* [FFmpeg-devel] [PATCH v2] avcodec/ccaption_dec: honor transparency of leading non-breaking space
@ 2024-03-11 0:44 Marth64
2024-03-11 16:38 ` Stefano Sabatini
0 siblings, 1 reply; 3+ messages in thread
From: Marth64 @ 2024-03-11 0:44 UTC (permalink / raw)
To: ffmpeg-devel; +Cc: Marth64
In Closed Captions (US), the non-breaking space (0xA0) can be used to align
text horizontally from the left by using it as a leading character.
However, CC decoder does not ignore it as a leading character like it does
an ordinary space, so a blank padding is rendered over the black CC box.
This is not the intended viewing experience.
Ignore the leading non-breaking spaces, thus creating the intended transparency
which aligns the text. Since all characters are fixed-width in CC, it
can be handled the same way as we currently treat leading ordinary spaces.
Also, as a nit, lowercase the NBSP's hex code in the entry table to match
casing of the other hex codes.
v2 only updates the commit message which mistakenly referenced avformat.
Signed-off-by: Marth64 <marth64@proxyid.net>
---
libavcodec/ccaption_dec.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
index faf058ce97..591013d202 100644
--- a/libavcodec/ccaption_dec.c
+++ b/libavcodec/ccaption_dec.c
@@ -91,7 +91,7 @@ enum cc_charset {
ENTRY(0x36, "\u00a3") \
ENTRY(0x37, "\u266a") \
ENTRY(0x38, "\u00e0") \
- ENTRY(0x39, "\u00A0") \
+ ENTRY(0x39, "\u00a0") \
ENTRY(0x3a, "\u00e8") \
ENTRY(0x3b, "\u00e2") \
ENTRY(0x3c, "\u00ea") \
@@ -471,7 +471,8 @@ static int capture_screen(CCaptionSubContext *ctx)
const char *row = screen->characters[i];
const char *charset = screen->charsets[i];
j = 0;
- while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
+ while ((row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN) ||
+ (row[j] == 0x39 && charset[j] == CCSET_SPECIAL_AMERICAN))
j++;
if (!tab || j < tab)
tab = j;
@@ -491,7 +492,9 @@ static int capture_screen(CCaptionSubContext *ctx)
j = 0;
/* skip leading space */
- while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN && j < tab)
+ while (j < tab &&
+ (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN) ||
+ (row[j] == 0x39 && charset[j] == CCSET_SPECIAL_AMERICAN))
j++;
x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
--
2.34.1
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [FFmpeg-devel] [PATCH v2] avcodec/ccaption_dec: honor transparency of leading non-breaking space
2024-03-11 0:44 [FFmpeg-devel] [PATCH v2] avcodec/ccaption_dec: honor transparency of leading non-breaking space Marth64
@ 2024-03-11 16:38 ` Stefano Sabatini
2024-03-12 2:29 ` Marth64
0 siblings, 1 reply; 3+ messages in thread
From: Stefano Sabatini @ 2024-03-11 16:38 UTC (permalink / raw)
To: FFmpeg development discussions and patches; +Cc: Marth64
On date Sunday 2024-03-10 19:44:11 -0500, Marth64 wrote:
> In Closed Captions (US), the non-breaking space (0xA0) can be used to align
> text horizontally from the left by using it as a leading character.
> However, CC decoder does not ignore it as a leading character like it does
> an ordinary space, so a blank padding is rendered over the black CC box.
> This is not the intended viewing experience.
>
> Ignore the leading non-breaking spaces, thus creating the intended transparency
> which aligns the text. Since all characters are fixed-width in CC, it
> can be handled the same way as we currently treat leading ordinary spaces.
> Also, as a nit, lowercase the NBSP's hex code in the entry table to match
> casing of the other hex codes.
>
> v2 only updates the commit message which mistakenly referenced avformat.
>
> Signed-off-by: Marth64 <marth64@proxyid.net>
> ---
> libavcodec/ccaption_dec.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
> index faf058ce97..591013d202 100644
> --- a/libavcodec/ccaption_dec.c
> +++ b/libavcodec/ccaption_dec.c
> @@ -91,7 +91,7 @@ enum cc_charset {
> ENTRY(0x36, "\u00a3") \
> ENTRY(0x37, "\u266a") \
> ENTRY(0x38, "\u00e0") \
> - ENTRY(0x39, "\u00A0") \
> + ENTRY(0x39, "\u00a0") \
> ENTRY(0x3a, "\u00e8") \
> ENTRY(0x3b, "\u00e2") \
> ENTRY(0x3c, "\u00ea") \
> @@ -471,7 +471,8 @@ static int capture_screen(CCaptionSubContext *ctx)
> const char *row = screen->characters[i];
> const char *charset = screen->charsets[i];
> j = 0;
> - while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
> + while ((row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN) ||
> + (row[j] == 0x39 && charset[j] == CCSET_SPECIAL_AMERICAN))
> j++;
> if (!tab || j < tab)
> tab = j;
> @@ -491,7 +492,9 @@ static int capture_screen(CCaptionSubContext *ctx)
> j = 0;
>
> /* skip leading space */
> - while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN && j < tab)
> + while (j < tab &&
> + (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN) ||
> + (row[j] == 0x39 && charset[j] == CCSET_SPECIAL_AMERICAN))
> j++;
Patch LGTM, will apply the complete patcheset if I see no comments
after a few days.
Thanks.
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [FFmpeg-devel] [PATCH v2] avcodec/ccaption_dec: honor transparency of leading non-breaking space
2024-03-11 16:38 ` Stefano Sabatini
@ 2024-03-12 2:29 ` Marth64
0 siblings, 0 replies; 3+ messages in thread
From: Marth64 @ 2024-03-12 2:29 UTC (permalink / raw)
To: FFmpeg development discussions and patches, Marth64
I am working on an improved patchset to consolidate these patches, also
address feedback and other improvements. Will submit soon, thank you!
On Mon, Mar 11, 2024 at 11:38 AM Stefano Sabatini <stefasab@gmail.com>
wrote:
> On date Sunday 2024-03-10 19:44:11 -0500, Marth64 wrote:
> > In Closed Captions (US), the non-breaking space (0xA0) can be used to
> align
> > text horizontally from the left by using it as a leading character.
> > However, CC decoder does not ignore it as a leading character like it
> does
> > an ordinary space, so a blank padding is rendered over the black CC box.
> > This is not the intended viewing experience.
> >
> > Ignore the leading non-breaking spaces, thus creating the intended
> transparency
> > which aligns the text. Since all characters are fixed-width in CC, it
> > can be handled the same way as we currently treat leading ordinary
> spaces.
> > Also, as a nit, lowercase the NBSP's hex code in the entry table to match
> > casing of the other hex codes.
> >
> > v2 only updates the commit message which mistakenly referenced avformat.
> >
> > Signed-off-by: Marth64 <marth64@proxyid.net>
> > ---
> > libavcodec/ccaption_dec.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
> > index faf058ce97..591013d202 100644
> > --- a/libavcodec/ccaption_dec.c
> > +++ b/libavcodec/ccaption_dec.c
> > @@ -91,7 +91,7 @@ enum cc_charset {
> > ENTRY(0x36, "\u00a3") \
> > ENTRY(0x37, "\u266a") \
> > ENTRY(0x38, "\u00e0") \
> > - ENTRY(0x39, "\u00A0") \
> > + ENTRY(0x39, "\u00a0") \
> > ENTRY(0x3a, "\u00e8") \
> > ENTRY(0x3b, "\u00e2") \
> > ENTRY(0x3c, "\u00ea") \
> > @@ -471,7 +471,8 @@ static int capture_screen(CCaptionSubContext *ctx)
> > const char *row = screen->characters[i];
> > const char *charset = screen->charsets[i];
> > j = 0;
> > - while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
> > + while ((row[j] == ' ' && charset[j] ==
> CCSET_BASIC_AMERICAN) ||
> > + (row[j] == 0x39 && charset[j] ==
> CCSET_SPECIAL_AMERICAN))
> > j++;
> > if (!tab || j < tab)
> > tab = j;
> > @@ -491,7 +492,9 @@ static int capture_screen(CCaptionSubContext *ctx)
> > j = 0;
> >
> > /* skip leading space */
> > - while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN
> && j < tab)
> > + while (j < tab &&
> > + (row[j] == ' ' && charset[j] ==
> CCSET_BASIC_AMERICAN) ||
> > + (row[j] == 0x39 && charset[j] ==
> CCSET_SPECIAL_AMERICAN))
> > j++;
>
> Patch LGTM, will apply the complete patcheset if I see no comments
> after a few days.
>
> Thanks.
>
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-03-11 0:44 [FFmpeg-devel] [PATCH v2] avcodec/ccaption_dec: honor transparency of leading non-breaking space Marth64
2024-03-11 16:38 ` Stefano Sabatini
2024-03-12 2:29 ` Marth64
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