Re: [FFmpeg-devel] [PATCH 1/2] lavfi/ebur128: add support for smaller video sizes
On Sat, Nov 22, 2014 at 03:28:06PM +0100, Marton Balint wrote:
>
>
> On Fri, 21 Nov 2014, Clément Bœsch wrote:
>
> >(sorry for the delay)
> >
> >On Sun, Nov 16, 2014 at 10:53:15PM +0100, Marton Balint wrote:
> >>Signed-off-by: Marton Balint
> >>---
> >> doc/filters.texi| 4 ++--
> >> libavfilter/f_ebur128.c | 11 ---
> >> 2 files changed, 10 insertions(+), 5 deletions(-)
> >>
> >>diff --git a/doc/filters.texi b/doc/filters.texi
> >>index 53f4cb2..713989c 100644
> >>--- a/doc/filters.texi
> >>+++ b/doc/filters.texi
> >>@@ -10146,8 +10146,8 @@ activated. Default is @code{0}.
> >>
> >> @item size
> >> Set the video size. This option is for video only. For the syntax of this
> >>-option, check the "Video size" section in the ffmpeg-utils manual. Default
> >>-and minimum resolution is @code{640x480}.
> >>+option, check the "Video size" section in the ffmpeg-utils manual. The
> >>default
> >>+resolution is @code{640x480}, the minimum is @code{480x102}.
> >>
> >
> >Quoting the EBU 3341:
> > An ‘EBU Mode’ meter shall offer two scales, for when a scale is shown,
> > selectable by the user:
> > 1. range -18.0 LU to +9.0 LU (-41.0 LUFS to -14.0 LUFS), named ‘EBU +9
> > scale’
> > 2. range -36.0 LU to +18.0 LU (-59.0 LUFS to -5.0 LUFS), named ‘EBU +18
> > scale’
> >
> >When you go down to 480x102, the printed range becomes [-16;+8] LU for +9
> >scale and [-32;+16] LU for +18 scale (see meter option). I think these
> >range boundaries should be preserved in the output.
> >
>
> The proper range is still shown in the graph, only the legend lacks the
> value for the up and the bottom of the graph.
>
> If you insist on showing the values for the top and the bottom of the graph,
> then in order for the lines to remain simmetrical, you will have to start
> showing rounded or non-whole values. Or if you insist on whole values, you
> may will not be able to show the lines with the same distance from each
> other.
>
> What would be the approach you prefer in order to be able to show smaller
> graphs?
I think the boundaries are important, so what about printing a warning if
the grain of the legend can't be kept?
(note: sorry about the delay between my replies)
--
Clément B.
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Re: [FFmpeg-devel] [PATCH 1/2] lavfi/ebur128: add support for smaller video sizes
On Fri, 21 Nov 2014, Clément Bœsch wrote:
(sorry for the delay)
On Sun, Nov 16, 2014 at 10:53:15PM +0100, Marton Balint wrote:
Signed-off-by: Marton Balint
---
doc/filters.texi| 4 ++--
libavfilter/f_ebur128.c | 11 ---
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 53f4cb2..713989c 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -10146,8 +10146,8 @@ activated. Default is @code{0}.
@item size
Set the video size. This option is for video only. For the syntax of this
-option, check the "Video size" section in the ffmpeg-utils manual. Default
-and minimum resolution is @code{640x480}.
+option, check the "Video size" section in the ffmpeg-utils manual. The default
+resolution is @code{640x480}, the minimum is @code{480x102}.
Quoting the EBU 3341:
An ‘EBU Mode’ meter shall offer two scales, for when a scale is shown,
selectable by the user:
1. range -18.0 LU to +9.0 LU (-41.0 LUFS to -14.0 LUFS), named ‘EBU +9
scale’
2. range -36.0 LU to +18.0 LU (-59.0 LUFS to -5.0 LUFS), named ‘EBU +18
scale’
When you go down to 480x102, the printed range becomes [-16;+8] LU for +9
scale and [-32;+16] LU for +18 scale (see meter option). I think these
range boundaries should be preserved in the output.
The proper range is still shown in the graph, only the legend lacks the
value for the up and the bottom of the graph.
If you insist on showing the values for the top and the bottom of the
graph, then in order for the lines to remain simmetrical, you will have to
start showing rounded or non-whole values. Or if you insist on whole
values, you may will not be able to show the lines with the same distance
from each other.
What would be the approach you prefer in order to be able to show smaller
graphs?
Thanks,
Marton___
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Re: [FFmpeg-devel] [PATCH 1/2] lavfi/ebur128: add support for smaller video sizes
(sorry for the delay)
On Sun, Nov 16, 2014 at 10:53:15PM +0100, Marton Balint wrote:
> Signed-off-by: Marton Balint
> ---
> doc/filters.texi| 4 ++--
> libavfilter/f_ebur128.c | 11 ---
> 2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 53f4cb2..713989c 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -10146,8 +10146,8 @@ activated. Default is @code{0}.
>
> @item size
> Set the video size. This option is for video only. For the syntax of this
> -option, check the "Video size" section in the ffmpeg-utils manual. Default
> -and minimum resolution is @code{640x480}.
> +option, check the "Video size" section in the ffmpeg-utils manual. The
> default
> +resolution is @code{640x480}, the minimum is @code{480x102}.
>
Quoting the EBU 3341:
An ‘EBU Mode’ meter shall offer two scales, for when a scale is shown,
selectable by the user:
1. range -18.0 LU to +9.0 LU (-41.0 LUFS to -14.0 LUFS), named ‘EBU +9
scale’
2. range -36.0 LU to +18.0 LU (-59.0 LUFS to -5.0 LUFS), named ‘EBU +18
scale’
When you go down to 480x102, the printed range becomes [-16;+8] LU for +9
scale and [-32;+16] LU for +18 scale (see meter option). I think these
range boundaries should be preserved in the output.
[...]
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Clément B.
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[FFmpeg-devel] [PATCH 1/2] lavfi/ebur128: add support for smaller video sizes
Signed-off-by: Marton Balint
---
doc/filters.texi| 4 ++--
libavfilter/f_ebur128.c | 11 ---
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 53f4cb2..713989c 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -10146,8 +10146,8 @@ activated. Default is @code{0}.
@item size
Set the video size. This option is for video only. For the syntax of this
-option, check the "Video size" section in the ffmpeg-utils manual. Default
-and minimum resolution is @code{640x480}.
+option, check the "Video size" section in the ffmpeg-utils manual. The default
+resolution is @code{640x480}, the minimum is @code{480x102}.
@item meter
Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
index c18ae79..8780062 100644
--- a/libavfilter/f_ebur128.c
+++ b/libavfilter/f_ebur128.c
@@ -114,6 +114,7 @@ typedef struct {
int scale_range;///< the range of LU values according to
the meter
int y_zero_lu; ///< the y value (pixel position) for 0 LU
int *y_line_ref;///< y reference values for drawing the LU
lines in the graph and the gauge
+int line_step; ///< LU steps for drawn lines
/* audio */
int nb_channels;///< number of channels in the input
@@ -257,9 +258,9 @@ static int config_video_output(AVFilterLink *outlink)
AVFrame *outpicref;
/* check if there is enough space to represent everything decently */
-if (ebur128->w < 640 || ebur128->h < 480) {
+if (ebur128->w < 480 || ebur128->h < 102) {
av_log(ctx, AV_LOG_ERROR, "Video size %dx%d is too small, "
- "minimum size is 640x480\n", ebur128->w, ebur128->h);
+ "minimum size is 480x102\n", ebur128->w, ebur128->h);
return AVERROR(EINVAL);
}
outlink->w = ebur128->w;
@@ -285,6 +286,9 @@ static int config_video_output(AVFilterLink *outlink)
ebur128->graph.w = ebur128->gauge.x - ebur128->graph.x - PAD;
ebur128->graph.h = ebur128->gauge.h;
+/* compute line step based on graph height and needed lines */
+ebur128->line_step = (ebur128->scale_range * 8 - 1) / (ebur128->graph.h) +
1;
+
/* graph and gauge share the LU-to-pixel code */
av_assert0(ebur128->graph.h == ebur128->gauge.h);
@@ -309,8 +313,9 @@ static int config_video_output(AVFilterLink *outlink)
for (i = ebur128->meter; i >= -ebur128->meter * 2; i--) {
y = lu_to_y(ebur128, i);
x = PAD + (i < 10 && i > -10) * 8;
-ebur128->y_line_ref[y] = i;
+ebur128->y_line_ref[y] = ((i % ebur128->line_step == 0) ? i : 0);
y -= 4; // -4 to center vertically
+if (i % ebur128->line_step == 0)
drawtext(outpicref, x, y + ebur128->graph.y, FONT8, font_colors+3,
"%c%d", i < 0 ? '-' : i > 0 ? '+' : ' ', FFABS(i));
}
--
2.1.2
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