[FFmpeg-devel] [PATCH v2 2/3] avcodec/jpeg2000dec: add support for HTJ2K block decoding

Tomas Härdin git at haerdin.se
Fri Apr 14 16:04:07 EEST 2023


>  #define JP2_SIG_TYPE    0x6A502020
>  #define JP2_SIG_VALUE   0x0D0A870A
> @@ -436,12 +437,13 @@ static int get_cox(Jpeg2000DecoderContext *s,
> Jpeg2000CodingStyle *c)
>      c->cblk_style = bytestream2_get_byteu(&s->g);
>      if (c->cblk_style != 0) { // cblk style
>          if (c->cblk_style & JPEG2000_CTSY_HTJ2K_M || c->cblk_style &
> JPEG2000_CTSY_HTJ2K_F) {
> -            av_log(s->avctx, AV_LOG_ERROR, "Support for High
> throughput JPEG 2000 is not yet available\n");
> -            return AVERROR_PATCHWELCOME;
> +            av_log(s->avctx,AV_LOG_TRACE,"High Throughput jpeg 2000
> codestream.\n");
> +            s->is_htj2k = 1;

Still no support for per-CB style? Or, this still looks a bit strange,
see below

> -                if ((ret = get_bits(s, av_log2(newpasses1) + cblk-
> >lblock)) < 0)
> -                    return ret;
> +                if (newpasses > 1 && s->is_htj2k) {

Is this not per-tile? See codsty further down

> @@ -1863,9 +1882,12 @@ static inline void tile_codeblocks(const
> Jpeg2000DecoderContext *s, Jpeg2000Tile
>  
>      /* Loop on tile components */
>      for (compno = 0; compno < s->ncomponents; compno++) {
> -        Jpeg2000Component *comp     = tile->comp + compno;
> -        Jpeg2000CodingStyle *codsty = tile->codsty + compno;
> +        Jpeg2000Component *comp      = tile->comp   + compno;
> +        Jpeg2000CodingStyle *codsty  = tile->codsty + compno;

Here

>                      for (cblkno = 0;
>                           cblkno < prec->nb_codeblocks_width * prec-
> >nb_codeblocks_height;
>                           cblkno++) {
> -                        int x, y;
> +                        int x, y, ret;
> +                        /* See Rec. ITU-T T.800, Equation E-2 */
> +                        int magp = quantsty->expn[subbandno] +
> quantsty->nguardbits - 1;
> +
>                          Jpeg2000Cblk *cblk = prec->cblk + cblkno;
> -                        int ret = decode_cblk(s, codsty, &t1, cblk,
> -                                    cblk->coord[0][1] - cblk-
> >coord[0][0],
> -                                    cblk->coord[1][1] - cblk-
> >coord[1][0],
> -                                    bandpos, comp->roi_shift);
> +
> +                        if (codsty->cblk_style &
> JPEG2000_CTSY_HTJ2K_F)

And here

/Tomas



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