[FFmpeg-devel] [PATCH] movtextdec.c: Add support for font names

[Philip Langdale]

On Fri, 31 Jul 2015 19:25:58 +0530
Niklesh Lalwani <niklesh.lalwani at iitb.ac.in> wrote:

> From: Niklesh <niklesh.lalwani at iitb.ac.in>
> 
> The font names are extracted from the font table, present in text
> sample entry. More than one fonts can be present, which is taken care
> of in the patch.
> 
> Signed-off-by: Niklesh <niklesh.lalwani at iitb.ac.in>
> ---
>  libavcodec/movtextdec.c | 86
> +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 83
> insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c
> index 869358c..7d4dead 100644
> --- a/libavcodec/movtextdec.c
> +++ b/libavcodec/movtextdec.c
> @@ -36,10 +36,17 @@
>  #define HCLR_BOX   (1<<2)
>  
>  typedef struct {
> +    uint16_t fontID;
> +    uint8_t font_name_length;
> +    uint8_t font[20];
> +} FontRecord;
> +
> +typedef struct {
>      uint16_t style_start;
>      uint16_t style_end;
>      uint8_t style_flag;
>      uint8_t fontsize;
> +    uint16_t style_fontID;
>  } StyleBox;
>  
>  typedef struct {
> @@ -56,11 +63,13 @@ typedef struct {
>      StyleBox *s_temp;
>      HighlightBox h;
>      HilightcolorBox c;
> +    FontRecord **ftab;
> +    FontRecord *ftab_temp;
>      uint8_t box_flags;
> -    uint16_t style_entries;
> +    uint16_t style_entries, ftab_entries;
>      uint64_t tracksize;
>      int size_var;
> -    int count_s;
> +    int count_s, count_f;
>  } MovTextContext;
>  
>  typedef struct {
> @@ -80,6 +89,56 @@ static void mov_text_cleanup(MovTextContext *m)
>      }
>  }
>  
> +static void mov_text_cleanup_ftab(MovTextContext *m)
> +{
> +    int i;
> +    for(i = 0; i < m->count_f; i++) {
> +        av_freep(&m->ftab[i]);
> +    }
> +    av_freep(&m->ftab);
> +}
> +
> +static int mov_text_t3xg(AVCodecContext *avctx, MovTextContext *m)
> +{
> +    char *t3xg_ptr = avctx->extradata;
> +    int i;
> +    // Display Flags
> +    t3xg_ptr += 4;
> +    // Alignment
> +    t3xg_ptr += 2;
> +    // Background Color
> +    t3xg_ptr += 4;
> +    // BoxRecord
> +    t3xg_ptr += 8;
> +    // StyleRecord
> +    t3xg_ptr += 12;
> +    // FontRecord
> +    // FontRecord Size
> +    t3xg_ptr += 4;
> +    // ftab
> +    t3xg_ptr += 4;
> +    m->ftab_entries = AV_RB16(t3xg_ptr);
> +    t3xg_ptr += 2;
> +    for (i = 0; i < m->ftab_entries; i++) {

Need to validate that ftab_entries is a sane value.

> +        m->ftab_temp = av_malloc(sizeof(*m->ftab_temp));
> +        if (!m->ftab_temp) {
> +            mov_text_cleanup_ftab(m);
> +            return AVERROR(ENOMEM);
> +        }
> +        m->ftab_temp->fontID = AV_RB16(t3xg_ptr);
> +        t3xg_ptr += 2;
> +        m->ftab_temp->font_name_length = *t3xg_ptr++;

Need to validate font_name_length is a sane value

> +        memcpy(m->ftab_temp->font, t3xg_ptr,
> m->ftab_temp->font_name_length);
> +        av_dynarray_add(&m->ftab, &m->count_f, m->ftab_temp);
> +        if (!m->ftab) {
> +            mov_text_cleanup_ftab(m);
> +            return AVERROR(ENOMEM);
> +        }
> +        t3xg_ptr += 10;
> +    }
> +    return 0;
> +}
> +
>  static int decode_hlit(const uint8_t *tsmb, MovTextContext *m,
> AVPacket *avpkt) {
>      m->box_flags |= HLIT_BOX;
> @@ -118,7 +177,7 @@ static int decode_styl(const uint8_t *tsmb,
> MovTextContext *m, AVPacket *avpkt) tsmb += 2;
>          m->s_temp->style_end = AV_RB16(tsmb);
>          tsmb += 2;
> -        // fontID = AV_RB16(tsmb);
> +        m->s_temp->style_fontID = AV_RB16(tsmb);
>          tsmb += 2;
>          m->s_temp->style_flag = AV_RB8(tsmb);
>          tsmb++;
> @@ -147,6 +206,8 @@ static int text_to_ass(AVBPrint *buf, const char
> *text, const char *text_end, MovTextContext *m)
>  {
>      int i = 0;
> +    int j = 0;
> +    int k = 0;
>      int text_pos = 0;
>      while (text < text_end) {
>          if (m->box_flags & STYL_BOX) {
> @@ -164,6 +225,14 @@ static int text_to_ass(AVBPrint *buf, const char
> *text, const char *text_end, if (m->s[i]->style_flag &
> STYLE_FLAG_UNDERLINE) av_bprintf(buf, "{\\u1}");
>                      av_bprintf(buf, "{\\fs%d}", m->s[i]->fontsize);
> +                    av_bprintf(buf, "{\\fn");
> +                    for (j = 0; j < m->ftab_entries; j++) {
> +                        if (m->s[i]->style_fontID ==
> m->ftab[j]->fontID) {
> +                            for (k = 0; k <
> m->ftab[0]->font_name_length; k++)
> +                                av_bprintf(buf, "%c",
> m->ftab[j]->font[k]);

Use av_bprint_append_data.

> +                        }
> +                    }
> +                    av_bprintf(buf, "}");
>                  }
>              }
>          }
> @@ -215,6 +284,8 @@ static int mov_text_init(AVCodecContext *avctx) {
>       * it's very common to find files where the default style is
> broken
>       * and respecting it results in a worse experience than ignoring
> it. */
> +    MovTextContext *m = avctx->priv_data;
> +    mov_text_t3xg(avctx, m);
>      return ff_ass_subtitle_header_default(avctx);
>  }
>  
> @@ -265,6 +336,7 @@ static int mov_text_decode_frame(AVCodecContext
> *avctx, m->style_entries = 0;
>      m->box_flags = 0;
>      m->count_s = 0;
> +    m->count_f = 0;
>      // Note that the spec recommends lines be no longer than 2048
> characters. av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
>      if (text_length + 2 != avpkt->size) {
> @@ -313,6 +385,13 @@ static int mov_text_decode_frame(AVCodecContext
> *avctx, return avpkt->size;
>  }
>  
> +static int mov_text_decode_close(AVCodecContext *avctx)
> +{
> +    MovTextContext *m = avctx->priv_data;
> +    mov_text_cleanup_ftab(m);
> +    return 0;
> +}
> +
>  AVCodec ff_movtext_decoder = {
>      .name         = "mov_text",
>      .long_name    = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
> @@ -321,4 +400,5 @@ AVCodec ff_movtext_decoder = {
>      .priv_data_size = sizeof(MovTextContext),
>      .init         = mov_text_init,
>      .decode       = mov_text_decode_frame,
> +    .close        = mov_text_decode_close,
>  };




--phil