[FFmpeg-devel] [PATCH 2/2] movtextenc.c: Support for Bold, Italic and Underlined styles

[Clément Bœsch]

On Wed, Jun 17, 2015 at 08:43:26PM +0530, Niklesh Lalwani wrote:
> From: Niklesh <niklesh.lalwani at iitb.ac.in>
> 
> Support for Bold, Italic and Underlined styles. The style information is appended into the buffer after the text. Dynarray is used to account for multiple style records. Tested on QuickTime OSX and iPhone.
> Signed-off-by: Niklesh <niklesh.lalwani at iitb.ac.in>
> ---
>  libavcodec/movtextenc.c | 165 ++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 145 insertions(+), 20 deletions(-)
> 
> diff --git a/libavcodec/movtextenc.c b/libavcodec/movtextenc.c
> index 1b8f454..56c599d 100644
> --- a/libavcodec/movtextenc.c
> +++ b/libavcodec/movtextenc.c
> @@ -24,14 +24,38 @@
>  #include "libavutil/avassert.h"
>  #include "libavutil/avstring.h"
>  #include "libavutil/intreadwrite.h"
> +#include "libavutil/mem.h"
> +#include "libavutil/common.h"
>  #include "ass_split.h"
>  #include "ass.h"
>  

> +#define STYLE_FLAG_BOLD         1
> +#define STYLE_FLAG_ITALIC       2
> +#define STYLE_FLAG_UNDERLINE    4

#define STYLE_FLAG_BOLD      (1<<0)
#define STYLE_FLAG_ITALIC    (1<<1)
#define STYLE_FLAG_UNDERLINE (1<<2)

it's more obvious they are combinable flags that way, and you can see when
you reach a 8, 16, 32 or whatever boundary.

> +#define STYLE_RECORD_SIZE       12
> +#define SIZE_ADD                10
> +
> +
> +typedef struct {
> +    uint16_t style_start;
> +    uint16_t style_end;
> +    uint8_t style_flag;
> +} StyleBox;
> +
>  typedef struct {
>      ASSSplitContext *ass_ctx;
> -    char buffer[2048];
> -    char *ptr;
> -    char *end;
> +    AVBPrint buffer;
> +    StyleBox **style_attributes;
> +    StyleBox *style_attributes_temp;
> +    int count;
> +    uint8_t style_box_flag;
> +    uint32_t tsmb_size;
> +    uint32_t tsmb_type;
> +    uint16_t style_entries;
> +    uint16_t style_fontID;
> +    uint8_t style_fontsize;
> +    uint32_t style_color;
> +    uint16_t text_pos;
>  } MovTextContext;
>  
>  
> @@ -79,32 +103,98 @@ static av_cold int mov_text_encode_init(AVCodecContext *avctx)
>      if (!avctx->extradata)
>          return AVERROR(ENOMEM);
>  
> +    av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
> +
>      memcpy(avctx->extradata, text_sample_entry, avctx->extradata_size);
>  
>      s->ass_ctx = ff_ass_split(avctx->subtitle_header);
>      return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
>  }
>  
> +static void mov_text_style_cb(void *priv, const char style, int close)
> +{
> +    MovTextContext *s = priv;
> +    if (!close) {
> +        if (s->style_box_flag == 0) {   //first style entry
> +
> +            s->style_attributes_temp = av_malloc(sizeof(StyleBox));

sizeof(*s->style_attributes_temp)

> +            if (!s->style_attributes_temp)
> +                return AVERROR(ENOMEM);
> +
> +            s->style_attributes_temp->style_flag = 0;

> +            s->style_attributes_temp->style_start = AV_RB16(&s->text_pos);

there is no risk of alignement constraints that wouldn't be honored here,
right?

[...]
> -    if (s->ptr == s->buffer)
> -        return 0;
> -

> -    AV_WB16(buf, strlen(s->buffer));
> +    AV_WB16(buf, s->text_pos);

Any risk of having a len too large? Maybe you should initialize the
AVBuffer with a max limit size.

[...]

No other comment from me.

-- 
Clément B.
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