On Mon, 6 Apr 2020 11:52:05 -0600
John Stebbins <jstebb...@jetheaddev.com> wrote:
> Font sizes are relative to the subtitle frame dimensions. If the
> expected frame dimensions are not known, the font sizes will most
> likely be incorrect.
> ---
> libavcodec/ass.c | 30 +++++++++++++++++++++++-------
> libavcodec/ass.h | 28 ++++++++++++++++++++++++++++
> libavcodec/movtextdec.c | 30 +++++++++++++++++++++++++++++-
> 3 files changed, 80 insertions(+), 8 deletions(-)
>
> diff --git a/libavcodec/ass.c b/libavcodec/ass.c
> index a51673fb4e..7c26e3fd6d 100644
> --- a/libavcodec/ass.c
> +++ b/libavcodec/ass.c
> @@ -26,11 +26,13 @@
> #include "libavutil/bprint.h"
> #include "libavutil/common.h"
>
> -int ff_ass_subtitle_header(AVCodecContext *avctx,
> - const char *font, int font_size,
> - int color, int back_color,
> - int bold, int italic, int underline,
> - int border_style, int alignment)
> +int ff_ass_subtitle_header_full(AVCodecContext *avctx,
> + int play_res_x, int play_res_y,
> + const char *font, int font_size,
> + int primary_color, int
> secondary_color,
> + int outline_color, int back_color,
> + int bold, int italic, int underline,
> + int border_style, int alignment)
> {
> avctx->subtitle_header = av_asprintf(
> "[Script Info]\r\n"
> @@ -67,8 +69,8 @@ int ff_ass_subtitle_header(AVCodecContext *avctx,
> "[Events]\r\n"
> "Format: Layer, Start, End, Style, Name, MarginL,
> MarginR, MarginV, Effect, Text\r\n", !(avctx->flags &
> AV_CODEC_FLAG_BITEXACT) ? AV_STRINGIFY(LIBAVCODEC_VERSION) : "",
> - ASS_DEFAULT_PLAYRESX, ASS_DEFAULT_PLAYRESY,
> - font, font_size, color, color, back_color, back_color,
> + play_res_x, play_res_y, font, font_size,
> + primary_color, secondary_color, outline_color,
> back_color, -bold, -italic, -underline, border_style, alignment);
>
> if (!avctx->subtitle_header)
> @@ -77,6 +79,20 @@ int ff_ass_subtitle_header(AVCodecContext *avctx,
> return 0;
> }
>
> +int ff_ass_subtitle_header(AVCodecContext *avctx,
> + const char *font, int font_size,
> + int color, int back_color,
> + int bold, int italic, int underline,
> + int border_style, int alignment)
> +{
> + return ff_ass_subtitle_header_full(avctx,
> + ASS_DEFAULT_PLAYRESX,
> ASS_DEFAULT_PLAYRESY,
> + font, font_size, color, color,
> + back_color, back_color,
> + bold, italic, underline,
> + border_style, alignment);
> +}
> +
> int ff_ass_subtitle_header_default(AVCodecContext *avctx)
> {
> return ff_ass_subtitle_header(avctx, ASS_DEFAULT_FONT,
> diff --git a/libavcodec/ass.h b/libavcodec/ass.h
> index 314b43b686..2c260e4e78 100644
> --- a/libavcodec/ass.h
> +++ b/libavcodec/ass.h
> @@ -47,6 +47,34 @@ typedef struct FFASSDecoderContext {
> int readorder;
> } FFASSDecoderContext;
>
> +/**
> + * Generate a suitable AVCodecContext.subtitle_header for
> SUBTITLE_ASS.
> + * Can specify all fields explicitly
> + *
> + * @param avctx pointer to the AVCodecContext
> + * @param play_res_x subtitle frame width
> + * @param play_res_y subtitle frame height
> + * @param font name of the default font face to use
> + * @param font_size default font size to use
> + * @param primary_color default text color to use (ABGR)
> + * @param secondary_color default secondary text color to use (ABGR)
> + * @param outline_color default outline color to use (ABGR)
> + * @param back_color default background color to use (ABGR)
> + * @param bold 1 for bold text, 0 for normal text
> + * @param italic 1 for italic text, 0 for normal text
> + * @param underline 1 for underline text, 0 for normal text
> + * @param border_style 1 for outline, 3 for opaque box
> + * @param alignment position of the text (left, center, top...),
> defined after
> + * the layout of the numpad (1-3 sub, 4-6 mid, 7-9
> top)
> + * @return >= 0 on success otherwise an error code <0
> + */
> +int ff_ass_subtitle_header_full(AVCodecContext *avctx,
> + int play_res_x, int play_res_y,
> + const char *font, int font_size,
> + int primary_color, int
> secondary_color,
> + int outline_color, int back_color,
> + int bold, int italic, int underline,
> + int border_style, int alignment);
> /**
> * Generate a suitable AVCodecContext.subtitle_header for
> SUBTITLE_ASS. *
> diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c
> index f3a504b47b..4b4da5e0d9 100644
> --- a/libavcodec/movtextdec.c
> +++ b/libavcodec/movtextdec.c
> @@ -21,6 +21,7 @@
>
> #include "avcodec.h"
> #include "ass.h"
> +#include "libavutil/opt.h"
> #include "libavutil/avstring.h"
> #include "libavutil/common.h"
> #include "libavutil/bprint.h"
> @@ -96,6 +97,7 @@ typedef struct {
> } TextWrapBox;
>
> typedef struct {
> + AVClass *class;
> StyleBox **s;
> StyleBox *s_temp;
> HighlightBox h;
> @@ -110,6 +112,8 @@ typedef struct {
> int size_var;
> int count_s, count_f;
> int readorder;
> + int frame_width;
> + int frame_height;
> } MovTextContext;
>
> typedef struct {
> @@ -481,9 +485,17 @@ static int mov_text_init(AVCodecContext *avctx) {
> MovTextContext *m = avctx->priv_data;
> ret = mov_text_tx3g(avctx, m);
> if (ret == 0) {
> - return ff_ass_subtitle_header(avctx, m->d.font,
> m->d.fontsize,
> + if (!m->frame_width || !m->frame_height) {
> + m->frame_width = ASS_DEFAULT_PLAYRESX;
> + m->frame_height = ASS_DEFAULT_PLAYRESY;
> + }
> + return ff_ass_subtitle_header_full(avctx,
> + m->frame_width, m->frame_height,
> + m->d.font, m->d.fontsize,
> + (255 - m->d.alpha) << 24 |
> RGB_TO_BGR(m->d.color), (255 - m->d.alpha) << 24 |
> RGB_TO_BGR(m->d.color), (255 - m->d.back_alpha) << 24 |
> RGB_TO_BGR(m->d.back_color),
> + (255 - m->d.back_alpha) << 24 |
> RGB_TO_BGR(m->d.back_color), m->d.bold, m->d.italic, m->d.underline,
> ASS_DEFAULT_BORDERSTYLE, m->d.alignment);
> } else
> @@ -601,12 +613,28 @@ static void mov_text_flush(AVCodecContext
> *avctx) m->readorder = 0;
> }
>
> +#define OFFSET(x) offsetof(MovTextContext, x)
> +#define FLAGS AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
> +static const AVOption options[] = {
> + { "width", "Frame width, usually video width",
> OFFSET(frame_width), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
> + { "height", "Frame height, usually video height",
> OFFSET(frame_height), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
> + { NULL },
> +};
> +
> +static const AVClass mov_text_decoder_class = {
> + .class_name = "MOV text decoder",
> + .item_name = av_default_item_name,
> + .option = options,
> + .version = LIBAVUTIL_VERSION_INT,
> +};
> +
> AVCodec ff_movtext_decoder = {
> .name = "mov_text",
> .long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
> .type = AVMEDIA_TYPE_SUBTITLE,
> .id = AV_CODEC_ID_MOV_TEXT,
> .priv_data_size = sizeof(MovTextContext),
> + .priv_class = &mov_text_decoder_class,
> .init = mov_text_init,
> .decode = mov_text_decode_frame,
> .close = mov_text_decode_close,
LGTM. When I last looked at frame dimensions, I could never
find a sane way to set these values to the actual video frame
dimensions. I'm guess you couldn't either? :-)
--phil
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