKT_DURATION] = frame->pkt_duration *
av_q2d(inlink->time_base);
+    s->var_values[VAR_PKT_SIZE] = frame->pkt_size;
     s->metadata = frame->metadata;