[FFmpeg-devel] [PATCH v2 2/2] libavcodec/jpeg2000dec.c: ROI marker support

[Andriy Gelman]

On Thu, 23. Apr 00:04, gautamramk at gmail.com wrote:
> From: Gautam Ramakrishnan <gautamramk at gmail.com>
> 
> This patch adds support for decoding images
> with a Region of Interest. Allows decoding
> samples such as p0_03.j2k. This patch should
> fix ticket #4681.
> ---
>  libavcodec/jpeg2000.h    |  1 +
>  libavcodec/jpeg2000dec.c | 67 ++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 65 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/jpeg2000.h b/libavcodec/jpeg2000.h
> index 7b78c0193e..0f82716981 100644
> --- a/libavcodec/jpeg2000.h
> +++ b/libavcodec/jpeg2000.h
> @@ -210,6 +210,7 @@ typedef struct Jpeg2000Component {
>      int *i_data;
>      int coord[2][2];   // border coordinates {{x0, x1}, {y0, y1}} -- can be reduced with lowres option
>      int coord_o[2][2]; // border coordinates {{x0, x1}, {y0, y1}} -- original values from jpeg2000 headers
> +    uint8_t roi_shift; // ROI scaling value for the component
>  } Jpeg2000Component;
>  
>  /* misc tools */
> diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> index 5a7d9e7882..bcc6cc628b 100644
> --- a/libavcodec/jpeg2000dec.c
> +++ b/libavcodec/jpeg2000dec.c
> @@ -117,6 +117,7 @@ typedef struct Jpeg2000DecoderContext {
>      Jpeg2000CodingStyle codsty[4];
>      Jpeg2000QuantStyle  qntsty[4];
>      Jpeg2000POC         poc;
> +    uint8_t             roi_shift[4];
>  
>      int             bit_index;
>  
> @@ -598,6 +599,31 @@ static int get_coc(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c,
>      return 0;
>  }
>  
> +static int get_rgn(Jpeg2000DecoderContext *s, int n)
> +{
> +    uint16_t compno;
> +    compno = (s->ncomponents < 257)? bytestream2_get_byte(&s->g):
> +                                     bytestream2_get_be16u(&s->g);
> +    if (bytestream2_get_byte(&s->g)) {
> +        av_log(s->avctx, AV_LOG_ERROR, "Invalid RGN header.\n");
> +        return AVERROR_INVALIDDATA; // SRgn field value is 0
> +    }
> +    // SPrgn field
> +    // Currently compno cannot be greater than 4.
> +    // However, future implementation should support compno up to 65536
> +    if (compno < s->ncomponents) {
> +        if (s->curtileno == -1)
> +            s->roi_shift[compno] = bytestream2_get_byte(&s->g);
> +        else {
> +            if (s->tile[s->curtileno].tp_idx != 0)
> +                return AVERROR_INVALIDDATA; // marker occurs only in first tile part of tile
> +            s->tile[s->curtileno].comp[compno].roi_shift = bytestream2_get_byte(&s->g);
> +        }
> +        return 0;
> +    }
> +    return AVERROR_INVALIDDATA;
> +}
> +
>  /* Get common part for QCD and QCC segments. */
>  static int get_qcx(Jpeg2000DecoderContext *s, int n, Jpeg2000QuantStyle *q)
>  {
> @@ -947,6 +973,9 @@ static int init_tile(Jpeg2000DecoderContext *s, int tileno)
>          comp->coord[1][0] = ff_jpeg2000_ceildivpow2(comp->coord_o[1][0], s->reduction_factor);
>          comp->coord[1][1] = ff_jpeg2000_ceildivpow2(comp->coord_o[1][1], s->reduction_factor);
>  
> +        if (!comp->roi_shift)
> +            comp->roi_shift = s->roi_shift[compno];
> +
>          if (ret = ff_jpeg2000_init_component(comp, codsty, qntsty,
>                                               s->cbps[compno], s->cdx[compno],
>                                               s->cdy[compno], s->avctx))
> @@ -1615,9 +1644,9 @@ static void decode_clnpass(Jpeg2000DecoderContext *s, Jpeg2000T1Context *t1,
>  
>  static int decode_cblk(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
>                         Jpeg2000T1Context *t1, Jpeg2000Cblk *cblk,
> -                       int width, int height, int bandpos)
> +                       int width, int height, int bandpos, uint8_t roi_shift)
>  {
> -    int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1;
> +    int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1 + roi_shift;
>      int pass_cnt = 0;
>      int vert_causal_ctx_csty_symbol = codsty->cblk_style & JPEG2000_CBLK_VSC;
>      int term_cnt = 0;
> @@ -1691,6 +1720,19 @@ static int decode_cblk(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
>      return 1;
>  }
>  
> +static inline int roi_shift_param(Jpeg2000Component *comp,
> +                                   int quan_parameter)
> +{
> +    uint8_t roi_shift;
> +    int val;
> +    roi_shift = comp->roi_shift;
> +    val = (quan_parameter < 0)?-quan_parameter:quan_parameter;
> +
> +    if (val > (1 << roi_shift))
> +        return (quan_parameter < 0)?-(val >> roi_shift):(val >> roi_shift);
> +    return quan_parameter;
> +}
> +
>  /* TODO: Verify dequantization for lossless case
>   * comp->data can be float or int
>   * band->stepsize can be float or int
> @@ -1775,6 +1817,20 @@ static inline void mct_decode(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
>      s->dsp.mct_decode[tile->codsty[0].transform](src[0], src[1], src[2], csize);
>  }
>  
> +static inline void roi_scale_cblk(int x, int y, Jpeg2000Cblk *cblk,
> +                                  Jpeg2000Component *comp,
> +                                  Jpeg2000T1Context *t1)
> +{
> +    int i, j;
> +    int w = cblk->coord[0][1] - cblk->coord[0][0];
> +    for (j = 0; j < (cblk->coord[1][1] - cblk->coord[1][0]); ++j) {

> +        int32_t *datap = &comp->i_data[(comp->coord[0][1] - comp->coord[0][0]) * (y + j) + x];

This creates a warning during build.
datap is unused in this function

> +        int *src = t1->data + j*t1->stride;
> +        for (i = 0; i < w; ++i)
> +            src[i] = roi_shift_param(comp, src[i]);
> +    }
> +}
> +

-- 
Andriy