[FFmpeg-devel] [PATCH v13] libavcodec/jpeg2000dec.c: Add support for PPT marker

Michael Niedermayer michael at niedermayer.cc
Sun Apr 5 22:45:49 EEST 2020


On Sun, Apr 05, 2020 at 04:13:28PM +0530, gautamramk at gmail.com wrote:
> From: Gautam Ramakrishnan <gautamramk at gmail.com>
> 
> This patch adds functional changes to support the
> PPT marker. This patch fixes bug ticket #4610.
> ---
>  libavcodec/jpeg2000dec.c | 88 +++++++++++++++++++++++++++++++++++-----
>  1 file changed, 77 insertions(+), 11 deletions(-)
> 
> diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> index 732d88e6fc..2af3c61c37 100644
> --- a/libavcodec/jpeg2000dec.c
> +++ b/libavcodec/jpeg2000dec.c
> @@ -83,6 +83,10 @@ typedef struct Jpeg2000Tile {
>      Jpeg2000QuantStyle  qntsty[4];
>      Jpeg2000POC         poc;
>      Jpeg2000TilePart    tile_part[32];
> +    uint8_t             has_ppt;                // whether this tile has a ppt marker
> +    uint8_t             *packed_headers;        // contains packed headers. Used only along with PPT marker
> +    int                 packed_headers_size;    // size in bytes of the packed headers
> +    GetByteContext      packed_headers_stream;  // byte context corresponding to packed headers
>      uint16_t tp_idx;                    // Tile-part index
>      int coord[2][2];                    // border coordinates {{x0, x1}, {y0, y1}}
>  } Jpeg2000Tile;
> @@ -855,6 +859,37 @@ static int get_plt(Jpeg2000DecoderContext *s, int n)
>      return 0;
>  }
>  
> +static int get_ppt(Jpeg2000DecoderContext *s, int n)
> +{
> +    Jpeg2000Tile *tile;
> +
> +    if (s->curtileno < 0)
> +        return AVERROR_INVALIDDATA;
> +
> +    tile = &s->tile[s->curtileno];
> +    if (tile->tp_idx != 0) {
> +        av_log(s->avctx, AV_LOG_ERROR,
> +               "PPT marker can occur only on first tile part of a tile.\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    tile->has_ppt = 1;  // this tile has a ppt marker
> +    bytestream2_get_byte(&s->g); // Zppt is skipped and not used


> +    if (!tile->packed_headers)
> +        tile->packed_headers = av_malloc(n - 3);
> +    else
> +        tile->packed_headers = av_realloc(tile->packed_headers,
> +                                          tile->packed_headers_size + n - 3);

why is the special case with av_malloc() needed ?


> +    if (!tile->packed_headers)
> +        return AVERROR(ENOMEM);

this is looks like a memleak as the original array has been overwritten but
not deallocated

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In fact, the RIAA has been known to suggest that students drop out
of college or go to community college in order to be able to afford
settlements. -- The RIAA
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